Looking at the recent post re removing cats, I think my UK 92 tt (Jan 92) could 'reasonably legally' have a straight thru exhaust.

 

I'm not so bothered about the legality, more

concerned (as previous posts) about the turbos, ie rear oil seals smoke etc...

 

My Zed has 90k miles, although the turbos were reconed at around 50k according to some paperwork i had with the car. It also had a 'short motor' fitted and the previous owners warranty company stumped up £5,000 for the work! Christs knows what happened, but it runs fine.

 

Anways, IF I put on a Scarab or something similar with the milage I have what is the chances of the dreaded smokes?

 

This seems to be a good starting point (along with an intake upgrade) for big power hikes.

 

I wish it was a simple as GT2/3 ....

 

Glenn

Glenn - assuming you run stock boost (or at least don't push them above about 16/18psi), and look after your turbos (warm-down, regular oil changes) and the recon job was good (think you would have noticed already if it wasn't) then you should be fine, since your turbo's only have 40k on them..

 

The reason they start smoking when you remove the cats btw is (I think) because of both a) the reduced back pressure and b) the fact that the cat isn't there to 'soak up' the oily smoke..

 

My best answer is that you 'should' be fine..

The reason the turbos start to smoke is because when you remove the CATS the back pressure on the turbos is a lot more and that breaks the seals and knackers them. But I hear you can gain about 20-50bhp depending on mods.

 

Stuart

There is reduced back pressure on a 'straight through' pipe, it does break the seals, as back pressure is what 'keeps' oil in, pressurises the seals, no back pressure, seals forced open, and oil leaks in.

Less back pressure is better on a turbo car, so long as the exhaust diameter is a constant from the turbo back, otherwise the exhaust's back pressure increases and will not be as effective.

Remember the seals will only break if they are inherently weak therefore if the seals are in good condition etc etc then there will be no problem.

 

 

Before getting the scarab see if you already have failing seals.

 

There are a few ways to test this, but the easiest way to tell if the seals are on their way out is by pulling off the lower rubber intake-hoses and see if there is oil inside the rubber hose(s) or the metal pipe(s) it connects to (the ones on either side of the plenum that run to the turbos)

 

If there is oil, I wouldn't recommend to get rid of the cats

 

-Eric

 

Thanks for the info guys.