Testing Stage 1 AC With Stock Mufflers No Tune On 2017 Tri Glide-Outcome After A Week



My 2017 Tri Glide is bone stock and runs great and I don't mind the sound of the stock exhaust at all. I do like the cleaner look of the stage 1 AC systems that utilize the stock 107 M8 AC cover. They really clean up the look of the factory air intake by removing the bulky black air box. I chose the SE stage one because it is CARB approved here in California.

With that said the 2017 trikes don't seem to be as lean running as previous years, they seem to be tuned better. I am running a test right now with a stage 1 air cleaner installed only, no tune useing the stock tune and stock mufflers.

To my surprise the trike runs even stronger through the RPM range and did not seem to lean out. The spark plugs look very good. I have run many spark plug cuts (the old fasthion way of checking how rich or lean a motor is running) at all diffrent RPM ranges and diffrent steady cruise speeds this week.

All of these spark plug cuts so far have looked very very good no lean readings at all (all the spark plug cuts looked very much like the plug pics below). Over all this tells me nothing is being hurt and nothing is to lean with this set up. I don't plan on changeing the mufflers which would increase the air flow out of the combustion system.

A muffler change more than likely would for sure start leaning things out more (more air through the combustion system). The bike can only take in and expel so much air with the stock exhaust system. As said my trike runs stronger and shows no signs of leaning out. The factory tune on the ECM looks to be compensating just fine for the AC upgrade only.

In my opinion the 2017 stock Harley fuel injection compensates much better than what folks are being lead to believe. Yes it will control to an EPA tune but that's not going to burn a stock bike up and will still run ok and still get decent fuel mileage. That's what my testing this week has shown me.

I also talked with S&S cycle by phone the other day (was also looking at one of there CARB approved AC units) and they pretty much varified my conclusions here before I started my testing.

They said my 2017 bike will run fine and not burn up with the stock mapping. They said that is what there dyno runs and testing has shown with an AC mod only. They also said if I tune the bike even richer than the EPA map it will even have more gains and if I add mufflers even more gains.(we all know that to be true). They also said the 2017 do very well compared to past years and run well stock.

All this testing has led me to believe the changes below with the stock 2017 tune will work just fine. While maintaining decent fuel mileage. Going to run more test this week and if All looks good I am going to leave the Trike this way as said it runs great.

I have seen a few dyno runs out there that support my finds. As a mater of fact DK Customs has tested AC stage 1 install only with the rest of the bike stock with the stock tune on the M8 with great results (dyno charts to support). Also have seen other dynos to support this as well from other folks. My testing supports these results as well so far.

* Add - Mufflers only stock tune= ok

* Add - Stage 1 AC and stock mufflers =ok

Plug pic in spark plug socket= Front plug.

Plug pic without plug socket= Rear plug.

Ride Safe All,

Bill G

 

I'm very surprised that your butt meter would notice the improvement made by a stage 1 air Cleaner. The new cleaner systems are already much more open than they were in the past.

As far as everything else, glad you're happy with it.

 

[QUOTE=TriGeezer;16082650]I'm very surprised that your butt meter would notice the improvement made by a stage 1 air Cleaner. The new cleaner systems are already much more open than they were in the past.


Well brother you can. The dyno runs I have seen show up to a 8% to 10% gain in HP and a 5% to 7% gain in torque with a stage 1 AC added only with the M8. That can be noticeable at the butt if you know your bike.... The m8 is a different beast and HD did a better job on it than the 103. It responds to mods much better even small ones. I notice a slight increase in the low & mid when rolling through the gears.

I love how someone always tells ya what your feeling on a forum.Lol..

Ride Safe,
Bill G

 

No doubt the M8's are rolling out of the factory with a much better tune than the Twin Cams.

As the charts you posted show, they are not running lean at all....even when a Stage I A/C is added.

 

So with these findings will adding stage one air cleaner and slip ons be safe or do I need to get a tuner

 

This is some good to know information, my wife now wants to Stage 1 her Freewheeler but I'm still skeptical until somebody who does the ac and muffs sans the tuner reports back in October after a long hot tortuous Summer of hard riding. At least we now have an official tester! Looking forward to your long term review

 

I may be the official tester but,

If you read what I said not to say you didn't you will see I am running the stock mufflers on our 2017 trike with the AC upgrade only and no tune. All is good with the testing plus DK testing shows this as well. I do not plan on running after market mufflers.

I like the sound of our trike and being able to hear the radio in our helmet speakers. Loud pipes tend to compete with that so as said I am sticking with stock EPA legal mufflers. Also mentioned with stock mufflers the M8 will only let so much air through the intake and exhaust system. The throttle body will only take as much air as needed right now.

So if after market free flowing mufflers are added to will that change the flow enough through the intake and exhaust to lean things out to much with the stock tune? I really do not know. Again I think if a guy on the M8 adds mufflers only keeping the stock air box he will be ok without a tune. Or a person can add only the stage 1 AC and be ok without a tune and that seems to be the case in my situation as stated.

Ride Safe,
Bill G

 

Maybe Kevin at DK Customs can answer that, I personally do not know. I only know and as said my testing and DK Customs dyno runs show the stage 1 AC upgrade to work with stock mufflers and the stock tune and performs without being overly lean. Adding about 7% torque and about 10% HP of course that could vary a little from bike to bike. Pretty darn good in my opinion for an AC upgrade only. The M8 I believe has a lot of un tapped potential and I feel HD did a much better job with it than the 103.

Ride Safe,
Bill G

 

I may be in the minority but I have RCX slip ons, screaming eagle high flow with stock cover and I ran my bike with stock tune for about a week, ran simply awesome! To be on the safe side of warranty I had harley install the street tuner and my bike has ran like crap since. Everyone here said it may have been a bad download so it was reflashed and although it did run a little better it has not been the same. I'm no expert (like some of the guys on here&#128521 but I can tell you my bike ran a hellava lot better before the street tuner.. The best way I can describe it, it feels like driving a car with the parking brake 1/4 of the way pressed, feels like something is holding it back. I'm either going to flash back to stock or put a FP3 on it, still undecided on that but the street tuner is a goner for me.

 

i read it and i get it and it makes sense especially with the exhaust as a bottleneck, and all the supporting opinions that things are not the same with the M8 as the twinkies, but with almost $30k spent i'm like Missouri, The Show Me State, and short time in the Winter isn't enough validation for me. That being said, i won't be shocked if you end up being right about all this!