zbrewha863

^^That or the test pipe.

After installing my test pipe, I can actually feel the ECU retarding timing over 8500rpm, not fun.

NA20

12.5 is too rich for NA.... I bet if your tuned your car to 13.5, you'd see a lot more power...

devs2k

13.5 would yield more power; however, I bet he is tuned on 93 octane.. the tuner must account for the fact that the tunee might fill up with 91 (either on purpose or by accident) and in that case, 13.5 isn't all that safe anymore..

besides, that 1 point change in AFR, especially in a NA setup, can't be worth more than a few whp..why risk it?

c32b

hi guys....so just checking, with intake, cat back (cat still intact) and header, i'll probably be running lean like 14+?

Mor.gan

For everyone else who hits this thread please read up on "Stoich". Air Fuel Ratio

If 13.9:1 was unsafe then why would the major car companies have the car adjust fuel ratio to 14.7:1 when running open loop?

From what I've seen on the dyno 13:1 for N/A is the best place to run for power. Hondata's tune for the AP2 and all of their Flashes for other cars run at 13.1:1 also.

ShocK

If your not worried about a few hp then why did you bother tuning at all? NA is about every hp you can get, we have 93 octane available anywhere in Ky, I did numerous top speed runs and my car was fine with 13.8:1 all the way up to redline. Mugen tunes to 13.5 so I'd say they know more about the car than just about anyone. Honda had a track prepped CR out at the Detroit auto show last year, it said tuned by Honda R&D I'd like to see what they did! How lean you go is related to how competetive/big ur balls/ your wallet etc etc... Within obvious limitations

Also another fact to remember is every single engine is going to like a different air fuel ratio, also different timing in different rpms and different coolant temps. Tune every aspect of each and your engine will be at max with reliable tuning foundation that will give it a long life. Me personally I go for max and if the engine only lasts 100-150k miles then who cares.

ShocK

What dyno are you using? 250whp+ has been done a few times without internal work, seems easy if you have the right parts combination. Ap2's make about 10whp more stock for stock than a 02-03. There are two threads of 300 pages worth of NA tuning tuning info, I've read the whole thing and helped put it together as well. 13.8 for a 2.0L engine is fine. My car walked with a comptech supercharged car on 6psi, by top of fourth he pulled 3/4 car on me, I'd say my car was tuned pretty well with just a vafc and bolt ons.

iDomN8U

From a racer perspective, yes tune to get every ounce of power regardless of reliability.

From a reliablility stand point, keep it below 13 like Honda did stock. They left a margin of richness for a reason.

Hero

exactly.

for an overall street car keep your tune a little more conservative. for the s2000, 12.9-13.1 seems to be the sweet spot.

something also to keep in mind is that any of the legit tuning devices usually have a couple different switches for different settings. you can tune the car on pump gas at a more reliable afr, and then you can tune the car on race gas at a higher afr.

all it takes to pop back and forth is a flip of a switch ( and the right gas in the car ).

ShocK

I see your point but if your not a racer then why tune at all though? Seriously, why waste money on 5-10hp, just to say you've got a "tuned" S2000 thats going to last 50k miles longer than my car tuned for racing, then your just being a tool, not pointing fingers, just generalizing. If you just want to be looked upon as a "tuner" that sounds lame to me. Race parts are for racing not driving around revving at mustangs. Why buy a J's header and 70mm exhaust if your not racing with it or doing something with it, its a full race exhaust not a street setup. I dunno about you guys but I put the exhaust on my ap1 and couldn't give a shit less about the a/f ratio being a half point off, did the same to my ap2, exhaust systems never melted any pistons.
/rant
/thread