I have a 2018 107 M8 Softail and when looking at the canned maps on the Dynojet website for Power Vision they show several different maps for my bike. All the maps show high flow air cleaner with a selection of different exhaust options. My question is what do they mean by " high flow air cleaner"? Do they mean stock air cleaner or an upgraded air cleaner I.E
Screaming Eagle or other aftermarket air cleaner?

 

Anything OTHER than stock.

 

I spoke to Dynojet today and they said that the stock air cleaner is considered a high flow air cleaner as far as they are concerned. So according to Dynojet the maps on their website are intended for a stock air cleaner. Go figure

 

That sounds contrary to everything that has been said about removing the stock cleaner and going to a "high flow" cleaner. The wisdom has always been that stock is not high flow.

 

Yes I agree, but that is what the guy at Dynojet said.

 

Then why did you come here asking questions if you're just going to take whatever some rando button-pusher at Dynojet tells you.

 

Changing an air cleaner assembly or airfilter for more HP gains has been one of the most exagerated "HP" mods out there for decades. Id like to see a real HP shootout between a modern OEM filter assembly vs say something like a SE air cleaner and what the gains REALLY are/

 

Who did you speak to over there? They usually have tunes for stock air cleaner and HFAC, which was generally tested with the Screamin' Eagle air cleaner.

 

I tuned a Sportster 883 on the dyno with slipons and the stock AC, stock AC without cover was 55 horses, with cover on 52 horses, 3 hp lost above 5500 rpm

 

According to Brand Manager and Dyno Man Bryan at V&H the stock 103 HO only gains a little bit with a high-flow intake:

"The 103 HO compared to 103 is really just a 4-6% increase due to a slightly bigger cam and a better flowing air cleaner, though you can still eek out more with a higher flowing air cleaner."

The new 103 HO has adequate flow for a stock engine so increasing potential CFM for a given pressure drop will result in little increase in VE. Stock pre-Rushmore (pre-2014) intake flows 171.2 CFM (not too sure how many inches Hg or H2O that was) and a 103 CI IC engine at 100% VE moves 185 CFM and, as we know, these engines are nowhere near 100% VE. Therefore this supports the findings Bryan at V&H is speaking of.

An air cleaner/filer and/or airbox that is highly restrictive for whatever reason(s) acts as a partial choke at high engine loads/speeds and very large throttle openings. At low engine loads/speeds and small throttle openings VE is low due to low cylinder pressure so affects of intake side become minimal.

In other words in the context of a bone-stock engine don't expect huge gains or losses with the proper late-model stock intake and clean element while at cruising operation.

Interesting... With a carb a dirty cleaner/filter element raises signal across the mains (partial choke) so VE goes low but AFR goes low (rich). With EFI a dirty cleaner/filter element MAP goes low and VE goes low but Delphi ECM compensates so AFR remains on target.

Here is a great test of incremental changes and how they affect RWHP on old XL1200: http://www.drdyno.com/AIM_2002-12.html