Okay here are my dyno results...these are SAE numbers. I changed the cap/plugs/rotor/wires/valve adjustment so it would finally dyno properly

These two runs were done consequtively...i.e. Dyno...slow down...dyno.


Okay looks like a pretty standard Prelude Dyno....now when I put the Air Fuel On, I get a little suspicious...


Is it really that bad?? Is that hella rich? And look at the difference in a back to back dyno? What the hell is going on? There's even more fuel on the second run!

Thoughts/Comments?

 

looks fine.

my a/f was at 11.9 on nitrous before leaning it out a lil.

 

What year prelude to you have, I'm guessing its not a 5th gen as the RPM range is high than that.

 

Read sig

 

what does the year have to do with anything??? it would still be an H22, the 5th gens dont rev higher than the 4ths..same motor.

 

I just realized the Dynojet graph numbers for A/F are of for some reason...here are the A/F numbers at various rpms...

3500 - 13.82
4000 - 14.07
4500 - 13.79
5000 - 13.67
5500 - 13.64
6000 - 13.44
6500 - 12.92
7000 - 12.15
7500 - 11.32

7800 - 10.96

 

H22A1's peak at about 6800 rpms...

H22a4's peak at 7400rpms

They aren't the same motor

 

I would say its alittle rich(12.15 @7000 RPMs) I would lean it out.. 14.7 is the correct Air/fuel ratio, but I myself would not sit their. 14.2-13.7across the board would-be something to shoot for.. Get a VAFC and tune it, you will feel a differance.
IMHO

 

No no, that's way off. 5th gen's peak at 7,000 exactly.

Your graph says two things. One, its very rich in the late rpm's. Two, kinda proves shifting at around the real redline is optimal, not fuel cut.

 

7000...yeah but according to my 5thgen friends dynos they were peaking at 7200-7400 just with bolt-ons


Hmm so can I choose V-AFC settings based on this? Apparently my tq numbers are good


[Modified by satan_srv, 12:52 AM 9/6/2002]

 

yeah your torque #'s are pretty good. I've seen a lot of 5th gens with mods that can't even hit 140 wtq. I know stock 5th gens peak at 7000. With bolt-on's I guess it could shift upwards.

 

I'm also thinking that maybe the stock ignition can't produce enough spark to properly burn all the fuel at such high rpm, hence the flooding of fuel in the air/fuel ratio...?

 

Well I justchanged all of my ignition except the coil....but i thought something like an MSD ignition would do nothing for an N/A engine

I think I'll try again in a week with 92 octane instead of 94, I used to have problems with 94...


[Modified by satan_srv, 1:26 AM 9/6/2002]

 

get an afc or more bolt ons and get the top end to lean out more

you want the a/f line flat

 

Nice

 

one thing i was thinking is, you see that big jump where vtec engages, i think you could make more power by having it engage a little sooner, may also help smooth out the curve some also.

one way ive heard of doing iot is, dyno w/vtec engeaing at like 7000 rpms, and againg at 2000 rpms, where they cross would be a good point to start at for vtec engagement. then just fine tune the fuel and the exact point. do some more tuning and lets us see the next one...

damn i cant wait to get my car back!

 

yeah like running both the cams separately...but there's not that much area to gain...the vtec cam drops pretty quick on the graph...I'm engaging at 5000 there..maybe lowering it to 4900 would help...

 

I thought if you engaged it later like 5700k or 6k would solve a lil of the dip before vtec engages...or what else...I think I heard of maybe an integra ecu would fix alot of the dip problem but would lean it out more frequently.

 

Actually I really don't see any dip on the graph...VTEC crossover looks good to me...

 

you should lower your engagement to 4700, thats where mine is...also what rpm a car makes its max power is dependant on alot of things, mine makes its max power well above 7 grand i can assure you that, i cant wait to get my car to a dyno...peace

 

lol

what you want to see is nothing...a good graph is when you cannot tell where the vtec crossover is...your's you can obviously tell, just like any other stock H22

4700 is usually the best point to smooth it out...

making it higher will just make it worse

right now your just missing power from 4700-5000, there's a potential for about 20-25 hp to the wheels right there

 

Is there always a dip in the powerband past 7k on all h22's?

 

Looks perfectly normal to me. After 7000 rpm, it gets a little rich, but that's by design just for safety's sake to accomodate a wide range of environmantal conditions. You could stand to lean it a tad in the upper rpm range and gain a HP or two. But don't go too crazy.

Andrew

 

Thanks for the input, I'll have a new dyno up in a few weeks...looking for big gains

 

If you could lean it out up top the tq wouldn't drop off so bad I'd imagine. That'd also keep your hp climbing in the upper revs.

Tom