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The mkiv Supra Owners Club

Marham Killed my Manifold too.....


Mike B

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I have managed to weld an old manifold on my S14, and it didn't crack again, i am now a firm believer in not wrapping the manifold as it can change the metal structure and make it weak/brittle, down pipes seem to be OK don't think they get quite hot enough, but after hearing about the possibility of the GT4088 exhaust housing possibly distorting due to heat, is one of the reasons i have not fitted a turbo blanket.

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I have managed to weld an old manifold on my S14, and it didn't crack again, i am now a firm believer in not wrapping the manifold as it can change the metal structure and make it weak/brittle, down pipes seem to be OK don't think they get quite hot enough, but after hearing about the possibility of the GT4088 exhaust housing possibly distorting due to heat, is one of the reasons i have not fitted a turbo blanket.

I removed my turbo blanket after my GT4088R failure too

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More bad luck mike:(, to get to the lower nuts under the mani you may need to grind a 14mm ring spanner down, you know the ring bit then grind the open end off so you can fit a socket and small extension bar on the end, thats how i did mine, also have you got any support on the downpipe, i made a bracket bolted to the bottom of the gearbox then clamped to my downpipe to take the weight of the exhaust and make the exhaust move with the engine.

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to get to the lower nuts under the mani you may need to grind a 14mm ring spanner down, you know the ring bit then grind the open end off so you can fit a socket and small extension bar on the end, thats how i did mine,

 

I have a set of extended ring spanners I got from my mates tool van, they are invaluable most of the bottom bolts can be had from the front of the engine bay with these, the last two nearest the bulk head can be had from the DP area

 

 

Thats another advantage of Arnouts mani, easier maintenance!

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also have you got any support on the downpipe, i made a bracket bolted to the bottom of the gearbox then clamped to my downpipe to take the weight of the exhaust and make the exhaust move with the engine.

 

Ahhh.. now that is a good idea... if the flex of the system is adding stress to the manifold this wuould cure it.

 

More bad luck mike:(, to get to the lower nuts under the mani you may need to grind a 14mm ring spanner down, you know the ring bit then grind the open end off so you can fit a socket and small extension bar on the end, thats how i did mine,

 

Cool... thanks; good idea. I'll need some scrificial ringspanners.

 

here are some photo's from the manifold

manifold.jpg

manifold2.jpg

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It's boost logic.... I will not heatwrap the next one and I think I may leave the turbo blanket off as well. Will look for that bracket guys.

 

gloves off tonight... the operation begins.

 

Thats the 1st bL ive heard of cracking, the stock bracket probably won`t fit unless you could make some sort of clamp or adapter to mount onto the downpipe, i just knocked 1 up from angle iron and bolted it to the stock bracket, i posted a picture up not so long ago in tricky`s thread, i`ll see if i can find it.

103_0373.jpg

103_0374.jpg

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Ahh.. you are putting a mount on the DP.. I see.. :)

 

Wrap is coming off and staying off.

 

Gloves it is though, that fibreglass stuff is nasty.

 

You are right, I have never heard of a BL failing either. I shoot them a mail once I have it off.

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Yes Mike,

found this out the hard way with the old cast manifold., which cracked the downpipe at the v-band flange to the turbo.

without the bracket, when the engine moves the exhaust was flexing at the downpipe.

Without the bracket on our system, I would imagine that you are getting some flex at the manifold.( not as rigid as the cast manifold)

with the bracket, the whole downpipe & manifold is now rigid, any flex is taken up by the mounting rubbers of the exhaust system ( from the downpipe back)

hope that makes sense.

john

Edited by foodfreak (see edit history)
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Thanks guys,

 

This is really good info.

 

I fully see how the engine twists and having a solid connection to the ex can't be good. Don't normal cars have a flexible section at the base of the DP?

 

I remember John's car at marham this year - he sheared the V band off his DP.. I remember wondering how the hell he did that...

 

I bent a wideband on the DP at the beginning of the year on 2nd gear power down and lift off such was the twist on the engine (it was too close to the brake reservoir - bust still 3-4cm away at idle).

 

So really the DP/manifold needs to be supported or the dp needs a flexi section....

 

totally obvious!

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"EGT"in the biggest possible letters. check your tune. youve killed an turbine wheel and a manifold. evidence enough to me, check you timing at high rpms. are you running loads of boost and big reduction in timing to cope??

iam new here so slap me if this has been covered.

 

My system has been well documented; it's self correcting and afr's are bang on. Timing is close to max on mine, but it's det throttle protected, and I can retard it further. I do retard it quite a bit for hot trackdays, not that it really has any effect on engine temps to be honest.

 

I use W/I too, although it was not working at marham for some reason.

 

Ryan will give the ecu a look over when I get it back on the road, although the program is locked down it is the same system as a lot of other cars. My injectors are all flow balanced too and sit richest at the back, so I know what I'm doing :)

 

This tune has been on the car for 4 years, fine on the 35R and the 4088R is just a weak turbo.. 5(?) other failures on the board, and the manifold is twisting I recon not temp.. the crack is a shear. I'll post more pics up if I get it off tonight.

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All the top bolts came off easily, and a good friend of mine told me about c shaped spanners which should do the job for the inside bolts, so I'll be outside the toolshop at 8.30 tomorrow morning.

 

The crack in the runner is not a complete shear as I thought, it's actually only 40% of the way round. It's a big leak though.

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