M8 114-117 dyno numbers and exhaust

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08-02-2018 | 07:50 AM

Patrick Eubanks

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From: Farmville, NC

M8 114-117 dyno numbers and exhaust

im looking for some experience. I have the 114-117 stage IV kit installed on my 2018 and am looking for realistic Dyno numbers. I am currently running the Vance & Hines big radius 2 into 2 pipes. My dyno guy is struggling with the HP. Im missing 15 hp or so. He is pulling the baffles out today to get some numbers. Does anyone have any experience with this setup? Harley 515 cam installed (HP). His initial tune was a disaster. Rev limiter was too low and power was peaking too early. The graph was confusing as it looked identical to the stage 3 kit target chart. I thought he had installed the wrong cam. He assures me its the power cam. Im just ffeeling lost. Could the exhaust be making that much difference on HP? Torque numbers are fine

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08-02-2018 | 08:08 AM

Ghost_Glide

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From: Aiken SC

it could be your exhaust. the M8 engine is finicky with the back pressure certain exhausts do or do not produce. Ive not heard of too many people using the big radius as an exhaust for HP gains. All told that could be your problem right there.

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08-02-2018 | 08:51 AM

Patrick Eubanks

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Joined: May 2018

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From: Farmville, NC

Quote:

Originally Posted by Ghost_Glide

I curious to see what the numbers are with the baffles removed. I find it hard to believe that the pipes with cats removed are not more free flowing than their target pipe with cats. I will change the pipes if thats the problem but I love the look of the big radius. I was curious if anyone else has dyno number and what pipes they were running.

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