Jump to content
SAU Community

Recommended Posts

Hi Guys,
I know this has been repeated in alot of places but I just want some hand holding before I connect a compressor to my engine :P

I have the old hesitation issue where as the car is coming onto boost (boost gauge reads 0) the car hesitates, get over that hump and all is good. I have read that vacuum leaks can cause this so wanted to check for leaks.

I have done the soapy water test with nothing so I was going to follow http://www.gtr.co.uk/forum/174597-gtr-boost-leak-tester-diy.html and http://www.skylinesaustralia.com/forums/topic/250275-boost-leak/?p=4337070#entry4337070 but am not clear on which hose to pressurise.

My plan was to take of the Apexi air filters and sensors, block these both off with PVC piping and caps. Once the intake to both turbos is sealed I would remove the bottom hose (the hose on the right of the pic) off the PCM (photo attached) and slowly pressurise the system.

I cant figure out why to remove all the hoses as the link on GTRUK did.

My other option was to block one intake (say to the front turbo) and pressurise the other with a boost leaker tester? This may be easier

Please let me know if this is daft, sorry if the answer is here but I have searched the forum and couldnt see a clear answer as to which pipe to pressurise.

Alternatively if you are in the Newcastle area i would be happy to part with a case of beer :)

Thanks,

Dean

Edited by djrobertshaw

Hmmm did this test and think I have found some leaks but the dipstick popped out :(

Is this normal or have I pressurised the wrong but?

Edit: reading a bit about valves :( could be very bad

Edited by djrobertshaw

you had alot of pressure in there for the dipstick to come out, before the dipstick came out did you hear any hissing or any leaking coming from anywhere? put water all on the hoses / clamps and see if you see any bubbles.

I had the regulator on the compressor set to about 7psi (but it never even got there before the noise from the dipstick)

There where some leaks down near the intercooler which I am checking out but just concerned that maybe there is a bigger problem.

I took the hose of the PCM that faces the engine, that is where I pressurised the system.

do gtr's have pcv's? on gtst's the pcv should stop the crankcase getting pressurised by boost when doing this test. Pressurising crankcase will cause dipstick to pop out. First time i was doing this test, was getting leaking from loose/faulty pcv, no further leaking from there after i replaced with new one.

this is with sort that i used

http://www.ebay.com.au/itm/2-UNIVERSAL-TURBO-BOOST-LEAK-TESTER-Tests-any-turbo-with-a-2-comp-inlet-/140922559674?pt=Motors_Automotive_Tools&hash=item20cfa39cba

goes over front of compressor house.

not that expensive, gauge makes it easy to see if leaking from somewhere, just plug in a compressor to the nipple and fire her up.

yeah just a one-way valve going into crankcase somewhere, don't know where it is on gtr's sorry. Should hold boost one way, and not the other. Mine rattled when take off and shaken, and wouldn't seal against pressure properly.

Thanks for your help hardsteppa, I have found some leaks.

Seems to be all around the IC piping so have taken the blinkers off to reach in and tighten things up, trying to avoid taking off the front bar :(

Its booked into a workshop with a dyno to check out the problem in more detail.

For the record pressuring from the pipe as above does seem to work :) but made a second tester with a valve stems and did it the good ol fashion way anyways.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I think my main complaint with your idea is that there is a veneer of idealism spread across it. You want the simple numbers to make it easier, but all they will do is make it easier for someone to come to the wrong conclusion because the fine details will kick them in the nuts. As it is right now, the tiny bit of arithmetic is NOT the obstacle to understanding what will fit and what will not fit. The reality of trying it is what determines whether it will fit. If you had a "standard rule" that R34 GTT guards have that magic 100mm space from the hub face to whichever side you were worried about, and someone said "excellent, this wheel is only 98mm in that direction, I'll just go spend $4k on them and jam them on my sick ride".....they would just as likely find out that the "standard rule" is not true because the rear subframe is offset to one side by a fairly typical (but variable) 8mm on their car and they only have 92mm on one side and 108 on the other.
    • It still combines inches with mm, especially when you have .5 inches involved, and mm and inches that can go in either direction. This would give a clear idea on both sides of the rim, right away, with no arithmetic. Even better if somebody gives you the dimensions of the arch of multiple cars. i.e GTR may be 125mm, a A80 Supra may be 117mm, or something along those lines. Yes, you can 'know' that going from a 10in rim to a 10.5in rim with the same offset moves both sides about 6mm, but you still have to 'know' that and do the math. Often it's combined. People are going from 9.5 +27 to 10.5 +15. You may do the math to know it, but if it was going from (I had to go look it up to be sure) 241mm/2 - 27 - 93.5mm from the center line to (more math) 266/2 - 15 (118mm) from the center line. Versus 93mm vs 118mm. It's right there. If you know you have a GTT with 100mm guards you can see right away that one is close to flush and the other absolutely won't work. And when someone says "Oh the GTR is 120mm" suddenly you see that the 10.5 +15 is about perfect. (or you go and buy rims with approximately 118mm outward guard space) I think it's safe to say that given one of the most common questions in all modified cars is "How do offsets work" and "How do I know if wheels will fit on my car" that this would be much simpler... Of course, nothing will really change and nobody is going to remanufacture wheels and ditch inches and offset based on this conversation :p We'll all go "18x9+30 will line up pretty close to the guards for a R34 GTT (84mm)" but 'pretty close' is still not really defined (it is now!) and if you really care you still have go measure. Yes it depends on camber and height and dynamic movement, but so do all wheels no matter what you measure it for.
    • But offsets are simple numbers. 8" wheel? Call it 200mm, near enough. +35 offset? OK, so that means the hub face is that far out from the wheel centreline. Which is 2s of mental arithmetic to get to 65mm to outer edge and 135mm to inner. It's hardly any more effort for any other wheel width or offset. As I said, I just close my eyes and can see a picture of the wheel when given the width and offset. That wouldn't help me trust that a marginal fitment would actually go in and clear everything, any more than the supposedly simple numbers you're talking about. I dunno. Maybe I just automatically do numbers.
    • Sure! But you at least have simple numbers instead of 8.5 inches +/mm, relative to your current rims you do maths with as well, and/or compare with OEM diameter, which you also need to know/research/confirm..
×
×
  • Create New...