mhewitt

i have a boosted ls vtec civic and with the manual boost controller turned all the way up my t3/t4 turbo would only boost 16psi. but sometimes randomly when i go full throttle it only boosts 9psi despite running a 1 bar spring in my wastegate. does this mean that my turbo is starting to go bad or could it be some other problem? all vacuum lines are still hooked up and boost controller is still turned all the way up. using a gsr oem intake manifold with vacuum line disconnected from the butterfly which means its always open, right? has been tuned by very reputable tuner in va.

2k.civic.si

1bar spring should get you around 14-15psi. either the wastegate has an issue or you have a boost leak.

mhewitt

what would cause it to only do it sometimes?

pinki07

ebay!!!bump

mhewitt

its a tial wastegate

0dancing_ninja

At first glance, I would be inclined to think either the spring is really only a .5 bar spring, you have a boost leak somewhere, or the boost controller could possibly be installed incorrectly. A lot of times if the turbo is going bad it would make unhappy sounds or be starting to emit smoke in the exhaust.

mhewitt

i know the spring was 1 bar. the controller was installed professionally. so gotta be a boost leak, i noticed a little bit of an oilly spot around where the vacuum lines all t together might b a pinhole leak in that but would that cause it?

0dancing_ninja

A boost leak test would be the easiest way to evaluate if boost is escaping the charge system.

93egSLEEPER

Humor me, what color is the spring and what is the diameter? Sounds like a boost leak to me but doesnt hurt to double check.

What shape is the motor in? Is it getting constant oil pressure? Plugs/wires/cap rotor? All are a contributing factor.

ralph11sec

remove the controller.

connect side nipple directly to the compressor housing.
open up top port. try it.

it should get you 14-15psi.

at idle, what is your vacuum?
check tb boost leak. etc.

mhewitt

i aint openin wastegate back up to check color of spring but i think it was blue n it was a big one, it was a bitch to put in lol. dont have anything to test for a boost leak other than visual inspection, i have istalled boost/vacuum, oil press, n fuel pressure gauges so i keep check on the motor everything is fresh only a lil over 6000 miles on engine, constantly 40 oil press at idle gets up to about 80ish under full throttle. theres no place on my compressor housing to hook vacuum line but i have tried unhookin controller but nothin changed cuz its not boostin enough to even open the 1 bar wg spring so controller is useless for now. ill check where vacuum is at idle next time i drive n i will update, thanks for ideas guys keep em comin

Pro-Am 1934

Well when you put the wastegate back together you very well could have pinched and tore the diaphram inside. That could be casuing your leak. I would strongly suggest you take it back apart and verify. If you know someone that has a press, ask them if you can borrow it for 15 minutes to check it out.

Jason

mhewitt

the mbc is a cheap one n it was an "in cabin" design however when the shop tuned it they moved it to underhood with line comin from side of wastegate to a "t" that came with mbc, u can blow through straight through side but not through intersecting side of "t", goes straight through "t" to vacuum port on back of mani that boost gauge n fuel regulator both tie into. then a line comes off intersecting side of "t" n goes to one nipple on mbc n the other nipple is just open on mbc. then blow off valve and 3 bar map tie into a vacuum port on t/b. does any of that sound wrong?

mhewitt

i see your point but this wasnt happening until recently and i put the spring in 3500 miles ago wit no problems till now so i will keep that in mind but will check for other boost leaks first. where i live nobody has any tools other than me, lol without having to pay a machine shop or something like that to do it. my town sucks n no one really gets into imports around here, last time i used 3 pairs of vice grips to hold it all together so i could put allen screws in, wasnt easy lol

mhewitt

tttt

TheShodan

iTrader: (14)

Kinda nothing to ttt here. You need to get a boost leak tester. Visual inspection is only have the battle. Once you get that boost leak tester setup, then you'll have a better idea of where you are. Otherwise, you're just asking the same questions here.

http://www.turboboostleaktesters.com...101/Categories

Q&As
http://www.turboboostleaktesters.com...26A/Categories

mhewitt

ok thanks for the help guys

mhewitt

my vacuum is @ 22 @ idle. does it sund like there is a problem with the way my vacuum lines r run?

tasco

you wont be able to tell if you have a leak by the readings on a vacuum gauge. you have to do a pressure test.

Tony the Tiger

Is the wastegate actually opening at 9 PSI?

If it doesn't appear to be fully open, then you have a boost leak somewhere.

If the wastegate is blaring loud and 100% opening, then there is a huge system restriction somewhere. Excessive exhaust pressures will cause the wastegate to underboost. A very resctrictive intercooler, or one with big pressure drop will also cause it to underboost.

Start with the easiest things first --> test for boost leaks.

mhewitt

i found a hole in one of my boost pipe couplers behind the bumper that could be my boost leak problem, i also was curious about the way they ran my vacuum lines thats why i aked about it. meant it in a separate way from my under boost problem

TOPHERS-RACING-LOGISTICS

depending on your exhaust set up you could have too much back pressure. This will cause the gate to open soon and bring down boost. try running off of down pipe and see if you dont recover lost boost.

75w90

i don't think it is any of those, is it a internall wastgate or external. if it is internall than i think that the waste gate is stuck half way open all the time and never close all the way so you are loosing a lot of the pressure and you never get all the boost that you are building and than when you do get the full boost is when the gate actually closed and this has happen to me on my dsm.

mhewitt

its an external, tial wastegate

Tony the Tiger

How? If the leak is before the throttlebody, it won't lower the vacuum.

If the vacuum leak is so big that you can lose most of the boost, then I doubt the car will be idling at 800-1000RPM... It will be idling at 3000+ RPM...lol

What you are speaking of is a vacuum leak, AFTER the throttlebody.

A leaky intercooler for example, will not reduce overall manifold vacuum...