slowride

iTrader: (3)

I've got a 383 ZO6 that I just built from H/C only a few months back(bought the car H/C). It has a forged 383(Mahle, Compstar, Eagle), CNC LS6 heads(~300cfm at .600" intake), Comp 238 242 .605" .610" 114+0, LG Pros w/3" cats, Borla stinger, Haltec CAI, ported TB, ASP pulley, TR6's and slightly ported ls6 intake. It's 11.8 SCR and 8.41 DCR.

Questons are how much will the ls6 intake and tb hold the car back? I figured it might be in the ~470/440 range as it sits in the cool fall air. The old H/C setup was suppose to be good for 445/405 cats and all. I'll probably do a Fast 90/90 setup next year (ported of course). Just curious as to what the expected gains might be with a 383 at this level?

I'd also like to know if the cats will hold the car back much on the dyno? They are the nice 3" ones LG sells with pro long tube kit. I like how the car sounds with them as they take the edge off the stingers, but if it's going to hurt power a lot I can install race pipes. I've heard that having cats might throw off the wideband if installed behind the cats, but don't have any solid information. Any problems with cats and widebands on the dyno

Thanks,
Ed

1slowls1

iTrader: (1)

I would say the 90/90 ported over the ls6 and stock tb youd see +/-20hp maybe close to 30hp depends on the dyno the location of the weather station etc....

The cats obviously holds back some flow but nothing major maybe +/- 10hp if there good highflow cats id say no more than 5hp.

slowride

iTrader: (3)

I was figuring about 20hp from what others have said and searches turn up, but I haven't seen any good dyno sheets to back this up. I'd like to see a good back to back dyno done on the same day, etc. I think the cats are some of the better ones if they are included in the LG pro longtube kit. I hope they don't hold it back much. I'd pull them, but it's kind of a pain seperating all the slip fits after they have been clamped down and heat cycled. Plus I drive the car like this anyway.

Anyone know if there are problems with wideband operation running behind the cats? We'll be heading out to Speed Inc. in a week or so and I want to have everything ready

1slowls1

iTrader: (1)

give speed a call and ask them, that would be my recommendation.

300bhp/ton

The Ls6 will hold it back in the upper rpms mainly. What rpms are you spinning it too?

From what I've read/seen the FAST 90/90 is usually worth 15-25rwhp on a good h/c setup. Ported should be even better.

As for the CATS, well I guess not too many people know about them. LG uses Random Technology 7000 Series Metal Matrix CATS, these are the mother of all CATS and flow really well.

598cfm which is good for zero restriction at nearly 550bhp. So I really doubt they are having any noticable affect on your setup. The only thing they do is affect exhuast pressure wave. But in all honesty I would be staggered if they are costing 5rwhp.

slowride

iTrader: (3)

I emailed Larry the main dyno guy a few days ago, but no response yet It's suppose to be the best way to contact him.

slowride

iTrader: (3)

I guess we'll see what happens next week. Adding the intake next year gives me something to look forward to. I might add a 100-150 shot of nitrous next year with fuel pump upgrades. That should be fun

slowride

iTrader: (3)

Car put down 483whp and 445wtq. Thats with a ported tb, slightly ported ls6 intake, cats, 92 octane and 3.90 gears.

Louis

iTrader: (7)

Congrats on the results Ed! Glad you got it running, I know you had a long road, but it sure payed off

As for the cats, as someone mentioned, they are the mother of all cats *meow* We see less than 4 rwhp loss at the 500rwhp level

Louis

slowride

iTrader: (3)

Thanks Louis, I've learned a lot about these cars in a very short time you could say. I think a ported 90/90 setup in the future would really set the package off. and help me get over 500whp NA.