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Originally Posted by RalliartRsX
1) 5 20 min sessions in 100 degree heat WILL back out the 5 bolt turbine outlet bolts. They just simply do not have the thermal capacity to expand and contract and not loose clamping force after numerous heat cycles. Simple. Every single one of my exhausts have both a flex pipe and the tranny mount. That is not the issue. The not having flex pipe is manifested in pulling bottom mount turbos off the manifold, NOT the downpipe off the turbine housing.
2) If your welder is unable to weld a vband, then you have an idiotic welder. Buy a stepped v band. Clamp both v bands halves together. Weld. Zero concerns of warping as flanges will expand/contract at in the same axis and is constrained by the other vband flange.
Meh. I just think less things to clamp together (5 bolts with nuts and all sorts of headaches vs a single v band clamp). Simplicity is lost when you are fumbling around in the engine bay for 2-3 times the amount of time it would take to attach a single v band downpipe  . That and I do not have to spend $2-$300 on Inconel hardware and fancy lock nuts and tabs. |
I had stretched lots of M8 bolts on the 5 bolt turbine outlet housing. If you put a stronger bolt on it, it starts pulling the threads out of the turbine housing itself. Not much room to helicoil the threads either, which then makes the turbine housing itself just crack down the length of the threaded portion.
It's all fine on street usage, or even light track usage, but you start hammering on the car on track and the design shows that it's pretty marginal.
V-band outlets are way more robust. It's worth the effort to switch over if you drive your car hard.