Rob04C5LM

I've seen a lot of guys on here saying that unless you get into the headers on a C5, you don't get any gains on a cat-back system. I've also consistently seen vendors and manufacturers making claims of the gains. I've excerpted the manufacturer claim from Magnaflow below, I've seen similar claims from others. Personally, I think it's worth doing just for the sound, but I'm curious if it's as good as they claim. Anyone done any before/after dyno runs on their cars? The manufacturers claim to...

CHJ In Virginia

I remember some time back seeing a dyno test on stock Z06 Titaniums and several other "performance " cat back systems. Minor < 5 HP gains on any of the systems VS the stock. Do it if you want more sound, but if you are expecting a noticeable HP boost - forget it.

GT2BHPPY

Long tube headers w/ hi flow cats and Z06 TI's are the way to go.

bumble-z

Cat back system may give the bark your looking for, but not the bite.

Rob04C5LM

Thanks guys. I'm just surprised that a manufacturer could make such a claim on their product without worrying about false advertisement suits. In business you typically weasleword these sorts of claims with "results not typical" or something similar. Case law would support a false ad claim/suit if I went and tested this and found it generated only 5 when they claim 16. My attorneys would have drafted a whole disclaimer around this, Magnaflow is MUCH bigger than my firm, no such disclaimer...what gives?

zeevette

Right. What the world needs now is not love; it's litigation.

lucky131969

You are absolutely right. I think you should spearhead an effort, to bring these companies to justice. Fortunately, every other product sold in this country, works exactly as advertised.........right?

Rob04C5LM

Wow, that got away from me didn't it. I am not a litigious person in the slightest. I do everything I can to keep myself and my business out of courts, most others do the same. My only point was that it seems odd that a manufacturer would take the risk of making such a specific claim that you would "expect" this result unless there was some validity to it.

All of you fine people here seem to contradict a reputable manufacturer's claim. I generally find this group to be well informed and I value your opinions to the extent that they arent just argumentative or inflammatory. I am just interested in any objective evidence that would support the popular CF wisdom that there are negligible gains. Thanks for chiming in with your bright and sunny commentary. Are there any dyno sheets, flow results, improved ETs you might post or provide a link to? Thanks.

bumble-z

You may have a miss interpetation into their (Magnaflow) add .
They don't say that their cat back(ALONE) you can expect to gain 16.2 HP. They first roll into their add that you can go with their x pipe in conjuntion with their cat back & EXPECT gains of 16.2 HP.
The word EXPECT & the add on of the x pipe are smoke & mirrors to the actual HP number of their C/back compared to stock.
And no deffinition as to what stock c/back is? GM's stock Titanium c/back is hard to match or beat for flow.

Rob04C5LM

Excellent! I have the x-pipe with mine. Reasonable to expect the advertised gains? Or reasonably close?

chevy406

Do not expect to "feel" any increase in power if you are simply changing the cat-back and even adding an x-pipe along with it. You will "feel" the increase in power with long tube headers though.

Just make your cat-back selection based on the sound you want.

bumble-z

Do you have their (Magnaflow)2 1/2" x pipe compared to a stock GM H pipe that came w/your car?
There is a much better 3" x pipe (Borla) that you could have gone with.
You can , & here we go again w/that word (EXPECT) an improved HP
gain but 16.2? That's an awfull alot to EXPECT from over a stock what GM c/back.

Bill Curlee

Lets look at all the other clains that all the other manufactures also claim with their products. If you add all the products on the engine at the same time, you would seem to have massive HP.

It just doesnt work that way. like others have said, "If you want measureable HP/TQ improvements, your going to have to jump into your bank accound a bit deeper.

- Long Tube Headers ($400-$1200)
- True Cold Air Intake like VARARAM ($350)
- Professional TUNE ($350-$500)

That will net you approx 35-45 HP

My 02 ZO6 responded excellent with the following mods:

1- Stainless Works Complete LT SS Header, 3" mid pipe with high flow CATs and 3" mufflers

2- Ported LS6 Throttle Body

3- VRARARAM Cold Air Intake

4- Professional Tune

RWHP = 390 RWTQ = 375

NOTE! All ZO6 and 2001+ LS engines have the improved LS6 Intake manifold. The improved intake manifold maks a difference.

BC

TNRAT

Most of the catback and intake mfgs HP claims are true but misleading...they record HP gains within the RPM curve....not max RPM....so you may gain 16 HP at 3500 RPM but only 5 HP at 6000.....plus some are posting crank HP instead of rear wheel...

Rob04C5LM

Thank you! That's sort of as I expected. Again, I bought magnaflows because I liked the sound and got the x-pipe because I plan to do LTs at some point, so it wasn't the basis of my purchase.

Again, thanks for all the helpful suggestions

zeevette

That's what you buy aftermarket catbacks for; sound. I had the Magnaflows on mine when I ran with an O/R X pipe, and they were my favorite of 5 different systems I've had. Deep, mellow sound, without any hint of "motorboat" sound. They did have two problems, though . They have cabin resonance @ 65-75 MPH in 6th (3.42s), and even with H/C no cats, they're too quiet. No noticeable HP gains, but SOTP is all I have to judge by. It's common knowledge (gossip, really) that there's no meaningful HP to be gained from a catback change, but nobody that I know of has dyno'd before and after. I am surprised by your reaction to manufacturer's claims. Only ricer math is less accurate.

lionelhutz

I would expect that a gain of 10hp is possible. Instead of heresay you can look here and see some actual results;

http://forums.corvetteforum.com/1574509068-post43.html

Peter

Rob04C5LM

Thank you Peter! These ACTUAL dyno numbers (http://forums.corvetteforum.com/1573303063-post11.html) are precisely what I was looking for and seem to provide support to the manufacturer claims after all - though their numbers, as previously identified, are probably cherry-picked from the points in the RPM range that provides the greatest gains, rather than peak.

I definitely agree with the previous posters who said serious noticeable performance gains are only going to come after I dig deeper (heads, cam, and LTs are coming after my July bonu$ ). I was just surprised to see so many people on this forum claiming that there was NO performance gain to be had from these.

zeevette

Don't discount the improvement in sound that a replacement catback gives. Especially if you have a regular C5, the stock sound is really wimpy. Shop around the forums, and other resources for used aftermarket catbacks. My first two sets, after stock were bought for a total of $750, and I even resold them for a profit. The quality brands are all stainless steel, and if not physically damaged, will clean up to brand new looking. Even if they don't make the quarter mile any quicker, they make it sound faster.