Thread: Compression / Free Flow exahust
09-25-2006, 04:58 PM #1
Compression / Free Flow exahust
I have seen some conflicting information on the Free Flow exahust - hoping you guys can help clear it up.
Would like to run compression right @ 150. I understand the free flow could lower the chances of deto but is it necessary ?
I strongly prefer the stock exhaust due to the sound. Does this mean I should lower the compression ? I would like to err on the side of caution.
09-25-2006, 05:04 PM #2
What year boat ?
09-25-2006, 05:26 PM #3
Sorry... 2001 1200 GPR
09-25-2006, 05:49 PM #4Originally Posted by mrbtd
You can use PVC pipe instead of the metal pipe to deaden some of the sound.
09-25-2006, 07:03 PM #5
Is that to say I could use a 1300 waterbox and the sound resonator instead of the free flow ?
09-25-2006, 07:06 PM #6Originally Posted by mrbtd
09-25-2006, 08:56 PM #7
I am running 170 lbs without a FF using a 1200 exhaust set-up.
I was at 160, when I went to 170 my rpms stayed the same so anything higher than 160 would appear to be a waste (for top end anyway).
I have easy access to Sunoco 94 and I have lowered my timing advance.
Last edited by philip_gpr; 09-25-2006 at 09:25 PM.
09-25-2006, 09:00 PM #8
I have an 02' 1200 ported and I'm using the rubber 1300 free flow tube. It's much easier on the ears and has a good throaty rumble to it.
09-26-2006, 03:22 AM #9
I have been running the stock exhaust on my 1200 GPR with a 150lb Protec head for 99 hours w/no problems (with or without d plate). I much prefer it to my old noisy free flow GPR.
09-26-2006, 12:23 PM #10
I just did a back to back test on my 2001 with 145 psi. compression and the free flow actually pulled 20-30 more rpms. I was able to gain back the rpms by leaning out the high speed screws another 1/8 turn, but I don't feel comfortable doing that to gain speed back compared to the free flow.
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