Need help ASAP...not hitting full boost!

[MM BOOST]

OK...so the past few weeks or so, I've noticed my car just doesn't feel like it used to. I didn't pay much attention to it because I don't get very many opporunities to get down on it hard cause of traffic and such. So the other day, I took the car out on some back roads and was doing some WOT pulls...and come to find out, my car is only hitting about 12-13 pounds of boost MAX...and this is even in 3rd and 4th gear. Used to the car would spike to about 18-20 and settle around 16ish or so, and now I can't even get it to spike. It goes right to 12ish. It just doesn't pull as strong. Today, I took the whole intercooler off and redid all the clamps on the intercooler piping and the intake and inlet, and STILL, its not hitting full boost. Has anyone ever had this problem or can anyone think of a reason why its not spiking like it used to and why I can't hit full boost?

My mod list:
-street unit boost tubes
-injen intake
-exhaust mod
-Greddy RS BOV VTA with recirc pipe plugged
-autometer boost gauge

The ONLY thing I can really think of as I don't have much experience with boosted cars is my blow off valve. Would me having the blow off valve adjusted too tight or too loose cause me not to be able to hit full boost? But, I only put this bov on last saturday, its been doing this for a little while now. Would the fact its VTA and not recirculated cause it not to hit full boost? This is really bothering the hell out of me and I want to get it fixed QUICK. Please help me!!

[coyfish]

Try it while running ur greddy on recirc. Also double check your hoses and clamps on your BOV.

[Darkhorse]

the blow off valve could be bleeding a little air if its not adjusted correctly. this happened on my gti when i had a greddy type s. Try reinstalling the stock DV valve and see if it still occurs. If it doesnt, then its your blow off.

[lil_red_wagon]

i wouldn't know what to say other than that you may need to relocate the maf.

that may not have anything to do with your problem, but it will prevent you from bombing the hell out of your valves.

[MM BOOST]

well i cant put my stock back on right now, im at home for christmas, and my stock valve is sitting about 3-1/2 hours away at college.

What do you recommend darkhorse...going tighter or going looser??

[spdjnke]

If your spiking before at 18-20 psi, my guess is you probably "cracked" a seal in the wastegate, 18-20 psi is WAY to high especially with our cars, but that's just my opinion, I had that spike once at 18.2 and I loosened the BOV WAY DOWN so it wouldnt' peak anymore then 17.25 and no issues so far. But then again when it's 18 degrees out it usually peaks at 16.3 according to DH. so Temp has a lot to do with it, but definately not 12 psi.

And I'm VERY suprised that you haven't gotten a CEL from running VTA.

[MM BOOST]

nope, not a single cel and car runs like normal. i capped off the recirc tube with a plug and i have zero problems. the 18-20 spike is normal, i did a search, alot of people had the spike and then it settles at 15/16. It just won't even spike to 16 now. It was spiking that when the car was stock with just an intake. So i know thats not the issue. So you think i should loosen or tighten my bov or is that not the problem here?

[phillyb]

If your spiking before at 18-20 psi, my guess is you probably "cracked" a seal in the wastegate, 18-20 psi is WAY to high especially with our cars, but that's just my opinion, I had that spike once at 18.2 and I loosened the BOV WAY DOWN so it wouldnt' peak anymore then 17.25 and no issues so far. But then again when it's 18 degrees out it usually peaks at 16.3 according to DH. so Temp has a lot to do with it, but definately not 12 psi.

And I'm VERY suprised that you haven't gotten a CEL from running VTA.

you know, i've read other people say that you don't know what you're talking about and i wanted to turn the other cheek, but this post puts me over the top. 18-20 psi is not necessarily ideal, but it's certainly not "way too high," or as you put it, "way to high." (to/too/two, use a dictionary)
i can think of at least 10 people running 18 psi on this turbo...and i'm 100% certain there are more. in fact, 10 people is a highly (read:amazingly highly) conservative number for people pushing 18 psi.

op, don't listen to this clown. your wastegate is probably fine. check for leaks again. if you're just idling, you obviously won't be able to feel a leak with your hand, since the car idles in vacuum.

check the valve, check the ic. take the ic off and check to see if there's anything in the end tanks. and check the throttle body to make sure nothing got in there as well.

what changed in your scenario?
what did you install?

[Circle9]

From all that I've heard and read, phillyb is correct, 18 psi is not "way too high".

[RC08MS3]

not to steal a thread, but what if you spike to 18, cut back down to 15.5, and then gradually loose boost before 5800? usually it'll cut back down to around 12, which sucks.

[MM BOOST]

that sounds normal to me...it don't hold all the way to redline on this turbo with the stock tune...they have tunes that gets rid of this, but thats the only way its achieved.

Yeah I figured he was full of it by reading that post. I really don't know what could have caused this...the only thing i've really changed on the car is putting in this blow off valve last week. Before, I was running a POS knock off type s blow off valve...and actually now that I am thinking about it, that could be the problem. You know how people talked about how boost is limited in 1st and 2nd gear? Well...i was seeing full boost in 2nd gear with that BOV and I am pretty sure it had a leak, cause it would fluctuate some. With this greddy rs, when I nail it, it goes flat to 12 psi in 2nd gear and it doesn't budge...which shows that its a stronger and more well built blow off valve. Maybe I need to take the car out driving again and pay attention to 3rd and 4th gears. Would cold temperatures make a difference? it's been 20 degrees past few days. I am just trying my best to figure this out...the car still pulls hard as shit, im just not seeing the numbers I used to in terms of boost.

Keep the ideas coming guys, this is bothering the shit out of me.

[phillyb]

we get cold weather cut, not necessarily cold weather boost-loss.
do you have an oring between the valve and the flange?

[MM BOOST]

hmmm...i think i do.

[phillyb]

by the way, i'm running 18 psi

[UHATEIT]

Im rocking the Greddy type-S right now in vta, just for shits n giggles. Damn it sounds amazing :) I used b-ron's idea and shoved a D battery in the recirc tube and it blocked it right up nicely.

I am spiking at 18-19 and settle arouns 16. I just get some rough/aggressive driving in vta mode, and some minor backpops but nothing crazy. My CEL came on after 50 miles or so. So I'm waiting to meet up with phillyb to check out the CELL and see what's up.

Basically my car runs with boost perfectly fine like normal, just that I got a CEL and I see you didnt get one.

[phillyb]

kyle, sometime this week, we can get together. tonight would even work for me

[UHATEIT]

kyle, sometime this week, we can get together. tonight would even work for me


I'm driving to Utah tonight for the holidays with my family, I wont be back until Sunday night. If Sunday is cool??? I assume it has something to do with beign VTA tho there are others that dont have this problem with VTA like the OP

[DaleNixon]

I've never seen my boost spike that high, but I've only been at WOT for probably a total of 10 minutes in the 6 months i've owned my car.

[phillyb]

I'm driving to Utah tonight for the holidays with my family, I wont be back until Sunday night. If Sunday is cool??? I assume it has something to do with beign VTA tho there are others that dont have this problem with VTA like the OP

aight, call me when you return. drive safely and have fun man

[MM BOOST]

yeah see I don't think its because of the car being run VTA...because its running fine otherwise. And no, no cel. Did you reset the battery when you did it? I did...let it idle for a while, then took it for a drive after installing. Blocking the recirc pipe makes a huge difference in terms of how the car runs VTA.

[UHATEIT]

yeah see I don't think its because of the car being run VTA...because its running fine otherwise. And no, no cel. Did you reset the battery when you did it? I did...let it idle for a while, then took it for a drive after installing. Blocking the recirc pipe makes a huge difference in terms of how the car runs VTA.

for sure! Yeah when i was talking about vta months ago and how shitty the cars runs vta, that was because I didnt plug the recirc tube! Now that tried it with the D battery in the recirc hose it doesnt run too bad. Its a harsh drive, as in the car seems to struggle a tiny bit and the car runs rougher when shifting gears. But I have a CEL that I need to check, but there is no low boosting like you were having.

Apparently on this one website on how to adjust a BOV, you can actually hold MORE boost when venting! Crazy concept. Here is the link:
http://www.siliconeintakes.com/stpg.php?page_id=bov

So if you're not getting full boost, it shouldnt be from vta, it may be the valve isnt shutting all the way when you floor it and may need to be tightened or the rubber ring around where the plunger inside makes a seal at the bottom is leaking out. You arent mentionging you have a problems HOLDING boost, you are talking about not reaching full boost all together. So its probably not a problem of the valve leaking and not holding the pressure, it seems the pressure isn't there initially and can be leaking around the flange or the O-ring on the plunger that keeps it shut.
As phillyb said, you wont really feel the leak at idle, you mak need a friend to give it some gas and hold the pedal while feeling around the valve yourself for rushing air, or put a bag around the valve like a plastic grocery bag and see if it starts to get air in it or see the bag move meaning air is leaking out.

I sued a mirror while a friend pressed the gas to check this: The valve plunger shuts and blocks the hold when you hit the gas, the boost sucks it shut, the vac from the top hose is what tries to pull it up and open and does it when you let off the gas. What you SHOULD try, is put the bag over the empty vent hole and they have a friend hit the gas and see if the bag starts to suck in a bit, if it does, then your valve is not shutting all the way when you hit the gas and it is not having a full seal (could be that o-ring on the plunger) then the ring would need replacing or you may try tightening the top screw and seeing if it stops the bag from sucking in while having a friend press the gas.

[MM BOOST]

alright guys...got an update!! Took her out tonight and romped on it some, and it looks like she is back to normal!! Don't know what the issue was...I put some new gas in it (it was near empty) and plus yesterday i redid all my boost tube clamps and inlet clamp and intake clamp and retightened everything and now she is back to normal. But, i think this blow off valve is legit, because in 4th, i hit right at 15-16 psi and did not spike ONE BIT. It went straight there and held steady. My old blow off valve, when I ran it in VTA, i would floor it, it would spike 18-20 and hit boost cut and the car would fall flat on its face. Now, with the new greddy, its not spiking one bit. Car ran great tonight!!! I think my tubes was loose on it. maybe I can stand to loosen the bov a notch or 2, but as of now, the car is back to normal.

[UHATEIT]

alright guys...got an update!! Took her out tonight and romped on it some, and it looks like she is back to normal!! Don't know what the issue was...I put some new gas in it (it was near empty) and plus yesterday i redid all my boost tube clamps and inlet clamp and intake clamp and retightened everything and now she is back to normal. But, i think this blow off valve is legit, because in 4th, i hit right at 15-16 psi and did not spike ONE BIT. It went straight there and held steady. My old blow off valve, when I ran it in VTA, i would floor it, it would spike 18-20 and hit boost cut and the car would fall flat on its face. Now, with the new greddy, its not spiking one bit. Car ran great tonight!!! I think my tubes was loose on it. maybe I can stand to loosen the bov a notch or 2, but as of now, the car is back to normal.

dude make a drive by video I want to hear this type rs in action!

[hectik1]

alright guys...got an update!! Took her out tonight and romped on it some, and it looks like she is back to normal!! Don't know what the issue was...I put some new gas in it (it was near empty) and plus yesterday i redid all my boost tube clamps and inlet clamp and intake clamp and retightened everything and now she is back to normal. But, i think this blow off valve is legit, because in 4th, i hit right at 15-16 psi and did not spike ONE BIT. It went straight there and held steady. My old blow off valve, when I ran it in VTA, i would floor it, it would spike 18-20 and hit boost cut and the car would fall flat on its face. Now, with the new greddy, its not spiking one bit. Car ran great tonight!!! I think my tubes was loose on it. maybe I can stand to loosen the bov a notch or 2, but as of now, the car is back to normal.I gotta ask....what was the temp? I just have an intake with stock BPV(freak) and I have noticed temp has A LOT to do with boost. 0-20 degrees I literally can't get more than 14 psi max. When it was warmer 30-60 degrees I would get 16-16.5 max. All my tubes, etc are tight.

[MM BOOST]

yep, been in the 20's here.