Wierd boost problem in my 99gsx ### HELP

[2g617awd]

I'm having this wierd problem in my 99 gsx, it has a few minor mods, no boost leaks, it spools up just fine and hits 14-16 psi, but as soon as i hit 5800-6000 rpms the boost drops back down to 8-9 psi, i know there are no leaks and the boost controller is tight, what tha hell is goin on...

 

[The_EE]

what kind of turbo? is it the T-25?

 

[talonracn49]

you have a stock turbo, and it cannot keep up with the airflow needed to maintain 14-16lbs at 5800+ rpm.

thats all, all stock ones are like that.

 

[Jeff822]

The other replies are true, but just to double check when was the last time you did a boost leak test? You should do another just to make sure if it has been a while.

 

[2g617awd]

there are no leaks i just redid the ic piping system i double checked with soapy water, its a t25, but i hear of people boosting up to 17psi on a t25 no problem. maybe its my boost controller?

 

[The_EE]

the T-25 will loose power in the top end. its a very small, weak turbo.

 

[Jeff822]

there are no leaks i just redid the ic piping system i double checked with soapy water, its a t25, but i hear of people boosting up to 17psi on a t25 no problem. maybe its my boost controller?

Do a real boost leak test, go to home depot or any hardware/plumbing store, get a coupler that only has one end in the plumbing section. Go to an autoparts store, buy a tire valve stem. Cut a small hole hole in the top of the coupler (just enough that the valve will barely fit), put the tire valve in it and tighten it down. Takes about $10 and 7 minutes of your time to make.

 

[2g617awd]

eh well this friggin car just lost me my license for 2 months haha so i guess its time to spend my money upgrading her whiles shes off the road, i trashing the t25 i was just wondering if it was a legit problem but i guess its jus a piece of crap haha thanks guys

 

[The_EE]

eh well this friggin car just lost me my license for 2 months haha so i guess its time to spend my money upgrading her whiles shes off the road, i trashing the t25 i was just wondering if it was a legit problem but i guess its jus a piece of crap haha thanks guys

It could just be a boost leak causing the drop off in presure. My t-25 used to lose psi at the top end as well. If you upgrade, make sure to do thw fuel and everything else as well.

 

[ILLiCliPSE]

T28@14psi > T25@16psi

I know this because I just swapped out my T2Small for a T28. The difference is night and day...the 28 actually holds boost to redline, unlike the T25. You my friend are suffering from a stock turbo. That is all.

 

[2g617awd]

should i just turn the boost back down?

 

[shiner6n]

well i kept my t25 at 16psi for a week and well lets just say it wasn't pretty

 

[The_EE]

You should keep the T-25 stock in my honest opinion. I made some mistakes being a newbie to turbo with my T-25. Turned up the boost to 17psi, added a FMIC and full 2 inch turbo back. Lets just say, that thing blew so much hot air, it didnt last too long. Then again, it did last 119,000 miles on the stock turbo so that isnt too bad.

 

[romeen]

there are no leaks i just redid the ic piping system i double checked with soapy water, its a t25, but i hear of people boosting up to 17psi on a t25 no problem. maybe its my boost controller?

There is a big difference between hitting 17 psi and maintaining 17 psi not to mention the efficiency of the turbo at that level. Having said that your T25 should be able to hit a psi even higher than that (although it won't hold it for long at all) so you may want to recheck your boost controller. BTW, I'm definitely not suggesting that you in fact should run your T25 that hard.

 

[2g617awd]

so do you all think 12 psi is a good pressure?

 

[romeen]

I would go about 14-15 psi. Just my opinion.

BTW, did you paint the inside of your rear,clear lenses the same color as the car? Car looks nice.

 

[2g617awd]

nope just black backround tail lights, thanks haha i love the exhaust i put on it it sounds nastey