420WHP944

Hi guys,
Need some advice on what to do. I was driving home and heard a "pop" sound coming from under the hood, the car seemed to run fine but would only rev to 3500 revs or so. Pulled over but couldnt see anything out of the ordinary and it being late at night on a dim country road didnt help matters either. Drove off again and the car started to develop what can only be described as a tractor sound coming from under the hood, I had no power to speak of so I was glad being only minutes from home.

It turns out the crossover pipe thats mounts on the turbo has broke all the way round the mounting flange? I could get a large screwdriver in there with ease and seen it was broke off all the way round? Never heard of this happen before, any suggestions on to why it happened and should I weld it back together or replace?

TIA

John.

OriginalSterm

Same thing happened to mine at Watkins Glen this year. I'd suggest finding a new crossover, welding that may not work for very long if you don't get the orientation exactly right because you could introduce stress into the weld joint when bolting it down. It would probably crack again under vibration and thermal expansion.

420WHP944

Thats what i figured, hoped a weld might do the trick but you are right, I dont want it to crack again and have to fix it again.

John.

samluke

There are a number of risk with welding. You would need the pipe off the car to do it, and withit being cracked, you might not get the alignement perfect. This will make installation harder and could put additional stress on the pipe that could lead to premature failure later.

Welded exhausts will likely fail again either in the same place or somewhere else.

I would recomend replacing it, not welding it.

I have a used two piece crossover if you need one.

xsboost90

i had to weld the one on the Rocks car because it had started to crack at the top. I welded it on the motor w/ the motor out though. Wonder what causes that besides alot of heat?

420WHP944

Replace it is then!

Sam, I'm in Ireland and can source the crossover here locally but I appreciate the offer - thank you.

I also noticed about 8 inches below the broken flange some sort of sensor coming from the crossover pipe - is this factory or is the sensor a mod the PO put there?

John.

bunch

I have one in the Netherlands its free for you if you pay shipping.

420WHP944

PM on the way

OriginalSterm

Factory O2 sensor

OriginalSterm

Mine failed shortly after replacing the turbo, I wondered if it was related to the "clocking" or orientation of the turbo flange to the mating xover flange. The new one seems to be holding up fine after 2 track events and some street driving without changing the orientation of the turbo.

420WHP944

Sounds very plausible.

special tool

No!

This is caused by ridiculous backpressure/heat caused by extremely undersized turbine and exhaust housing, combined with maybe a slight misalihnment.

evil 944t

+1 (although I'm not sure ST knows what he's talking about,lol)

420WHP944

What do you mean exactly? Its a super 61 with a no 8 hotside. What neds to be done to cure the problem?

special tool

Oh well - I thought you had a 27/6.
The #8 is still way too small for a 2.8, I know it spools quickly but you sacrifice the your maximun VE potential area (upper rpm's).