Today, just a few minutes ago, on the way to school: I noticed that when I gun it to the max (is that 'WOT'?) from a low RPM, before 3000 and not having the turbo spool up right away in 5th and 4th gear (more in 5th), that the RPM would surge with the boost (my boost surges at 4th and 5th gear, for example: it'll hit 16 then drop to 10/11 then up again to 15 then down to 10/11 again and up to 15...). It has never done this before with boost surging. The RPMs would also surge if I started WOT before 3000 rpm. RPM would jump up 500-900 for the same period of time my boost was surged, and then it would drop right back down. When I tried to test this above 3000rpm, 90% of the time I noticed that the RPM would just sit still for that split second (I guess since the surge in boost is less), but one time it still jumpped up 500rpm (i didn't see the boost guage then but i'm sure it was bigger surge) and come right back down again. It dosn't happen more than once or repeativily, the RPMs would just jump up once and come right back down. I will try to test it on the way back home if it does it more than once. It has never done this before. Is this something to be worried about? What could it be and what should I do?
matt...talk to scott at sog about it. have him look at it if u can. i try and leave it up to the experts. btw...how's your brothers vette runnin?
yes that's 'WOT'(Wide Open Throttle), and it could be several things depending on your mods... technically the ECU is only doing what it was programmed to do, if you modded again with respect to turbo (up/dp, wastegate, intake, etc) without a tune that may have something to do with it... definitely go to scott and do a datalog. um also, you said your RPM is surging too, so is your car "bucking" with the surges or not?
Slipping clutch? That was my first thought when you said the engine revs were "surging" around. It's a lot more likely to slip with the greater load of 4th and 5th gear. Maybe a bad tach signal if not.
as GTscoob said, if rpm's go up and down with surging boost, then ur clutch is slipping... here's my understanding... at higher boost, it makes more power hence the clutch slips... when the clutch slips, there's a reduction in load on the engine and the boost drops
Call Scott early in the day and see if he'll have free time to go out and datalog. He's been pretty friendly to the crew so he should be able to help diagnose your problems for the small fee of a Chipotle burrito. Are you going to be at the install day? You might be able to have somebody datalog or drive you car there. Just post up a request for somebody to bring their laptop and OBDII cable to the install day.
is it possible that the previous owner tuned the ECU for the mods that it had and now without those mods, his car is running crazy?.......clutch sounds more logical though....
reseting ur ecu won't take away the tuned maps... i am quite certain its the clutch... that sounds like what i experienced when mine was going out
agree with the clutch theory, but if its not then we can data log it if you want, ive got delta dash...