rb25 boost problem-high pitch scream and power loss

[happypanda]

Alright guys. My car has been acting up since after the new turbo install. It would drive "ok" during normal driving conditions meaning it would boost ok since its not under alot of load. But when I drive it more aggressive, it would sound like it builds boost and just about it kicks in, I hear a loud high pitch scream somewhere I cannot pinpoint just yet. The car also then would feel like the power hits a wall. The rpm keeps climbing but no kick and just feels like its NA. I have all manifold bolts torqued and tightened except for the furthest one from the front of the motor. The stud broke.

You think this is causing a big boost leak resulting in my problem? Any other ideas?

Car has

greddy intake maniq45 tbgreddy fmicz32 mafsafcgreddy profecfull turbo back exhaustnismo fpretc

Basically it has all bolt ons with stock motor having stock ecu and injectors.

Any help would be appreciated. Thanks in advance guys.

[Shocker]

Sounds like a smaller boost leak to me. Not enough to leak at low boost, but opens as the pressure increases and stays open. Check your BOV as well.

[Nissan2367]

I had the same thing on my civic, When i ran 12 lbs it would run great but when i would run 20 it would hit a wall and boost would fall off. I ended up buying all new couplers and t-bolt clamps and never had the issue again. How many psi are you running and what kind of clamps are you using? Sounds like boost leak for sure

[Darius]

My first guess is that the turbo elbow on the compressor side is loose. Second guess is that a coupler split. Make yourself a pressure tester for $2 or whatever and track it down.

[happypanda]

ill check that but im pretty sure everything is tight since i didnt have any issues prior to the turbo upgrade. idle is fine and car don't stall. bov has been replaced b/c i thought it might be the hks bov leaking so changed that. its worth a try to check the clamps since im not using any tbolt clamps.

you guys really think that one stud not being bolted shouldnt be an issue? since the other side of it bolted down? car is boosting only like 12psi by the way and it does this each time. about anything after 35% throttle it will do it. it would be fine anything lower than that throttle percentage.

any other ideas? any help would be great. i can't wait to get this car running to the way it should be. thanks in advance guys..keep them suggestions/ideas coming.

also..i have a boost tester using compressed air. it seems to be fine when tested. just to let you guys know.

it just happens when the turbo builds up boost but when its about to let it out, it becomes a super loud sound and then instead of feeling the pressure release and feel the power, it feels as if the pressure escapes when the high pitch sounds happens.

[Shocker]

Missing a stud you should be fine, I ran my stock RB with 2 broken studs that never leaked. This granted you have the rest of them tightened down properly.

Like Matt said, check over the compressor coupler, and also your IC ones. You running an FMIC or standard SMIC?

[happypanda]

Missing a stud you should be fine, I ran my stock RB with 2 broken studs that never leaked. This granted you have the rest of them tightened down properly.

Like Matt said, check over the compressor coupler, and also your IC ones. You running an FMIC or standard SMIC?

ok ill make sure everything is tight again to make sure. i have greddy fmic. ill check couplers again. last time i checked there wasnt any leak. so we'll see again this time. but if that checks out good, what other things could cause this? would the stock ecu and stock injectors play as a problem in this case? I mean, I'm only running 12psi, not sure if i'm maxxing out those things. any other ideas? thanks

[Shocker]

ok ill make sure everything is tight again to make sure. i have greddy fmic. ill check couplers again. last time i checked there wasnt any leak. so we'll see again this time. but if that checks out good, what other things could cause this? would the stock ecu and stock injectors play as a problem in this case? I mean, I'm only running 12psi, not sure if i'm maxxing out those things. any other ideas? thanks

No, maxing out your fuel would cause knock, and your engine would pull timing.. and kill power.. hmmm

Well what fuel pump are you running? What are you using to tune your car?

[happypanda]

walbro. nothing but an safc. any ideas?

[Shocker]

walbro. nothing but an safc. any ideas?

Whats this "upgraded" turbo you speak of as well? You might be maxing your injectors out...

[neonbomb]

I had this happen once on my 02 WRX when i didnt tighen down my BPV bolts tight enough. It sounded like a high pitched horn under boost.

Check all charge pipe fittings

[DriftingisLame]

I had the same problem on multiple occasions, both on my car and my roommates RB20.

Every time it was a very small boost leak, make a boost leak tester and find it.. I'm very confident that this is your problem.

Good luck

[happypanda]

QUOTE=Shocker]

Whats this "upgraded" turbo you speak of as well? You might be maxing your injectors out...[/QUOTE]

t3/t4 turbo.

I'll check boost leaks again. I have a question. I welded my own turbo elbow and exhaust dp since its a custom setup. If i have some pinholes on there, I'm sure it can create that high pitch sound (or would it?) and also would that cause my problem since I mean its the exhaust side passed the turbo. Just a thought. What you guys think? Also, intake piping from turbo to intake filter has been made the same way. Would pinholes cause it too? what you guys think?

Thanks..keep them suggestions coming. Help me fix this

[Shocker]

High pitched noise could be from "pinholes" due to missed weld. How much boost pressure are you running?

I'd almost drop it down to 5 ~ psi or so and see if anything changes. I'm questioning your injectors being maxed out, and your car knocking when boost hits pulling timing. This all of course taking into account you don't have a boost leak, and you also know what your doing with that SAFC your using..

Your TB and Intake Mani secured well and gasket ed as well? Also have no open nipples on the intake?

[happypanda]

High pitched noise could be from "pinholes" due to missed weld. How much boost pressure are you running?

I'd almost drop it down to 5 ~ psi or so and see if anything changes. I'm questioning your injectors being maxed out, and your car knocking when boost hits pulling timing. This all of course taking into account you don't have a boost leak, and you also know what your doing with that SAFC your using..

Your TB and Intake Mani secured well and gasket ed as well? Also have no open nipples on the intake?

Yeah its at 12psi right now. I'll try to drop it down to lower boost settings. What would cause the injectors to max out? I mean it should be able to handle 12psi right? I really think it might be the pin holes of my welding but my question is that wont it only leak out the high pitch pressure sound on the "pressurized" side of the setup? meaning the intake pipe to filter is not pressurized right? same goes for after the turbo which is the turbo elbow-downpipe. would that cause the loss of power even if its not pressurized?

As far as the safc? what are the desired settings so I can just make sure its in the basic settings w/o trying to "tune" or mess with it. Ill check the leaks on the intake mani and tb side but I'm sure theres none there b/c if its a nipple, it would be pretty big to affect idle etc.

I'll keep trying to mess with all these things and keep those ideas coming so we can hunt this problem down.

[moso240]

just remember a t3/t4 at 12psi is like running your stock turbo at 13-19psi its flowing alot more air...Might be maxxing injectors..

[happypanda]

ebc at low setting..still does it..ebc even turned off..still does it..boost leak test done and only spot you can hear some air is the dipstick..

anybody can give me the safc settings for my setup..rb25det w/ z32 maf?

any other suggestions or ideas??

[meet07]

i would say possible injectors as well. the stock injectors are probably maxed out at like 300-320 hp. and thats at the motor. shoot with basic bolt ons and 12psi thats putting u at like 275 whp....290-305 motor hp. t3/t4 on 12psi? i would say is well over the injector limits

[Shocker]

ebc at low setting..still does it..ebc even turned off..still does it..boost leak test done and only spot you can hear some air is the dipstick..

anybody can give me the safc settings for my setup..rb25det w/ z32 maf?

any other suggestions or ideas??

EBC off is at what pressure? Whats the WG spring at?

stock 370's will go to about 310-320whp before maxing, but that is pushing it.

[moso240]

Also Put into Consideration that these injectors are well over 10 years old and are most likely flowing at a lot lower rate..

[happypanda]

wg spring set for 10psi. so you guys really think injectors are being maxxed out? would that cause the loud high pitch noise tho? seems like a leak or something..what injectors would you guys recommend? that means ill need an ecu tuning program then. emanage? power fc? any cheaper routes? lol im dead broke

[Shocker]

Have you had your head in the engine bay, and free reved the engine seeing if if whistles then?

[happypanda]

Have you had your head in the engine bay, and free reved the engine seeing if if whistles then?

yea i have. it doesnt do it when free revving. it only does it when the car is under load. any other ideas guys?

[Shocker]

yea i have. it doesnt do it when free revving. it only does it when the car is under load. any other ideas guys?

Its gotta be something in the charge pipes, turn coupler, cracked coupler, something..... what does the boost pressure do when you hear this noise?

[happypanda]

yea if i remember correctly, when it builds boost and it makes this loud sound, the boost pressure shows dropping on the gauge. ill make another run again today to verify.

[Joe]

just make a damn boost leak checker and stop driving the car. if you ARE maxing out your injectors you are only risking damage to your engine.

[SullivanRacing06]

is this a china turbo or a real turbo?

china turbo mite be a pos

or maxxin out injectors

[Coolwhip]

as suggested in almost every post, make a boost leak checker for $5.

If your welds have pin holes they'll effect power.

If you have cheap couplers and clamps that arn't the right size and it flares a bit b/c it's not sealing correcly, you'll have air push past it and make the noises you're describing.

Had used cheap pipping before and crushed the pipping with the clamp causing it to pin hole leak past the bead and it made a high pitched noise. Power was noticable lower and boost pressure remained the same (manifold), however at the turbo it was considerably higher since it was working past this small leak.

Free-revving did not expose this problem only under load and mid-level boost at about 5psi it began to be audible.

Don't forget the possiblility of it being the intake manifold gasket as well, but I doubt it.

[happypanda]

not sure if you guys havent read the part that i said that i do have a boost leak tester using compressed air. no leaks other than the air being heard from the oil dipstick. let me ask you guys this. up to how high the compressed air pressure can i use to test it? i dont wanna put it up to much to mess the motor up but i want it high enough to possibly act out the leaking "sound".

[happypanda]

update...i connected the maf/intake filter straight to the turbo outlet with a coupler bypassing the intake pipe i welded. Still same sound. so thats not the problem. here is a question. would the vband area from the turbo exhaust to dp make this sound and also cause a boost leak? i ask because it seems to be a pre-turbo leak since it builds boost and looses it when the "sound" comes on. any ideas would be appreciated. I want to start eliminating areas in order to pinpoint the issue. thanks guys. keep those ideas coming.