Asura

Wiring was a Frog harness and it worked fine for leaning out when that was done. AFR was read off the wideband sensor and was in the mid to high 12's. Who knows what it was *shrug*.

pushinlsteg

Thanks for clearing some things up with me. 11.5:1 A/F is very...very conservative. There is definately room for it to run leaner and be safe but since you are saying it pulls timing thats kind of a downfall. Maybe what I am saying is somewhat confusing and not understandable. This small change in compression shouldn't be an issue. 93 octane is good for around 12:1 compression at least before detonation, and a solid 13:1 A/F ratio before it reaches detonation.

Any thing else that will spread some light on the matter would be good info Wisconsin. I am from the old school b series. I've done everything possible, and I'm more of a boost head than anything.

I just put together a turbo ls/vtec today, and had it boosting today, safely.

I just got my S in November, and its been off the road since.

As far as building a motor, thats any car any motor, everything is similar. I learned to build motors with V8's, then the B series, and my own S2000, and now another.

I am guessing you suggest an OEM head gasket to keep the stock compression, but honestly I dont think that slight difference will hurt anything, but i wasn't aware of the ECU's current abilities.

The newest car I've worked on besides the S2K is the RSX-S(girlfriends) and I must say with its own wideband o2 sensor, as far as modifications go towards the motor it does a good good job learning and compensating.

Wisconsin S2k

But what are you basing that off of? Have you built S2000's with such tolerances? As I said before, the S2000 IS NOT the same as other cars. The tolerances are much stricter, and you have to remember, this car is revving to 9000rpm. You can't just generalize and say "well you should be able to run 12:1 compression with 13:1 a/f on the S2000 before detonation", because quite simply, you CANT.

hell, try raising your a/f to 13:1 on a stock S2000 and run it to 9000rpm with a datalogger. You'll log detonation and the ECU will pull timing.

It's very obvious you have some knowledge, but take it from me, many a knowledgeable mechanic has come onto this forum only to be humbled by how different the S2000 is.

yes and no. again, the S2k is a different beast.

I am unsure if the S2000 responds similarly (i dont have experience with S2k's on wideband). But again, the problem with the compression is the fact that the ECU will pull timing upon detonation, not add fuel.

pushinlsteg

tolerances can be much stricter as you say, but if detonation doesn't occur at all, it shouldn't matter, and with that small increase in compression I dont see it happening. right now its not a question of power, its a question of do we need another gasket to get this thing together, safely. I understand your aspects of the s2000 being...a different beast as you would say, but facts are, this is a gasoline powered, combustion engine like all the rest, and the general rule of thumb out there is what has been stated as far as A/F ratios and compression in the cylinder, on top of that with this build, it wont even reach CLOSE to those tolerances, far enough away I'm going to go ahead and assume there will be no detonation period. You are one of my reliable resources, but a few others have chimed in on me, and its all of us VS you on this situation, I totally respect you because you know your shit, but I got some other local and distant tuners/engine builders that are giving me the A-OK.

I'm just trying to weigh out the options. Even if he we did do the install, he's getting an EMS soon, therefore the extra compression would be compensated for by the tuner, and .3 more compression is safe enough under light load reguardless.