Stock manifolds vs BBK 1-3/4" longtubes test results:
Before exhaust = Stock manifolds, Gibson 3" off road X, stock over axles w/18" Dynomax Race Bullets welded in, custom axle back consisting of 2-1/2", 3 Chamber (50 series) Flowmaster mufflers using the inlet elbow from the stock muffers.
After exhaust = same as above except BBK 1-3/4" longtubes and 3" off road X in place of the stock manifolds and Gibson 3" off road X.
So a true manifold vs header test...
Admittedly, these are compromised results due to me dynoing in 3rd gear. We didn't get clean comparison data until 6000 rpms which is my fault for not using a dyno file. Lesson learned. The Rwtq info isn't as helpful so high in the rpm range, but it's all I have, so here ya go:
SAE Rwhp:
6000 = +1
6500 = +3
7000 = +.5
7300 = +3
7600 = +9
SAE Rwtq:
6000 = 0
6500 = +3
7000 = +1
7300 = +2
7600 = +7
Peak rwhp before: 818
Peak rwhp after: 825
These were dirt cheap, used, will drop boost a bit and I enjoy the sound, so in my eyes it's still a win.
Part two:
Another dyno test. This one features two results.
#1: I removed the Flowmaster 50 series axle back and added a Kooks axle back. I gained 7 rwhp peak and a similar amount through the curve. So this puts me at a 14 rwhp peak gain between BBK 1-3/4" longtubes and swapping axle backs. The car had an off road X on it for all tests. Why BBK longtubes and 1-3/4" you may ask? Well, longtubes weren't on my radar to be honest, but they were offered to me so cheap, I couldn't refuse.
Peak rwhp before these changes: 818
Peak rwhp after: 832
The gains were pretty close to 14 everywhere when it was all said and done.
#2: I dynoed the car in 3rd gear and made 831 rwhp Sae. I then dynoed the car in 4th gear and made 832 rwhp with 1* less timing. So today, my car made basically identical power in 3rd or in 4th gear on the dyno.
Here's a rundown of the current mod list and a screenshot of my current dyno sheet. I couldn't be happier. Such a simple, no maintenance required combination that just works and is a blast to drive.
JLT Super Big Air
Whipple mono blade
VMP Gen 2 TVS (ported blower case and lower intake by Bret Barber at Airflowsolutions)
69mm upper, stock lower, 6 rib drive
Hasty Bracket
11'-14' style Aluminator (11:1)
BBK 1-3/4" Longtubes & X
Factory over axles with race bullets welded in
Kooks axle back
Return fuel system
6R80
Tuned on E85 by the man, Ken Bjonnes at Palm Beach Dyno
Sent from my SM-G955U using Tapatalk
Before exhaust = Stock manifolds, Gibson 3" off road X, stock over axles w/18" Dynomax Race Bullets welded in, custom axle back consisting of 2-1/2", 3 Chamber (50 series) Flowmaster mufflers using the inlet elbow from the stock muffers.
After exhaust = same as above except BBK 1-3/4" longtubes and 3" off road X in place of the stock manifolds and Gibson 3" off road X.
So a true manifold vs header test...
Admittedly, these are compromised results due to me dynoing in 3rd gear. We didn't get clean comparison data until 6000 rpms which is my fault for not using a dyno file. Lesson learned. The Rwtq info isn't as helpful so high in the rpm range, but it's all I have, so here ya go:
SAE Rwhp:
6000 = +1
6500 = +3
7000 = +.5
7300 = +3
7600 = +9
SAE Rwtq:
6000 = 0
6500 = +3
7000 = +1
7300 = +2
7600 = +7
Peak rwhp before: 818
Peak rwhp after: 825
These were dirt cheap, used, will drop boost a bit and I enjoy the sound, so in my eyes it's still a win.
Part two:
Another dyno test. This one features two results.
#1: I removed the Flowmaster 50 series axle back and added a Kooks axle back. I gained 7 rwhp peak and a similar amount through the curve. So this puts me at a 14 rwhp peak gain between BBK 1-3/4" longtubes and swapping axle backs. The car had an off road X on it for all tests. Why BBK longtubes and 1-3/4" you may ask? Well, longtubes weren't on my radar to be honest, but they were offered to me so cheap, I couldn't refuse.
Peak rwhp before these changes: 818
Peak rwhp after: 832
The gains were pretty close to 14 everywhere when it was all said and done.
#2: I dynoed the car in 3rd gear and made 831 rwhp Sae. I then dynoed the car in 4th gear and made 832 rwhp with 1* less timing. So today, my car made basically identical power in 3rd or in 4th gear on the dyno.
Here's a rundown of the current mod list and a screenshot of my current dyno sheet. I couldn't be happier. Such a simple, no maintenance required combination that just works and is a blast to drive.
JLT Super Big Air
Whipple mono blade
VMP Gen 2 TVS (ported blower case and lower intake by Bret Barber at Airflowsolutions)
69mm upper, stock lower, 6 rib drive
Hasty Bracket
11'-14' style Aluminator (11:1)
BBK 1-3/4" Longtubes & X
Factory over axles with race bullets welded in
Kooks axle back
Return fuel system
6R80
Tuned on E85 by the man, Ken Bjonnes at Palm Beach Dyno
Sent from my SM-G955U using Tapatalk
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