Adding A Lower Radiator To A Gen6

With summer with us in NZ now the 825 has been struggling with heat in heavy traffic.

So I decided to add a bottom radiator.

This has added more area, directly in the air stream, and a second fan that pulls thru the radiator and blows out the bottom of the fairing.

So I got hold of an old and munted VFR400 rad and fan and made up some bracketing etc. to fit it.

Next I bought a Chinese knock off rad from E-Bay and modified it to fit.

Photos below of the first fit up and pressure leak test.

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Fits well inside the fairing

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Just finishing off the wiring of the second fan at present and then I need to make a protection guard.

I'm going to try and use the guard section of the Gen 8 as it's only $38.00 new.

I'll post more photos as it all progresses.

Phil

Well it is all finished and operational.

There is now a lower radiator, hooked up to both bottom outlets from the stock rads, and then feeding directly to the water pump inlet.

It has a fan on it's rear and a second thermo switch.

I've set it up so as either thermo switch will bring the fans on, so I have some redundancy if one fails.

Here is the finished product.

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I've used the front fairing section from a Gen 8 and chopped it up to fit when the standard inner fairing section goes.

This has air flow holes and a centre section completely blanked off to stop the wheel flinging crud in to the rad core.

I'm thinking of getting an expanded aluminium rad guard and modifying it to fit which will be a little more tidy, but this will do for the moment.

A mod like this cannot be done with the stock pipes but my RC45 system had the front primaries splayed to take the standard RC45 fan/rad.

Cheers

Phil

HSNZ, yours has to be the most extensively modded 6th gen - or even VFR period - in existence!   This looks great.  How do you find the operating temps now? 

Also wondering - how is it getting to the oil filter? 

You answered my question at the end of your last post... I knew you had the modded RC45 system and I was wondering if the gen 8 front pipes would work.

Once again... nicely done, Sir!

Very cool, Highside (see what I did there???). I find I worry more about myself overheating than the bike at present...

Thanks guys.

Yes the oil filter is a bit of a mission, but you can get to it thru the side between the crankcase the left header pipe.

Nowhere near as easy as it was without the rad!!

Also need to let the pipes cool before trying to drop it.

I'm going to see what the temp is like later on today.

From my testing in the garage, kicking the extra fan in works a treat.  Temp drops well.

So I'm thinking that anything that is directly in the air stream should work somewhat better than the side pods.

We will see, I expect.

the direct air flow works much, much better than the side mounted rads. Next you'll be deleting the oil cooler.

really nice work.

I think you could be right Keef.

On this afternoons ride the thermostat got a real workout.

The cooling whilst mobile is extremely good with it hovering between 77 and 80 deg C

When I eventually ended up stationary the fan kicked in at 105 deg C and back out at 92 deg C.

With just the side rads, and the stock thermo switch, it cut in at 106 and out at 96.

So I'd have to say that the thermo switch from the NC30/VFR400 must have a broader range so anyone looking to alter the cut in/out this could be worth a look.The part number, as far as I can tell is: 37760-MR1-003

I may need to cover one of the rads during winter as it may be too well cooled.

Time will tell I expect.

But, overall, a good success.

Another great idea, perfectly executed.

You, Sir, are a freakin' genius. And yes, it's winter here and I block off half the rad on my 4th Gen to get/keep the temps up riding in 25F temps. 

I think you could be right Keef.

On this afternoons ride the thermostat got a real workout.

The cooling whilst mobile is extremely good with it hovering between 77 and 80 deg C

When I eventually ended up stationary the fan kicked in at 105 deg C and back out at 92 deg C.

With just the side rads, and the stock thermo switch, it cut in at 106 and out at 96.

So I'd have to say that the thermo switch from the NC30/VFR400 must have a broader range so anyone looking to alter the cut in/out this could be worth a look.The part number, as far as I can tell is: 37760-MR1-003

I may need to cover one of the rads during winter as it may be too well cooled.

Time will tell I expect.

But, overall, a good success.

That's the same sort of temp range i was getting with the single TLR top rad.

Although, on a stock motor.

That is interesting.

Just goes to show how crap the flow is on the side pods then.

Top tier work as usual Phil  :cheerleader:   :wink:   :beer:   :cool:   :beer:

Nice. What temps were you reaching before this mod?

do you think that without the fan it would fit with stock headers?

With that set up isn't the flow from clutch side radiator just going to sort cycle aux lower radiator with it's inlet same side as outlet to pump?

No, I don't think so.

The overall flow goes like this:

Coolant out of engine on right hand side from thermostat and in to top front of R/H rad.

Out of R/H rad at bottom rear.

In to R/H side of lower rad.

R/H rad, top front feeds top front of L/H rad.

Out of L/H rad at bottom rear.

In to L/H side of lower rad.

 

Out to water pump inlet from lower L/H side of lower rad.

Sorry can't see anyway it will just cycle.

It maybe different but the radiators are side flow so a tank each side, one side inlet, one side outlet normally. Looking at your setup you have a side radiator outlet feed into one side of bottom radiator & that same side also has the outlet back to pump. So wouldn't the flow from this radiator bypass bottom radiator cooling as the tank other side only has one feed from other side mount radiator.

Can I get an MSPaint drawing of what you guys are saying? I am having a hard time following.

Shouldn't it just flow from the thermostat to the RH radiator, out from the bottom to the right side of the lower, into the top right of the lower, through the lower, out the left side of the lower radiator, to the bottom of the left upper radiator and then out the top of the left radiator to the water pump, to create one continuous flow? Seems like the water is crossing itself with the way you wrote above. Or am I not taking into account that there is more directions of flow in the radiators? I guess the part that really confuses me is:

R/H rad, top front feeds top front of L/H rad.

What does this accomplish?

Seems as if you would want the flow from the thermostat to Radiator A ( upper right), to Radiator B (lower) to Radiator C (Upper Left) to the water pump, with as little of restriction as possible.

Or, I could be totally confused... :wacko: