Power increase with dual exhausts?

[MaineShark]

How much horsepower and torque increase should I expect on a 79 L82 with dual exhausts, vs. the same car with the stock (y-pipes, cats, etc) exhaust? I'm fairly certain the pipes on the dual setup are 2"

Joe

 

[Bob Chadwick]

People will disagree on this. I modified my completely stock 180 hp 77 with 2 1/4 dual exhaust including dual high flow cats and Delta 50 Flowmasters. Sounds great but I don't think it increased the acceleration at all. I stayed with the stock ram horns

However, as I make changes to the manifold, cam, etc., the system is supposedly set to flow properly up to HP in the high 300's.

As I said, others will disagree. I didn't go with headers and had some substantial decay in the single cat and perhaps that is why I didn't notice any difference.

I've got pictures and a sound clip posted here. http://home.attbi.com/~jchadwick/exhaust.htm

Heidi, aka 78SilvAnniv, recently went with dual exhausts and chambered exhaust. Maybe she'll view the post and have something to say.

Anyway, the exhaust sounds great and I would do it again in a heartbeat.

Bob

 

[78SilvAnniv]

hp or just breathing right!

I love the new chambered exhaust! It has a mean, big block, muscle car sound.

Kenny says he noticed an increase in hp, I feel that the engine is more 'peppy' because it appears more responsive to throttle contact.

I also feel that if I gained hp, it has been in the upper rpm levels, I notice she doesn't 'squat' as distinctively as before, which may change when she is cold vs when she is warmed up. I also felt she was a little 'boggy' at acceleration from a stop, she was, and that was fixed with some vaccum hose adjusting. Now she goes just fine.

Overall, I am very pleased with how the engine is performing with this new exhaust. I don't treat my vette very often like the performance car she is. (the 2002 late October trip to Helen, GA was the first time in 12 years) I am happy with her being reliable, looking good and now...sounding schweeeeet!
Heidi

 

[Bob Chadwick]

Heidi makes a good observation about the off the line performance. These increased flow exhausts have the possibility of actually reducing low end torque on these low HP engines. Perhaps what I am seeing is no increase from a standing stop but more power on the top end. I didn't really pay attention to that so I can't say.

Bob

 

[Dave L.]

true dual exhaust

MaineShark- I installed the Mid-America dual system on my car with no cat-converter(s) and noticed a big difference in power compared to stock set up. For the money,I can't think of a better performance upgrade you could make. You will notice in the range of 20-30 hp gain with the no-converter setup. Check your emission laws in your area before removing the stock setup.

Dave

 

[MaineShark]

I wonder if the difference is based on L48 vs. L82?

Anyway, the question is mostly out of curiosity, since the dual exhausts are a done deal (previous owner put them on).

I'll be putting a pair of Dynomax stainless Ultra-Flo's on this week, since the current mufflers are 1)rusting out, and 2)el-cheapo-bargain-basement-mufflers.

I'm curious to see if the noise level goes up or down. On the one hand, the Ultra-Flo's are probably louder than these mufflers should be, but on the other hand, these mufflers have holes in them due to rust. In either case, it should sound nicer with the Ultra-Flo's, from what I've read here.

Joe