I am running a DET, and am wondering about how the boost should build. I know that the T25 falls off a little up high, but is it *very* noticable on my boost gauge? Like when I accelrate at WOT, should my boost go up fast to like 8-9psi and then immediately fall down to 6.5-7psi?

I ask because I just hooked up a boost controller, and am trying to figure out how high I can set it and still be safe. when I do a 3rd gear pull with it turned up some, the boost flies up to like 13psi, then immediately falls down to about 10-11psi and stays there solidly. Am I running 13psi (dangerous) or 11psi (somewhat safe)? Oh, and the boost controller is an HKS EVC EZ.

It's almost like the needle on the boost gauge had momentum, and then keeps going a little, then returns to the actual boost level at WOT...but I know that's unlikely

thats your boost spiking. if you have an electronic controller, turn the sensitivity down, this should reduce your spiking a little.

I have an electronic controller, an HKS EVC EZ. I don't believe there's any way to turn the sensitivity down. So should I set my controller where it steadys out at 11psi (letting it spike for a second and then go down to 11) or am I really risking blowing stuff up?

I knew about boost spike, I just didn't realize that it spiked like 2-3psi, *every* time I accelerate hard.

well, with the 370's you may be risking it, if you get on it at around 6K rpm, boost 13 psi, you will be running out of injector headroom real fast.

11 psi on pump gas out of a T25 is risking it, IMHO. i would turn it down to 10 psi, max. if you live in california, 8-9 psi is the most i would risk on our crappy 91 octane.

save the 11 psi for the track, on higher octane gas.

with T25s and internal wastegates, a 2-3 psi spike is not out of the question. terrin spikes to 9 from 6.

recheck your vacuum lines and make sure they arent too long, or binding, or leaking.

I'm in Utah, but we also have 91-octane piss gas. They justify it somewhow with the altitude. We used a consult when calibrating the boost controller, and all the way up through the powerband it was rich, so I guess that's a good sign. I'll go through all my vacuum hoses though

did you use a wideband O2 sensor? the stocker is almost useless at WOT.

also, do you have especially long I/C plumbing?

The I/C plumbing is especailly *short*. Also, we used the diagnostic computer (you know, the thing that plugs into your ECU to read codes and stuff) to check the rich/lean condition, among other things. I imagine it is fairly accurate, but only to tell if it is running rich or lean, not proportions or varying levels.

at WOT, it is useless, it doesnt work for anything, only tells you if it is rich or lean at part throttle operation. your plugs are a better indicator of A/F than the O2 sensor, unless it is a wideband.

Oh, ok. I knew a wideband was the only useful 02 for tuning, but I didn't realize that the diagnostic tool was no good also, like a regular 02 sensor. Just to remind me, what do I need to see on the plugs to indicate rich/lean conditions?

your plugs should be a light grey/brown color. check them after a hard run. cruising/idling for a while will mar the results. they should NOT be white, or off white, if they are, youre too lean. also, check for little blue crystals on the porcelain, and check for any chips, inperfections, etc. these are all signs of detonation.

detonation sounds like a bag of marbles being rattled together.