2G Turbo maxing out

[walmic679]

Hey guys, on my 95 gst, my turbo seems like it is maxing out just before 3000 rpms. Any advice???????

 

[gieri002]

What do you mean by maxing out? Do you mean not building any more boost? Do you have a boost gauge?

 

[jrohner]

What's the problem - overboosting?

 

[Cdc1221]

Not sure. You really need to fill out your mod list. Do you have a boost gauge? The stock t25 on stock tune and boost level doesnt max out til like 6k

 

[91stocker]

Id hope a t25 would make full boost before 3k.

 

[Cdc1221]

Id hope a t25 would make full boost before 3k.

Oh, ha yea, i mean it doesnt start saying "nope, im done" until 5-6k. If a t2small aint at max spool by 2.5k, somethings wrong.

 

[walmic679]

It is a stock turbo and yes I do have a turbo gauge. Seems like right around or on 3000 rpms its already maxed out when it should just be kicking in???

 

[spydergstftw]

stock boost gauge is not worth looking at.

 

[walmic679]

agreed, but you can just tell. after 3000 there is no more boost

 

[RvlutionMtrsprt]

So you're saying your car is falling on its face at 3000rpm? You probably have a boost leak or you're getting knock that's pulling timing.

 

[clipto]

Save up for 16g install kit and buy a 14b or 16g turbo. Get rid that t25 to start. Or can look into just getting a t28 turbo and call it a day.

 

[MJBean420]

Put a boost gauge in there and figure out the psi its running at...

 

[91stocker]

It is a stock turbo and yes I do have a turbo gauge. Seems like right around or on 3000 rpms its already maxed out when it should just be kicking in???

Perform a boost leak test and install a proper aftermarket boost gauge.

If all else is stock, it should make 12ish psi by 2500rpm and hold that through till the gear change. They really do feel like a n/a 4cyl above 5k with the t25 at stock boost levels. Still revs out nice but just quits pulling. If thats the case then its perfectly normal.

Grab a boost gauge, mbc, and a ebay intake. It will wake it up nicely.

 

[walmic679]

That's kinda the situation stocker, but when I'm on the freeway in 5th gear at 65-70mph, i just have to give it gas, don't need to down shift. It has one hell of a 5th gear pull!

 

[n0de]

That's kinda the situation stocker, but when I'm on the freeway in 5th gear at 65-70mph, i just have to give it gas, don't need to down shift. It has one hell of a 5th gear pull!

Boost gauge should be your first mod. If you are able to tel us the exact psi you are running just by using your butt gauge then I would be impressed.

 

[marcman804]

+1 on the boost leak test and get a boost gauge. There is no way to know for sure whats going on without either of these being done.

 

[walmic679]

How is an actual boost leak test done?

 

[RvlutionMtrsprt]

You hook up a tester to the inlet of the turbo and pressurize the charge system to whatever you desire. On a stock car like yours I'd do 20-25psi, on setups that are going to run a lot of boost I do them to at least 30psi. You can listen for leaks, they're usually obvious when pressurized, you can also spray soapy water on all the connections and look for the bubbles to find leaks. Pretty straight forward.

 

[ktime]

do you have any exhaust leaks?

 

[walmic679]

I finally got around to putting an aftermarket boost gauge in it. Doing a bunch of research, says stock boost is 11lbs, and oh ya, turbo is a 14b. Anyways, it is at or around 3000 that my boost gauge is at 9-11lbs. I did in the past do a complete engine leak test by taking off my airfilter, wrapped it up real good to prevent any air leakage, then took my air compressor and went through a vacuum line that was going straight into the manifold, put bout 12-20lbs through it, and sprayed soapy water EVERYWHERE.....only thing i found leaking was the intercooler itself, and the big set screw on the actual throttle.

 

[WES_393]

Anyways, it is at or around 3000 that my boost gauge is at 9-11lbs.

So does it stay at around 9-11psi until redline, or does it drop off suddenly?

 

[evokid1390]

I think that big screw would be your idle screw and it should have a rubber seal I think

 

[clipto]

I would not even worry about it. The t25 was put on the 2g for helping giving a little boost like if you need pass somone on the freeway it's no way a turbo you should be racing on. Your not going to make much more power out of it then stock. I would not really worry about it until you upgrade. The only thing you can do is get a wide band and lean it out to make more power the stock air fuel ratio is to rich anyways all your doing is dumping fuel when your boosting.

 

[walmic679]

well i have never redlined it yet, by 4000rpms is where the boost seems to stop and its all on just engine power i guess to say.

 

[-Boosty-]

Do your boost leak test like this. Then fix any leaks and take it back out and see how it runs.

[ame]http://www.youtube.com/watch?v=fdjadhUP1u4[/ame]