My GMPP Catback Dyno Results!
03-27-2008 | 09:00 AM
#178
New Member
Joined: 11-16-07
Posts: 81
Likes: 0
From: Frederick, Maryland
This is a terrific post you made, very helpful. I am thinking about getting this exact exhaust and also the GMPP Extruded Honed Exhaust Manifold as well.
Part of the rationalization of putting this $ in a car I know I will never get back out is better gas millage. Did you notice any Gas Millage improvement after install of the low restriction exaust?
Also, you do a great job on these forms!
Part of the rationalization of putting this $ in a car I know I will never get back out is better gas millage. Did you notice any Gas Millage improvement after install of the low restriction exaust?
Also, you do a great job on these forms!
03-27-2008 | 10:25 AM
#180
Member
Joined: 02-26-08
Posts: 223
Likes: 0
From: Colorado Springs, CO
With a 2.8 I was making 18.5 PSI, which is more than I should be making. I felt the stock exhaust was restrictive so I started replacing it. Switched to a 3" DP w/cat and the boost went up to 19.1 when I was expecting to go down. Was confused at the time. Thinking about it I realized that with the 3" DP I was creating more back pressure then even before. All that air rushing through the 3" and then get really slowed down with 2.25 stock exhaust. So I bought a 3" exhaust, havent put it on yet but Im betting that my boost will drop to 17PSI right where I want it. If this turns out to be a bad choice I'll swap to TAG 2.5 header back and buy you guys a E-beer 
or keep it because ill be turbo next summer 
np, but I think ur looking at the single tube numbers the dual numbers are to the right of the other numbers and says that a 1.5-2.0 would be good for ur 500+ rank hp
or keep it because ill be turbo next summer np, but I think ur looking at the single tube numbers the dual numbers are to the right of the other numbers and says that a 1.5-2.0 would be good for ur 500+ rank hp
03-27-2008 | 07:11 PM
#183
03-29-2008 | 12:49 AM
#186
i got my gmpp performance exhaust installed today.. man, that thing sounds sweet.. i really cant tell if i got any performance gains from it though.. ive heard that you should disconnect the battery for a half hour when you add an intake so the computer can learn the increased airflow or whatever but is that the same with an exhaust?
03-29-2008 | 01:09 AM
#187
Senior Member
Joined: 04-24-07
Posts: 2,134
Likes: 0
From: a
i got my gmpp performance exhaust installed today.. man, that thing sounds sweet.. i really cant tell if i got any performance gains from it though.. ive heard that you should disconnect the battery for a half hour when you add an intake so the computer can learn the increased airflow or whatever but is that the same with an exhaust?
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