Turbo cat bypass - Bursch

mikemdd · 02-04-2006, 02:34 PM

I have an 87 930 that I put a B&B muffler on to get rid of the cat and get better turbo spool (which it definitely does). However, it was too loud and had excessive backfire to my liking under deceleration (no exhaust leaks). I bought a used euro muffler to replace the B&B, but the angle of the flange coming out of the turbo is a little off and the muffler won't seat flat on the flange. I really don't want to rearrange all the plumbing to make it fit.

I had a Bursch cat bypass that I put on with the stock muffler as you can see in the picture. The bypass (black pipe) goes on top of the stock muffler where the cat usually lays. The car is in storage right now, so I don't want to start it yet. Has anyone ever used this setup? Any other comments? I'm guessing/hoping it will have better sound than stock, better turbo spool characteristics, but not as loud as with the B&B.

Thanks

Mike

mikemdd · 04-13-2006, 10:37 AM

Just a quick update (for anyone that cares). Spring has come in Chicago and I fired up the car. In short, I am really happy with the setup. The sound is very deep and not as harsh as the B&B. Also, while there remains some "cackeling" from the exhaust, it is not the hillbilly explosions coming from the B&B. Finally, there is no resonance. I can't tell any difference in turbo spool time, but is a huge difference over the stock setup with the CAT. Again, very happy with the sound and utility of the Bursch bypass.

Mike

RarlyL8 · RarlyL8's Garage

That's interesting, I've got a muffler just like that laying in the garage. How much does the Bursch unit run?

mark '87 930 · mark '87 930's Garage

mikemdd,

I put a B&B over the winter and actually didn't find it that much louder (and I have exactly the same car as you). I really couldn't tell you anything about spool up time as it was months before I got the car out again. She still pulls and now she purrs....

rsrfan · 04-13-2006, 01:30 PM

Rarely,
I've got a used turbo cat bypass laying on a shelf in the garage ( just needs the exhaust "donut" gasket to fit a stock muffler. I pulled it to fit a dual out Monty. If interested, I will trade you for one of your Zork type turbo dump pipes that you have laying around. (pictures from zork tube thread). Let me know.

JP

mikemdd · 04-13-2006, 05:04 PM

rarleyL8,

Our host has them listed here...part number PEL BA7923 for $290. I bought mine on ebay, but I'm sure the business would be appreciated here. One other benefit of this part is that adding back the CAT, if needed (!), is a simple task. Obviously, if I were to track the car, I would switch back to the B&B.

Mike

RarlyL8 · RarlyL8's Garage

$290 !!!! For THAT !!!!
Time to get out my welder and head over to the muffler shop. I'm thinking $30 tops.

I have a Euro exhaust on my car, don't need smog stuff in AL. You had my curiosity working, I really like fiddling with exhaust systems. One of these days I'll finish that home made muffler I started a year ago ......

The Zork tube. Forgot about that guy. Loud as he!! Your neighbors would string you up for sure. If that Cat Tube sells for $290 you better hold on to it until the right buyer comes along (one that doesn't have a welder - HA!)

rsrfan · 04-13-2006, 08:02 PM

Actually, I agree with you. I don't want it and thought you might swap it for the Zork. I like LOUD. Heck if somone paid the shipping they could have it for free.

JP

RarlyL8 · RarlyL8's Garage

I'll pay shipping, I like to fiddle with this stuff.
The Zork tube is for track events. A competent muffler shop can make you one up for under $50. Give it a try!

Gino · 04-14-2006, 01:46 PM

back to your question... I did as you, MikeMDD when I put on my K27-7200. there was definitely a quicker spool. it came in around 2600 rpm.

I yanked that setup when I installed B&B headers. now I go into a single exhaust Fabspeed. it's loud, burbles and farts on decel. not sure I like it this way.

I was thinking of reinstalling my cat bypass and stock muffler to see if it makes better sound. if not, I've heard of a few 930 guys who have used Magnaflow and swear by it. there's are a few options:

weld the cat flange onto the Magnaflow, exit straight out on the passenger side.
use the bypass into a U-pipe and repalce the stock muffler with a tubular Magnaflow, exit out the driver's side.
weld the cat flange onto the dual Magnaflow, exit both sides.

I'll probably play around with this over the summer and will report on it