So this is the description from the MOCO website:

This Screamin’ Eagle® 55mm Extreme-Flow Intake Manifold features enhanced, 55mm, air-guzzling geometry and hand-polished intake runners to provide uninhibited airflow to the engine resulting in a 2% - 4% increase in horsepower that you will notice.

• Cast-aluminum construction withstands sustained high-engine temperatures for reliability even under the harshest riding conditions
• Fits the stock throttle body and all Screamin' Eagle® Intake Kits
• Works with all current Screamin' Eagle® Pro Street Tuner calibrations
• All models require ECM calibration with Screamin’ Eagle® Pro Street Tuner for proper installation
• 50-State U.S. EPA compliant

My question is, what is the size of the OEM manifold on the M8's? Is it 50mm? Since this works with ALL SE air intake kits, what is the pros cons to upgrading or if you had the choice to get the original (if yours breaks or has issues) or upgrade to the 55mm?

Secondly and most important to me, the Powervision, FP3, and other well known tuners are all tuning with the OEM intake manifold size, so If someone were to get this put on, you would almost certainly HAVE to go full on DYNO. Right? or how could we make sure the proper tune is being ran?

thanks

 

The stock m8 is 55mm. Doubt it’s worth the time and money.

 

They have been out for awhile now and we have tested a few of them on the 107 and 114 engines. Are they worth the price tag......... who knows, but at least in our testing they showed a very slight improvement over the stock one.

 

We actually test the air flow here.
Some gains to be had as shown on our SuperFlow 600, flow bench.
Scott

 

Buy an hpi , not a Krispy chicken.

 

So just an update. I found the leak around the rear intake seal. now some may not know but the M8s intake manifolds are polymer/Plastic and my dealer has had at least 3 that they have had to warranty due to cracking and or leaking. Mine had about 6k on it but the leak i know has become worse over time, but this year it was really bad. So instead of putting the OEM plastic intake manifold back on, i opted to put a metal one on, the 55mm HD extreme flow in the photo above. Well the leak is gone, no more popping, or weird idle issues. AS for performance, nothing to note by seat of the pants. If there is any perf gains, the only way to know is to test it on dyno or other machine.

 

I have a '17 Tri Glide with about 30000 miles. Was told by dealer at recent service that I have a "small" intake leak. Going to replace with the metal one and get rid of the polymer thing!!

 

A tech on another forum has reported seeing at least two of the plastic manifolds melt.

__________________________________________________ ____
For ROCKOUT information & purchasing please click HERE For all Twin Cams and Evo Big Twins & Sportsters