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Spiking at 20.. bye bye T-25?

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20+ Year Contributor
Jan 17, 2003
Bridgewater, New_Jersey
ok im trying to run at 16 psi, i spike to 20 then eventually my boost controller kicks in and drops me down to 16. She never felt as fast.. but am i gunna kill my T-25?
im asking with anticipation, i can't wait to have an excuse to spend all my hard earned money on a T-28 killer :thumb:
I ran mine like that for over a year, I beat LT1's with that, but yea get a bigger turbo, there is no compairison.
yea poor little thing was dealing with a boost leak for years b4 the new BOV and boost controller. she hadda b hurting then. i wonder how shes gunna feel when i put my 3" O2 eliminator dp on...
OH WOW< a DP will wake it the #### up, more torque down low, especially at 300RPMS just THWACK, you'll love it, I went from stock to ported manny, ported 02, and 3.0 turbo back exhaust in a day, so I mOVED
Mine did the same thing when I had just a removed BCS restrictor. It would spike to 20 and settle to 15 or so, and would fade to 12 by redline. The little turbo went 155K before the boost was increased, then it only lived about 10K. I remember on one cold January morning it hit 23 PSI for half a second. It was a lot of fun, though, and gave me an excuse to put a 14b in. Spiking like that isn't really great for the turbo or the motor, as you may be subjecting the engine to detonation at the spike. Get a datalogger and check your timing advance at redline, that should tell you a little bit about what the motor's doing. Anything below 14 degrees of advance at redline tells you that you're detonating a fair amount.

Mine would spike to ~20, then settle to where I had it set at 19. Lasted 30K and was still running fine when I decided to throw a 14b on there instead.
yeah had the mbc in for a day tunin git kept spiking to 20 or so, kep in mind my car has about 145k on it, then th enext day at wot boom, 5000000ft of white smoke and today i'm picking up my 14b:shhh:
Originally posted by nine5raptor
145k on a 98!?! DAYMN!

yeah the dude one owner before me was a computer travlere guy and drove all around new england all highway miles... its startin to feel the mile snow though ,puttin in my 14b tongiht or tomorrow depending on rain
its probably your wastegate, if you are running a certian amount of pounds and then when you get to higher rpm's it spike to more pounds thats called boost creap which means your wastegate is bad. if you want a cheap affective upgrade buy a 14b, port it, and put a small 16g clip that is a bad azz combination.
Hell dont know how you guys are holding that much boost, mine will only hold about 10-12 psi from about 5k on, even though I have the mbc set at about 15psi. Think its cause of the stock exhaust?
it the BOV.. my car would do the same thing untill i changed it (to a greddy type S)... then itll spike at 20 LOL
Boost spike and boost creep are two entirely different things. ;) Spike is a WG/boost controller that dont react fast enough, and is more pronounce on smallquick spooling turbos. Creep is the inabilty of the WG system to bypass enough exhaust around the turbo to properly control compressor speed. And also bare in mind that spiking to 20 psi at low rpm (3-4k) requires a relatively low shaft rpm to accpomplish, so its not all that bad for the turbo. Be more concerned about the spike causeing a bit of knock retard that the ECU may carry through most of the gear, even after the spike is gone. ;) In order to reduce spike, you need a WG/boost controller that reacts faster. Use good stiff, short vac lines, and an appropriately sized vent hole. Its tough to eliminate on a t25, but my Profec B did a great job of it. Hope that helps.
thanx man.. but im saving up for a big T28 killer.. with my setup u guys think thats a good plan for the money?
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