Boost pressure question/ concerns

[oODanKNesSOo]

Good morning y'all... on the heals of up pipe down pipe install and Cobb stage 2 91 map flash- (and redoing the leaking UP gasket) I took her out and had the Cobb gauge for boost on. This is the result- *sign of a serious boost leak right?

**target boost being about 4x this number clearly shows something is Fd up..

 

Sorry so stoopid. New to this boost game

[Hirschman]

Boost should be quite a bit higher than 4 PSI, something is not right there. Have you checked for any leaks and ensured that all the hosed to the turbo are hooked up correctly? Was this a full throttle pull or just tooling around?

[oODanKNesSOo]

This was both... stepping on it and driving at posted speed limits :/

 

As for anything hooked up wrong, I have only removed the banjo filter, and installed it right back...

 

I haven't seen anything obvious as for leaks... but it's obviously no where near the 13-15 psi it should be

[coldsoda]

A couple of things here....

1) you should have read the map notes that go along with the map you downloaded from Cobb. You didn't list the year of your car and your profile says '99L so I can't imagine that's what you are posting about. For example, if the car is 2007 - 2009 LGT AT, stage 2 the map notes specifically state "Boost Targets: ~16.0psi peak boost pressure tapering down to ~13.0psi by the 6900RPM redline, +/- 0.8 psi" (Reference)

 

2) we cannot look at a picture of an AP screen and correctly gather enough information to tell you if the boost level is correct. If you need advice on data, please do a datalog per Cobbs instructions: https://cobbtuning.zendesk.com/hc/en-us/articles/200025134-How-to-Datalog

[oODanKNesSOo]

Sorry.. it's a 2006 LGT. I never found the map notes you provided- just what was needed to use said map(s). Thanks for the info. I do know that stock boost is well above 4, and closer to 13.

 

So I guess I have a massive leak, and now I get to try and find it.

 

Is there any advice for the hunt, or is it just, "good luck"?

[coldsoda]

Sorry.. it's a 2006 LGT. I never found the map notes you provided- just what was needed to use said map(s). Thanks for the info. I do know that stock boost is well above 4, and closer to 13.

 

So I guess I have a massive leak, and now I get to try and find it.

 

Is there any advice for the hunt, or is it just, "good luck"?

 

In that case, here are the map notes for your car:

https://static.cobbtuning.com/cobbtuningweb/site/maps/subaru/map_notes/SUBA_US_LGT_05-06.pdf

 

Stage2 91 v300:

Boost Targets: ~16.5psi peak boost pressure tapering down to ~13.0psi by the 7000RPM redline, +/- 0.8 psi

[oODanKNesSOo]

^^^ thanks... I saw that in your first post.

 

My 4.34 peak has a ways to go!

 

I'm trying to remain positive amidst the headaches.. like I mentioned there isn't any obvious leaks-

 

Is there any sneaky leaking places that are common?

 

I'm beginning to think I bought her with a leak and have yet to feel the true boost. It runs better now then it did, so hopefully I can get the leak under control and be boosting!!

[oODanKNesSOo]

Funny thing is, before I had the gauge to show me how shitty my life is, I thought the build was going good! Car sounds good, drives good.. is quick-ish... not quite where it SHOULD be tho. And The "noise" I had thought was my turbo spooling apparently is a big ass leak... that I've yet to find. Maybe later in the week- I'm at the "bandana in the gas tank light a match I'm done" point.

 

In other words, this is devastating... have had the LGT all of 2 weeks, and the turbo may or may not have shat the bed. Awesome

[BrianEarlSpilner]

Have you done a boost leak test to help locate your massive leak? If not here's a little help to start

 

http://legacygt.com/forums/showthread.php/intake-vacuum-leaks-and-you-pics-inside-235626.html

 

http://legacygt.com/forums/showthread.php/checking-general-health-your-engine-and-tune-210369.html

[magnusonsubie]

Check your intercooler connections on both the turbo side, throttle body side, and the BPV flange. Then check all the crimped connections on the intercooler to see if any appear separated.

[oODanKNesSOo]

Everything passed the eye test; although I haven't removed the IC or anything... I've done some googling and know I need to do a leak test. I don't have all the pieces I need so I haven't yet.

 

Like when you aren't feeling well google can be a blessing and a curse. Convincing yourself you are deathly ill, or in this case my turbo might be.

 

Glad it's not all gloom and doom in this thread tho... the 4psi is discouraging, but on the bright side ~15 will be MUCH funner!!!

 

 

Is it OK to drive with low boost on this stage 2 tune? 3500 rpm shifts of course

[magnusonsubie]

I wouldn't drive the car at all if you suspect the turbo is bad. Best bet is to drop the downpipe and check for shaft play

[oODanKNesSOo]

I don't suspect anything... I HOPE it's OK.

 

I hear boosting under the hood- now I may also be hearing boost LEAKING... however pressure is being built. The whistle I thought was the turbo doing it's job might be it being wasted- at least I hope it's that simple.

 

I will make the leak tester after work, and go crazy with zip ties and hopefully seal everything up.. fingers crossed

[Phillip J. Fry]

stock bypass valve? what is your avg mpg?

[oODanKNesSOo]

Ya stock bpv- I DO feel air coming from around it tho, I thought that was normal? What makes u bring the bpv up?

 

 

 

I know everyone is against BOVs, but if the stock bpv is done I have a hard time not getting a bad ass BOV.

 

Mpg seems decent... nothing to compare it to tho :/

[Phillip J. Fry]

Ya stock bpv- I DO feel air coming from around it tho, I thought that was normal? What makes u bring the bpv up?

 

 

 

I know everyone is against BOVs, but if the stock bpv is done I have a hard time not getting a bad ass BOV.

 

Mpg seems decent... nothing to compare it to tho :/

 

i trust stock bpv before any aftermarket. its less throttle response but easy to get good mileage.

 

shouldnt feel air around it. should be sealed. no leaks etc...you may have found a direction to go with.

 

i ask stock because aftermarkets can stick if not maintained.

 

what is your mpg?

[oODanKNesSOo]

Thanks for getting back to me... the display says I'm getting 17.7 mpg . Even at idle I feel a little air coming from around the bpv... should I start with gaskets or just throw a new bpv at it?

 

Another possibility i thought of- I started it with out the o2 sensor on the exhaust manifold plugged in... I cleared the code and plugged it in of course- but could I still be in "limp mode" due to the original code?

[Hirschman]

Thanks for getting back to me... the display says I'm getting 17.7 mpg ��. Even at idle I feel a little air coming from around the bpv... should I start with gaskets or just throw a new bpv at it?

 

Another possibility i thought of- I started it with out the o2 sensor on the exhaust manifold plugged in... I cleared the code and plugged it in of course- but could I still be in "limp mode" due to the original code?

 

Hmm. At idle the system should be under vacuum, and air would be sucking in at the source of a leak. Are you sure there is air coming OUT? Try spraying soapy water on it and see if it bubbles up.

[oODanKNesSOo]

Good call... it probably is sucking- in which case water might be a bad idea right? Can some throttle body cleaner be used instead? If the rpms fluctuate then I'd know that I have a leak there is my thought process

[Hirschman]

I've never had luck finding a leak that way, probably easier to make a leak tester. I did the super poor mans version and used a 750ml belgian beer bottle to plug the intake and then added pressure through the BPV vacuum hose using an air compressor. Gave me an excuse to drink a Westmalle tripel.

[oODanKNesSOo]

NICE!! I should pick up some 1554 Otw home.... to fix my car of course Lmao

[gimpydingo]

NICE!! I should pick up some 1554 Otw home.... to fix my car of course Lmao

 

Send some 1554 my way!

 

I ended up making a smoke machine from a paint can, a hose/tip kit for my compressor and of course a compressor. Only way I found the leak in my TVG cover for where the sensor goes on the 05/06 models.

 

But the plugging the inlet, adding pressure to the BVP line and soaping everything up should help find the culprit.

[oODanKNesSOo]

How'd you do the "smoke"? I was thinkn bout using my ecig vapor, and blowing into the line... sounds stupid but it SHOULD work.

 

Only question I have, is if I'm blowing into the vacuum line for the bpv- what's to confirm if IT is a/the leaking culprit??

[coldsoda]

a new use for vape! car diagnostics! lol

[gimpydingo]

How'd you do the "smoke"? I was thinkn bout using my ecig vapor, and blowing into the line... sounds stupid but it SHOULD work.

 

Only question I have, is if I'm blowing into the vacuum line for the bpv- what's to confirm if IT is a/the leaking culprit??

 

Bit of a long answer.

 

You could do the vape thing since some can really produce a good amount of smoke. You would need someone else to look for leaks while you blow into the BVP though. If you are blowing into that line it will fill the tract all the way to the inlet and will find all the vac leaks.

 

For the smoker I made. I looked at quite a few DIY online to make mine.

 

Similar to this, except I have the holes on the side of the can, inlet on bottom, outlet on top.

 

http://www.r3vlimited.com/board/showthread.php?t=274418

 

I have a hose from my compressor to the paint can (driller hole and expoxy) and have an hose coming out from the opposite side.

 

Can't find online, but I bought a smaller $6 kit from home depot with a hose and various tips:

 

http://www.homedepot.com/p/HUSKY-16-Piece-Air-Compressor-Kit-41250HOM/205331894

 

 

My compressor came with a plastic free flowing tip which I stick in the BVP line, plug the intake with my boost tester I made (but a beer bottle or small paint can would work).

 

I got some mineral oil, covered some old rags in it, light the rags, let them burn a bit, smother and put in the paint can, close lid.

 

Then I pressurized the BVP line at just a few psi to not blow the lid off the paint can. Should eventually start seeing smoke from any possible leaking areas.

 

I'll post up a pic on of these days.