calinator

Or none at all, or anything performance related like throttle response? Just thought I'd make a post cause I haven't posted in a while haha. I believe it's been debated on both sides that it does or doesn't. I've got Corsa Xtremes by the way

DSTURBD

I'll trade you whichever answer you want for your Corsa's!!

Then we'll both be tickled!

DSTURBD

lionelhutz

Good catbacks can add a few HP, in the 8-12HP range.

Vetteman Jack

Catbacks are not going to add enough HP to be noticable IMO. But they will sound great when compared to the stock system.

jcsperson

A good set might give you a couple hp. A bad set might take several away.

strand rider

That's all I have ever heard, The can add part, not will add , or guaranteed to add, just can add.

Well, as you know, almost anything "can" happen , the future is largely unknown. Being able to do something is close enough for me, since Magnaflow tips came on my lowered car.

I don't mind the look , and the "fact" than I might possibly have as much as 14 hp over stock, if I don't think about it too much, makes me extra special. I don't mind the BS involved in selling these parts, because I would have to tear the thing off if I did, and it is not that big of a deal.

I think the added power claim could be factual if you have enough other mods that you now require a different exhaust design, the ads never specify, but that is the only thing I could think of to get the additional facts needed to make the ad true.

Not that the claim was wildly untrue, just somewhat incomplete. It's advertising , I get it. There is a company selling copper core spark plugs that says their design burns better etc. As you read the honest testimonies, all the cars mentioned are old carb race engines pouring massive poorly regulated fuel through the pistons. Nothing about the situation that is transferable to computer controlled fuel injection, it is up to you to figure out that the documented performance gains are for a completely different situation than your vette.
I found this from a posting on this forum, about , guess what, power gains from these super great plugs.

lionelhutz

Well, now you have 4 actual results.

http://forums.corvetteforum.com/c5-t...post1573303063


I will change what I posted before. A good catback systems will gain 8-12hp. It's nothing to get very excited about but there is definitely a small gain possible over the stock C5 system.

strand rider

this day just keeps getting better. Even my car is now faster then when I woke up, with no additional effort, just by reading this post.

Thanks.

NukeC5

The over axle sets are more for sound and looks. It's when the car becomes heavily modified that it will make sense as a performance move. Say you were pushing potentially 600whp out of a supercharger and cam upgrade. The stock exhaust could be holding you back 20 or 30whp or more at that point. That being said. Most of us have further aspirations for power in the future. An axle back is a good place to start and a supporting mod to anything else down the line.

Camjamsdad

Cut the claims in half. 10 to 12 is like 5 to 6. Don't feel bad cause gm started it. 345 is really like 290.

Cybermind

Please explain. How did GM "start it" and how is GM's horsepower rating procedure different than any other manufacturer?

Isn't there an international specification that all car manufacturers have to follow to come up with horsepower ratings for their vehicles?

F&Yb0dluvr

Depends what brand and kind etc..an X pipe and bullet type mufflers will give the most power about 15-20 rear wheel a regular catback might be only 5-10.

jcsperson

No. Vehicles sold in the U.S. have used "SAE net power" standards since the early '70s. Those were revised in 2005 to require third-party testing for "certification," but use essentially the same method. The 505 hp LS7 was certified according to the 2005 standard.

Other countries use their own standards.

sfc rick

Really, this like Nascar officials debating whether or not the move from satin finish over a gloss finish paint gives an unfair advantage over the guys who have two painted numeral's over the ones who only sport a single number.

Camjamsdad

My point was gm over stated the hp ratings on the c5's. Call me old fashioned but if I buy a car advertised as 345 or 350 horsepower I expect to receive that. Instead I get a car with an anemic 290 horsepower. I could tolerate being off a little but we're talking 60 horsepower or almost 20% less.

RetiredSFC 97

Will they? Yes. It comes down to air in-air out. If you're getting more air with your intake than your exhaust system can push out, if you add a free flowing exhaust it will help.

But typically to get real numbers you have to open up your intake air, and then adequately get it out in the same volume.

When they say up to, that up to is conditional on what else you do for the air in air out ratio. Same applies to headers or any bolt on mod.

troyguitar

Most cars have advertised power ratings at the crank, not the wheels.

Some of the German stuff in particular is underrated to protect higher end models, but those are exceptions. BMW N54/N55 335's were underrated to protect the M3, VW 2.0T's underrated to protect Audi, Audi 3.0T's underrated to protect Porsche, etc.

Since the Corvette is at the top of GM's range, it is not underrated by GM.

Cybermind

So, which manufacturer do you know of that states rear wheel horsepower and not crank? Just curious. You seem to be blaming GM for false HP numbers. What is it that GM does different than any one else?

If anything, GM showed initiative by being the first auto manufacturer to voluntarily comply with the new certified SAE standards in 2005.

Damn, this Corvette bashing is getting on my nerves!

3boystoys

I seem to recall a lot of base line dynos I've seen on this site correspond closely to the factory advertised numbers.

F&Yb0dluvr

I don't know where you're getting your information from C5's put down anywhere from 290-320 at the wheels depending on year and transmission which is right with GM's flywheel rating.