Single exhaust on 90 SC.....???

S

SK_BlownThunder

Registered User
Ive been humming and hawing on it, but I have to do something with the rest of my exhaust before winter. So far I've had the cats and stock resonator replaced with 2.25" downpipes from factory manifolds, then expanded into a dual 2.5" in, single 3" out muffler. Right now I still have the stock 2.5" pipe leading around the tank but I had to chop the stock mufflers from the back just after the y-pipe because they were starting to shake, rattle, and role. Being I really don't want to spend the money on a good system for the rear end right at the moment, I just need to know if a single system would do the trick as a temporary fix until spring. Basically I would go with 3" all the way back to a single 3" in, 3" out muffler (Dynomax Race Magnum, or a Flow-Pro, whichever will sound better), and then a single 3" tip sliced off flush with one side of the rear valence. I know it will be weird running single exhaust with dual cutouts in the valence, but if I leave the tip so you cannot see it, it might not be so bad until someone notices the exhaust gases coming out only one side of the car during the winter temps, oh well.

I just need to know if this would have any effect in regards to increasing/decreasing backpressure and in turn making the car run any better. As I said it would be temporary fix, as I will eventually be running duals again when the budget calls for it. (These cars suck for evening out the rear pipes for equal flow).

If anyone has any idea whether or not I should do this, please let me know. One question to get things straight, is backpressure good for a supercharged engine? (Torque-wise, not?) thanks.
 
SK_BlownThunder said:
One question to get things straight, is backpressure good for a supercharged engine? (Torque-wise, not?) thanks.
Click to expand...

Backpressure is never "good". If a car is tuned for a lot of backpressure then reducing backpressure may cause it to run a little lean, but done responsibly, reducing backpressure is always a good thing.

When you reduce backpressure and experience a loss of torque it can be from the reason noted above or it can be due to loss of exhaust velocity. If smaller yet free flowing pipes/mufflers are used, performance (and velocity) will be better than if large diameter but kinked or crimped pipes and crappy mufflers are used.

For example, hollow cats are bad because they cause a drop in velocity followed by an forced increase. This robs energy from the exhaust gas and actually increases the losses from "pumping" the gas out of the pipes.
 
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