Feeling that $1,000+ is absolutely ridiculous for a set of headers, I spent my money on a set of the much debated "ebay headers". I've had them for a while and just installed them last weekend. In addition to the headers I also bought a couple of cheap "Thunderbolt Cats"; the metallic spun versions.

Upon receiving the headers, the first thing I noticed was the absolutely gorgeous welding job done on the mid-pipe, and the second thing I noticed was how ridiculously thick the mating flange for the heads were (there is no way in hell that flange will ever warp). Otherwise though the headers were of average build quality, sure the pipe walls are a little thin, but no worse than I've seen on many other headers.

Now onto the installation; the C6 is the absolute easiest car I've ever done exhaust work on. I had the stock exhaust down and manifolds off in about 2 hours. Had I been using a lift I could have done it in 45 minutes to an hour. The new headers slid right in with zero drama nor fitment issues, my father bolted them down while I held the header from under the car, we had this done in 15 or 20 minutes. Now here is where things went awry, the mid pipe is not quite wide enough to accommodate the spacing between the headers, while annoying I was expecting this problem. So a quick visit to my new favorite exhaust shop ( The Muffler Man in Placentia CA ) and he modified the mid-pipe and welded in my cheap-o cats in about an hour; to a very reasonable sum of $140.

Fast forward to this morning and I drove out to visit Ryne and the crew at Cunningham Motor Sports in Lake Elsinore, for a tune. Everybody there was very affable, and equally important knowledgeable. Within a couple of hours my car was tuned and running like it did when I bought it several months back.

My car is a 2008 2LT M6 (no Z51) with the only modification being these headers with the Thunderbolt brand cats.

All in all I've got under $700 wrapped up in this and the results speak for themselves.


Note: Numbers are pre-tune and post-tune, not pre-headers and post-headers.

 

I can't see the dyno sheet, what was the HP gain?

 

Were the dyno runs before and after the headers or just two pulls after the headers were installed? 411 hp with nothing but headers is very good. I haven't seen the headers on eBay for several weeks now. I wonder if there will be any more.

 

The runs, were pre-tune and post-tune, unfortunately I didn't dyno before installing the headers.

 

You got what you paid for! About half price for half the results!
Glad to see it really, ARH kook's or Lg would put those to shame!

 

I unfortunately didn't dyno stock, but given most manual ls3s are in the 380ish range, we're looking around 30HP at the wheels gained.

 

So around 60HP with those?

 

Are these numbers with the cats on?

 

Without a baseline dyno to compare his before and after... I don't see how you can come to that conclusion..

 

I think he came to the conclusion I did before I read this was an after headers, before and after tune dyno.

 

There is no way to come to that conclusion.

 

How do you figure?? He didn't dyno the car stock?

 

Without having done a before dyno, you'll never really know how much you gained. We don't know if the 411.6 HP from your run is SAE, STD, or uncorrected. Also, the 380ish number you're quoting is from DynoJet chassis dynos while your car was done on a Dyno Dynamics...apples to oranges all across the board. The true test will be at the drag strip but again if you don't have a baseline, it won't tell you anything either.

The main thing is if you're happy with the way the car feels now for the money you spent. It sounds like you are so the numbers don't really mean anything, go take a nice Sunday drive and enjoy the fruits of you and your Dad's labor. I'd say your Dad helping with the install is priceless as you'll have that memory forever. My Dad passed away recently and my best memories are all the late night wrenching we did underneath various cars. Forget about the numbers and go make more memories.

 

Well said Glass Slipper! You realize the important stuff! BZ!

 

What a great post.

 

Yes the numbers certainly are with the cats on.

 

It seems as though no matter what one is to do, people will call these headers crap, the point of this post was not to argue with anyone, it's simply a quick review and a dyno showing some decent gains.

Per Ryne when I asked him yesterday (and he tunes A LOT of Corvettes) most of the LS3s are doing in the 380s on his dyno. At which point using VERY rough math you can say even if my car was on the high end (388 for arguments sake) 411-388 = 23 HP gain at the wheels, which no matter how you cut it is a very nice power gain. Additionally Lake Elsinore sits at ~1250 feet in elevation, so corrections would be absolutely minimal.

However as I said before I'm not arguing anything, I'm simply presenting the facts, for those like myself who wanted them.

 

I agree...my dad and I do everything to my vette...it's fun and great father+son time.

 

Ok, now you have something to go on if the same dyno has other LS3s doing in the 380s and yes that's a nice gain even using "very rough math". BTW, the correction factor is for temperature, absolute pressure, and humidity...elevation gets resolved in the absolute pressure term so there is no correction for elevation alone. Since you're using the same dyno/operator as the other LS3s, I'd say you have a pretty good apples to apples comparison so it doesn't matter which correction factor he used. Now go enjoy all that hard work!

 

I like the fact that you posted your install and tune factors with the headers. Thanks.