aja

Hi, I have been having this problem with my boost for the pass few weeks, it was originally set up at 1bar and over the pass few weeks it has gone down to 0.7bar. Tried looking for leaks in the piping,IC etc but could not find any, Even turning the boost controller all the way up doesn't make much difference. The wastegate doent even open as I got a 1bar spring in it and I dont hear anything. Tried searching and I found in 1 of the thread that rice racing mention that the boost could be leaking from the side seals. As I did see some black oil leaking on the ground but havent found the source of the leak.

Is there a way to confirm that it is in fact the side seals that is giving the problem (compression test...etc) or the engine need to be open up? I just had the rebuild done less than 6000km ago and hope I dont have to open the engine up again

alberto_mg

are you running a cat? could be clogged? what are your mods?

dgeesaman

iTrader: (7)

First off, boost doesn't really leak through a bad side engine seal. Yes, a bad side seal will allow engine combustion gasses into the coolant (or oil, depending which side seal) but it won't be of enough volume to affect your boost pattern.

Compression tests are mostly effective for finding larger leaks like broken apex seals or a big coolant seal break. It's a good test to do just to be sure, and now that it's broken in, it will show how well your reman was built.

What is your boost pattern? Are you runnign the stock sequential setup?

The problem must lie in your turbo control system, just a standard boost problem. Find out if the wastegate actuator is being supplied the proper pressure at the right times. If that works, find out if it opens at the proper pressure and that the E-clip is still holding the rod in place. Check that the wastegate solenoid is working properly and not stuck open.

If all that's ok, feel free to come back here or do the more in-depth troubleshooting processes on www.scuderiaciriani.com. Wael El-dasher and Steve Wynveen outline some good procedures for troubleshooting secondary problems.

Dave

aja

Some of the related mods...Microtech LTX-12 ecu, Garret T51, RE Amemiya exhaust with 4' mid-back piping, 3 1/2' front with mid pipe (no cat), Greedy 3 row hybrid intercooler, SARD racing BOV, Tial 46mm with 1 bar spring etc...

dgeesaman

iTrader: (7)

Oh, you're single turbo.

That's VERY important information - so you can disregard what I said about troubleshooting the turbo controls. However, if your only symptom is boost change, the problem very unlikely to be your engine seals.

Dave

GoodfellaFD3S

iTrader: (213)

I *highly* recommend that you not do this again. It is possible that you have a leak in your intercooler piping. In which case, cranking the boost controller to the max will overwork your turbos, even thought your motor isnt seeing the boost. This is a great way to destroy your turbo.

In addition to checking the ic piping again, check your BOV and also the vacuum line for your wastegate.

mad_7tist

a 1 bar spring is a bad idea. i am with goodfella check those items again. you dont hear any squeeling noise of a boost leak?

aja

Don't hear any hissing sound while boosting....but than again the exhaust sound is pretty loud

poss

iTrader: (5)

OK i'm being nit-picky, but it doesn't really matter what his boost controller is set at since it's not even building enough pressure to open the WG spring. (yeah you might crack it open if you get close to 1 bar, but that's kinda irrelevant in this case)

Since you are single, there's not much reason that you shouldn't be seeing boost.
It's either a leak somewhere (IC/Piping, bov, loose manifolds, etc.) or your turbo isn't flowing enough to begin with.

Did it gradually decline or was it rather sudden?


I just thought of something. Maybe your wastegate is sticking slightly open??

aja

The thread that is getting me worried that it might me my side seals .... going to open up the manifold and check there is a leak or any one of the gaskets

https://www.rx7club.com/showthread.p...=boost+problem

GoodfellaFD3S

iTrader: (213)

He is reading boost from his boost gauge, which I assume is sourced from the UIM. If he has a leak between the compressor and the tb, then his turbos are making way more than 0.7 bar.....that is just what the motor (and the gauge) are seeing.

Also, did you get the PM I sent ya the other day? Unless my memory is shot, I don't think I got a reply back .

poss

iTrader: (5)

I don' t disagree that they are getting overworked, but the boost controller will have a negliable impact. They are still only producing ~.7 bar (maybe a little bit more due to IC restriction, etc)
With a boost leak pressure will stay more or less the same through out the system, you are blowing out tons of volume. Does that make sense? Oh, well, it's neither here nor there.

1 pm coming right up!

Sorry for the thread hijack.

Mr rx-7 tt

iTrader: (5)

Also IF the problem is intermittent and he has the boost jacked to hi hell guess what is going to happen? Kaboom. I have seen many cars fix themselves temporarily while trouble shooting. Turning up the boost is a BAD idea anyway you look at it.

Aja,
Your problem isn't a side seal, it sounds like a boost issue. If you so desire get a compression test.

dgeesaman

iTrader: (7)

So are you getting excessive pressure in your oil sump? That's kind of important. It seems like the main symptom in their case was noticeable pressure in the oil sump (dipstick popping out), not change in boost pattern. I don't think an engine would even start if it the kind of side seal leak that could vent boost to the point of affecting boost levels.

But again, if you suspect a leak this major, start with a compression test.

Dave

aja

The boost drop was kind of gradual.... it started a while back while I was still on my old kit (turbo, manifold and wastegate) it was set at 1 bar.... boost was good until one day I went WOT and it peak at 0.8bar... than about a week after that once again I went wot and saw that the boost peak at 0.6 bar(in all instances the wastegate open). so I thought there was some problem with the boost controller, had it adjusted fully and it peak about 0.7bar (if I would by pass the boost controller and hook it up direct the wastegate would open at 0.5bar). So I thought that it might have been the wastegate problem.

So happen my friend was selling his T51, so I got it along with a manifold and a new wastegate. Hoping that the problem would go away. Guess it didn't. Anyway some update... there was some leak in the manifold gasket...got that fixed...now the wastegate opens up but at 0.7bar when its connected directly and peak at 0.9bar when connected to the boost controller (with settings at maximum). All the hoses, coupling, ic has been check and there was no leaks. So even the mechanic is stump now... and that is why I am here trying to get some ideas of what else could be wrong

Currently the I don't see any noticeable pressure in the oil sump (dipstick popping out), etc, just that the bottom of the engine bay looks wet from the oil. Also wouldn't it smoke like hell if the side seals are gone?

aja

Isn't the pressure suppose to be the same at point A and point B even if there is a leak between them since its a close system? Anyway on the possibility of the system I got the microtech set to cutoff at 16psi to safeguard from any possible over boosting. On that note I would also like to mention that I even when as far as pulling off the vacum from the wastegate on my old set up to see if its possible to bring the boost up but the wastegate still open up at about 0.6bar

dgeesaman

iTrader: (7)

I think so, but don't have experience with it. So the rest of this is just me thinking openly.

The oil spray is still consistent with a boost leak. Oil is still commonly blown by the shaft in the turbo bearing, and only a small amount will spray a long way. Where exactly is this oil spray developing in the bay? Wipe it all clean, warm up the car, and take it for a short run, then look again. With less oil mess, it may show you the source.

Since the oil is leaking on the engine bay, it's unlikely to be an engine problem. Engine oil seals are internal, and the oil leakage is into the combustion chamber and causes lots of smoke, particularly when oil pressure is high.

Maybe a broken OMP line can cause this, maybe another part of the pressurized section of the oil system - oil cooler line perhaps?

Dave