Ran slower with the cutout open
#32
TECH Junkie
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I tested it multiple times at teh track. Closed, full track open,launch then open,2nd gear then open.
In the end open the full 1/4 netted me the fastest times in 60ft,1/8and 1/4.
Normally netting me overall at least a full tenth evertime i open it up.
So with a stock stall i can only leave at a max of 1800rpms and i still get benefit from it. In the end 13.7@99 with it open. 13.8@98 with it closed.
Also my truck is tuned like donkeydick lol. Just FYI for everyone.
#33
I bet mine would dyno higher with it open but it was the lower RPMs that killed me at the track... That is why I believe in track times vs dyno number...
Also my friend with a 6.0 runs better with his cutout open, I guess teh larger cube motors like a free flowing or non existant (cutout) exhaust system...
Also my friend with a 6.0 runs better with his cutout open, I guess teh larger cube motors like a free flowing or non existant (cutout) exhaust system...
#34
Staging Lane
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also i would feel it alittle weak with it open.thats y i never took it off.at the track i an the same time when it was open or closed
#35
On The Tree
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You have to tune for the lower backpressure or you can actually lose power. I did a GTO tune for a friend with and without his cutouts open. He gained 20RWHP with them open over the top numbers I could achieve with them closed.
You also have to remember that if you tune for the open exhaust when you put a cork in it you will likely lose power for your everyday driving. For my GTO I had 2 tunes ... 1 for open and 1 for closed because I couldn't figure out how to make them both work simultaneously at that time.
I intend to borrow a great idea from the newer corvette exhaust. A vacuum actuated exhaust cutout so it is subtle in everyday driving but when you floor it you can have the benefit of the open exhaust similiar to how the newer corvettes work and it should be tunable.
You also have to remember that if you tune for the open exhaust when you put a cork in it you will likely lose power for your everyday driving. For my GTO I had 2 tunes ... 1 for open and 1 for closed because I couldn't figure out how to make them both work simultaneously at that time.
I intend to borrow a great idea from the newer corvette exhaust. A vacuum actuated exhaust cutout so it is subtle in everyday driving but when you floor it you can have the benefit of the open exhaust similiar to how the newer corvettes work and it should be tunable.
#40
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This past weekend with the same tune for closed and open cutouts.
closed 60' 1.60,s
open 60' 1.59's and picked up about .10 in the 1/4 mile.
I had to run true street through mufflers and could run open cutouts in the LSX class.
closed 60' 1.60,s
open 60' 1.59's and picked up about .10 in the 1/4 mile.
I had to run true street through mufflers and could run open cutouts in the LSX class.