leaking turbo gasket

[Lucas van Altena]

I know in our gt40's you will find no turbo's, but my other car is an xtr4 with an audi 1,8 rs engine with a garrett 4 turbo watercooled with 250/350 hp.
I have toubble with the original audi gasket and a selfmade redcopper gasket, they will blow away after 100 km and revving the engine to plus 7000 rpm.
I made extra cooling the headers by a nacaduct.
Taped the exhaust, don't use a db-killer but 90 degrease bended pipe.

What i want to do is milling a hole in turbo and the adjestdment piece of the header and put there in a pipe of 10 to 20 mm lenght.(sorry for bad english)

What is wise?

Regards,

Lucas

[JohnC]

Assuming you're referring to the gasket between the turbo and the exhaust manifold, you must have some very high backpressure in your manifold if you're blowing that gasket!

Perhaps O-Ringing the flange & turbo would be a solution, or consider going to a larger A/R turbine housing?

[Julian]

Don't be so sure about no GT40's with turbos. There's one (a GTD40 also) in my city with twin turbos... I'm not that brave (silly) and have gone 8 stack injection for mine, but I sure miss turbo boost kick of my old car, sigh.

Anyways, back to your problem - have you checked both the exh manifold and tubine housing inlet flange for flatness? May be warped, which gives gasket a chance to blow out.

[Lucas van Altena]

John,
The copper gasket was melted, so an o-ring wil not hold that temperatur.
Mine manifold get red hot.
John what do you mean whit A/R turbo house.
I have got the biggest turbo that will fit the Audi .

Julian,
I did read on this forum of a twinturbo, so as i understand it is yours.
I know the 8 throttlebodys looks great, but is that the only reason why you chanche that or problems with the turbo's or the durability of the engine.
Yes every time i put on a new gasket, i check the flatness and i have a few times machined it.

I heard that a Cosworth turbo flat flanges?

[Lucas van Altena]

Just spoke a friend of me, he put the problem to an engeneer of Musubishi.
They think, its the lambaprobe, the engine is running lean.

I had in the past cooling and turboproblems, mayby that's the answer.
I will messeur the exhaust temp.

[JohnC]

Hello Lucas, sorry I wasn't referring to a conventional o-ring, but something metallic like you would use to o-ring a head to a block.

Here's some new technology that I understand works very well for a drag race team who are running over 45psi boost on a Japanese motor: Helicoflex. They have o-ringed their head to the block with this gas filled SS o-ring and it works well, and is also reusable because it does not deform permanently after installation, but will retain its original shape.

The A/R ratio I was referring to is illustrated in the photo below. Turbos with a small A/R ratio spool up very quickly, but are also more restrictive to the exhaust system.

[Lucas van Altena]

John,
I cannot find A/R ratio now, because its not here right now.
Most dragsters use methanol as fuel, methanol burns less hot as gasolline, but as i saw on their website they made thoose seals of stainless steel, that will be an option.

The turbo and manifold went to the enginebuilder.
I called them this morning, the connectionplate of the manifold is not flat.
They will machine all parts and use bolds locked with wires.
Make what we called "a mom / dad connection"".

Regards,

Lucas