I'm supposed to tune my car on a dyno Monday. I was hoping to have a better coil pack and plug wires on the car to run 15 psi during that tuning session. But it looks like it's not gonna happen. So I was wondering if you guys think it'd be okay to run that high of boost w/ a stock coil pack and wires. This wouldn't be a big deal if the company wasn't so busy but if I don't make it Monday it'll be a couple more weeks before they can get me in again.
Thanks

Matt

The worst thing that could happen is you don't ignite the mixture (misfire).

If you arn't misfiring then it works, if you are there is a lot of power to be had.

I've run 15 psi all day with the stock coilpack and some aftermarket Taylor brand wires. Never had a misfire, even under 11.0:1 A/F :) I've found that we need maybe another degree or 2 of timing at that boost level, so unless you tune it rich, EGT's can get pretty hot on a real long pull(using 93 octane pump). Shoot for 11.5:1 and it should be ok. Be sure to run plug gaps of .028-0.30 though. I use the NGK BKR7E

Originally posted by XtremeRS
I've run 15 psi all day with the stock coilpack and some aftermarket Taylor brand wires. Never had a misfire, even under 11.0:1 A/F :) I've found that we need maybe another degree or 2 of timing at that boost level, so unless you tune it rich, EGT's can get pretty hot on a real long pull(using 93 octane pump). Shoot for 11.5:1 and it should be ok. Be sure to run plug gaps of .028-0.30 though. I use the NGK BKR7E

Cool man. I guess we'll find out if it'll work or not tommorrow. As for the a/f ratio, there was a post over at asec that talked about the differences in a/f ratios between running on the street and on the dyno. It seemed that there's around a one point difference. So I figured that I'd shoot for about 10.8-11.0 on the dyno to make it right when on the street. Does this sound about right?

Matt

Isn't 15psi max before you have to retard ignition timing?

Just about...after 15psi things get nutty.

With a 16G and stock cams, yeah. I was never able to go much above 15 PSI with the stock ignition system without hearing detonation between 3000 and 4000 RPM's.

some people have told me that the stock ignition is pretty strong up to just under 20psi, of course i myself havn't done it, thats just what i heard

I used to get small amounts of detonation at 15 psi with both the SFMU and 8 injector setup, but now with the MS, its totally gone..I'm not so sure its a timing issue so much, but more of the stock ECU doing something goofy with the fuel map during peak torque(where i got the detonation). From my tuning efforts with the MS, and my gauge readings, 17 degrees of timing(what the stock ECU starts out at for timing), is really close to what we need for 15 psi and 93 octane fuel. My EGT's get a bit warm even with a 11.5:1 A/F, which indicates we either need one or two more degrees of timing, or we are running out of fuel octane for that boost pressure. The bad thing about just "retarding the timing" for higher boost,is that it hurts your power curve, and also makes for higher EGT's. To me, thats not a properly tuned engine. You are straying away from what the motor really should have. Turbo size and efficiency has a lot to do with this also. A larger, more efficient turbo should be able to run a little bit more pressure for the same fuel octane, mostly because it's more efficient. 15 psi on 93 octane, for the S16G is getting really close to pushing the limits of the fuel. Colder intake temps, water injection, ect will help greatly also for more boost.