Exhaust HP hype.....
Thread Starter
Le Mans Master
Joined: Mar 2002
Posts: 5,253
Likes: 50
From: Sandy Eggo Calif.
St. Jude Donor '06-'07-'08-'09-'10-'11-'12, '16
Exhaust HP hype.....
I just read a thread from Chris at Speed Demon, that the airflow restrictions are mostly in the intake and the engine(H/C) and not in the exhaust(catback). He said that there is no HP gain from an after market exhaust and it should be for looks & sound only.
Weren't suppliers and users claiming a 5 to 7 HP increase with the Stingers? Or are those numbers too small to claim, considering dyno/conditions variance.
So the only other thing to consider is weight. The new Corsa Z titanium "Street" series is claiming 28 lbs. lighter than stock and 10 lbs. lighter than Z06. Thinner titanium?
Catback OEM weight?
OEM ZO6 ?
Stingers weight ?(2 or 4 tip/ half or both sides) Thanks.
Weren't suppliers and users claiming a 5 to 7 HP increase with the Stingers? Or are those numbers too small to claim, considering dyno/conditions variance.
So the only other thing to consider is weight. The new Corsa Z titanium "Street" series is claiming 28 lbs. lighter than stock and 10 lbs. lighter than Z06. Thinner titanium?
Catback OEM weight?
OEM ZO6 ?
Stingers weight ?(2 or 4 tip/ half or both sides) Thanks.
Le Mans Master
Joined: Nov 2000
Posts: 6,266
Likes: 156
From: Galloway Twp. NJ
Cruise-In VII Veteran
Re: Exhaust HP hype..... (Powerhungry)
It's true.
there's not much HP gain from catback exhaust.
but for me, the Corsa Indy's were well worth the money! :D
:cheers:
there's not much HP gain from catback exhaust.
but for me, the Corsa Indy's were well worth the money! :D
:cheers:
Melting Slicks
Joined: Dec 2001
Posts: 2,765
Likes: 0
From: Dana Point Ca
Re: Exhaust HP hype..... (Powerhungry)
In an article a couple months back in vette magazine, a 01 ZO6 picked up almost 25 REAR WHEEL horsepower with the blackwing and the slp exhaust. The slp exhaust without the baffles produced 8 hp and 9 lbs ft tq on an independent dyno done by the magazine. It would be rediculous to assume that you would get no horsepower. :D
Pro
Joined: Aug 1999
Posts: 514
Likes: 0
From: Roseville California
Re: Exhaust HP hype..... (vettethret)
I happened to notice on Speed Demon's own website that he sells an exhaust system that claims something like 15 hp increase over stock. I'm confused by all this.
I'm still buying the Corsa Indys, but not for hp..........
I'm still buying the Corsa Indys, but not for hp..........
Team Owner
Joined: Jun 2001
Posts: 26,714
Likes: 344
From: Houston, TX
Re: Exhaust HP hype..... (DI2FLY)
About a year ago one of the "Corvette" magazines tested before and after stock vs B&B PRT's. On the dyno, about an hour apart, the B&B's picked up around 11 or 12 rwhp. I can dig up the magazine if anyone wants specifics, but that's about where it was.
Race Director
Joined: Nov 1999
Posts: 12,952
Likes: 0
From: Greer SC
Cruise-In II Veteran
Re: Exhaust HP hype..... (Powerhungry)
We had our car dynoed three times in a 20 minute period & there was a 7 HP difference from the highest to the lowest. There are three reasons for changing out the exhaust... Sound, Sound, & Looks. No way are you going to see any true gains from a cat-back system. The cats are much more restrictive than the exhaust.
[Modified by Sully C5, 9:34 PM 4/11/2002]
[Modified by Sully C5, 9:34 PM 4/11/2002]
Team Owner
Joined: Sep 1999
Posts: 20,054
Likes: 44
From: Swansea IL
Re: Exhaust HP hype..... (Powerhungry)
I could be wrong but I don't believe any cat-back system is sold/purchased because of any HP claims. While it's true they flow more exhaust gases and may infact increase a cars HP by some small margin I doubt it's noticeable. These systems are ear candy. Just like chrome wheels are eye candy. Some mods just make you feel better about the car. My Indy's do that everytime I row the gears.
Any HP claims I'd ignore or cut in half.
Tom
USAF Retired
Any HP claims I'd ignore or cut in half.
Tom
USAF Retired
Le Mans Master
Joined: Aug 2000
Posts: 6,447
Likes: 0
From: Scottsdale, AZ
Cruise-In III Veteran
Re: Exhaust HP hype..... (Powerhungry)
When I changed my cat-back I mainly did it for sound and looks, not performance. If you look at the stock exhaust it is pretty well made, nice big pipes coming out of there. The only real restriction in the system is the internals of the muffler, and even that isn't too bad.
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Drifting
Joined: Feb 2002
Posts: 1,332
Likes: 0
From: Appalachian Mtns
Re: Exhaust HP hype..... (Powerhungry)
I just read a thread from Chris at Speed Demon, that the airflow restrictions are mostly in the intake and the engine(H/C) and not in the exhaust(catback). He said that there is no HP gain from an after market exhaust and it should be for looks & sound only.
Weren't suppliers and users claiming a 5 to 7 HP increase with the Stingers? Or are those numbers too small to claim, considering dyno/conditions variance.
Stingers weight ?(2 or 4 tip/ half or both sides) Thanks.
Weren't suppliers and users claiming a 5 to 7 HP increase with the Stingers? Or are those numbers too small to claim, considering dyno/conditions variance.
Stingers weight ?(2 or 4 tip/ half or both sides) Thanks.
Corvette Fever had a short blurb on this subject a couple of months ago where they reported someone's test with a variety of stuff in the exhaust system. They reported the stock Cats were not very restrictive at all, and that virtually all the gain to be had from exhaust mods was in headers and cat-backs. FWIW.
:cheers:
Drifting
Joined: Feb 2002
Posts: 1,332
Likes: 0
From: Appalachian Mtns
Re: Exhaust HP hype..... (Buckmaster)
HP gains from exhasuts are :bs IMO.
"From the dyno test results I've seen, a fair amount of power can definitely be liberated through exhaust system modifications. The stock catalytic converter assembly is definitely restrictive, but it appears that the after-cat portion of the exhaust system is even worse.... Clearly the after-cat portion of the system is the biggest bottleneck."
There's a lot more info, including dyno results from several tuners, in that article, but it's too long to re-type here. There is also the documentation of many forum members who've dyno'ed before and after with cat backs. The point is that there are no huge gains to be made, but to say there are no gains is also extreme, and not supported by the facts. :cheers: :seeya
Safety Car
Joined: Feb 2001
Posts: 3,569
Likes: 0
From: Greenville NC
Re: Exhaust HP hype..... (Powerhungry)
Dyno tests seem to vary a lot... a couple years ago there was test done with some aftermarket exhausts on a C5.. most where between 0-5hp (but there a lot of better flowing exhausts out now)... and that particular car turned a 8 or 9hp gain when the entire rear exhaust section was removed. In theory, no exhaust should go over 8-9hp then on a bone stock c5. I've only heard of 2 dyno results from the Borla stinger (both impressive), Jim Hall gained 9.5 rwhp on a Z06 that had a COI on it over the stock Ti system...( the Ti system flows better than a regular C5 exhaust. I think someone else gain 5rwhp over a Bassani exhaust on a modified car. I have a Borla Stinger on order... mainly for looks and sound.
Heel & Toe
Joined: Dec 2001
Posts: 21
Likes: 0
From: CA
Re: Exhaust HP hype..... (ncvetteman)
Mike at B&B himself says that if you remove the cat back altogether there are minimal gains. Certainly noy over 10 HP. Exhausts ar all about sound and looks on our particular vehicles. Go with what you like. If one particular supplier say's their system adds more HP than another it's BS
