[Mk2] [Turbo] Gasket/ flange issues

[GTMatt]

Hi,
Hoping the wealth of knowledge on here can help me best formulate a plan going forward.

Car is 400hp, forged engine, gt3076r running 1.7 bar as a bit of background.

The following issue didn't occur for the first year to 18 months after finishing this stage of my build, but now has become a reoccurring nightmare.

Problem is that currently on a regular basis after any hard driving (most recently a short 20 mins on track at trax this weekend) one of either the manifold to turbo join, manifold collector to tee off for wastegate joint or tee off to wastegate joint is blowing, either as a result of warpage or the gasket getting damaged. I have replaced all gaskets at least once. Some twice now, so there is clearly an underlying issue with regard to heat that needs sorting.
What's people's opinions on best approach?
It's also worth mentioning that the porting and flow on the manifold (custom made) looks very poor which I'm unhappy with, also the map seems extremely rich.
My thoughts are get the car running and take to a exhaust fabricator, get a new manifold made, then hit the dyno for a remap.
Ideally individually egt sensors would be sensible but I just don't have the budget anymore since buying a house.

Input and thoughts please

[simpson_eh]

same problem with mine, the adapter to turbo blowing as well, ive gone for an oem gasket for the skyline thicker so shouldnt blow so easy just not fitted yet

http://www.ebay.co.uk/itm/Siruda-Turbo- ... SwYSlXh72X

im hoping this will be better

also had an issue with the turbo resting on the clutch slave cycling pipes and bent them no clutch

[GTMatt]

I've gone for a thicker copper gasket on the turbo to manifold joint, so far that's held out, so I've ordered up a sheet of 1.5mm copper to make up some gaskets for all the joints to see if it helps. Even if it works a bit of me feels its just symptom solving not solving the underlying problem though?

[Odin_S]

This is so weird, same spec. My downpipe to exhaust was blowing, we took off the manifold and found it was cracked too although not blowing.

Just replace both mine this week at Drift-limits, OEM on the manifold and i much stronger T3 gasket on the downpipe. I'll see if i can get the name of the company. Think its cosmet or something

[C35Rob]

you 100% shouldn't need a copper gasket, however if you do use them they do need to be annealed before installation to make them work, and they should only ever be installed on a freshly ground surface..

assuming your manifold and turbo exhaust housing aren't warped (it may be prudent to have them all surface ground to eliminate this) then all you should need is OEM gaskets and locknuts.

I can also vouch for the skyline OEM T3 gasket, much nicer than the single layer stamped stainless gaskets available (although I use a genuine nissan one, not the pattern one in that link)

I use Nord-Lock washers on all of my turbo-adapter block-manifold studs and have no leaks at all, I also have two flexi's - one in the downpipe and one in the B pipe, which will help eliminate any addiditonal stress on the setup

[ashley]

Hi,
Car is 400hp, forged engine, gt3076r running 1.7 bar as a bit of background.

What size turbine housing?
Any idea what kind of ignition timing your map has in it?

TBH once the flanges have warped, even if you have them surface ground- tis only a matter of time until they go again...the grinding leaves the surface flat, but the flange is now thinner in places where the material as removed, and so is more prone to distortion under extreme heat.

What diameter exhaust do you have?

[GTMatt]

The turbo flange wasn't warped but the manifold collector flange was slightly out, but it was very marginal, I'd be more inclined to say it was the gasket that failed. The turbo to manifold joint that I replaced with a copper gasket has been the only joint not to blow twice (probably cursed it now lol)

Turbine housing is .63 small I know but I assumed would be adequate for my power goals. No idea about ignition timing. Pretty sure it's a 3" exhaust. I purchased and spec'd all this so long ago I'm 90% sure of these figures.

Would it be prudent to get it to a mapper to be remapped? Any recommendations on the south coast for someone familiar/ happy to make link g4's?

[C35Rob]

did you replace your fasteners when you changed the gasket?

in my experience, the majority of times that this sort of thing happens its the fasteners losing their clamping force through heat cycling and vibration that causes this (i.e slackening off and allowing the gasket to blow) the gasket blowing is the symptom, not the cause.

aftermarket turbo set ups are a perfect storm for this kind of thing - old used fasteners, tubular manifolds or adapter plates, removal of OEM turbo hangers/braces and inadequately flexi'd downpipes etc.

it's a huge problem on RWD nissans, people even end up tacking the nuts to the studs to solve it. the right way to do it is to replace the fasteners, use nord-locks and make sure there's enough flexibility in the downpipe and even use a turbo brace/hanger if you can.

as Ashley has alluded to, having a small hot side or excessively retarded Ign timing will cause higher temps in the manifold but there's no way you'll map out a mechanical issue.

[ashley]

Yeah- as Rob says- you can't map round the kit you've got...but 1.7bar is a lot of boost on a relatively small turbine housing, I'm betting you're timing is pretty retarded and hence your exhaust is getting hot...which is fine for a while, but will significantly add wear and tear to your setup. I think the suggestion of renewing your fasteners and gaskets at the same time is a good one...and be prepared to do it again in the future.

What ECU are you on? If you send me your map I'll have a look for you...

EDIT: G4...if you pm me, I'd be happy to take a look at your ignition table

[Odin_S]

If you have a Link G4 like me, i'd recommend Fensport, they have a new guy who deals with Link.

As far as the turbo gasket goes, I'm still running OEM manifold with an adapter primarily because i didnt want to deal with cracking issues

[GTMatt]

As you have suggested, whenever I've changed the gaskets I replace the studs and nuts. Genuine Toyota studs and stiffnuts.
One thing the mapper did say was the difference in power at 1.5 bar to 1.7 bar was pretty small. So I'm assuming it's just blowing hot air basically, hence my thinking a remap could reduce egt's. He also mentioned the cam timing being the problem, but I was reluctant to plough more money into the car at that time as it was getting stupid really. In hindsight this extra time could have resulted in a better more refined end product but I really was at my witts end.
I have heard good things about fensport, but I live on the Isle of Wight so is a 9-10hr round trip and lots of money, so anywhere closer is better really.

I'll take you up on that ashley if you can talk me through it. Cheers

[ashley]

Happy to try and help, but sounds like your plan should be:

1. Turn the boost down to 1.5bar immediately
2. Get your map checked to see just how much advance you aren't running
3. Get on a dyno and find the point at which the turbo is no longer making gains with boost increases, map it there with as much advance as it will safely take
4. Swing the cams on the dyno and see if there is anymore to come.

After that if it's not pulling hard enough for you, consider the 0.82AR turbine housing...

[GTMatt]

sounds sensible suggestions.
I'm working on borrowing a laptop to get the map files to send to you for a check. Question regarding your build, your lower power/ smaller turbo setup was that a gtx3071? I can't remember. What rpm was that full spool at? My 3076r is between 4-4500rpm. Question is would a gtx3071 offer the same power now but a noticeable increase in spool? due to smaller turbo and increased/ more modern design so efficiency?

[ashley]

GT2868HTA




An HTA 3071 should make nigh on 500hp (flywheel) on the 0.82 turbine housing I would have thought, and should certainly spool earlier than a GT3076....but I don't know this as fact

[GTMatt]

Peak torque in yours being around 4200 and mine being around 5000. Definitely earlier power/ torque, and my torque peaks quite low imo for setup and power but holds all the way. Would that be attributed to cam timing? It's definitely a unique torque curve, never seen a 3sgte like it.

[GTMatt]

Also Ashley what swayed you to go hta over the gtx series? Or was the gtx never in contention in your plans?

[ashley]

I spoke to Garrett, Forced Performance, Borg Warner, Precision, Owen Developments, Dave Rowe, and a bunch of other folk I know in the motorsport industry with relatively impartial points of view.

The general consensus was that the GTX range just weren't doing the business promised on the box- later spool, and lower peak flow, in comparison to the HTA compressor wheels. Maybe something to do with the extra blades on the wheel strangling flow at higher revolution speeds?

So I went with HTA...Forced Performance were really good to talk to as well (which helped sell them to me), I spent a lot of time chatting with them and they were really helpful in helping me form a realistic view as to what I needed to give the levels of performance I was after.

[ashley]

Peak torque in yours being around 4200 and mine being around 5000. Definitely earlier power/ torque, and my torque peaks quite low imo for setup and power but holds all the way. Would that be attributed to cam timing? It's definitely a unique torque curve, never seen a 3sgte like it.


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Yeah- that does look odd- it holds torque for ages into the rev range instead a tailing off, but then peak torque is too low...I think you are missing a big chunk of peak torque- almost like you have the top of the curve cut off.

You're making a nice top power figure, but that is partly as you are reving the engine to get it.

Timing and Fueling are probably the culprits, but depends on a number of things (like intercooling, engine compression and health, etc etc). Might be cams...what are they? Generally swinging them will just move the peak torque to the left or right a bit, but you might have something else going on there.

Really hard to tell without having it on a dyno and playing with it- I suspect you've got more to come if you wanted it...are you 100% sure that is the 0.63 turbine housing??

[GTMatt]

Might be worth looking into a hta unit one day then by the sounds of it. I like the idea of earlier spool for same power, what's not to like hah

I would agree the torque curve looks chopped, quite by accident it makes it really nice on track though, nice progressive power and not a huge spike of torque, very tame on exit.
Cams are hks 264's exhaust and inlet.
That dyno plot isn't the whole story though, it definitely isn't making that power, after dyno mapping I drove it with the mapper on the road and had to loose some ignition advance as in the real world it started knocking between heavy/ agressive gear changes. Whether that's right/ wrong or normal I'm not very clued up on mapping, something I'd love to gain some experience in though.
To all my knowledge it's a 0.63 turbine housing, I'll check later on though for some part marking of some kind. I purchased a turbo second hand off here, which later turned out to be goosed, and my current turbo is (was) a brand new chra with the second hand exhaust housing.

[jimGTS]

I use Nord-Lock washers

+1 this

i use these on my mani to turbo flange, as my nuts kept on coming loose.

loose nuts can blow gaskets afaik.