my prelude likes to be richer for some reason (11's)

First off, tuning on a dyno is going to be difficult unless you can vary the load......best way to figure out the vtec xover point is to make a dyno run on only the low cam, then a run on only the high cam (starting at something reasonable like 3K rpms) and set vtec where the high cam starts making more power than the low cam......

Brian

Of late, I have spoken at length with several of the respected tuners on this board. And since then, conversations with todacivic, nab20c5, and trey on this board prompted me to create this thread. I thought this thread would help educate others, but mainly my intent was to educate myself. If I have posted anything wrong, please correct me so we can all learn.
Here's what I have learned so far:

Street Tuning can help you save $ and time on the dyno. We all know that the dyno is going to be very consistent and help you get your best operating parameters dialed in. Many also believe that the dyno is a tool, and while it does not lie, it may not be showing the whole picture as far as what real-world driving will be like. It is an approximation, and an invaluable resource, but by no means is it necessarily the end all be all for tuning in the real world. As a matter of fact, there are some very competent tuners who only do their tuning at the strip. They don't care what the dyno says. If they can get lower et's by doing something, then that is what they are concerned with ultimately. And the dyno may not necessarily agree with their results...

From what I have read and spoken to people about, it seems like the average enthusiast (myself included) is interested in two things: getting the most whp/ tq out of their setup, and getting streetability/ driveability/ good mileage out of their ride. Now sometimes (most of the time) these two are polar opposites. You can't have 2000whp setup that gets 44 mpg, and rides like a lexus. But as with everything there are compromises, and many have been able to get close to 200whp out of a stock itr with relatively mild setups and close to 40 mpg. Many on this board have very similar goals, and knowing it isn't unattainable is a good thing for us.

How to tune for this on the street? Well, we can definitely benefit from dyno time with a wideband o2. But if we do a little street tuning before hand, we can cut down on the amount of time and $ we have to spend on the dyno to get our setups dialed in.

What you need:

voltmeter or accurate o2 sensor
fpr/fpg
cam gears
vafc
egt
accelerometer


It seems the more of these you have the better, and there are opinions on which you actually need based on your setup. Ex: I have been told that with a setup like mine (spec b's, cam gears, vafc, header, stock compression, injectors, and ecu), I don't need an fpr/ fpg because the stock ecu already pushes enough fuel... I guess we'll see soon enough.

What you do:

Easiest thing is to get a buddy with a car closely matched to yours and do some 1st or 2nd gear pulls from 2k rpms to rev limiter. Do 3 good pulls for each change you make and keep notes. Of course you have to do this on a deserted stretch of road, or you can do 3rd or 4th gear pulls on the highway... Remember to do this far away from other traffic and cops. This gives you a baseline.

Next, follow Jeff (importreview)'s instructions, but do this with a buddy on the street. You'll be trying different things and later do this on the dyno again, but already with some settings you want to try (based on your street pulls):


quote:
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And now I want to talk about Dyno's...so I can clear up any mis-conceptions that people have about them.
I have the state of the art Dyno. It is quite thourough. And when I say it works "well" this is what I mean....

this is exactly what I mean.....

1) it took less time to get from A to B.
2) it made more HP and torque at X RPM's.

I do not care about peak HP and torque, I just use them as a took for tuning a car. Tuning is simple. Somebody who calls themself a tuner is not saying much. Its not hard to tune car..

its called...the process of elimination. You try a setting....say 18 timing...make a pass...and then just narrow it down so you can positively say at what timing the motor liked it. Same things with the cam gears. Same things with the fuel.

And David Stadulis is even so great as to let Tuners have another thing to play with....length of tubing on the headers....

So now that we all know tuning is a piece of cake, back to the Dyno...

The Dyno will tell you which motor will out-accelerate another motor. It will tell you which motor has the best powerband based on gear ratio's and final drive.

What it will not tell you is this:

1) which driver is better.
2) which tires are stickier
3) what wind drag is on your car.
4) weight of your car.

But I can tell you this. If there was a perfect world, and you took 2 motors....and on the Dyno motor A out accerated motor B...

that at the track, everything being equal...weight of car, wind drag, gear box....everything...that motor A will win.

The Dyno is the tool used to guage how fast the car is going to run at the track. An engine builder knows immediately after he dyno's a motor which motor is superior.

A motor that makes 590 HP but accerates faster will beat a motor making 660 HP but accerates slower..every single time. If the drivers are both good.

So now I think I explained how the dyno works...and I explained how simple tuning a car really is.

I can tell you, step by step how to achieve the maximum HP out of your car on a dyno...and you can attain it in about 18 passes.

here is what to do.

1) set cam gears at 0.0
2) set fuel pressure at say, 40 PSI.
3) set timing at 17
4) set VTEC so the graph is smooth with no dips....JUN cams its about 5700..Toda cams its anywhere from 6200-7300...Type-R cams its a little over 5,000, GSR cams its 4500. On a Prelude its like 4700.

Make a pass....look at graph...make judgement call...

2a) go with fuel first....move the fuel up to 45 PSI....did the graph change? Better, worse? Better? Then try 50 PSI....go up until it gets worse...then back it off 2 PSI at a time until you are maxed out with Fuel...
then we come back to fuel later...

3) GO with timing....try it at 19 degrees....did it gain? Did it detonate? Look at graph....go up higher until it detonates if it is still making the power...on the motors I put together with all Endyn parts, it likes it between 12-15. BUt I have seen motors like 25-27 and not detonate. If it makes the power there, so be it. Take a black magic marker and put a line across distributor where it likes the timing...

4) now play with the intake cam GEAR. Move it to +2 and adjust your distributor to keep the previous best timing you had before....make a pass...the pattern is simple....usually! not always...if it liked +2, its going to like +4 also. But your going to run into valve/piston clearance if you go to much....+4 is ok on most motors...clay it to find out...RARELY will intake cam settings be -2, or - anything.
4a) now go to the exhuast cam gear...try +2, then +4...in my experience the + will give you great mid range to high mid area but lessen peak....thats BETTER. But see for yourself what works....the -2, or - anything will promote more valve overlap and you will be more likely to blow up your motor on a mis-shift. If your +4, dont go -4. thats alot. If your +4, to keep it safe depending on clay, go max -2. Depends on cams too..alot of factors...this is the basics...

5) now you have your fuel, timing and cam gears set....lets micro manage with a v-afc... change the HIGH RPM settings so you can micro tune the powerband...then go -5 all through the powerband....make a pass...if it gained power try -7...if it lost go +..narrow it down....see on the graph where it gained and did not gain...and tune the RPM it needs...

6) when you get the max power out of your motor, start gapping the plugs...try 35, then 40, then 45...

7) when you make pulls on your dyno, run the car in 3rd gear for a SET number of seconds at like 3,000 RPM so the intake air temperature falls down to the lowest point it will go....at 3k on a turbo car its usually around 116. After the run, it will be like 105. And if you just go through the gears and run the car it will be about 130. This is important.

Notes: Alot of people brag or talk about air/fuel meters....get that out of your head. If the car makes the power and accerates the fastest at 13:1 air/fuel....(example, not real) then leave it at 13:1. There is no set air/fuel ratio that is the best for any set motor. Air/fuel meters just help to achieve the fuel PSI faster....that is all.

And in conclusion, I will argue until I hear something better than on the dyno, I can flat out tell you which motor can achieve faster times at the track all things beiging equal...

The Dyno is your best friend...it NEVER lies. You also in no way can drive your car effectively without comparing the dyno chart to your gear ratios...The dyno will tell you exactly where to shift for fastest times...and with a Honda...its usually the higher, the better...

Jeff

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Now, there's no question that Jeff is opinionated. But that's one of the things I like about him. He is basing his opinions on his own personal observations. I do the same.

Here are some questions I have:

What is the best way to adjust cam gears? I have seen some people use the rubber handles from pliers or something and wedge them into the gears and twist to the desired setting. This is hard, so they sometimes use a leverage of some sort to help or hammer the pliers to make it twist... Others loosen the gear bolts and then rotate the crank, but this is hard too because of the compression in the pistons...

What is the desired setting for the volt meter? Here's a site that trey sent me that has instructions on making your own wideband o2 sensor: http://www.diy-efi.org/diy_efi/projects/diy_wb/ How does temperature and other variables affect the voltage reading? And how accurate is the voltage reading? Does the signal degrade or become less accurate after you have been driving for a while and the temperature has gone up? Or is it only roughly accurate during cooler (70 degree or lower) weather?

4) now play with the intake cam GEAR. Move it to +2 and adjust your distributor to keep the previous best timing you had before....make a pass...the pattern is simple....usually! not always...if it liked +2, its going to like +4 also. But your going to run into valve/piston clearance if you go to much....+4 is ok on most motors...clay it to find out...RARELY will intake cam settings be -2, or - anything.
4a) now go to the exhuast cam gear...try +2, then +4...in my experience the + will give you great mid range to high mid area but lessen peak....thats BETTER. But see for yourself what works....the -2, or - anything will promote more valve overlap and you will be more likely to blow up your motor on a mis-shift. If your +4, dont go -4. thats alot. If your +4, to keep it safe depending on clay, go max -2. Depends on cams too..alot of factors...this is the basics...