3.1 Exhaust--poor design?

[peeeot]

I noticed today how (to my perception) poorly designed the exhaust system is on my 91 Cutlass Supreme (single exhaust, 3.1). The "log"-style exhaust manifolds are restrictive, and the cylinders from the front bank have to pump their exhaust part of the way through the other manifold to get to the beginning of the exhaust pipe, which is at a sharp 90 degree angle. It seems like the middle cylinder on the rear bank is the only one that has a fair chance to breathe.

 

This can't be good for efficiency. Well, I guess it's good for space efficiency, but that's it. Just how much does this crummy exhaust setup hamper the engine's performance? I know my convertible weighs about 300 pounds more than the coupe but that poor little 3.1 seems like it has to work really hard to get it going. And slowly, at that.

[pitzel]

Efficiency and power-wise, it probably doesn't make a difference. However, there definitely are better designs from an acoustics point of view.

[peeeot]

why wouldn't it affect efficiency and power?

[J]

headers would really wake up our cars, but no one makes them. Unless you want your own, and pay to have some shop make them it's pointless to even think of them.

[peeeot]

Is the factory dual exhaust setup any better?

[THe_DeTAiL3R]

Is the factory dual exhaust setup any better?

 

No.

 

It's the same thing, except a Y pipe at the end and add another muffler.. LOL

 

The main pipe may be larger in diameter though, but I'm not sure at all about that.

[peeeot]

Oh well. I guess I'll give up any hope of freeing up exhaust flow to speak of any time soon. I mean, I'll replace my rattling cat with a high-flow one, because it costs the same as a stocker (or less), but with all those small-diameter 90-degree turns at the engine I don't expect it will make much difference.

 

I think it's funny that they call the y-pipe setup dual exhaust from the factory. It used to be that every time they said dual exhaust, they really meant it.

[ToroToro]

Actually, GM only advertised dual exhaust outlets, which would be accurate.

 

And really, from what I hear from people with headers, they aren't really worth the struggling to get them in and out. Doesn't make that huge of a difference.

[mfewtrail]

Actually, GM only advertised dual exhaust outlets, which would be accurate.

 

And really, from what I hear from people with headers, they aren't really worth the struggling to get them in and out. Doesn't make that huge of a difference.

 

They didn't start calling them "dual exhaust outlets" until the later years as far as I can tell, my '01 GTP's window stickers says just that. My TGP's window sticker states "stainless dual exhaust" and my '93 SE's window sticker states "split dual exhaust."

[Brian P]

I noticed today how (to my perception) poorly designed the exhaust system is on my 91 Cutlass Supreme (single exhaust, 3.1). The "log"-style exhaust manifolds are restrictive, and the cylinders from the front bank have to pump their exhaust part of the way through the other manifold to get to the beginning of the exhaust pipe, which is at a sharp 90 degree angle. It seems like the middle cylinder on the rear bank is the only one that has a fair chance to breathe.

 

This can't be good for efficiency. Well, I guess it's good for space efficiency, but that's it. Just how much does this crummy exhaust setup hamper the engine's performance? I know my convertible weighs about 300 pounds more than the coupe but that poor little 3.1 seems like it has to work really hard to get it going. And slowly, at that.

 

yeah it's one of the many obstacles to hurdle, and another way GM stifled the motor. Look at the factory exhaust manifolds on a 3.8L for example. MUCH better and it allowed that engine to make more power.