XtremeSS

I am not a turbo junkie and still dont completely understand everything about turbocharged engines so forgive me if this is a dumb question. I have the stage 1 gm upgrade installed along with a wastegate spring. The boost will rise to about 20-25psi with the pedal to the floor and then somewhere between 4k and 5k rpms it sundenly drops to 15 psi until it shifts(auto). Is this normal? And will someone please explain how boost lag affects perfomance?

T-Rodius

Are you in D? Put it in I and it will or should hold that 20-22psi boost.

XtremeSS

Yes i was in D because i still dont know what I means. Just got the car a month ago. Can i get an explanation of what I does?

XtremeSS

Ok so i just tried flooring it with the tranny in the I position and it did the same thing. It went up to 22psi boost and dropped again to 15psi at 5000 rpm. Am i missing something?

asanti

When you say you have the wastegate spring installed, was everything reinstalled correctly? Was the cover for the wastegate put back on tightlyafter the swap? I've yet to get a new spring for my stock BOV, but I'd start there to make sure you're not bleeding air and losing boost. Just my .02.

Later
Allex

BAD1200XL

I have auto too and it does the same thing. It starts dropping boost when it is coming up to a shift point. 20psi to about 15psi when it does 2-3 shift. When shift is done it's back to 20psi and you can tell, starts pulling hard. I just ordered the dejon spring to see if any different. We'll see when I get it installed. The other issues I have is that sometimes it will not boost over 12-14psi. Will never boost 20psi if I let it do the 4-3 downshift. "D" or "I" does not matter for me all the time. I have 15kmi. on kit and I am still learning when it will boost 20psi.

XtremeSS

I did some research and found that the boost drop right before a shift is called "limp mode" and it is normal. the only way to cure this is with another tune such as the trifecta tuneor a boost controller. I may be purchasing this tune because of all the different features it has including chossing between the stage 1 tune and the trifecta tune EVEN WHILE DRIVING! As far as the other boost issue you have, i found that droping the trany into th I position right as you floor it did cure that prob.

XtremeSS

No bleeding air i checked and double checked that part of the spring install. If my research is correct turbo went into limp mode which is normal

harleysshhr

My salesman told me D was for Dumbass and I was for Intelligence. I always drive in I mode and my boost (ego) never drops.

XtremeSS

Im pretty sure your boost drops right before a shift if you have a gms1 tune w/ auto tranny(not sure if tranny matters in this situation). To my knowledge, this limp mode is only curable with a different tune or boost controller.