egsir

i got my h22 with high compression pistons 12.5.1 tuned and i got 195 whp and 168 tq on pump gas.. how much do you guys think i would get with race gas c16 tunned..? is it worth retuning it? its not my daily driver so im not worried about gas prices..

Jarrod

What cams? My friend made 200 on a stock longblock, Skunk2 manifold, rmf header, 2.5 inch exhaust and a doodoo ebay intake.

DORKO

Are you running Type S cams?


and yes i would DEFINITELY re-tune it.

egsir

yea type s camshafts

King Of 04

Stock header? Stock throttle body? If not, you'll see a very large gain with those two add ons. That big 2.2 needs to breath. This is one of the few honda motors you actually see a big difference from those two parts.

You probably won't want to use C16. Higher octne gas doesn't neccesarily mean more hp. Infact, it's possible to lose hp. If your motor doesn't have the ability to "use" the higher octane, it won't burn/combust....loss of power. If this is a daily driven car, your timing won't be too crazy.

egsir

no its actualy a stock tb. i just took the butterflies out..

zcferio

it makes a diffrents with the race fuel but not so smart to waste money on a tune with stock TB, and manifold .... you should get that upgraded first

Fabrik8

That doesn't really make sense. Octane doesn't work that way. The higher the octane, the more controlled combustion. Octane isn't a rating of how hard it is to ignite, it's a rating of combustion stability, meaning resistance to detonation (from a practical standpoint). You'd have to have a complete crap engine or some really low compression (naturally aspirated) to actually lose power because of the slower rate of burn with high octane gas. You could theoretically lose power at high RPM with high octane gas (and no tuning) but again, I wouldn't want an engine that would make that true. You have to get into some pretty good engine optimization (combustion chamber, etc.) to see a difference in anything close to a street engine between regular and high octane, and that's without a knock sensor, etc. Most anything you can say differences from rate of burn, etc., is largely theoretical in anything but a race engine usually. So yeah, I guess it works both ways; if you have a crap engine that has problems, you could lose power with higher octane, or if you had an engine that was totally optimized for low octane then you could lose power too. I'm assuming you don't have either.

So if you are tuned for pump gas, or low grade, or whatever, and you make a BIG leap in octane, you might lose a little bit at high RPM. This all assumes that you don't do any tuning, don't have a knock sensor, etc., because as soon as you advance the ignition timing you'll gain much more power than you would lose without advancing timing.

You can either advance ignition with tuning, or the ECU can do it for you. That's what a knock sensor is for. The ECU will advance timing until it detects combustion problems, and then it will dial it back into the safe region. Add higher octane, and that safe point of ignition advance will be greater. You can get the same thing through tuning without a knock sensor, but then you're stuck using high octane because you've probably gone above the safe point for lower octane gas.

An engine can always "use" higher octane, you just might have to do some tuning to make full use of it depending on the engine management.

Sorry if it sounds like I'm contradicting myself; you can't really make generalizations about this because there are so many factors involved.

Ninja11

^ you sir, are a genius

BAD4DR

I'd make the argument that holds true most of the time. Specifically, an engine wants a certain timing to be optimal. If that's 42 degrees, but the race fuel would allow 52, then simply setting it to 52 will reduce torque and lower power throughout the range.
Also, lower octane #'s not only indicate the fuel is more volatile, but it usually is also a good indicator of the energy potential of the fuel. Basically, Diesel (about 40 octane) has far superior power making potential to Gasoline (usually in the 87-120 range) which is superior in potential to most aircraft fuels. Once you factor that in, then in a naturally aspirated engine, with a limited potential for air, the less fuel you have to run, the more fuel you're able to run, and the more power you can make....
The basic rule of racing is to run the lowest octane gas you can get away with and still maintain the timing you desire. First, it's cheaper to do so. Secondly, more octane will not improve performance, and may hurt it. Third, oh, wait, I'm fairly sure the first 2 covered it.

For the gentleman who started the thread - Yes, race fuel will help. 12.5:1 is too hot to advance the timing in the proper range for most any Honda motor (or any motor for that matter) on 93 octane pump. But I wouldn't be looking at C16. C16 will handle high HP turbo cars, and 16:1 compression or higher N/A cars without problem generally. I'd be looking to run Cam2 (108) or something more similar to that, as it should show all the gain you'll get, with about half the cost....

And, as to whether it would make a difference - the motor was seriously timing pulled for a tune if it's 12.5:1 running 93..... It should be quite noticeable.