jkel1124

iTrader: (3)

So now that my rear is solid again I'm ready for some additional mods. I have the Maggie and Corsa cat-back exhaust, but still have the stock exhaust manifolds and cats. I was told that most of the added power from the long tubes comes from the removal of the cats. This makes me wonder if I should just try the cat delete pipes first to see what kind of power gains I can get with a tune. Does anyone have any experience with this...power gains with long tubes and no cats vs. cat deletes alone (on a supercharged LS)? Also does anyone know where to get the cat deletes? Thanks for any info you can provide!

GulfM3

iTrader: (14)

LS6 manifolds flow very well, IMHO, your maggie will max out before they become a restriction. Back when I had a maggie I was at about 510 rwhp, to get there I had a 8" OD crank pulley, cam, heads and headers.... With the stock cam, heads and crank pulley the car made 450rwhp, I think the majority of my power gains came from the 8" OD crank pulley.

In short, I'd do test pipes and an overdrive crank pulley and see what numbers that puts down.

NeverSatisfied02

iTrader: (12)

I see a lot of people saying the crank pulleys make a pretty big difference. How much do they run and is there one that's ideal for optimum performance gain? I think it's prob a good mod for the money from what I've been hearing so I'll prob look into that next along with a cam and supporting parts.

As far as headers, they do show good gains but if GulfM3 says you'd be fine just losing the cats, I'd do that and spend the money on something else. Hell... Had I known that, I would have just done cat delete so I could keep my stock manifolds and not have to worry about smashing my headers on the ground when I crank the car down on my coilovers. Lol

jkel1124

iTrader: (3)

Thanks, great information. Thats kinda the direction I was thinking of going. Anyone know where to get a set of test pipes that will bolt up to my stock manifolds and Corsa?

NeverSatisfied02

iTrader: (12)

I think someone just posted about some high flow cat pipes they offer on eBay to work with stock headers and stock catback. Not sure if they only come with high flow cats but I'm assuming you could order catless ones. You'll have to tell them u have a corsa catback because I believe the connection on your corsa is different than on the factory exhaust. Buy even if u can't order them catless, im sure an exhaust shop can prob fab some up for you to fit your setup.

itsslow98

iTrader: (18)

I dont get how the stock manifolds flow so well when guys are picking up 25rwhp on bone stock cam/head motors. I picked up 22rwhp just by adding kooks and high flow cats. Then I added the cam and made 35rwhp more.

You should easily see 30-40rwhp gains with a maggie from 1 7/8 long tubes.

jkel1124

iTrader: (3)

Yeah having them fab'd will be the next step if I can't find any bolt ons. It's just difficult around here to get an exhaust shop to do custom work when it comes to cat removal.

NeverSatisfied02

iTrader: (12)

I've never had a problem getting it done on vehicles in the past around here but I can imagine some shops would be hesitant to do it. I'm sure you'll be able to find someone that will though if u can't order them pre-made.

jkel1124

iTrader: (3)

I wonder how much of that 22rwhp was due to the high flow cats though instead of the headers.

itsslow98

iTrader: (18)

My guess is 5hp tops. Its not like i deleted the cats and high flow cats are still somewhat restrictive compared to running no cats. Have you ever seen the inside of a high flow cat?

NeverSatisfied02

iTrader: (12)

Cats are for females... Lol

But I have seen the inside of more than a few high flow cats in my day. I prefer them to be a tight and restrictive myself but to each their own. Lol

GREG O.

iTrader: (4)

The stock manifolds from what i heard are not that restrictive..but the cats are, especially on a boosted rear mount turbo...My cats are being cut off as i speak...Going catless...a lot less backpressure of power robbing hp

Also the cats on ebay,are junk.was told they flow worse than stock,http://cgi.ebay.com/ebaymotors/ws/eB...84.m1423.l2649
I was going to buy them but did some research....Don't buy thunderbolt crap....

NeverSatisfied02

iTrader: (12)

I too have heard the factory cats flow well but I'm wondering compared to what? Because there seems to always been a good gain to be had by getting rid of them.

VforMe

I'm having trouble understanding why you would spend a couple of hundred bucks having someone make cat delete pipes when you could get headers for $500. With the maggie you're leaving a good chunk of hp on the table with stock manifolds, plain and simple.

jkel1124

iTrader: (3)

Yeah I keep hearing that the stock LS6 manifolds flow pretty well so it seems just going catless is the thing to do. But from what I gather I will also loose boost at the same time by freeing the restrictive gases. Will the loss of boost cancel the power gains of the cat delete? Should I wait to do this mod untill I get some pulleys to get the boost back up?

V8EATR

yes you will loose boost but it will make more power. boost is simply a restriction of air. so if your boost drops, more of that air is making it in. a smaller pulley to bring the boost back up will be even better but yes it will still make more power.

tektrans

iTrader: (23)

Even if you dont gain a ton of hp with long tubes you WILL gain a shitload of torque.

jkel1124

iTrader: (3)

Well I talked to a local exhaust shop today and he said if I bring him my pipes (not the car) he can weld straight pipes through the cat housings (for my "off-road" vehicle). For $100 it's worth a shot to see what kind of power improvements it will do (and will still pass inspection). I haven't dyno'd this car so I can't provide any exact before numbers, but I've got a pretty good feel for power ;-). I am also going to order the 2.6 pulley for the Maggie to make up for the boost loss. We'll see what kind of problems I run into with belt slip, but the 8" OD pulley is going to have to wait a few weeks ($).

NeverSatisfied02

iTrader: (12)

Sounds like a fair deal to me.

GulfM3

iTrader: (14)

Are the ebay V header still around? I thought people were having trouble buying them.

For 500 I see your point, but if Kooks are your only option they are dam expensive.