Cooling system improvement ?

I've tried a search & not found anything interesting. So, has anyone upgraded the cooling system on a 5th gen or reconfigured it for a better performance ?

Since adding the TBR system last year & combined with all the other mods, it seems to run a fair bit warmer than stock. Now this was suppressed to some degree when I had a PC3 due to the excessive amount of fuel that it pumped in the midrange. Plus Honda seemed to program it rich in the top end, again I feel to assist cooling. I've proved this with a separate AFR sensor/gauge & run an MTB to set the fuelling now.

So I'm looking for ways to improve the cooling & wondered if anyone has done anything already ?

Options are to increase radiator size, or reconfigure the rads to be serial flow rather than parallel, I'll be lloking at changing the fan system this winter & using radiator ducting to improve flow throgh the rads on the move.

I'll also be upgrading the oil cooler system, to hopefully improve that area too.

Any sensible input is welcome.  Thanks

• I've read that some have used a VTR fan as it pushes air out from behind the rad, instead of pulling as it does in stock config. Also fits perfectly.
• Maybe increase fan speed?
• Only one rad has a fan at all, but that may be due to internal clearance. Maybe if you move some bits around you could fit a second fan? I don't know if that's be practical, however....
• I guess you could also change the temperature sensor so that the fan/s come on sooner, or install a manual switch.
• If you want to go the ducting route; You may end up having to make new fairing holes or getting quite severe on the changes. Really depends how far you want to go and how much you're prepared to spend.
• Larger rads may also be an option, as you suggested, space permitting.
• Would increasing the coolant flow rate/pressure be an option at all?
• If you haven't already; Consider wrapping your exhaust system and/or installing heat shielding to keep thermal bleed to a minimum
• You may also be able to fit an extra rad down low at the front behind the pipes for the the forward two cylinders, though that's almost pure speculation on my part, and i have no idea how practical it may be.

You can gain up to 10% more cooling efficiency by changing coolant to something like "water wetter". Actual water is the most efficient but the engine will rot and if you live in a place that gets to freezing temperature you trade efficiency for no freeze and with the other side of that coin,  no  boil. The Honda has a quite high glycol mix of 50/50 making it inefficient but durable with a 120C + boiling point with the fan cut in at 108C .

I think all  mods are kinda hard to measure for effectiveness when it comes down to a really hot day stuck in a traffic nightmare travelling at walking pace. You can't even measure eg: 20 degrees  difference on a Dyno as using a dyno means using a fan to keep the engine cool in testing.

A mod that I did to my Ducati St4 ( it really hates traffic and makes me pay miserably for putting it there) was to replace the plastic fan blades with a metal blade.  This I could test. it was about 10% faster at reducing fan start (108C) to  fan off (98C) time.

Haven't seen this mod for the Honda so maybe worth looking at.

As mentioned above the VTR fan could be a good trade for the 5th gen depending on your riding profile. The stocker is likely more effective in the 0 to 10mph range, but the VTR is much better at 10mph +. ( I am running the VTR blade) 

The 6th gen radiators are 15% larger(so I have read) and would be an easy drop in to a 5th, with minor trimming. There is a thread about this but I havent been able to find it.   

15% you say Hmm ?  then this VTR fan blade,   Double interesting.   Does these VTR blade fit the stock VFR fan motor?  Guess I could google it ;)

Front mount radiator, and drop the oil cooler down low.

I've used a slightly modded TLR top rad which was so effective i was going to drop the oil cooler entirely. And this is in aus where a heatwave is 40*, not just high 20's.

Instead, i made a narrower custom rad, so kept the SP1 oil cooler.

The TLR rad should fit in between the fairings, it was (from memory) 450mm wide.

A bit too wide for my streetfighter, but will be hidden inside your fairings.

Or you could put a third rad in like highside, but that would mean a bit heavier, and your bike has been on a serious diet. A single rad and coolant weighs less than 3 rads and coolant.

Thanks all, it's not really a fan related thing, I did all of those way back when tuning the bike, so it has a VTR fan blade & yes it cools much quicker when in traffic. I already have a fan on the front half of the right rad as well & this also helps reduce temps much quicker in traffic. I also have a lower temp fan switch which worked great under my old setup, where the bike used to run at a constant 79C, fan would come on at 92C & off at 82C, which was perfect. Like everything else you will always suffer in traffic.

The concern I'm trying to address is cooling on the move ! The bike now runs at a constant 84-86C which is fine, but the current fan switch never goes off if it comes on !  The bike also gets up to 90C much quicker when you stop if the ambient temps are high for the UK, so the fan comes on much more now than it used to.  I've ordered a higher temp fan switch with a narrower range, to see if the bike can maintain cooling efficiency on its own (I can't find the original Honda one). This should come on at 95C & off at 90C so if the bike can stay below 95C on the move then that will help.

i've read up on cooling efficiency & the various cooling mixes, from what I've read water wetter works great as a corrosion inhibitor for water only cooling, the real reason it's sold, it does not appear to improve the cooling properties of antifreeze mixes. I do have a feezing issue where I live, So I intend to reduce antifreeze level to 30% giving a greater percentage of water & thus a higher cooling efficiency.

My next thoughts were to add ducting to ensure the rads get a good air flow on the move. This winter I will strip & deep clean the rads. May look at 6th gen rads or a custom additional rad to replace the cross rad pipe above the oil cooler. I intend to fit a larger oil cooler too. The best place for fans is on the back of the rads pulling air through, this cause low pressure air in the rads which is cooler, they also allow better airflow to the rads as its uninterrupted. But due to the side mount rads it's a bad place to have them in a crash as they will try to crush the rads if the bike goes down. 

I spoke to to the designer of the Vyrus race bike which has a front swingarm, so no place for the rads, he placed them where the belly pan is on a normal fairing as side mount rads & the air enters through the centre of the fairing & this causes a high pressure area, then exits through the rad due to pressure differential. Their wind tunnel testing showed this was more efficient than front mounting the same area of radiator by reducing the frontal area drag & the air flow through the rads is more even with the side mounts.

another thing I'm looking at it re working the right rad, so the hose from the thermostat goes straight into the right rads rear end, then coolant flows up through the rad to the front, then across to the left rad. This will increase the fluid velocity through the rads which is supposed to increase their efficiency.

Thanks for the ideas & comments.

When I finally get around to rebuilding the 98 I was contemplating on doing a mod I've seen on VFR800P bikes in Japan. It involves cutting the fairing to create a larger opening for the radiator.

[image: DSC_3028-thumb-480x319-2647.jpg]

10 hours ago, Mohawk

I've tried a search & not found anything interesting. So, has anyone upgraded the cooling system on a 5th gen or reconfigured it for a better performance ?

Since adding the TBR system last year & combined with all the other mods, it seems to run a fair bit warmer than stock. Now this was suppressed to some degree when I had a PC3 due to the excessive amount of fuel that it pumped in the midrange. Plus Honda seemed to program it rich in the top end, again I feel to assist cooling. I've proved this with a separate AFR sensor/gauge & run an MTB to set the fuelling now.

So I'm looking for ways to improve the cooling & wondered if anyone has done anything already ?

Options are to increase radiator size, or reconfigure the rads to be serial flow rather than parallel, I'll be lloking at changing the fan system this winter & using radiator ducting to improve flow throgh the rads on the move.

I'll also be upgrading the oil cooler system, to hopefully improve that area too.

Any sensible input is welcome.  Thanks

Mohawk, you thought of changing the Honda fan for a Spal fan? Shifts a lot more air than standard. Just fitted twin 5" Spals to my Bird, difference in cooling is markedly better. Birds are notorious for running hot in traffic now she doesn't suffer at all. I think a single 5" shifts approx 360 cfm. Merlin do a range as well but not sure on the specs. https://www.merlinmotorsport.co.uk/p/electric-radiator-cooling-fan-6-5-inch-diameter-rad-fan-65

I've replaced the right side radiator with a 6th gen, it is 2 rows higher from memory and has better shaped tanks to ease flow.

It only needed some trimming to the inner fairing to fit.

My next step was to replace the fan side radiator with a 6th, but haven't found one at the right price yet.

I've also added a fan switch override that I use in traffic lights as it gets to near 90*C, it stops it from run away temps.

I have been looking for a larger oil cooler which I think is a must for Australia as I ride in over 40*C temps sometimes, but again haven't found one at the right price.

A better fan is by far the best option, but I'm still looking for something that will fit.

[image: DSCF2359.JPG]

1 hour ago, Vee-Ef-Ar

When I finally get around to rebuilding the 98 I was contemplating on doing a mod I've seen on VFR800P bikes in Japan. It involves cutting the fairing to create a larger opening for the radiator.

[image: DSC_3028-thumb-480x319-2647.jpg]

I think you will find this (and most of the answers so far) was to facilitate better cooling when stationary or at low speeds. The side rads use pressure differential to pull air through the rads, so larger opening will be less efficient at speed, due to the reduced pressure differential. I'm looking to improve the cooling at speed, in traffic the current fans work fine.

Another option is adding some vortex generators in front of the fairing openings to reduce the pressure outside the opening & further enhance the pressure differential. I'm thinking that the original front indicators did this to some degree above the top opening, but I have no referen es for this, just my expectation from the aerodynamics.

Then I would try the 6th gen rads, 8% more capacity as on my picture above.

I'll say it again, a front mount rad. If a numpty like me can make it work, it'll be a piece of cake for you, Mohawk. 

TLR and SV650 have been made to work on mine and paladin reeds. 

If you wanted to get super fancy, TLR top rad which usually connects to a lower rad. You could connect it to a water cooled oil cooler thing, like toro used in his supercharger kit, or that is on a heap of modern bikes. 

Hey Mo,

I swapped out my 2 row oil cooler that was standard on the 5th gen with an RC51 oil cooler.  it is substantially larger.  Temps under normal cruising are in the 190 F range now, as opposed to the 200-210 F range before.

Go with the '00-'01 RC51 oil cooler as it has the correct bend on the ports.  Don't double o ring them, cut and weld the correct ends on.  i dont trust "double o rings".

I was trying to post pics but it wont let me for some reason.  There are quite a few threads on this topic, and I believe there are some pics of the conversion in my build thread on my Gen 5.5

Installing the RC51 oil cooler was pretty simple and straightforward on the 5th gen.  For my next trick, I am going to try to install one on my 6th gen.  That should prove to be a challenge because of how the stock oil cooler is positioned under the front fairing (great idea Honda- put it where there is no air flow).  So I will need to watch the clearance with the front fender.  I would prefer to move it where the 5th gen oil cooler is positioned for more air flow. 

Found on UK eBay ( 252441514058 ):

[image: s-l1600.jpg]

They claim a 30% cooling improvement (cough, cough)...

Do you feel lucky?

Ciao,

12 hours ago, RVFR

15% you say Hmm ?  then this VTR fan blade,   Double interesting.   Does these VTR blade fit the stock VFR fan motor?  Guess I could google it ;)

The VTR fan is a drop in to the OEM VFR fan motor. Unbolt stock, bolt in the other. Easy...

2 hours ago, JZH

Found on UK eBay ( 252441514058 ):

[image: s-l1600.jpg]

They claim a 30% cooling improvement (cough, cough)...

Do you feel lucky?

Ciao,

Put one of these (similar, )http://www.ebay.co.uk/itm/FOR-Honda-CBR1100XX-Blackbird-Fuel-Injected-1997-2008-ALUMINUM-RADIATOR-/152060263063?hash=item23677f7a97:g:pgkAAOSwKfVXFYaq along with the Spal fans and did make a big difference. Should imagine it will on the VFR.

http://www.honda-rc51.de/Parts_price_list.htm#Radiator Air-Scoops

Thanks CR, yeah I found the scoops for RC51 + VTR1000's which both suffer from heat soak or lack of airflow when used on track, where low gears, high revs when combined with technical low speed track layout means lots of heat but little cooling.

The Trackday I just did, was in 33C ambient and over 50c track temperature, when I tried to up my pace once I'd learned the track using lower gears/higher revs, the bike went into melt down mode. Average speed on my best lap was 61mph, so you can imagine how tight & slow the track was. Thus was the worst scenario for my cooling issue. Even with both fans on, the temp reached 108C & I it started dribbling excess coolant from the overflow, I have a minimal sized expansion tank !

But I feel a combination of the ideas above will cure it.

The fan never came on when i was running the TLR rad, slow stop start traffic, or high speed track day work.

Before i wired in my fans on my smaller custom front mount, it was close to overheating (well, close to spewing coolant out teh expansion tank)in slow traffic when it didn't have airflow - this was riding to a track day.

But actually on track, it was running around 95*, and this was a hot sydney track day, so similar temps to the above.

The TLR rad ran cooler than my new one, but was uglier.

So I can't run a front mount rad, due to my ramair inlet being where it wants to live. Further research implies that the parallel radiator setup is considered the best, so I'll leave that. I'll give the rads outside a deep clean & see if that helps. Plus I'll upgrade the oil cooler. I might upgrade the electric water pump if the stuff above fails.

Here is my newest plan.  Unfortunately I can't take credit for it.  Kevin @ Fatty's Cycles in Fortville IN (the wrench behind my Gen 5.5 coming to life) actually proposed it to me.  We looked at the space available in my 6th gen and we are concerned that a larger oil cooler such as the RC51s will interfere with the fork travel.  That would be a very bad thing.  So I don't think the answer on a 6th gen is the RC51 cooler.

Fattys works on sportbikes, drag bikes, heavily modified Harleys (I thought i wasted money well) but alot of racing quads as well, and their racers have had success with inline coolers.  From reading the quad forums (scary), racers have noted temp drops of 5-7 degrees in engine temps after running one of these.

http://www.modquad.com/product/2-inline-super-cooler-en-2-3/

The easiest and (*probably-disclaimer- I am not an engineer with a PhD in fluid dynamics) most effective place to install it would be the upper central hose connecting the radiators, by the horn.  These are about 3 inches long and would be easy to fit here.  Plenty of open air flow as well.

For those of you that love to see the numbers, they even sell coolers with a gauge on them.

Not only are these cheap, but they are much easier to install than another larger oil cooler.  For the 6th gen, with really tight packaging and no room for a larger oil cooler where the stocker is mounted, then this could be a good solution.  On my '01 5th gen, its getting one of these plus the RC51 oil cooler that worked so well on my Hybrid 5.5.

More research to follow.

Hm... Wonder if I can fit that between the rads on my 8th.

Got a pic of the cooling system on the 8th?  not very familiar with the 8th gen.  Although at some point if I ever wear out my 6th gen that's what i will be getting.

I have come across those, but all the. Ones I've found seem to be smaller bore, or very short. I already added alloy pipe to replace the cross rad pipe & the pipe for thermostat to rad cap. I'm looking into the possibility of replacing the cross rad pipe with a custom rad. Basic check shows the gap to be approx 330mm & I could probably squeeze in a 140mm deep rad & still keep my ramair intake.

10 hours ago, Mohawk

So I can't run a front mount rad, due to my ramair inlet being where it wants to live. Further research implies that the parallel radiator setup is considered the best, so I'll leave that. I'll give the rads outside a deep clean & see if that helps. Plus I'll upgrade the oil cooler. I might upgrade the electric water pump if the stuff above fails.

That makes sense.

Since you are in the UK, what about  a racing VFR400/rvf400 setup?

the top rad is wide, not very tall, 32 or 43mm core. Bottom rad as well.

Actually, the bottom rad may fit between the 2 existing side mounts.

Yes, that's the last front mount idea I've got. Can you tell I like em?  I cant remember how low your ram mount setup goes.

The ramair intake is above the oil cooler & below the water hose/pipe between the rads. I'm thinking I might be able to get a small rad in there & maybe one where the bottom hose crosses behind the front headers, so long as there is enough clearance to remove the oil filter. I intend to make the ramsir intake smaller whith a new airbox this winter. So rad should fit. Gonna do some measuring this weekend.

Well the higher temp fan switch failed, its supposed to be on=95C, off=90C, but heat cycle testing shows on=95C & off=75C have to turn the engine off to get down to that temp :(  I assume they have supplied the wrong one of its faulty, as rad is full & external IR thermometer shows the same temps as before the switch.

I've ordered a CBR1000F oil cooler to replace the VFR one, might be a while before I get it swapped though.

Interesting,  I was just thinking of seeing if an oil cooler being enlarged might fit and aid in this, then you mention 1000f.  What about the XXX  http://www.ebay.com/itm/311662903839?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Well I looked at those, but that has 3.5 times the cooling area, which may cool the oil too much, on cooler days, due to not having any kind of thermostat. The plain bearings in our engine require the correct heat range to reach their optimum working temperature for best clearance. Plus cold oil is harder to pump, so consumes energy.

Plus it would be hard to mount in the available space.

The CBR1000F rad is twice the size & if possible I will rig up some fans to it to be switched on with the radiator cooling fan, so that should help when stuck in traffic.

deltaboxii, 8/5/2016 at 0:48 AM

Here is my newest plan.  Unfortunately I can't take credit for it.  Kevin @ Fatty's Cycles in Fortville IN (the wrench behind my Gen 5.5 coming to life) actually proposed it to me.  We looked at the space available in my 6th gen and we are concerned that a larger oil cooler such as the RC51s will interfere with the fork travel.  That would be a very bad thing.  So I don't think the answer on a 6th gen is the RC51 cooler.

Fattys works on sportbikes, drag bikes, heavily modified Harleys (I thought i wasted money well) but alot of racing quads as well, and their racers have had success with inline coolers.  From reading the quad forums (scary), racers have noted temp drops of 5-7 degrees in engine temps after running one of these.

http://www.modquad.com/product/2-inline-super-cooler-en-2-3/

The easiest and (*probably-disclaimer- I am not an engineer with a PhD in fluid dynamics) most effective place to install it would be the upper central hose connecting the radiators, by the horn.  These are about 3 inches long and would be easy to fit here.  Plenty of open air flow as well.

For those of you that love to see the numbers, they even sell coolers with a gauge on them.

Not only are these cheap, but they are much easier to install than another larger oil cooler.  For the 6th gen, with really tight packaging and no room for a larger oil cooler where the stocker is mounted, then this could be a good solution.  On my '01 5th gen, its getting one of these plus the RC51 oil cooler that worked so well on my Hybrid 5.5.

More research to follow.

My research indicated that these are all made for 7/8" ID radiator hose...and I think the radiator hoses on my 5th gen are 25mm ID (~1").  :mad:

Ciao,

I was interested in the in-line coolers but also identified that they are only 7/8".  I have done a Google search and EBay search but no company makes an aluminium inline cooler for 25mm dia radiator hoses.  Anyone looked at having these made up on a CNC as a group buy? Just needs to be the same design but maybe 4" or even 5" in length.

[image: modquad-radiator-inline-cooler-red-rzr-r]

11 hours ago, JZH

My research indicated that these are all made for 7/8" ID radiator hose...and I think the radiator hoses on my 5th gen are 25mm ID (~1").  :mad:

Ciao,

Search for RZR800 ones, they are for 25mm hoses :) When you next in the states, can bring me a couple !

8 hours ago, Marooncobra

I was interested in the in-line coolers but also identified that they are only 7/8".  I have done a Google search and EBay search but no company makes an aluminium inline cooler for 25mm dia radiator hoses.  Anyone looked at having these made up on a CNC as a group buy? Just needs to be the same design but maybe 4" or even 5" in length.

[image: modquad-radiator-inline-cooler-red-rzr-r]

More like 11"-12" for the cross rad pipe & about 8" for the thermostat to rad cap hose !

14 hours ago, Marooncobra

I was interested in the in-line coolers but also identified that they are only 7/8".  I have done a Google search and EBay search but no company makes an aluminium inline cooler for 25mm dia radiator hoses.  Anyone looked at having these made up on a CNC as a group buy? Just needs to be the same design but maybe 4" or even 5" in length.

[image: modquad-radiator-inline-cooler-red-rzr-r]

yep, its a 1" diameter.  Missed that in my excitement.  I have a contact at Mod Quad and am waiting to hear back from him to see if they could do a 1" diameter.

if not, then for $50 this is an alternative and it says 1" diameter.

http://jjandaracing.com/contents/en-us/d48.html

What year VTR fan fits? Looking on eBay, there are a lot of different fans for 88-90 VTR250, and not much from a VTR1000, plus the sizes/blade configs are different.

2 hours ago, rc51jim

What year VTR fan fits? Looking on eBay, there are a lot of different fans for 88-90 VTR250, and not much from a VTR1000, plus the sizes/blade configs are different.

Hi - buy a new one.....

http://www.procaliber.com/oemparts/p/honda/19020-mbb-003/fan-cooling

Cheers  :beer:

Got a 6th Gen project going right now, and have one of them on the way. Should be here by Saturday. Cooler is 5" with an inch on each side to go into the hose for an overall 7" length. Considering Mohawk is having some success with a plain aluminum pipe, the fins should help nicely. Going to look at fitting it on the right side first. If it fits ok, then get a second for the front crossover.

Incidentally, they have an ebay store and sell them for $3 less, shipping included:

Inline Cooler

19 hours ago, deltaboxii

yep, its a 1" diameter.  Missed that in my excitement.  I have a contact at Mod Quad and am waiting to hear back from him to see if they could do a 1" diameter.

if not, then for $50 this is an alternative and it says 1" diameter.

http://jjandaracing.com/contents/en-us/d48.html

18 hours ago, rc51jim

What year VTR fan fits? Looking on eBay, there are a lot of different fans for 88-90 VTR250, and not much from a VTR1000, plus the sizes/blade configs are different.

Agree with Mello Dude above. Doesn't cost much and you don't need anything else related to the fan or motor. It's the Super Hawk 1000 Twin, btw.

On our 6th Gen project, I get absolutely zero cooling at a stop. A bunch of people use it on RC51s and VFRs, so I can't say it won't work, but it doesn't for this bike. Works at low to mid speed to keep the temp below the danger zone, and then natural air flow takes over at speeds about 50 or so. Enough to get the bike back below fan off temp.

If the inline cooler(s) work enough, I'd prefer to put the VFR fan blade back on to keep it under control at lights or in town traffic

Hey - thats kinda cool....

[image: rzrcooler300.jpg]

6 hours ago, KevCarver

Got a 6th Gen project going right now, and have one of them on the way. Should be here by Saturday. Cooler is 5" with an inch on each side to go into the hose for an overall 7" length. Considering Mohawk is having some success with a plain aluminum pipe, the fins should help nicely. Going to look at fitting it on the right side first. If it fits ok, then get a second for the front crossover.

Incidentally, they have an ebay store and sell them for $3 less, shipping included:

Inline Cooler

Let me know what you think of it Kev.  If it works, I think I will have one going in each of my 3 VFRs and possibly the Hawk GT.

Hopefully have at least one installed by next week. 

Out of the box, the fins are 2" diameter. Don't remember if that was in the description. 

I've got some Goodyear hose marked 1" (25mm) that fits nicely. The stock Honda hose is very tight! 

Yeah sold as 7" long, 2" diameter for 1" hoses, with 5" finned section.

Fitting a set of temperature sensors to the radiator outlets this week to get a handle on the temperature reduction through the rads & see if both left & right are cooling to the same degree.  There is some incidental claims from a guy on the RC51 forum that swapping to a series radiator setup helps the bike run cooler. I may play with that idea at somepoint once I'm able to measure the results.

I might be wrong, but I understood that heat exchangers transfer the most energy when there is the biggest temperature difference between the hot liquid and the cooling medium. So I would have thought that running the radiators in parallel, so the hottest liquid was entering both equally, would mean the best heat transfer effect to the air. If they were run in series, the second radiator would be receiving cooler liquid and so would dissipate less heat. However all that is just conjecture. It has been said that in theory, there is no difference between theory and practice, but in practice there is. 

Any luck installing it yet Kev?  I am ready to buy 3 of these for my bikes, just waiting to see what you think as far as the effectiveness! 

I got it installed Saturday and went for a quick ride to make sure I didn't cause any leaks. Because this specific 6th Gen has a lot of extra stuff crammed into every conceivable place, the only open spot was between the headers and the engine in the hose that connects the bottom of the rads and the water pump. It would probably fit fine in a stock 5 or 6th Gen between the radiator tops, but I was getting too much interference with the fork tubes. Might be able to get it into the right fairing also, but hard to say for sure.

So, with only a short test, I do think it cools better. But it also might actually heat up faster from the headers in low speed situations. I think the high mount option is the best bet. I might try a plain aluminum pipe like Mohawk.

On this bike, before the cooler install, CornerCarver and I took it and his 5th Gen out together. This project 6th Gen runs 20-25 degrees warmer than the 5th Gen, but it doesn't get overly hot. Fan turns off, and you can get it down to 200 or even under pretty easily with higher speeds and higher gears.

I plan to get a longer ride on better roads in the next couple of days. Get some twisties in on the same roads I was on last week for a direct comparison.

Before I hear from the POIDH Police. [image: image.jpeg][image: image.jpeg]

Yeah you definitely need to ceramic coat and maybe even wrap as well, those headers to keep the exhaust heat from cooking that inline cooler.

2 hours ago, CandyRedRC46

Yeah you definitely need to ceramic coat and maybe even wrap as well, those headers to keep the exhaust heat from cooking that inline cooler.

Yep! As soon as they get finished being repaired and having O2 sensor bungs added they are going to get coated. Probably wrap them as well.

Terry, you are correct, further reading indicates that the biggest temperature difference gets the best effect.

I fitted a couple of thermometers to the radiator outlets on each rad & ran up an idle test followed by road use today. On idle up, the temperature rises very little until the thermostat opens, then evens out, when the fans come on the temp stays a little higher in the right rad by approc 5c, but that one is only half covered by a fan, so is to be expected.

On the road in 20c ambient at 70-80mph the engine temp stayed constant at 80c, with the left rad exit temp being 10c higher than the right, with average temps of L=54c & R=44c. It was 28c ambient on the way home, same road speeds, engine temp was 85-86c constant, exit temps were approx 10c higher on both rads @ L=64c & R=54c.  So when rolling the right rad is more efficient at heat transfer.  Now the question is WHY ?

So one option is as Terry says the heat differential, why ? because the left rad is fed from the right side via the crossover pipe, which in my case is an alloy pipe in the airflow, so may reduce the input temp to the left rad. That's one option. I will test that by adding some pipe insulation to crossover & see what temps are on the next run.

As an aside, when I was running Motad headers with PC3 the bike was running very rich in the mid range & in 20c ambient would sit at 79c constantly, the current setup runs hotter with the RB Racing & TBR exhaust running @ 13.2 AFR. I'm also running an electric 15L/min water pump, so water speed is constant through the system.

More news when I have some.

I'm far from a physicist, but even if the right is cooling more efficiently because of a higher temperature differential, I wouldn't expect the output temp to be higher than the input temp, unless it's picking up a ton of heat in its short run through the crossover pipe.


Sent from my iPhone using Tapatalk

I think you mis read, he output temps are always lower than the input ! Just not the same out of both rads.

I figured with the left being fed from the right, the input temp on the left would be the output of the right. The output of the left is higher than the output of the right, though.


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The rads are in parallel. The coolant enters the right rad top & a pipe the feeds to the left rad top, so they both get the coolant at the same temperature in theory.

Oh, sorry, I'm getting previous posts confused. I thought you have them in series.


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OK so I forgot to mention that I added a couple of deflectors in front of the main radiator air outlets on the sides of the fairing to increase the pressure drop there, they were on the bike yesterday.

For the run to work today I removed the deflectors, I also added some foam pipe lagging to both the t-stat to rad top hose (pipe) & the cross rad hose (pipe), so they no longer act as cooling points. Ambient temp was 21.5c, bike ran at 84c with L=62c & R=54c, temps varied slighty depending on speed, but maintained approx 10c difference from left to right outlet temps. But for a 2c increase in engine running temperature there was approximately a 10c increase in radiator outlet temps, which matched the 28c ambient temp exit readings from yesterday trip home, so NO improvement in cooling.

So the left rad is a problem area. I'm looking at removing some of the stone shields I put there after the VTR fan was fitted to stop any flicked up stones mashing the rad face.

I'm also looking at removing the fan altogether & fitting outside fans, which should improve air flow to the rad & assist when the fan is engaged, as puller fans are in the region of 20% more efficient.  I'll then look at adding Durbahn type ducts as used on the RC51 to improve air flow throgh the rads.  Last resort will be larger rads from 6th gen with some or all of the above !

Reading that the left rad is warmer, I was going to say it's likely due to the fan blocking air flow at speed while not spinning. But, of course, you knew that. ;)

I'm thinking of doing some kind of spoiler on the side fairing as well to create low pressure at the outlet. Any pics or suggestions?  

I just cut up some square plastic that a curtain rail came in so I have an L shaped piece same length as the lower fairing slot. Folded it down tight so it sprang back like V then added double sided sticky tape to one side & cut a couple of pieces of sticky backed foam & stuck them in the V so the air pressure would not collapse it. This gave a approx 35 degree angle to the air once stuck on.

I've been looking at the VTR fan blade & the VFR one, the  VFR one has large open areas, the VTR has virtually none.  My thoughts are to remove the fan then add some thinn alloy ducting with louvres to bend the air into the rad. See how that works.  I found a site earlier where VTR1000 rider had removed his fan & his cooling issues vanished, so i suspect the fan motor & blade act as a baffle to air flow on the left rad.

Strangely I was expecting the rest rad to be the hot one, as my add on fan blocks the flow to most of the front half of the rad & the rear half is only served by a very small opening beside the cylinder head !

I might try some vortex generators to see if they help reduce the pressure on the outside of the fairing.

A picture is worth a thousand words they say, so here ya go, temporarily re-attached so you can see how it was. Raining today & working from home, so no trip. I think I'll add them again & leave the lagging on the alloy pipe to see how the temps compare. Thinking about it afterwards on the way home in 28c with the deflectors fitted, I definitely had my legs sitting in a pool of hot air, it was noticeable compared to normal without them.

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That's cool, I see what you did there. I'm wondering if a louvered panel could be fit in the large vent I cut. Had to move the right rad down and forward, so most of it was no longer in the vent opening. 

Any pics of those mods ?  Why did you move the rad ?

There was stuff in the way, so rad had to shift. 

KevCarver There was stuff in the way, so rad had to shift. 

Inline coolers ordered.  hopefully by the time i get a chance to get them on, the weather will not  have cooled down much so I can give them a more accurate test!

So did another test today, I fitted my temporary deflector to the left side only & the temp differential on the left rad was 5c lower than previously compared to the right. This was consistent on both runs today, so where I had a 10c difference I now only had 5c. So this proves the airflow through the left rad is restricted in normal configuration.  Looks like I'll have to strip it off & check, so replacement fans might be an idea.

What if the fan was just on all the time? I did a system test without fairings with a lowered temp fan switch and VTR fan, and the temps were really good. Even without fairings, the fan cooled the left rad enough to keep it at a very nice temp. I too tried a lower temp switch and the one I got was way below the listed specs (I think it was supposed to be fan on at 90c and off at 83c) and would never have shut off with the engine running. But I was surprised that even without fairings it was cooling well. I just figured the fan would burn out way too soon, but would that actually be cheaper than chasing mythical solutions? Just wire up a manual switch and turn it on when necessary, or even wire it to be on with the ignition? Probably only necessary in summer actually... So manual switch.

A small thought about the deflectors:

1. Cool idea.
2. Would a second deflector rearwards of the first help ...deflect.. some of that more noticeable hot air? Just thinking from a comfort POV.

We'll it's possible, but not likely to work. Anecdotal evidence yesterday did feel like  my left leg was warmer than the right & definately warmer than normal. I think I'll add some tell tales & a camera to see how the air flows out of the rads.

deltaboxii, 22 August 2016 at 6:43 AM

Inline coolers ordered.  hopefully by the time i get a chance to get them on, the weather will not  have cooled down much so I can give them a more accurate test!

Deltaboxii

did you have any improvement in reducing the temperature of the coolant  with fitting the inline cooler between the rads?

Sorry been busy with work i have not had a chance to install them yet

Marooncobra, 9/5/2016 at 6:44 PM

Deltaboxii

did you have any improvement in reducing the temperature of the coolant  with fitting the inline cooler between the rads?

Ok gang,  so I finally got the inline cooler installed on my 5.5 hybrid.  To answer the question quickly, YES.  It did help in reducing the coolant temps.  YES, I would recommend the mod.  YES, I will be tackling this on my Gen6 next.  But Read on if you want to know the details!

Disclaimer-I am not a scientist or engineer.  Just a regular guy with a full time job.  So, that being said, the "scientific method" that I learned in school did not happen here.  Just plain ol' seat of the pants "feel" and watching the temp gauge.

I could not tell you exactly how much the inline cooler reduces coolant temps.  I can tell that it is helping, but my best guess is anywhere from 5 to 7 degrees on average, maybe 10 degrees max.  I put about 100 miles on the bike today with temps in the mid 80s here in Indy and lots of humidity.  Not the worst day I have been out riding, but overall it was hot and muggy.  And I did ride the bike in the same traffic flow that I usually do on my way back from work.

If there was maybe a downside, I would say that I can feel just a SLIGHT bit more heat on my thighs. Like a very minimal difference.  I am guessing that the air that is moving over the cooler being heated is getting pushed back through the fairing onto my thighs.  This is not uncomfortable but I can feel it a bit more than I used to.  Again, not scientific but just an observation.  But certainly not enough to put me off from doing the mod again.

Installation- The inline cooler was really easy to install.  Probably took about an hour max.  Just cut and plug and play.  The cooler fits in great between the radiators and clears the stock horn.  Everything fit easily and no major mods/ cutting to fit it.  All you will need is a few hose clamps.

Bottom line... it is a great product and great find.  Its also relatively inexpensive at $46.00 shipped.  Would I say that it was worth it?  If the cooler was $200 and took hours to install with alot of other mods, then I would say no it was not.  But for as easy and as cheap as this was, I would say yes.

While I had the fairing off, I thought about trying to install another identical inline cooler to the return line before it goes back into the radiator. No go.  This line is down by the lower fairing and there is just not enough clearance there for this cooler.  I am afraid that the cooler would damage the paintwork and or melt the fairing. Just not a chance I am willing to take. 

Still, the best "bang for the buck" that I have done so far to lower engine temps was adding a factory Honda RC51 oil cooler to the 5.5 hybrid.  That made a huge difference over the stock tiny oil cooler on the 5th gen.  They are cheap and easy to find on eBay (get the SP1 cooler, '99-'00 I believe) and it is also relatively easy to install.  Plenty of members on this forum have done it so there is already alot of info out there about this mod if you search.  Do this first if you have to choose.

If anyone else tries this inline cooler mod, I would be curious to see what their results were for them.  YRMV, but I hope it works for others out there that are trying to get their VFRs to run a bit cooler.

Next up, I will be fitting one of these same inline coolers to my 6th gen.  That bike tends to run a bit hotter than either my 5th gen or 5.5.  An RC51 oil cooler is too large to fit, so I am really hopeful that this helps!

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Would be nice to get back to back (before and after) temps recorded under similar ambient temp and humidity runs.

Sounds and looks convincing though, even if just an "oculometer", seat-of-pants evaluation.

46 minutes ago, Auspanglish

Would be nice to get back to back (before and after) temps recorded under similar ambient temp and humidity runs.

Sounds and looks convincing though, even if just an "oculometer", seat-of-pants evaluation.

Like I disclaimed in the preface, I did not have the time or the dedication to get this done in an exact "apples to apples environment.  Sorry, I have to work to pay for all of these VFRs and way too much spending on mods like this.  :goofy:   So this is the first I could get it done, and unfortunately,  not all in the same day when I could test back to back.  I agree, that would have been ideal.

Today is a usual summer day (its not fall to me yet dammit!) in Indy- mid 80s and high humidity.  On a day like this, the bike usually runs in the 200-210 range for temps.  Today, after the inline cooler was installed, it was running 190-200 most of the time.  So its not a scientific calculation, but it did show improvement in a "like environment".

So now you've thrown some figures into the equation it sounds even more convincing.

Will be interesting to see how it behaves in the cold of fall-winter...

Thanks for reporting in!!

Any reason why you went off centre with mounting it in the hose? I will be purchasing one for my 6th gen. WRT the oil cooler on the 6th gen, I have made an air duct to direct more air into it which has also helped with temp drops. I will take a photo and post it.

Any concern that you are heating the air in front of the intake?

Marooncobra, 9/16/2016 at 11:56 PM

Any reason why you went off centre with mounting it in the hose? I will be purchasing one for my 6th gen. WRT the oil cooler on the 6th gen, I have made an air duct to direct more air into it which has also helped with temp drops. I will take a photo and post it.

More airflow to the cooler.  Installing it in the center would have blocked it more with the stock horn.

KevCarver, 9/17/2016 at 9:15 AM

Any concern that you are heating the air in front of the intake?

Seems to be ok at this point.  I will be putting alot of miles on the bike this weekend.  Temps today are in the low 80s in Indy, but the humidity is about 70%. 

Hopefully this week I will have a chance to get the other cooler installed in the 6th gen.  That bike seems to get hotter than my 5th gens.

Would there be any value in installing a heat barrier between the exhaust pipes and the sump.

random thought... has anyone considered opening up the fairing behind the front wheel or replacing it with mesh?

deltaboxii, 9/24/2016 at 3:20 PM

More airflow to the cooler.  Installing it in the center would have blocked it more with the stock horn.

Seems to be ok at this point.  I will be putting alot of miles on the bike this weekend.  Temps today are in the low 80s in Indy, but the humidity is about 70%. 

Hopefully this week I will have a chance to get the other cooler installed in the 6th gen.  That bike seems to get hotter than my 5th gens.

I put about 100 miles on the bike this weekend around town.  Temps in the mid 80s with about 60% humidity.  Coolant temps barely broke 200 degrees and that was when I was stopped at lights.  No noticeable change in anything else performance wise.

Still, The number one trick to cooling down your VFR is to allow yourself some space from vehicles in front of you.  About a 2 second rule and you get more airflow and lower coolant temps.  Which is probably safer anyways vs. following too closely!

17 hours ago, deltaboxii

I put about 100 miles on the bike this weekend around town.  Temps in the mid 80s with about 60% humidity.  Coolant temps barely broke 200 degrees and that was when I was stopped at lights.  No noticeable change in anything else performance wise.

Still, The number one trick to cooling down your VFR is to allow yourself some space from vehicles in front of you.  About a 2 second rule and you get more airflow and lower coolant temps.  Which is probably safer anyways vs. following too closely!

Two birds, one stone.

Has anyone considered running a larger oil cooler?  Back in the day, I use to build and race VW Bugs.  The secret to cooling those was to add deep sump oil pans, external oil coolers etc.  The oil cooler on the VFR has a little bit of room to fit a larger one in that area.  I bet if you look around the web for a slightly larger one, it could be found.  Just a thought.

I've always been schooled that cooler oil is always best.

But with wet clutches and sequential transmissions, I don't know where the 10w40 stands.

I want to install the popular rc51 cooler as soon as I can have the time to install one.

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7 hours ago, alwaysaware

Has anyone considered running a larger oil cooler?  Back in the day, I use to build and race VW Bugs.  The secret to cooling those was to add deep sump oil pans, external oil coolers etc.  The oil cooler on the VFR has a little bit of room to fit a larger one in that area.  I bet if you look around the web for a slightly larger one, it could be found.  Just a thought.

Good question.  When I jumped in on the thread, I mentioned that I wanted to do an RC51 style (larger) oil cooler.  There does not seem to be a way to mount it on the 6th gen, at least in the stock location.  The larger cooler would most likely come into contact with the front fender, which would cause some damage or worse.   If anyone figures out how to mount a larger oil cooler on 6th gen, I would love to see it.

A RC51 oil cooler is almost a direct bolt on (with few mods) on a 5th gen.  there are plenty of posts on this forum on how to do it.

Yeah, I saw some threads on that too, but was for 5th Gens. I got one for the Skunk Works 6G project (Silver Bullet) without really researching and I didn't see how to do it once I had it in hand.

I have one on my 5th.

I  think you'd be better off buying one with generic fittings. Get new braided lines made up - Vfr engine fitting grafted on to new braided lines with generic fitting on the other end.

The oil cooler does't necessarily need to be bigger, but of course that also helps, lowering it an inch or two into the air stream works wonders too.

Jes VFR I believe is a member on this site.  He posted a fan swap out  article that he did to his 6th Gen VFR on Sport-touring.net  

link  

 http://www.sport-touring.net/forums/index.php?topic=24684.0;all

He says the cooling actually works better than factory.

All the pictures are dead.

7 hours ago, CandyRedRC46

The oil cooler does't necessarily need to be bigger, but of course that also helps, lowering it an inch or two into the air stream works wonders too.

I would love to do that, but I am afraid that it will come in contact with the front fender under heavy braking.

I had to lower my oil cooler about an or so for cbr929 triple tree clearance. Still has fender clearance under heavy braking. But my set up is probably different than most other's.

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The best mod is the manual fan switch. My bike hasn't gone over 200 all summer. I turn it on at every stop. It also works in normal mode. Best $5 mod e er. Thanks to candy red.

Hey let's mod the mod. Make it speed dependent using the tachometer.

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12 hours ago, deltaboxii

I would love to do that, but I am afraid that it will come in contact with the front fender under heavy braking.

My front mount rad doesn't clip the front fender under braking, and I have shorter gsxr forks. 

Pas long as it above the little curve in the cylinder head you should be ok. 

My front mount Rad is up high, and my rc51 oil cooler is low, behind the headers.