18psi with mostly stock engine???

[JMiller]

I have a hard intake pipe w/ filter, 3in open down pipe and free mods (BCS, Dump tube, ect.). I just installed a boost gauge today and test drove it to see how much boost ive been hitting. I have t'ed off the line goin from the intake manifoild to the fuel solenoid as it says to do on vfaq. and for some reason in 1st and 2nd gear im hitting 18psi and 3rd it goes down to 16psi. I was under the impression that my car should only been around 12psi. My qeustion is why. Why ist it boosting so high.

 

[16gpoweredgsx]

If you did the freem mod to the BCS, that will usually give you a few more psi. You are also probably getting boost spike from the 3in exhaust.

 

[JMiller]

i thought the 3in open down pipe might make the boost go up a little but 18psi that just seems a little hight to me. im also about to install some comp cams so should i leave the boost alone or get a boost controller and turn it down.

 

[talonalex92]

3in open down pipe

Theres your problem. Im assuming you mean that you have no exhaust, just the DP.

 

[JMiller]

yea beacuse it runs bad connected to the stock catback because its 3in going to 2.5in so the exhaust backs up in the engine at high rpms.

 

[linksys42]

Go make your own MBC and install it turn the boost down. If you are still running the t25 its going to wear that turbo out fast boosting 18psi.

http://www.geocities.com/chmwatson/FAQs/mbc.html

 

[talonalex92]

yea beacuse it runs bad connected to the stock catback because its 3in going to 2.5in so the exhaust backs up in the engine at high rpms.

Then go 3'' all the way or just deal with it connected because if your still on the t-25 your going to be buying a new turbo soon. And thats no good!

 

[JMiller]

yea thats what i was worried about, that and the stock blow off valve isnt made for 18psi and i cant get a greddy rs for a few weeks.

same for the rest of the exhaust i have to wait to get the 3in catback megan system.

 

[talonalex92]

Then I would just make yourself a Home-Depot racing BC and just wait. Orrrrrrr you can stay out of boost till the systems complete..and who wants to do that?

 

[JMiller]

Good point. Thanks for all the help everyone.

 

[talonalex92]

=] np.

 

[hun6over]

You should put your bcs restrictor back to lower it 1-2 psi. That should hopefully put it back in the safety zone until you get a MBC. If you're initially spiking to 18 psi then settling down at 15-16 psi at higher rpms then thats normal for a t-25. They tend to spike 2-3 psi.

You can buy a MBC from ebay for like 15 bucks or spend 10 bucks to make one yourself and risk fudgin it up.

 

[kmoore]

You are spiking.... you need to get a MBC (Like already stated). You need to get a 3" catback, and you do NOT want a Greddy Type RS BOV. Do some research and you will find out why.

 

[GS-T_Newboost]

the hard piping intake and filter sometimes ups the boost alittle

 

[talonalex92]

the hard piping intake and filter sometimes ups the boost alittle

Ive never heard that, and seeing as how it doesnt see boost at all I dont believe it. Any supporting evidence?

 

[deathbydsm90]

high flow filter= spool up
oem rubber hoses means stretching= less boost made
filter+ hard hoses=no stretching, boost increase, and turbo response
along with simple mods like gm maf, dump tube for boost creep...etc.

 

[talonalex92]

He said the intake, not the IC pipes.

 

[JMiller]

yea its just a SS intake pipe not intercooler pipe. Also i reconnected the down pipe and it still hits 18psi and i was wrong about it going down to 16 i did a few more test and it stays at 18psi from about 3grand in first through 3rd gear. I'm getting a MBC tomorrow im going with the home depot method if it doesnt work ill buy a turbo xs one later. Thanks for warning me about the Greddy RS kmoore.