how much boost will a stock 93 ssei ecm be able do understand? does it know how to handle an infinate amount or is it limited to a specific amount.

It is not how much the ecm or pcm or anything like that can handle. But much you can safely flow without KR (knock retard). Things must be done to your motor before cranking up the boost is safe.



Ed

If its too much it will retard the timing. You will see the term KR around a lot. That stands for knock retard. KR is a bad thing that is caused by adding too much boost causing predetonation. The PCM will sence this via the knock sensors and retard the timing to prevent engine damage. In order to run more boost you MUST have "supporting mods". For you to drop a pully size; intake, colder plugs, and a high flow cat are almost a must to prevent KR.

i have a cooling system for it and a/f mix computer to keep the detonation down. if there was no knock problem how much could it handle?

The limitation would probably be the heads hold down force. I know that is a problem with the Turbo Buick engine when they increase boost to 25 psi they blow out head gaskets. The sudden rush of coolant into the engine is not a good thing.

You would probably be safe to around 20 psi. Go ahead and try, then let us know.

i was thinking around 18 to 20 psi. so the ecm will still be able to manage the engine at 20 psi is what i am getting at?

I know I'm running the stock PCM/ECM and it def. doesn't like 14+ lbs of boost. Not exactly sure how much peak boost is because it dumps it before it can get their.

what do you mean it dumps it?

How'* he going to get 20 psi? the smallest pulley available is a 1.9" and that'd only get him about 15-16 psi, and that'* enough to pretty much put him even with a non-sc'ed bonneville performance wise.
16 psi is alot of boost from an M62, especially from a GEN I and he'd probably see around 15* KR, thus his computer would be pulling all the advance timing it can give, which would translate into the engine practically stalling.
That is unless he has the supporting mods. With a CAI, colder plugs, full exhaust, cam, ported heads, ported Exhaust mani'*, water injection, race fuel, and a pcm programmed for such mods he might be safe, but from what we've seen here on BC it'd take more than anyone has pulled from their wallet for a SI 3800, save maybe DR. J.

For the record, without my Jet Stage two chip, i was seeing 20 degrees WITH 2.2 on my 93...
that was in the winter as well..