Boost situation

[s14daver]

Ok so ive searched over the past few weeks to no avail. My question is...why the hell wont my t25 on my sr hold 12psi...From the sounds of it ppl say they can hold 12psi just fine, but is this true? Seems as tho mine will fall to about 9.5-10ish by the time its gettin near redline. If thats the norm then cool i can deal with it. THe only other things i can think of are1. I need to dial my AEM tru boost in better2. I have a small leak somewhere

Any ideas will be greatly appreciated sorry if i sucked at searching and missed something...

[IanS]

all three of my T25s have held 12 PSI, and I built my boost controler in home depot, what other mods do you have, and how are you vacume lines hooked up.

[s14daver]

i made a mbc b4 i got the aem as well and it wouldnt hold 12psi either...it slowly crept back down to 10. I have a cheap ss turbo elbow, 3" downpipe and test pipe, 3" megan catback Hks direct drive intake on the maf and thats about it. Running a spec r sidemount also. Ill have to look at the vacuum lines after work and give a good description of how thsoe are ran.

[Blown240sx]

its either an exhuast problem, wastegate problem, or Boost controller.

[S13FASTBACKSR]

if your idling fine, no bogging or misfiring then i dont think you have vac or boost leaks..getting near redline for that little t-25 i would think boost would start falling off seeing as how its used and been beaten on..who knows how long its been since its been rebuilt..all t-25s are gonna have different quality..yours is probably dying out seeing as how boost falls off towards redline..if thats not your problem then its either your wastegate actuator or boost controller..but i would probably put my money on the turbo itself..what you could do is get another wastegate actuator and mbc..actually what i would do is get the hks actuator for 100 bucks which is adjustable just like a mbc so your killing 2 birds with one stone..buy that and if the problem goes away it wasnt your turbo if it still occurs the problem is therefore your turbo

[redtop91]

I'd agree with the idea that it is your turbo. I wouldn't waste money rebuilding the T25 if it is though. Nail down loose ends, any leaks, tighten vacuum lines and if the problem persists, buy a T28

[S13FASTBACKSR]

and if the problem persists, buy a T28

No bro he means buy a T88..Turbo lag ftw..jk but honestly if the problem is your turbo and you decide to upgrade i would spend the extra money on a 2871r .64 a/r...I wish thats what I wouldve done instead of buying a t28

[s14daver]

^lmao...

Seriosuly tho im not thinking its the turbo itself...the motor was supposedly low mileage(ik ik) but i gotta say i believe them. Every heatshield and bolt on the motor was clean and easy to take out. When i put RAS in the damn thing looked brand new, id put money on my turbo being in good shape...

As for an exhaust issue...do you mean a leak near the turbo could cause this? like maybe on eitehr side of the elbow? Im not too worried as ill be changing set ups eventually i just figure for now ill squeeze what i can out of the lil guy and try to hold 12psi at the track...

[S13FASTBACKSR]

well then if you are confident in your turbo then u are probably confident in your wastegate..however if your turbo has been rebuilt then you pretty much have a newer turbo but the same wastegate...know what i mean?

as far as leaks check your intercooler connections, intake pipe, exhaust mani to head and to turbo and o2 dump to turbo and all of your vacuum lines..I would also try another boost controller.

[s14daver]

^yeah ill just have to comb thru it one day...its gotta be a smaller leak to still hold 10psi i would think. And id hope to god the AEM tru boost can handle the boost lvls on my sr....sigh

[dave37905]

No bro he means buy a T88..Turbo lag ftw..jk but honestly if the problem is your turbo and you decide to upgrade i would spend the extra money on a 2871r .64 a/r...I wish thats what I wouldve done instead of buying a t28

i agree with the 2871 idea but after owning all 3 t25 t28 and 2871(a/r .64) i wish i would have gotten something with a bigger turbine housing for better high end, less backpressure, and less detonation. the only reason i say this is because i cracked 2 of my pistons most likely because my EGT was too hot.

[redtop91]

Bah! Street turbos > Dyno queens.

[dave37905]

Bah! Street turbos > Dyno queens.

what i meant was make sure you have a big enough housing to wear your engine can breathe well because back pressure can kill your motor. or you can always just run higher octane fuel which will reduce knock but with gas prices the way they are id prefer pump gas. there is nothing wrong with the 2871, i just wish i had gotten the .84 a/r instead. i didnt mean buy a huge turbo that makes 800hp at 6000 rpms. unless of course you have a built head that can handle 11,000.

[s14daver]

lol thanks for the turbo suggestions but anything else random or obvious to my problem would be great haha....the time for a big turbo will come later this season