CMI and EMI exhaust for 502 vs 496
#1
CMI and EMI exhaust for 502 vs 496
IF people are really seeing 2-4 mph gains with the CMI and EMI exhaust why don't the 502 Mags see the same gains? I know they claim hp and tq increases but it seems in the real world an exhaust only changes on the 502 mag gives little or no top speed gains.
#2
Re: CMI and EMI exhaust for 502 vs 496
I have used both exhaust systems and have had very good luck. I have used the EMI Exhaust on a 454 mag and 454 mag mpi.
On the 454 Mag the increases were minimal (@2mph), until I made considerable engine modifications.
With the 454 Mag MPI, I included an ECU upgrade kit from Arizona speed and Marine. With some prop work (lab and 1 inch pitch increase), I saw a solid 4 mph gain on a Velocity 260. Still needed to run RPM @ 5200-5300.
Have had 3-4 MPH increase with CMI on 496 HO on a Velocity 290. Just received the Whipple reprogram back. Will be testing with that this weekend.
On the 454 Mag the increases were minimal (@2mph), until I made considerable engine modifications.
With the 454 Mag MPI, I included an ECU upgrade kit from Arizona speed and Marine. With some prop work (lab and 1 inch pitch increase), I saw a solid 4 mph gain on a Velocity 260. Still needed to run RPM @ 5200-5300.
Have had 3-4 MPH increase with CMI on 496 HO on a Velocity 290. Just received the Whipple reprogram back. Will be testing with that this weekend.
Last edited by Oh Deere; 04-27-2006 at 11:54 AM.
#3
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Re: CMI and EMI exhaust for 502 vs 496
Quote from 'Trailerboating' magazine: "Of all the modifications that we did to the 502 Pachanga over the 10 month period, the biggest single gain was Stainless Marine's exhaust. 225 rpm, 4.6 mph..........
#4
Re: CMI and EMI exhaust for 502 vs 496
Originally Posted by BROWNIE
Quote from 'Trailerboating' magazine: "Of all the modifications that we did to the 502 Pachanga over the 10 month period, the biggest single gain was Stainless Marine's exhaust. 225 rpm, 4.6 mph..........
#8
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Join Date: May 2005
Location: Austin, Texas
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Re: CMI and EMI exhaust for 502 vs 496
I put a set of Dana exhaust (only) on my twin 502's and saw between 2-3 mph gain. I did not expect to see that kind of gain so I was very happy! It looks and sounds alot better too!