Help! I Keep Warping Exhaust Manifolds And Turbo Housings

[Checkbuzz]

Hi Guys

I have a serious on going problem that is costing me $$$ and doing my friggin head in!

9 months fitted a brand new HKS GT-RS to my RB25DET with all the supporting mods. It was a direct replacement utilising the existing exhaust and manifold so no other physical changes in this area. New lock nuts, plates and gaskets were used through out.

After a few track days the car seemed to be down on power and response I took it to the mechanic and there was a blown gasket between exhaust manifold and turbo. I replaced the gasket myself not realising that the turbo flange was slightly warped at the time.

A couple of track days later and the gasket is again leaking like a sieve, the distortion of the turbo flange can be clearly seen.

Back to the mechanic who removes the manifold and turbo housing and has both machined to suit as both items were badly warped.

One track day later and there is a leak around the gasket again and I can see the distortion where the 2 surfaces meet

I am really pissed off because I spent big $$$ on the GT-RS and all I've had is grief so far and i wish I'd just gone the high flow route now. The main reason being that HKS do not have spare housings for this turbo (thanks HKS!) and the housing has to be replaced now with a modified Garret item (more money). The exhaust manifold also has to be replaced now but I do not want to do it until I know what the problem is and how to stop it reoccurring

The exhaust and engine mounts and movement is all ok so it doesn't appear to be a physical cause unless the HKS housing was made of tin cans. The car is not running lean but I am starting to suspect high EGT's being the culprit.

Has anyone seen this type of issue before?

Any idea what could be causing this and how to test it and resolve the problem?

Anyone selling a rear housing for a HKS GT-RS?

Any help would be much appreciated

[Mitcho_7]

Have you had it on the dyno recently to check everything out?

[bradsm87]

Sounds like it's getting too hot. I'd richen the mixtures which will also allow you to advance the timing a bit which will further lower your EGT. Also make sure you have inconel studs on the exhaust manifold to turbo flange.

[RRob]

Retarded ignition timing will create high EGT's.

[tricstar]

is the manifold stainless and is the turbo and dump supported ( braced back to the motor )

and yeah fit inconel studs if not already, also instead of the thin tin gasket try an asbestos ( exhaust style ) one,

[Dose Pipe Sutututu]

Get an EGT gauge, I wouldn't be surprised if your tune is bad and the EGTs are way too high.

[GTScotT]

I think it is more likely to be a warp in the manifold as that is a lower grade of metal, which would have burs in it like wood. The epic heat is forcing the turbo to warp with the housing.

IMHO i think a new manifold and a remachine of the turbine housing will do the trick. Use good studs like mentioned above.

[Moodles2]

Only GTR front pipes really have flex pipes, maybe putting a piece of flex pipe on the frontpipe might help prevent this in the future.

[R31Nismoid]

is the manifold stainless and is the turbo and dump supported ( braced back to the motor )

and yeah fit inconel studs if not already, also instead of the thin tin gasket try an asbestos ( exhaust style ) one,

+1 to this & also fitting of a flex pipe.

Could also be as others have said, issues with the tune simply being a bit off and too much heat getting into everything.

And if the OP comes back and says it's a china/ebay manifold, well that's probably another issue as well.

[Hanaldo]

He did say it was the stock manifold.

*EDIT* Actually after reading it again, I guess he didn't really. He said it "utilized the existing manifold" which I interpreted to be the stock manifold.

Edited July 26, 2012 by Hanaldo

[Rolls]

Is it making the expected power? could be something like the exhaust choking it up causing excessive temperatures, too lean tune, heavily advanced timing could also be an issue.

I don't know enough about the metals to comment on that side of things.

[The Dan]

I would be EXTREMELY surprised if your turbo 4 bolt flange was warped.

I would be even more surprised if the gasket leak wasn't caused by the improper installation using no conelock nuts etc.

I've never seen a turbine housing warp and we've had them so hot we lost a turbine wheel on a 3582R - it was still flat.

Just one more thing - don't EVER use one of the perforated shiny gaskets on your manifold or turbo. Even turbo to dump pipe is a no-no. They are rubbish gaskets and cannot withstand the heat and pressure of a turbocharged engine.

Genuine only

[R31Nismoid]

I've never seen a turbine housing warp and we've had them so hot we lost a turbine wheel on a 3582R - it was still flat.

Kinda off topic, have seen that occur once on a 500-550rwkw circuit car setup.

Was over a 18 month period of use and had a twist like the lid of a jar that you can tighten just that little bit more (no not talking big amounts). Should've gotten a pic of it, was a very long time ago (going 7 years now). Was a big frame GT40 IIRC

[Checkbuzz]

Thanks for all the feed back.

The manifold is stock

The studs could be made from "unobtainium" and they aren't going to stop the manifold and turbo warping like this;

The studs have actually been pulled closer together on the manifold and turbo by the warping so much so that even after machining the bolt holes in the gasket had to be enlarged and even though the machined surfaces are matched the studs have moved so much that both items now have to be replaced together i.e. a new turbo housing wouldn't fit the manifold any longer or visa versa!

Both manifold and turbo have been off the vehicle, machined and replaced with new gaskets and lock nuts etc - they warped again within one track day.

The 4 bolt flange on the turbo was warped about 5mm across the face!!!

Believe me I am not making this up and I have a very experienced machanic/tuner doing all of this work.

I am running a conservative tune for the track and the car does not run lean - I have a wide-band fitted just to make sure.

The vehicle was on the dyno for a check the day the machined turbo and manifold were reinstalled however I'm not sure if EGT's have been checked

The timing is not that retarded maybe 17 degrees at the lowest point

The car is making around 250rwkw which is about right for a GT-RS and not so long ago was dyno'ed with the exhust off to check for restrictions and it made little difference

The flex pipe is an idea but i really can't imagine how the manifold and turbo would warp before the mild steel exhaust pipe under load further to this the stock turbo was fine and had done plenty of track days with the same exhaust system etc nothing else was changed in this area.

So you can see my frustration guys I've spent good $$$ on an HKS turbo, had the work done by a good and respected tuner and mechanic, had everything checked on the dyno every step of the way, spent the $$$, done it all properly and yet here I am...

That's modding and racing cars for you I guess!

It's going back in the shop for analysis soom with EGT's at the top of the list but if the EGT's were that high (we are talking sustained 1000c+ EGT's) as my tuner said I wouldn't have a turbo left i.e. the blades would have melted on the turbine

AAAAARRRRRGGGGGHHHHH!!!!!

[GTSBoy]

If your EGTs had been checked, you would know, because at the very least you'd have a fitting in the manifofold to take a thermocouple, and possibly you'd actually have a thermocouple.

The hottest part of the exhaust manifold/turbo assembly when under load is usually the collector area. On a factory manifold this is essentially the turbo flange. If your exhaust temps are cooking, then expect the flange area to get really hot.

You need to drill the turbine housing just after the flange and install a thermocouple. You really do not want to be seeing 900°C there, and if you are, you need to look to your tuning, as suggested above, or quite possibly consider that there may be something else wrong (like too much back pressure - which youcan also check through the same hole).

[Checkbuzz]

Hi Daniel

Prepare to be extremely surprised then, because that is exactly what has happened... twice now!

You can see it quite clearly in this photo: http://i1260.photobu...arpedFlange.jpg

The warping on the 4 bolt flange is severe; it was bowed out nearly 5mm in the middle!!!

My mechanic used the same gaskets he uses on far more serious machines than mine without issue ditto for the lock nuts.

I find it difficult to believe that this severe problem could be caused by gaskets, studs or nuts.

Assuming we get to the bottom of what is causing this problem my next biggy is what to do for a replacement housing?

Do you know if a modified Garret housing will do the job and what the likely costs of purchasing the housing and getting it machined would be?

From your signature you appear to be someone who knows far more about this stuff than i do...

Any assistance would be much appreciated

I would be EXTREMELY surprised if your turbo 4 bolt flange was warped.

I would be even more surprised if the gasket leak wasn't caused by the improper installation using no conelock nuts etc.

I've never seen a turbine housing warp and we've had them so hot we lost a turbine wheel on a 3582R - it was still flat.

Just one more thing - don't EVER use one of the perforated shiny gaskets on your manifold or turbo. Even turbo to dump pipe is a no-no. They are rubbish gaskets and cannot withstand the heat and pressure of a turbocharged engine.

Genuine only

Edited July 27, 2012 by Checkbuzz

[Adriano]

How are you determining that you are running 17deg at full load, are you sure the base timing is correct?

[boxheadmr]

i have seen a std r33 warp the std manifold and also the exhaust housing on the turbo (twice for the manifold) on a street car, check your tune's exhaust temps.

[The Dan]

wow, that definitely looks bent alright.

The turbine housing is an easy one. I've probably even got a stock manifold you can have but there is something wrong and you need to work out what before you continue,

In that picture the bolts holding the turbo on look half melted. Am I seeing that correctly?

[r33_racer]

That is crazy hot. Looks like someone took to it with the oxy! I wouldn't be surprised if its something silly like a tooth out on timing belt. Its either super lean or highly retarded.