Avar928

This is for an '86 928S 32V Auto.

I purchased an X-pipe with 200 cell hi-flow cats from a fellow rennlister that I want to install on my '86.

However, I have a few problems.

The X-pipe is welded onto the hi-flow cats.
The previous owner had the cats welded onto their cat-back.

When they removed it from their car, they had it cut off. I now have two-inches of their cat-back still welded onto the cats. I can't install it because the cat-back is in the way of course. Not only that but the new clamps I bought from Roger don't appear to be able to fit over the lip of the cats themselves from my estimation.

If I grind at the weld and remove the cat-back piece, I may be able to slip the clamps over I believe. I have a strip of fiber glass wrap from Roger to fill in the gap to prevent leaks but I think I'll buy this instead:

http://www.ecstuning.com/Porsche-198...ance/ES261348/

I'll layer and layer to get it tight so no leaks. However, this is assuming that the clamps will go over once I get that pipe off.

My other option is finding an exhaust shop or independent and have them do all the work and just weld it onto my cat-back.

What's the best method?





Update:

Had a system fabricated for me by the guys at ASG in Fairfax, VA (http://www.autosportsystems.net/). They made it so I preserve the stock set up and can just switch out the X-pipe and cats with the stock system easy. They are great. HIGHLY recommended.

Loving the new x-pipe and cats. Feels and sounds like a whole different car. WOW.

MFranke

Personally I would try to keep the normal bolted clamp connections so its easier to drop sections for maintenance.

Stromius

I am a bit dissatisfied with clamps I got. On the S4 the pipes to the resonator are 2.125" but cat is. 2.5" of course. I am thinking of getting the proper 2.5" pipe with flared ends fabbed to receive the cats and weld this into the resonators. YMMV but wraps seems to disintegrate over time anyway.

Avar928

Yea, I'm hoping to keep it bolt on because I don't want to have to drop the whole exhaust just to work on stuff underneath. Too tedious.

Called around and am looking at some shops to see what they can do. If they or I can just grind that weld off and get that piece of pipe out maybe I could just clamp it on using the new clamps or the stock ones.

Do they have any type of sealant or gasket type of liquid I can lightly grease around the connection to prevent leaks? From what I have read, leaks will occur regardless of the wrap as it disintegrates but self seals when corrosion builds up and fills the gaps.

Stromius

^| Too hot in all likelihood

Avar928

Darn.

I'm stopping by a shop tomorrow to get a quote. Going to buy a grinder for my dremel and see if I can just get that pipe out. Maybe do a dry install.

Stefan,

Question, about the pipe. Do the cats attach to some support underneath the car or is it just held by the cat-back and the x-pipe?

MFranke

In my cases, 87-88, there is no separate support. Once you tighten up the flanged ends the next hanger you see is down past the resonators near the muffler. If the x-pipe or cat is snugged up to the resonator pipes the exhaust will be pretty rigid overall between the flanges and hangers.

ROG100

The new clamps are much better and require very little sealing and only at the overlap.
They are designed to pull down and literally flow to the exact shape of the two joining pipes.
You can really tighten them to the extreme without breaking the bolts. The tighter the better.

Avar928

Thanks Stefan.

Thanks Roger. Depending on the quote, I may just do the install myself if it's too expensive. I'll probably have them grind it if it won't cost too much otherwise I have a nice project this weekend

PC-85-928S

If I did my set up again,
In addition to the fiberglass wrap, and tightening the clamp like crazy with a air ratchet, I would put a healthy amount of exhaust paste, where the smaller pipe goes into the larger pipe- trust me

mickster

^^^^This

Ketchmi

We haven't used the fiberglass wrap for a considerable amount of time...the new clamps are stepped and have a small fiberglass patch that covers the joint of the clamp and they do work considerably better. All of the wide stainless clamps can be reused a maximum of twice, sometimes only once before needing replacement. They are designed to and do stretch. If you have a problem with the crossover sealing up give Roger, Carl or us a call and get a new set of clamps...problem solved.

http://www.ottawaproducts.com/produc...ries_photo.htm

Avar928

Thanks Dave. Did you guys ever sell 200 CPI cats? I thought it was only 150s. I'm thinking the cats aren't yours and some other aftermarket.

I took it to ASG down in Virginia. They'll grind away the weld and remove the cat-back piece. They may have to do some fabrication. A quick look under the car and a visual estimation and the guys at ASG think the cats may be a little short. They're pretty knowledge about 928s (saw a few Frenzy shirts at their shop too).

Ketchmi

We have only sold 100cpi cats for a long time, I don't believe we ever sold 200cpi. We did have some 300cpi but they were 3" for our "Y" pipe.

Avar928

How would shorter or smaller cats affect performance with the pipe? Would it restrict air flow more making performance worse?