Headers with CATS or Highflow CATS?

[timmayz]

Just called TPIS and they mentioned they updated their web site with V header info. The pic up there is of a C5, they are sending me pics and updating their site tomorrow.

They mentioned that the header and cat kit ($1175 total) comes with pipes to hook into the original exhaust...

Trying to decide whether to do headers or just high flow random tech cats ($680 ).

Anybody done either with magnaflows? Wondering how it sounds. I'm sure with tuning you can get the 20 hp...

[urbanski]

i've never heard of just doing aftermarket cats with the stock manifold...makes no sense.

[DILLIGAF]

Why so?Doesn't laasts run rc's with stock manifolds.More flow is more flow,Maybe?

[urbanski]

didn't he do something to the manifolds though?

[timmayz]

Originally Posted by urbanski

i've never heard of just doing aftermarket cats with the stock manifold...makes no sense.

Well at least if an emissions inspector opened your hood he wouldn't see headers and alot easier to install/uninstall than headers I'm guessing, no hacking up your exhaust, keep the power in the lower end....
All depends what gain there is with just cats.

I guess Random Tech thinks it makes sense though they want too much cents

[DILLIGAF]

I'm pretty sure Laasts honed his manifolds,I just thought the cats were the restrictive part in our exhaust.Saying that I might know of some cats for sale quite a bit cheaper than randoms.I haven't called yet though.And thats something I need to address with stealth before I do anything.

[timmayz]

Originally Posted by rp64ctsv

I'm pretty sure Laasts honed his manifolds,I just thought the cats were the restrictive part in our exhaust.Saying that I might know of some cats for sale quite a bit cheaper than randoms.I haven't called yet though.And thats something I need to address with stealth before I do anything.

I'm interested... We need a dyno guinea pig to see what the results are.

[willsctsv]

I have run the B&B headers with there crappy high flow cats. The power feel from the headers was all seat of the pants and by far the best bolt on. Period. After gutting the crappy cats, I felt a little more power, but not nearly as much as the headers when the were initially installed.
Don't just change the cats, Go for the whole kitten kabootle! It's worth it!

[timmayz]

Originally Posted by willsctsv

I have run the B&B headers with there crappy high flow cats. The power feel from the headers was all seat of the pants and by far the best bolt on. Period. After gutting the crappy cats, I felt a little more power, but not nearly as much as the headers when the were initially installed.
Don't just change the cats, Go for the whole kitten kabootle! It's worth it!

Was that with a tune or is that only needed if you don't O2 Sims? I guess our manifolds are more restrictive than the Z06 manifolds. I put long tubes on my Z and didn't notice much, never got it tuned of course...

[r_casino]

Originally Posted by urbanski

i've never heard of just doing aftermarket cats with the stock manifold...makes no sense.

Urbanski -- could you explain more?? Are you saying the stock cats are not restrictive? I'm trying to figure out how a free flowing exhaust could make a difference and a header could make a difference, but not a free flowing cat?

Not trying to "push", just trying to learn!

In fact, I have just random cats with b&b xpipe and stock manifold. I considered headers, but after researching it seemed there were lots of opinions that said it wasn't worth it for the gain. (According to others, apparently the stock manifold wasn't all that bad, it was built pretty well, and it was "mated" at the factory so one less concern with leaks, spark plugs, etc.) I realize those opinions are equally balanced with the guys getting gains, but I had to decide one way or the other so I chose to wait. (When I was shopping I couldn't find any before/after numbers so I had to go on just opinions.)

Since that time, b&b produced their headers and it seems they get good gains. But they also include high flow cats, so maybe they saw a restriction?

I figured, if I learned more about the benefits of headers with the cats, I could always add 'em.

[trukk]

I have Stock Exhaust Manifold mated to RT Cats, then to a Corsa.

I installed the RT Cats, after I had the Corsa on for a while, and definately detected a SOP difference. The car also felt as if it reved a lot more freely. It sounds a hell of a lot meaner now too. RT Cats + Corsa really sounds great IMHO. A lot 'deeper' sounding. It is REALLY loud on intial startup too. All heads turn.

I dyno'd mine two days after the RT Cats install, and ended up at 304 rwhp on a mustang dyno. I dynoed with two other V's (mine was done last so I probabaly had a bit cooler engine). The first, totaly stock, dyno'd at 283. The second (who also had RT Cats and a Corsa) dyno'd at 289 (I think). [Just to put into perspective, a supercharged z06, and a new stock '05 GTO also dynoed with us, and ended up rated at 385 (vs. 475 on a dynajet), and 301 respectively]

What are they truely good for? I'd guestimate about 7 rwhp??

The thing I am most happy about is their fit/finish. They went on with ease (aside from getting the old O2 sensors out of the old cats), and mated up to the stock manifold, and Corsa exhaust with no problem (go-go copper RTV).


On a side note, to clear up a few things about Martin's (LASSTSS) car. He was the first (AFAIK) to install the RT cats, and he had them mated up to stock (non honed) manifolds for at least 6 months. In the last two months or so, he got his monifolds extrude honed (basically 'sand blasted' with clay gloop), and then jethot coated. I still haven't been over to check them out since he's had it done. For the price (700 RT/cat + about 1k for extrude hone/ jet hot & shipping), it is not the way to go to get best HP/$, and it won't equal the same performance as a good set of headers, but what you DO get is a troublefree (i.e. no leaks, burnt wires, extra heat in the engine bay), emissions, and dealer friendly setup.

When you talk to Martin, you can tell he is very knowledgeable about cars. He was an SAE mechanic for a long while, and is a degreed Mechanical Engineer. When he recommended the RT Cats vice headers, due to the 'pain in the ass' factor of headers, I headed his advice, and am glad I did. Just look at the other threads hear about leaking headers.

If you don't care about emissions, just gut you current cats, and then have a tune remove the rear O2 sensors.

-Chris
[Very happy with RT Cats, rather than headers].

[timmayz]

Originally Posted by trukk

I have Stock Exhaust Manifold mated to RT Cats, then to a Corsa.

-Chris
[Very happy with RT Cats, rather than headers].

If they would just bring the price down on the cats... On the flip side I had LG Pro headers on my z06 for more than a year and no leaks or other problems. Little pain to install, had to lift engine up a little on one side...

[willsctsv]

Timmayz, even before the tune the car feels like a whole different beast with the headers!