Cant make more then 3-4psi ! help!

[turbo2nr]

heres the problem, i have a 8psi spring in my wastegate and the car only makes 3-4psi with the wastegate connected. when the wastegate is disconnected it makes as much boost as i want it too, i only went up to 14psi at 4000rpms.

my setup. ka24de with t4 , revhard manifold, fmic, tial wastegate 38mm vent to atm, ssqv , ect.

at first i taught it was my wastegate that was bad so i bought this tial unit. and it still does the same think it only makes 3-4psi.

next i checked for boost leaks. i pressurized the i/c pips with compressed air to see if i would hear a hissing form a coupler and nothing . so that eliminates a hole in a coupler or lose coupler.

im stumped its not the wastegate, its not the i/c pipes or couplers and its not the turbo to the manifold or wastegate to manifold or else it would leak out exhaust and not spool up the turbo.

so what can it be?

[SR20n00b]

u sure ur wastegate isnt getting stuck open/closed? did u try to recirc it and see if u still got the same problem?

[turbo2nr]

recirculating the wastegate wont solve anything its just dumped into atmosphere. as far as it being stuck open or closed. its was tested and working fine before installed

[SR20n00b]

is the 8psi spring new?

[SoguRacing]

try adjusting the wastegate actuator bar.

[johngriff]

try adjusting the wastegate actuator bar.

ITS A T4 IT IS EXTERNAL.

Are you sure the gauge is correct? Try moving the vacuum source?

[sr20boostn20]

what size wastegate is it?

tial 38mm have a flaw in their design, some of them work some dont,

best bet tial 44mm

the flange is cast onto the manifold right?

thers a company called synapse they make one without a diaphragm, i think they discontinued the 38mm though

[turbo2nr]

the wastegate works fine i had it tested before installations it opens at 8psi. the spring is not new but works.

any other thoughts? thanks so far

[johngriff]

Where is the vac line for the wastegate hooked to compared to the gauge?

T them, so you know exactly when it is opening.

[turbo2nr]

the vac line is connected form the turbo compressor housing, the boost gauge feed is taken off the brake booster vacuum via- vac block. it has been working fine like this for over a year now..

this problem has me soo stumped

[johngriff]

T Them together off the compressor.

[KwKouki]

are you using a electronic boost controller? my greddy unit was shutting down boost around the same time, only mine was going back to vacuum when it would reach 4lbs.

[TheArkitekt]

split or partially disconnected IC hose?

[turbo2nr]

im not running any kind of boost controller. its a line coming straight for them turbo comp housing to the wastegate.

as for the i/c pipes i did a boost leak test sending in compressed air 8psi and i was listening for a leak i didn't hear any. so i doubt it was that

[sr20boostn20]

this set up has boosted 8psi before? like this problem just started happening out of the blue?

definatly give what griff said a shot too, to see if prehaps the vac line to the gauge is slightly blocked

[downshift_sideways]

Did you check the lines with the throttle open while doing your pressure test?

seems like from the turbo to the TB you dont have leaks, but there are other vacuum sources that can be leaking when your throttle opens.

check all your gaskets from your manifold down to your turbo.

I've never dealt with finding the vacuum sources for the boost gauge I'm used to T'ing into a line on the TB.

[turbo2nr]

sr20boostn20: yea the car ran 8psi before and was fine this happened out of the blue. have no clue how. i will try the gauge thing but the car is defiantly hitting 3-4 psi the afc is only reading 79% throttle usually it will hit 100% around 4k on 8psi so its defiantly running only 3-4psi. also the boost taper off closer to redline so it will drop to 1-2psi.

downshift_sideways: the throttle was close and the pressure leaked into the engine a bit b/c the throttle doesn't form a direct seal. but still no leaks on the charge pipes. i checked all the gaskets on the turbo to manifold and the wastegate to manifold all are tight. and i would hear if it was a manifold exhaust leak.

im thinking it may be a leak on the intake manifold maybe one of those vac. lines there.

[sr20boostn20]

i was at my friends shop the same thing happend to a civic hey were trying to tune,

the problem turned out to be a severed vaccume line, that wasnt to visable.

[turbo2nr]

thats what it seems like any idea how they found that vac line? also which one was it? so far thats the only thing i can think of..

[S14DB]

Compressor housing is a bad source to run off of. Hook up to the "vac block"

[Slidin240Wayz]

Tighten all you IC clamps...they do come loose.

[sr20boostn20]

they had just unstrapped it off the dyno, we were jsut looking under the hood and saw a vaccume line looked a little cooked.

i guess just try and check around everything in extreme heat range?

[SR20d2fourT]

Shit happend to me. I just changed out the turbo to another from a blacktop and it had a 10psi spring in it. and it boosted 10. Great fun, solved problem. :) Not to say that's your problem, but that was mine. :)

[Z U L8R]

what are you using for your intake snorkel? sometimes the rubber snorkel's get hot and collapse together (implode) therefore the turbo can't ingest any fresh air, therefore it can't compress anything.

if you have or use a metal intake then you're fine. didn't see that mentioned but is something i've encountered before. gl,
Dave =]

[turbo2nr]

yea its a 3" metal pipe with silicone couples.

today i will hook up the mbc and see if its the wastegate spring.

aslo just to verify where am i suppose to hook up the waste gate vac souce? the vac port by the hat or the one toward the bottom close to the manifold?

thanks

[sr20boostn20]

^^

mine is coming from a barb on my ic piping.

it works.

[smelly240]

what size wastegate is it?

tial 38mm have a flaw in their design, some of them work some dont,

best bet tial 44mm

the flange is cast onto the manifold right?

thers a company called synapse they make one without a diaphragm, i think they discontinued the 38mm though

wtf - i have had 5 tial 38mm gates and a ebay one and they all worked fine... what is the flaw?

my guess is that u have a 3.5psi spring in there.

[turbo2nr]

well i connected the mbc today and turned it up. it first hits 8psi around 4300rpms and as i take it up to 6k it tapers off to 5psi.

im convinced its a boost leak.

it would make sense, b/c the spring in the wastegate is a 7.4psi spring and if its a 3psi drop or leak it would make the boost level around 4psi. and with out the mbc i was only making 3-4 psi. so therefore i have a 3psi leak some where in my system.

also the turbo is a little laggy to spool..

wow i miss boost i need to find this leak. its not any of my charge pipes..

[downshift_sideways]

Bingo.

Check all the lines off the TB Nipples.
(bov,fpr,boost gauge if you have it there)

I know you would assume that if there is a leak on the exhaust manifold side, you would hear it. Thats true, but sometimes you can have the smallest leak on your gasket, and you wouldn't recognize the difference between turbo spool and the leak. and it would drop the psi anywhere between .5-3psi.

I'm going to throw this out there, but you are using rubber hoses for all your vacuum sources? correct? Some people tend to use clear plastic lines, that collapse under pressure, and if they are used on the exhaust side, it heats up, and collapse not allowing air to flow.

[turbo2nr]

yea i have to go through all the lines by the intake manifold side..

interesting im going to check for leak around the turbo and see.

as for the vac lines they are all reinforced Goodyear vac. hose and they are pretty new..

but i hope i can find this leak its really bothering me.

[sr20boostn20]

ive had points where i was blowing the gasket between the manifold and the turbo, in my case that made the turbo spool real late but it still made full boost.

looks like its most definalty a hose now




wtf - i have had 5 tial 38mm gates and a ebay one and they all worked fine... what is the flaw?

my guess is that u have a 3.5psi spring in there.


i dont know then, ive had 3 and two of them failed and one of them didnt.

i asked my parts guy and he told me the 38mms were flawed.

[downshift_sideways]

Took me a month to locate where I was boost leaking.

Turns out it was on the Throttle body gasket. Very small small leak, but it wouldn't allow me to hit full boost.

Hope you get find the problem.