Help! I Keep Warping Exhaust Manifolds And Turbo Housings

[Checkbuzz]

Thanks for all the comments guys

OK the car has been in the shop so here's an update on the problem:

The timing is ok and the engine is not running lean

It appears that the GT-RS turbo is simply too small for an RB25 having it's neck wringed around a track for 10+ minutes at a time - even on a conservative tune.

The turbine wheel/housing is too small and restrictive causing high back pressure, heat and random detonation (plus the physical damage)

I have to say that I'm pretty disappointed with the HKS... but maybe i was expecting too much from it.

Anyway I'm currently leaning towards a GT3071R 56T or GT3076R 52T (0.82a/r internal gate)

Hopefully I'll fix this problem without creating another one!

[scotty nm35]

If you still hang the exhaust off the turbo and don't run a flex join, the 3076 will probably warp just like the HKS did. Don't blame the turbo, plenty of people have hit the track with them.

Doesn't sound like a conservative tune if the fuel was detonating, thought about e85 at all?

[The Dan]

I have to say that I'm pretty disappointed with the HKS... but maybe i was expecting too much from it.

I blame the person who picked the wrong turbo for the application

[The Sherrid]

hey checkbuzz,

i recently thought about keeping the exhaust temps down in the same area on my car.

I'm sure that if you check your EGT's they will be through the roof however obvious that may seem. From experience, this usually indicates that the tune that is not quite right however you seem confident in your tuner.

You could start by checking the amount of air flow in that region, it could be restricted by the type of front bar you have, position of your intercooler or if you have a sheilded air cleaner element (pod filter). i've seen people with large "cold air intakes" that resemble an air dam which can cause hot spots. see attached.

If you can't resolve the generation of heat then you might consider adding some ventilation to that area. On my spec m bar there are 4 inlets at the bottom of the bar. the 2 smaller ones i have already used as brake ducting to keep my brakes cool. bought some flex hose from my local rubber suplier and routed it cost me about $60 per side. the other two larger openings i plan on buying and making something similar for an oil cooler and turbo side.

Another option is getting the new turbine housing hpc coated. I had heard from a reliable source, (Dr Drift) that they make a coating that will reduce the turbine housing so significantly that after a short period you can almost touch it. cost apparently is around $150.

HPC -> http://www.hpcoating...-turbocoat.html

as for a new housing, a company in vic called MTQ, speak to gary, and he will tell you what will fit.

Ultimately, i'd want to know why the temps are so high in the first place.

[GTSBoy]

Um......you can't solve high EGT problems by either cooling the environment around the exhaust or coating the turbine housing. The gas is hot because it's coming out of the engine hot.

[R31Nismoid]

I cannot see how it's the turbos fault at all here if there is too much heat and detonation.

That shit isn't random.

Look @ Richo for instance. He is running a hypergear hi-flow with around the same power as you are making. Does lap after lap without an issue and the turbos would be reasonably close in size.

[wolverine]

For all money sounds like a tuning issue.

[R31Nismoid]

Yep exactly what everyone has been saying.

Tuning for street with the odd track vs a car that is setup for extended circuit laps (5+) are two different ball games far as I'm concerned as the heat factor is massively different. I'd also be surprised if you could maintain 10+ mins of solid trackwork with that brake setup. Surely after 2-3 flying laps the brakes need a cooldown which isn't 10mins?

Could also be as stated above about airflow. If using a stock front bar you might need some more ducting.

Is there a heatshield being used?

Perhaps a better radiator & oil cooler to aid in sufficient cooling during hot laps & cooldowns, even a vented bonnet perhaps (although that shouldn't be needed as i could manage 5mins of flying with my GT-R before a cooldown was needed - but then there was larger cooler/radiator to complement the extra power/heat).

etc etc.

Lots of things to look at but by and large the factor for heat is largely in the tune. Could mean you need to drop 1-2psi and/or drop a few degrees of timing, add a bit more fuel and similar.

[Checkbuzz]

I don't buy into this theory as not many cars I see at the track have flex joints and this problem is not common.

Also the exhaust is not "hanging" from the turbo, it is appropriately mounted to the vehicle.

I'm not blaming the turbo, ATP are based on previous experience with this exact problem and turbo (random detonation and all).

I have also met someone who experienced the same on going problem with a GTRS on an RB25 at the track and they never resolved it using flex joints etc

The detonation is random and only occurs when the engine is hot i.e. at the track.

It is not reproducible on a dyno or normal road run, only under continuous heavy load at the track.

The detontation appears to be closely related to the high EGT's and not the tune itself.

If you still hang the exhaust off the turbo and don't run a flex join, the 3076 will probably warp just like the HKS did. Don't blame the turbo, plenty of people have hit the track with them.

Doesn't sound like a conservative tune if the fuel was detonating, thought about e85 at all?

[R31Nismoid]

I don't buy into this theory as not many cars I see at the track have flex joints and this problem is not common.

Also the exhaust is not "hanging" from the turbo, it is appropriately mounted to the vehicle.

Talking street driven cars that go to track?

Or

Track only cars?

Reason being track only cars will generally have far less movement due to cages, solid mounts and so on.

Street cars going to the track will generally still have movement as there are no cages, solid mountings. It could even be a case of one of your engine mounts perhaps being a little more shagged than it should be + heat + more movement = warping

The detonation is random and only occurs when the engine is hot i.e. at the track.

It is not reproducible on a dyno or normal road run, only under continuous heavy load at the track.

The detontation appears to be closely related to the high EGT's and not the tune itself.

Well it doesn't sound random at all.

It sounds like it's reproduceable under circuit conditions, which if it is detonating, means you need can try some very simple things...

Simple & free

1. Actually go and pull some timing. If 2-3 degrees fixes it then you have your answer

2. Drop the boost 1-2psi

Simply but not free

3. Go out with 10L, mix in 10L of higher grade fuel like Martini/Elf//Sunco

If any of the above sees the detonation appear then I don't think there is anymore proof needed to say the tune needs to be revisited.

[Checkbuzz]

But they are not the same so your argument is null and void.

How can this be the turbo's fault? From what I've been told:

Small turbo = restriction

Restriction = heat build up and heat spots

Heat build up/spots = warped manifolds and flanges

It doesn't seem like a massive stretch to me...

I cannot see how it's the turbos fault at all here if there is too much heat and detonation.

That shit isn't random.

Look @ Richo for instance. He is running a hypergear hi-flow with around the same power as you are making. Does lap after lap without an issue and the turbos would be reasonably close in size.

[R31Nismoid]

But they are not the same so your argument is null and void.

They are both bolt onto OEM. They both have similar response, make similar power and require the similar levels of boost to do it. The turbos will reasonably close as opposed to different ends of the footy fields. There is only so many ways to can skin that cat in a OEM frame.

Small turbo = restriction

Restriction = heat build up and heat spots

Heat build up/spots = warped manifolds and flanges

It doesn't seem like a massive stretch to me...

Did those same people tell you that;

• Heat can be controlled by the tune/boost levels & overall cooling setup of the car.
  
• Housings/wheels are the contributing factors. They are NOT the single point cause.
  

What temps are we talking about here btw when the detonation occurs? I’m assuming you are logging it to safely say it’s not the tune?

End of the day mate you can here asking for help. Several people all saying basically the same thing, which mind you, is coming from the information you are giving us. Seems odd to me that a few different people would all have the same view. If it was not clear cut, then there would be many theories.

It’s a 15 second job to pull 2 degrees of timing with a PFC, and 30 seconds to pull 2psi. If the detonation stops, I’d be surprised if you should also see a drop in temps.

End of the day it you that'll be going and spending $2500-$3000 if you go the option you are looking at, and it sounds like you’ve already made your decision given the fact you don’t want to take anything on board that anyone is saying.

[Checkbuzz]

Hi Daniel are you agreeing that the turbo could be the problem here?

Have you seen or heard of similar cases?

I would really value your opinion here

I picked the turbo based on everybody telling me that "it was the best all-round turbo for the RB25...". "you can't go wrong..." etc

As well as dyno results, peoples experiences and the fact that HKS sell it with a full bolt on kit for an RB25.

I blame the person who picked the wrong turbo for the application

[scotty nm35]

Imagine the rear housing of the turbo at that temperature, the steel becomes pliable, almost like putty. If you don't support the manifold/turbo it will droop, the weight of the exhaust is helping this happen, along with hard cornering causing the weight of the mufflers to deform the housing using the massive leverage involved. Race cars don't have a full exhaust and generally use brackets over the engine to support the turbo in these situations.

It definitely doesn't seem like a massive stretch to me either...

[zebra]

Pulling timing may also raise EGT's , imo the RS is just too small for a 2.5 that spends lots of time at WOT

but, plenty of people use them (and similar) with no probs, I ran 20psi with a little high flow with no dramas even after a 40 min sesh at wakie

if its detonating than the tune is to blame, I would add more fuel before pulling timing (due to above) who cares if you lose 5-10 killerwasps

[gotRICE?]

Im with Nismoid. Pull the timing, maybe add a little fuel and try again.

Having the timing a couple of degrees in the wrong direction had my stock manifold flange glowing after a 15m cruise down the motorway. ( a little too much Rum the previous night then early morning tuning overlook ).

The only reason i noticed it was i was checking for coolant leaks after a radiator swap, and could see the orange glow in the dark. 1st thing i did was post up my timing map and i got an answer within a few mins that my timing was out. Easy fix.

So with the extended WOT of the track, and lots of boost, it doesnt surprise me its getting that hot.

And as Zebra said, 10-15kw on the track wont be overly noticeable, especially when your causing this much damage to your bolt ons. I Personally have a Track Tune with a couple % extra fuel, and 1.5 degrees timing taken out from 3000rpm and above. I also tend to run wategate boost when im feeling nice as i dont feel like replacing the engine.

[Checkbuzz]

Whatever dude...

My last post was an update not a cry for help, although I do value most opinions and feedback.

What am I supposed to do listen to a bunch of keyboard mechanics (and critics) over my experienced tuner and ATP?

Do you really think you know more about it than these guys?

The only person who is qualified to comment here appears to back the "wrong turbo for the job" theory and I would like to hear more from Daniel on the matter if he would kindly oblige.

They are both bolt onto OEM. They both have similar response, make similar power and require the similar levels of boost to do it. The turbos will reasonably close as opposed to different ends of the footy fields. There is only so many ways to can skin that cat in a OEM frame.

Did those same people tell you that;

• Heat can be controlled by the tune/boost levels & overall cooling setup of the car.
  
• Housings/wheels are the contributing factors. They are NOT the single point cause.
  

What temps are we talking about here btw when the detonation occurs? I’m assuming you are logging it to safely say it’s not the tune?

End of the day mate you can here asking for help. Several people all saying basically the same thing, which mind you, is coming from the information you are giving us. Seems odd to me that a few different people would all have the same view. If it was not clear cut, then there would be many theories.

It’s a 15 second job to pull 2 degrees of timing with a PFC, and 30 seconds to pull 2psi. If the detonation stops, I’d be surprised if you should also see a drop in temps.

End of the day it you that'll be going and spending $2500-$3000 if you go the option you are looking at, and it sounds like you’ve already made your decision given the fact you don’t want to take anything on board that anyone is saying.

[Rolls]

Just add fuel, can you get an afr graph at full load?

[Lithium]

What boost are you running through it? I'm a little surprised at the folks who are saying "Too high EGT = tune" without checking exactly how hard you are pushing it.

I have long said I don't like the idea of the GT-RS/GT2871R for an RB25 - I think their hot side is too small for it, and have for some time now tried talking people out of them when they have considered them for that application. I'm sure up to 1bar of boost they'd be OK, but for track use and anything over that there is no way I'd be keen.

The thing about increasing exhaust manifold pressure is you get more and more backflow into the engine and combustion temps will go up, EGTs will go up, everything will get hot and unstable. You can add more fuel to try and calm things down - that will only go so far. You can retard the timing to try and avoid knock, that will just raise EGTs and some of the knock may well be pre-ignition, has nothing to do with your actual timing curve and anything you do which will increase EGT CAN help encourage hotspots which will just make pre-ignition more likely. This stuff won't necessarily show up on dynos, the tune can appear at face value to be mint and safe (ie, never getting det etc) but the concern I've had with GT28-based turbos that flow like this on RB25s is after sustained thrashing.

There can be a point where you are just pushing a turbo or a setup too hard and really you need to either drop the boost and accept it is undersized for what you are wanting to get from it... or upgrade the turbo.

I'm not saying that this IS the case, but it'd be silly to not seriously consider it. Try dropping the boost as much as you can and take it for a thrash, perhaps.

If the tune is that bad that its doing this damage then it is still likely to be a problem on lower boost. If it still does it when running a boost level the GT-RS should shit out its not your turbo and there is further investigation to be done. If it doesn't, it doesn't necessarily guarantee the turbo but it certainly increases the likelihood that it could be that.

[mutex]

I had a hks gtrs on my r34 gtt for a year, I do a track day per month, it was warped as shown on your pics.

The car was tuned by a reputable gtr workshop in melbourne who deals with track gtrs and the like, he knew his stuff - so it wasn't the tune. Workshop said it was the size of the turbo and heat generated by long periods of boost and recommended a larger gt30x size turbo.

I sold the turbo and went to an iw gt3076. The warping is pretty much gone, just cracks in the oem exhaust manifold divider (middle of t3 flange) where two halves of manifold meet.

Sounds like it's time to move to something else if doing track work.