WTF!?!??! My Boost falls off at 5000 rpms!!!!!!

[Savior1974]

Ok Look, I just got a boost gauge installed in my car and I found out some wierd stuff is going on in that beast. Well When I launch it, In first gear, the boost gauge shoots up to about 20psi, bounces off the 20 and slowly falls down to about 12-14, then second, the boost goes to 18 and then down to 11-13 and third, the boost goes to about 16 then starts falling at 5000rpms down to like 8-10 by 6000 rpms. Seems like 3rd gear takes forever to reach 6000rpms!!! WTF IS GOING ON!!!!! Only mods I have are Act2600 clutch, Greddy type s bov, apex n1 3" downpipe, 3" exhaust, and boost/vac and air fuel gauge. Also today on the freeway, I was messing around with it watching what happens and I was driving in 3rd gear. I floored it and the boost gauge rose up to 15 and stayed there until 5000 rpms, and then it started to fall.

Also If I get a electronic boost controller, will that help fix what ever is going on?

This is the one I'm thinking about getting.....





Based on the very popular B-Spec., the all new PRofec B-Spec. II’s basic function to increase boost is as easy as the original, with an added built in boost pressure display and optional features like real-time, peak or last boost display (in either kPa or PSI). There are optional warning and boost limiter functions that can be programmed to offer much more control. The two presets values can be stored and are executed by a larger capacity inline solenoid valve. This unit does not require extensive programming and is ideal for low to high boost levels for single or twin turbos with actuator or external wastegates. The GReddy PRofec B-Spec. II is available in black or silver cased head units.

[scottsee]

got the same problem.

[Savior1974]

AHHHH SOMEONE SAVE ME AND SCOTTSEE!!!! Where's kevin when you need him

[Savior1974]

help please.....

[kjewer1]

Are you still on the T25 turbo?

[Savior1974]

yup. unfortunatly

[kjewer1]

Then what you are seeing is perfectly normal, and ideed it is the reason poeple upgrade. From 5500 up you are unlikely to ever see over 14-15 psi on the stock turbo. There is nothing wrong.

[JoeWagon]

Common knowledge that the T25 is a small turbo. Even Evo 16g's are known to drop boost if you are pushing them.

[kjewer1]

Thats more due to the fact that everyone buys them with 34mm flappers though. I proved by wiring that flapper shut that the turbo will hold boost to redline if the wastegate isnt open 25 psi anyway, on a regular 16g. On the 34mm flapper it would drop to 19 psi.

[RiceRocket18]

damn it.... you guys beat me to it LOL...

Kevin's right (that's something new). small turbos like the t-25 won't hold boost at high rpm. because it's so small, it eventually gives out at high Rev. boost controller will help tho won't cure it. it's perfectly normal. i get that too.