js2fst

iTrader: (12)

Ok 1 7/8 or 2 in headers these are my questions! On a lowered vert and a iron block Procharger clearance issues? Gains?

dschmittie1

iTrader: (64)

what size is the motor. 1 7/8 should be enough though

+badss+

iTrader: (12)

I went tsp 1 7/8 lq9 f1 I'm going for 800+ I'm 390 ci

js2fst

iTrader: (12)

408 f1-c or r not sure yet! 4l80e and 9 in stock k
Member for now but I will put my bmr in when I get the a arms.

LS1RedZ

iTrader: (19)

How about 1 7/8 stepped to 2". Best of both haha

Blown06

iTrader: (32)

The guys in "the know" will tell you there is no such thing as "too big" of an exhaust on a blown application.

The typical N/A principles are thrown out the window with FI.

Bob@BruteSpeed

iTrader: (16)

http://shop.brutespeed.com/Brute-Spe...d-Camshaft.htm

Take a look at the dyno graph at the above link. This is an LS2/402 and is using Kooks 1-7/8 headers. Bob

LS1RedZ

iTrader: (19)

Yeah prochargers like to get the air out fast! I picked up almost 70rwhp by opening my cutout. I'm prolly going to pick up some 1 7/8 kooks myself with the new toy. I have pacesetter 1 3/4 headers right now.

hellbents10

iTrader: (10)

2" would be my choice.

blue00ZZleeper

iTrader: (5)

2" if you can. As everyone has said, procharged cars need to breathe! The quicker and more efficiently you can get rid of the exhaust, the better.

The Alchemist

iTrader: (19)

What about someone like me with a stock cube motor with a D1? I currently have 1 3/4 QTP's so should I jump up to 2" or go to 1 7/8?

fatmat80

I have stock cubes here as well Alchemist..I went with 1 7/8 ARH and picked up 35 rwhp over my 1 3/4 i had previously. For a all out build I would go with the 2 inch primaries, however on a street/strip build my vote is for 1 7/8.. mainly for clearance issues as is a concern for the op.

dschmittie1

iTrader: (64)

What headers did you have before and did anything else change in the exhaust? Thats a pretty impressive gain

fatmat80

1 3/4 Pacesetters and tsp off road y 3 inch flowmaster catback. (before)
1 7/8 ARH headers and ARh off road y 3 inch slp loudmouth 2 catback (after)

I am looking for my graph but if i am not mistaken I also picked up about the same in rwtq as well. I want to say my peak tq before was 547 ft/lbs and now I am sitting at approx 575.

35thsscamaro02

Damn I guess I'll have to ditch my qtp headers when I switch motors and max out the d1

dschmittie1

iTrader: (64)

Well not to discount the gains you saw but when people see gains NA from switching out a flowmaster cat back it is no doubt that it would hurt an FI motor

02gangsta/ss

i agree 1 7/8 american racing headers are the way to go ...more on the pricey side but imo worth it same ones im running with my d1sc

LS1RedZ

iTrader: (19)

Y'all think kooks and ARH are the same quality and performance wise?

NoGo

iTrader: (2)

Are you folks rebelting to get these gains.

I'm asking because I used to have a cutout on the car at the 4" to 3" transition on the Y. I actually took it off because it never picked up anything on the dyno when I opened it up. All it did was move my boost around.

I run the stock cat-back with the stock over-axle piping - so its not free flowing with the cutout closed.

LS1RedZ

iTrader: (19)

Any dyno sheets out there in the different size headers? I'm goin F1A on my 370 and I want to swap headers. What size would benefit me y'all think?