I was going to fully de-cat my MY96 V2 STI, but have decided against it due to mot issues. At the same time I was going to change the up-pipe,which I had already bought.
What sort of a job is it to fit ( seized bolts etc ) and without the de-cat downpipe will there be any benefit in fitting it at all?

Thanks for any help

PS. I have access to a 2 post ramp

 

From what ive read its a bit of a mare to fit, removal of downpipe is required to access the uppipe bolts on the turbo,wish i knew that when i fitted a new downpipe,could of don ethe uppipe at the same time !

some have said you need to remove an engine mount for ease of fitment ??

for such a small piece of kit, its about a 4 hr job to fit !

 

Like Rig said, it's surprising how much else needs to come off the car, so it's a pretty time consuming job even if relatively straightforward. There's definitely plenty of potential for seized bolts, also.

Quick run-down of the job:
- remove heat-shields from o/s and n/s exhaust manifolds, if fitted
- unbolt manifold cross-pipe from n/s manifold
- unbolt o/s manifold from head and up-pipe, removing cross-pipe and o/s manifold as one unit
- remove airbox and associated parts
- remove intercooler
- loosen down-pipe at join with exhaust center pipe and at turbo, then remove
- unbolt up-pipe from turbo
- replace new/original parts as relevant in reverse order

Worth getting in advance, in case they're seized and get damaged during removal:
a spare manifold stud or two, likewise down-pipe to turbo studs; nuts for both the former (m10x1.25 thread); m10x60 and m12x60 bolts with nuts; gaskets if you don't want to take the chance yours are no good ...


To get the most benefit you would probably also want to fit ported manifolds and cross-pipe (replacement/exchange, or port your own - good die grinder and a long afternoon or two required), or a good-quality tubular manifold, and a high-flow sports-cat downpipe. This is the route I went down (except my up-pipe is still stock, as time and budget were a bit tight when the job was done), and the power-gain is very noticeable. With just the up-pipe, ported manifolds and x-pipe (no downpipe) you'll still gain a few bhp and probably improve throttle-response a little, but not nearly as much. With the up-pipe and nothing else, any difference would be very hard to spot from just driving the car.

I've never dealt with him personally, but reading of numerous threads on this subject suggests that Harvey's your man, for all things up-pipe and manifold related