AJK

I have been following the posts about exhaust system modifications and conclude that especially for older 928's (OBs.. I'm learning the lingo) headers and some improvised RMB is the way to go. However, I still haven't figured what the X-Pipe is. Is that just another word for a CAT delete?

Thanks,

Art

Big Dave

The x-pipe typically eliminates the cats and connects the dual exhausts in an "x" shape before separating them again to retain the dual exhaust set-up. On older cars where the exhaust is a single tube after the cats, an x-pipe isn't necessary unless you plan on dual pipes all the way from the engine to the mufflers.

Jim bailey - 928 International

For the cars with dual exhaust USA 1985 > they use a two in two out catalytic convertor with a crossover where the O2 sensor mounts. The early cars have a single exhaust basically a Y pipe two in one out. Old style cat bypass test pipes were made as an H two in two out with the balance pipe connecting the two. The current style is to make the pipes cross each other in an X so two in two out BUT the exhausts are crossing and theoretically help scavenge each other and smooth the exhaust flow.

mspiegle

ok, stupidest question of the month... what does OB stand for?

Big Dave

Old Bugger....model years 78-80

mspiegle

i think every other 'B' word came across my mind except for 'bugger'... thanks

Carl Fausett

I really dislike this new term "OB"
As one who concentrates on the early cars and their MERITS it isn't right.

Sierra Shark

How's this? The first time my wife heard me use the term "OB" she asked why anybody would name their car after a brand of TAMPONS! Now she thinks it's funny to call my white 928 a "the fish tampon". (really not funny)

MGW-Fla

So what set up would everyone recommend for my 85S, 32v auto if I desire mainly to pick up some HP?? A little bit more sound is ok, but not as necessary(though I know I'd get it anyways). I have read of those who have done away with the cat & some replacing it with new efficient brands, etc. If I understand correctly on my car, there is not the clamp in front of the cat, but instead its welded which causes it to not be as simple as loosening & tightening exhaust clamps. It wasnt until the 86MY that they had the clamps, correct?? Dave @ 928 Specialist told me last month that he had something upcoming for my MY, but didnt elaborate, was hoping he'd have it available in time for SITM next month! I just keep reading all I can on it & I swear sometimes I think the more I read the more confused I get!

I just had a local Mustang mechanic install a Magnaflow X pipe on my son's 03 Roush Mustang, with the cat delete, which added even more growl to it already having the Roush side pipes. It also added a bit more HP too it seems.

I just mainly want to get more "get up n go" for my Shark as economically as possible & keep hearing that changes to the exhaust can accomplish that. THANKS for the help!

Sierra Shark

If you want to keep it "economical" why not just install a RMB and call it a day. Small amount of HP gain and nice sounds.

James-man

A rear muffler bypass would have to be customized for an '85. It has been done before, but is much more involved than bolt-on.

James-man

I understand that Tom Cloutier has been very busy the past month or so.

Is he still selling X-pipes or has that been put on hold? Anyone know (before I bother him directly)?

Thanks!

James-man

Quick Carl,

I understand your position on "OB". At first, I had guessed that it meant "Original Build" but soon noticed a range of model years associated with the term.

I promise not to call your stuff OB. But with people calling their own cars _____ bastard, POS, etc, I don't think it is likely that people will drop the term entirely. Just so long as they only refer to their OWN car as #*$&@^% or OB.

AJK

Thanks for the information on what an X-pipe is. Since I have a '79, the X-pipe is not something I could use, so that leaves me with headers and a self made RMB. That sound reasonable?

Thanks,

Art

Normy

"OB" means "Old Boy" or "Old Bugger", and I thought it meant the cars with the original body style- '78-'86. I guess some think it means '78-'80, and for some it means two valves/ cylinder.

-I prefer "Original Series" or OS.\

The X-pipe is a pipe shaped like an X. It is really just two straight pipes slightly bent so that they "kiss", and an oval-shaped window exists between them. This increases exhaust scavenging- when a pulse of exhaust from a cylinder flows through one side of the X, the velocity of the gases causes a negative pressure [suction] in the other pipe as per Bernoulli's effect. This suction helps the engine breath = more power.

-I think I read on here that a GTS scored 30 horsepower when its cats were supplanted with Herr Ott's magic pipe... I can tell you from experience that it made a big difference on my 2-valve '85 S2.

Add a set of Random-Tech cats and you'll be legal, clean...and in need of a set of new rear tires real quick...

N!