JohnR

iTrader: (1)

I have a '99 Firehawk with the SLP dual-dual cat back system. I'm in the middle of a rear end swap and I got a good look at the exhaust pipe that goes over the rear and it is not pretty! This thing was flattened so badly that it is actually rolled into the center of the pipe creating a "C" cross-section. What a disappointment! I have FLP headers with high flow cats and then it all has to squeeze through the smashed SLP cat back system.
Here's my question. IS THIS NORMAL? Can i buy a separate pipe to replace the SLP POS, or do I have to replace the whole cat back system. I really like the sound, but I can't get over the way this thing looks. This can't be good for performance.

Please help,
Thanks,
John

jimmyblue

iTrader: (11)

It's normal, or at least mine's like that too.
You just can't bend stainless to that radius,
in the middle of a long piece, without that
crush going to happen (plus I reckon they
took the extra axle clearance as a bonus).

I guess if you were really worried about it
you could get the pipe out and either work
out the crush (like, drill a few 1/4" holes in
the top, and use a hammer & steel drift to
punch it back out, or just go find a piece
of tight-curved SS tubing for a donor and
cut out the divot and reweld).

Or get a cutout and forget all about it.

At least it's just a small section that's
squashed, and the flow biases to the outside
of the bend anyway at higher velocities so
it probably isn't as bad an effect as it looks.

kp

iTrader: (34)

dont be too worried, I pick up almost nothing on the dyno with a cutout on my dual/dual. At the track I pick up like .2 mph with the cutout open and thats at 470rwhp or so - I dont think the crushed over the axle pipe is hurting all that much..

Stew w/92&00

It's not costing you much if any hp.....

JamRWS6

Just wondering why SLP has this problem whereas the stock WS6 and my Corsa don't have this problem.

JohnR

iTrader: (1)

Thanks for all the quick responses. I know JamR said that his Corsa isn't smashed, but what about all the other aftermarket exhaust systems? Do they have to smash the pipe to get clearance over the axle?

Thanks,
John

Tranzor

My rumbler does not have a smashed in section going over the axle...

CGLHawk260

When I bought my 2000 FireHawk I noticed the same thing. I got rid of the oem slp dd and bought a Corsa set up. I wonder if i gained anything. What's interesting is that the aftermarket slp dd doesn't have the flat over the axle section. They probably did it for oem clearance?

BTW, the Corsa has about 3/8 clearance of the axle. Poor fit. Always adjusting to stop the vibration. If i had to do it again i would of spent less for the cat back.

WayneSS01

My B&B does not have that either. The chief engineer on the SLP board once said their pipe is done what way to meet with GM specs in terms of clearance.

JamRWS6

Somthing must be out of adjustment. My corsa was installed by the dealer under an insurance claim so I didn't install it but it does not rattle. I doubt GM would certify this exhaust if it had rattling problems. Might try loosening the clamps and moving the exhaust around to get a good clearance.

BackinBlack02SS

iTrader: (7)

Can you purchase just the over the axle piping from SLP?

BackinBlack02SS

iTrader: (7)

Well obviously you can, lol. Anyone know if it's also crushed? From the pic, it doesn't look like it, but I just want to be sure.

http://www.slponline.com/view_produc...66&BIG=10166-1

DanZ28

iTrader: (5)

That's funny, they sell a replacement over axle pipe, but if you buy the aftermarket DD it still has the crushed pipe. If you look at the Pic of the SLP DD on their site, it clearly shows the crushed pipe, so it must be normal.

Dan

technical

If you have the dual/dual as an option from the factory you will have the flattened pipe. Mine has it too. I believe when you buy the dual/dual outright, it doesn't have it.

TOOSLO5

I am looking at the DD also and noticed the crushed pipe. I called SLP a little while ago and was told the pipe is a "D" shape due to GM exhaust clearance rules also the tech guy told me the pipe is an actual "D" shape and it does not loose any volume over a round pipe. Without seeing it up close its hard to tell from a couple of pics on their web site. I was also told the Firehawk over axle pipe they have listed has the same "D" to it you just cant see it in the picture. The tech guy told me the DD muffler is slightly louder than the Firehawk/SS muffler and might be worth a HP or two over the Firehawk/SS part.

Scotty-Z

iTrader: (5)

This is why it is done.

Aftermarket catbacks won't have it because they don't have to conform to those regulations. Regardless, the SLP dual/dual catback you have is one of the top-flowing ones on the market, so that section of the piping obviously hurts performance very little, if at all.