VFR Discussion Group -> To gut or not to gut

:deer:

I'm sure there are a few opinions on this but the beauty of EFI is the dynamic capabilities based on various engine measurements handled by the electronics. I see posts with different maps for removal of o2 sensors or to increase fuel delivery for performance or to rid the bike of certain characteristics or modify in better characteristics...etc. �I'm hard pressed to think that I can improve upon what the Honda engineers created without sacrificing "x" for a gain in "y." �My thinking is they have the best overall mapping when you buy the bike with the least amount of compromises (rideability, power, performance, emissions, fuel economy, durability etc.). �When you change the exhaust some of this goes out the window so to speak but mucking with the fuel mapping sounds a little scary (coming from a guy who has done some pretty radical mods over the years).  

Mcspeed

McSpeed

I'm hard pressed to think that I can improve upon what the Honda engineers created without sacrificing \"x\" for a gain in \"y.\"  My thinking is they have the best overall mapping when you buy the bike with the least amount of compromises (rideability, power, performance, emissions, fuel economy, durability etc.).  

I fully agree. Except, their compromises appear to be made in favor of emissions and fuel economy. Presumably to meet federal regs. And the compromises take away from the ideal rideability, power, and perforance. To a small degree.

Which is one reason why people change exhaust and install power commanders or jet kits. A more likely main reason is more noise, but nuff said.  :laugh:

mcspeed, June 03 2004I'm sure there are a few opinions on this but the beauty of EFI is the dynamic capabilities based on various engine measurements handled by the electronics. I see posts with different maps for removal of o2 sensors or to increase fuel delivery for performance or to rid the bike of certain characteristics or modify in better characteristics...etc. �I'm hard pressed to think that I can improve upon what the Honda engineers created without sacrificing \"x\" for a gain in \"y.\" �My thinking is they have the best overall mapping when you buy the bike with the least amount of compromises (rideability, power, performance, emissions, fuel economy, durability etc.). �When you change the exhaust some of this goes out the window so to speak but mucking with the fuel mapping sounds a little scary (coming from a guy who has done some pretty radical mods over the years). �

Mcspeed

McSpeed

From what I have read, the VFR VTEC engine gives me the impression that Honda may have leaned too hard on the eco side of things, and a PC III with 02 eliminator and stock plumbing may make more of difference, than in other same year bikes in terms of low and mid range drive-ability.

One can’t prove any of this however unless one had two the bikes side by side and then did a bunch of testing.  Anyone know for sure?

gut it.  if you don't like it or butcher 'em up in the process, then you can buy some used OEM pipes.  It's about a $200 gamble, I guess. My originals and others are still available.

I've changed my exhaust, added a PCIII, O2 sensor eliminators, BMC air filter, Miguel's patented air box mod, disconnected the flapper valve and with the custom map I'm using It's making 110 HP, 65 ft. lbs. of torque, getting 45 MPG and still running almost as clean as it did when it was new.
Don't be afraid of modifying your bike (within reason) just make sure the fuel map that you use is professionally done.
(just my opinion, many disclaimers apply)   :P

Tejas, June 11 2004I've changed my exhaust, added a PCIII, O2 sensor eliminators, BMC air filter, Miguel's patented air box mod, disconnected the flapper valve and with the custom map I'm using It's making 110 HP, 65 ft. lbs. of torque, getting 45 MPG and still running almost as clean as it did when it was new.
Don't be afraid of modifying your bike (within reason) just make sure the fuel map that you use is professionally done.
(just my opinion, many disclaimers apply) � :P

The question is not the peak numbers, the question is drive-ablity, in particualr the low & mid range under a variety of different operating conditions.

Who rides WFO on the street :squid:

My bike is making 50 ft.lbs of torque from 5000 RPM and up.
It has a very smooth idle and the V-TEC transition is seamless. This combination is excellent for everyday street driving.
I am absolultely NOT a squid, I'm probably one of the more sedate riders around but I do like to modify my bike to have better drivability, power, torque and handling than a stock bike.
And yes I do occasionally ride WFO for short bursts and completely enjoy it.

Tejas, June 11 2004My bike is making 50 ft.lbs of torque from 5000 RPM and up.
It has a very smooth idle and the V-TEC transition is seamless. This combination is excellent for everyday street driving.
I am absolultely NOT a squid, I'm probably one of the more sedate riders around but I do like to modify my bike to have better drivability, power, torque and handling than a stock bike.
And yes I do occasionally ride WFO for short bursts and completely enjoy it.

Many people who “improve” their engines simply end up with a peak-ier, noisier, less reliable, generally less tractable machine.

The bike can seem faster because the power band has been narrowed, hence providing “better” acceleration within a narrower RPM range.  Even many pros can be fooled by this

I am not sure how meaningful the torque / HP figures you give are is as it does not indicate if it is rear wheel, what the original is in direct (not factory) comparison, and how even and smooth those curves are relative to the base comparator.

I am not denigrating your efforts (I know some do work, a good example is the well proven Ivan’s Yamaha FZ1 Jet Kit), but like I said, you really need two otherwise identical bikes side by side one modded, one stock to know the real deal when dyno testing and subsequent road testing.

Well I know in my particular case that my bike has more power and torque all the way through the powerband at various throttle openings and all conditions compaired to when it was stock. It delivers the power much smoother and also runs cooler than when it was stock.
I'm not saying that all mods are needed or benefical, I'm just saying that this combo is working very well for me.
It is my opinion that a custom fuel map is the most important thing that needs to be done after someone decides what mechanical bits he wants to put on his bike. I went through 5 different fuel maps before I was happy with the results.
And I'll be the first one to admit it when I make a mistake, I threw away $200 on a custom map and had to take it back 3 times and then said to hell with it and chalked it as a lesson learned.

I went down the path of used OEM pipes and gutting them.  I choose that route because I was originally drawn to this model by the exhaust.  They just fit.  But I have to admit the Lazers look pretty good, but not quite there.

Overall I have not done any other performance mod, but I did notice right away the engine felt more responsive and more "snappy" after the mod.  I imagine with the gut mod or an aftermarket pipe will free up some performance hidden in the bike.  I did not notice any noticeable increase or decrease of fuel economy.  

One thing that became very clear, though.  A V-4 sounds awsome when has it pipes cleared. :D

Tejas, June 11 2004Well I know in my particular case that my bike has more power and torque all the way through the powerband at various throttle openings and all conditions compaired to when it was stock. It delivers the power much smoother and also runs cooler than when it was stock.
I'm not saying that all mods are needed or benefical, I'm just saying that this combo is working very well for me.
It is my opinion that a custom fuel map is the most important thing that needs to be done after someone decides what mechanical bits he wants to put on his bike. I went through 5 different fuel maps before I was happy with the results.
And I'll be the first one to admit it when I make a mistake, I threw away $200 on a custom map and had to take it back 3 times and then said to hell with it and chalked it as a lesson learned.

Good on you that you have the brains to think this mod thing thru from cause to effect. �Most don’t seem to go the distance.

Were you not happy with the PC III / O2 Elim and the provided maps such that you had to go to a custom one?

When you say cooler are you refering to the cat or the coolant temp?  If coolant temp, it would suggest a richer mixture.

When I first put the PCIII and O2 sensor eliminators I ran the base map that was in the software, the fuel mileage dropped a little but it ran good. Then I decided to try to help the engine breathe more so it got the air filter, air box mods, new exhaust and I gutted the catalytic converter.
I knew there was a big difference in exhaust restriction, backpressure and the engine's ability to breathe so thats why I went for the custom map. The one I paid $200 for sucked but the one I got for free from one of our VFRD members was perfect so I guess it all evened out.
The coolant temp runs a little cooler and the cat is in a box in my garage...nice and cool.