BrntWS6

iTrader: (7)

I decided to swap to 1 7/8" headers after talking to people telling me my 1 3/4" could be a choking point in my setup. Wasn't expecting much....maybe 5 rwhp, but I wasn't out much money doing the install myself after selling my old Kooks headers so WTF.

ONLY thing that changed on my car was swapping from Kooks 1 3/4" to Kooks 1 7/8".....same dyno....after a touch up tune.


Setup:

2.5 LS6 heads from PRC
Torquer V3
FAST 92/92 ported
98mm Lid
UD pulley
Kooks TD's



Old numbers WCF
441.6 hp
391.4 tq

New numbers WCF
461.4 hp
406.5 tq

Again, ONLY thing changed is from Kooks to Kooks headers larger primaries.

alans02z

iTrader: (9)

Thats alot more than I would have guessed. Very nice

MeMz

Wow, that is pretty damn impressive

low2001gmc

iTrader: (148)

yeah wow....

Sales1@Texas-speed

Those are definitely some solid gains!

therat1989

Ive thought about switching to kooks ss and a borla catback. If i knew i could gain power and get phenominal sound i would do it in a heartbeat.
Your results have helped aid my decision. Thanks.

transamtom

iTrader: (8)

Wow 20hp 15tq very nice gains

1989GTA

I agree. That is double of what I would have guessed.

BrntWS6

iTrader: (7)

^ You and me both, I was shocked when the numbers popped up. Hopefully I can help people with their headers decisions with this, the primary debate still comes up here.

Tainted

iTrader: (9)

Very nice. I think the fact you are a heads and cam car is what really made the switch worth while. A bolt on car would be a lot less

JakeFusion

iTrader: (7)

Holy hell. LOL. And you didn't lose anything even down to 2500 RPM.

TSP did a test a few years back and had smaller gains (but gains everywhere) with their 1-7/8" vs Pacesetter 1-3/4" on a stock LS1 with just a FAST intake. Everyone wanted to see the difference between like Kooks 1-3/4" and 1-7/8". Hot damn! The True Duals are certainly helping

HioSSilver

iTrader: (8)

I can believe it. I went from mac 1 3/4 to Kooks 1 7/8's....think how big that change was....lol Good gains, these things like to breath!

venom ws7

iTrader: (13)

Great gains congrats on great mod..

I honestly would never buy 1.3/4 headers unless I want to keep the car as Boltons only...

RAMPANT

iTrader: (17)

Nice gains.

Are the new 1 7/8" headers the new design with the Merge collector? I have heard that alone can make 10 + horsepower with out even changing the tube diameter.

I hope I see similar in my change from a 1 7/8" to a 2" with a merge collector.

LeanPocket

iTrader: (6)

with stock heads and cam I gained 5+ hp switching from pacesetter headers w/ open cutout to kooks 1 7/8 headers and true duals. I have a tight gap on my plugs aswell and the redyno was in warmer temperatures by about 15 degrees.

amazing gains, those headers really wake up with heads and cam.

LeanPocket

iTrader: (6)

they were also very easy to install compared to the pacesetters and great fit n finish

yonerhottlt1

iTrader: (21)

Definitely great gains!

02TransAm/Batmobile

iTrader: (32)

Thanks for posting this info! I was hesitant about purchasing KOOKS 1 7/8" headers because I thought the 1 3/4" size would be more ideal for down low torque. (My goal is to hit 350TQ at 3000RPMS). This info makes me feel good about purchasing the 1 7/8" size headers!

I see you went to Straightline - live in the Chicago-area too?

JRENIGAR

iTrader: (37)

I wonder what the TSP 1 7/8ths setup would do over the hooker 1 3/4s in my sig?

TrentSS

As JakeFusion mentioned, it's interesting to see there was no loss at all in the powerband even at ~2,800 rpm's. Excellent gains across the board...