Input needed on tuners thoughts and comments

Started by BadHabit, April 27, 2019, 03:39:34 PM

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BadHabit

April 27, 2019, 03:39:34 PM Last Edit: April 27, 2019, 03:44:31 PM by BadHabit
So just got back from a 7 hour trip to drop the bike off. Didn't feel the best about having them do the tune after talking to the owner and service mgr. But since Don Dorfman (hdsp) and several others recommended them highly I decided to trust them... The reason I left very confused and concerned is that I explained that I had a white brothers pipe and wanted them add/remove discs as needed to get the best tune possible. The service tech AND owner both told me that it wasn't needed. "They all run the best with all of the discs possible" I explained I had purchased and installed extra (20 total 6 more than in came with). Doesn't make any difference they said waste of time...The owner George Roeder (a VERY successful builder and racer) steps in and tells me the same thing..."Waste of time not needed" ...grudgingly they agreed to remove "a couple of discs" and see if it made a difference. George explained that in doing this the tune would have to be started over from SCRATCH with each change made. I guess it really doesn't matter how I feel about them if they give my tune 100% and I get a noticeably better performing bike....Am I missing something here about the discs?

Build detail
2005
95"
Hdsp heads
570g cams
9.9:1 compression
Supertrapp head pipe with white brothers muffler
Stock fuel injection
Ness breather

harpwrench

20 WB discs is comparable to many more trapp discs. I don't know how you got that many stuck in your head, maybe if it were 117" that would make sense, or if you had a supertrapp muffler. I'd expect it to feel like crap or at least "not happy" below 3000 rpm, at anything less than full throttle, and it's going to be noisy. I seriously doubt you're going to be happy with that. Since they don't want to mess with it I think you'd be better off having it tuned with 14. Just my opinion, I really hope it all works out for you it looks like a nice build.

BadHabit

Bike seemed to like 16 or so with just a quickie pv tune. I just put 20 in because Roeders said to run them all...I found that hard to believe but I  thought the tune would show what the motor wanted. They seem to think more is always better...that's why I'm confused

harpwrench


rigidthumper

Each change of plates (exhaust flow) does modify the air flow at different RPMs, requiring changes to VE & timing.
Typically, but not always, fewer plates help the low end, but not too few, as you don't want to be restrictive with most cams.
Best peak numbers, but not necessarily best curve, usually come from more plates.

Testing takes time, and time costs $
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

BadHabit

April 28, 2019, 09:16:04 AM #5 Last Edit: April 28, 2019, 09:20:16 AM by BadHabit
That is what I have always understood to be true but they said VERY strongly that they always use all the discs possible. I understand the time involved that goes with testing. The muffler came with 12 discs. I added over 50% more for tuning on there recommendation. And yet they believe it will always run best with more discs. I mean they looked at me like I was bat "Potty mouth" crazy to even suggest it might be too many.

Durwood

Quote from: rigidthumper on April 28, 2019, 07:32:08 AM
Each change of plates (exhaust flow) does modify the air flow at different RPMs, requiring changes to VE & timing.
Typically, but not always, fewer plates help the low end, but not too few, as you don't want to be restrictive with most cams.
Best peak numbers, but not necessarily best curve, usually come from more plates.

Testing takes time, and time costs $
:up: :up: When tuning disc type mufflers I just add time to the tune, usually an hour or two depending on how much time it takes.

I like them but they are time consuming. Like Robin said here, the best overall curve will usually take less discs at the cost of peak numbers.

It's a balancing act for sure.

FXDBI

Quote from: BadHabit on April 28, 2019, 09:16:04 AM
That is what I have always understood to be true but they said VERY strongly that they always use all the discs possible. I understand the time involved that goes with testing. The muffler came with 12 discs. I added over 50% more for tuning on there recommendation. And yet they believe it will always run best with more discs. I mean they looked at me like I was bat "Potty mouth" crazy to even suggest it might be too many.

I have a Fuel Moto E-Pipe when it first got it bike was a 95in 220ccp S&S 585 and HQ-HVP heads @ 83cc it was very happy with the full load of discs from FM. Listen to the Tuner he has a very good reputation. Being @ 95in and a 570 lift cam the gains to be had from tuning the pipe would be very minimal and expensive.  Bob

BadHabit

I'm so confused lol. So you say 20+ discs like the tuner?  (The pipe only came with 12 brand new 15 for fuel moto e series btw)

Ohio HD

April 28, 2019, 01:21:05 PM #9 Last Edit: April 28, 2019, 02:17:04 PM by Ohio HD
Trying to illustrate what Robin is saying, with more discs you will most likely see better peak higher RPM numbers. The lower RPM numbers may be soft. And the reverse using less discs, may loose some peak upper RPM numbers,  but gain in the lower RPM's, meaning sooner torque.


[attach=0,msg1294359]

BadHabit

April 28, 2019, 02:25:21 PM #10 Last Edit: April 28, 2019, 02:30:40 PM by BadHabit
Ohio I understand that. I'm saying if 20 discs are good why not 30?  If I only had 8 discs installed and the pipe came with 12 I can see where running all the discs I HAD would be preferred. But I'm way over that and I asked them if I could have to many and they said emphatically NO!  More is ALWAYS better

Ohio HD

In theory, the more open the exhaust the higher the peak numbers. So in theory 30 is better "if" 20 is still restrictive.

The testing part is how many can I take away (discs) and gain lower power and not hurt the upper power much, or not at all. Theory only become reality with testing of different cams, and other components.

BadHabit

April 28, 2019, 03:06:06 PM #12 Last Edit: April 28, 2019, 03:23:29 PM by BadHabit
That was always my understanding. It was the blanket statement  more is ALWAYS better in reference to attempting ANY disc tuning that was/is concerning. I went there because of the reputation they had of being one of the best...They left me feeling like tuning my bike was a chore....

Don D

Consider going back to a butt dyno test. Maybe drop it back to a half dozen and take it for a short ride just for the feel. More is not better and when the exhaust is wide open it will have a horrible dip. Sometimes just some crude tests provide guidance where you are at and where you want to be at. I have taken a 2x4 and put it partially over the outlet at times just to see what the motor likes , or not.

kd

Quote from: Ohio HD on April 28, 2019, 02:37:46 PM
In theory, the more open the exhaust the higher the peak numbers. So in theory 30 is better "if" 20 is still restrictive.

The testing part is how many can I take away (discs) and gain lower power and not hurt the upper power much, or not at all. Theory only become reality with testing of different cams, and other components.


In fact the SuperTrapp instructions tell you to start at a full deck of discs and work down in number until you encounter power robbing changes.
KD

BadHabit

April 28, 2019, 04:09:06 PM #15 Last Edit: April 28, 2019, 04:22:00 PM by BadHabit
See more confusion....From supertrapp's site "NOTE: When tuning an exhaust system, start with fewer discs and add. Never start with a lot of discs and subtract."

BadHabit

I very much appreciate all the answers and comments everyone is giving please don't miss understand my frustration for anger or not being appreciative. I'm tempted to say go with 14 (which several others with similar builds have said worked out best on there dyno tune) and tell them to just tune it that way. Since they seem to be reluctant to tuning with discs maybe I should just give them a fixed parameter. I will sleep on it and call them in the morning before they get started...

Ohio HD

Given the motor size, and probably what will make you happy running wise, I agree, take the discs down. You'll be riding the bike in the lower 75% of the RPM range almost always.

Ohio HD

I will add, I have used Roeder for tuning. They will do all they can to make the bike run at it's best. When I had my '09 Ultra tuned, they were done, but wanted to know if I could wait a day or two more. They wanted to work on the lower RPM's more. I agreed, no rush at that point. I rode the bike (they prefer you do) before putting it in the trailer. I was very happy with what they did.

They made my stock 96" with Andrews cams and D&D exhaust wake right up.


https://harleytechtalk.com/htt/index.php?topic=98936.msg1155981#msg1155981



BadHabit

It's that reputation that made my decision to use them. A side note I did not actually speak with the tuner himself (Jake). It was the service mgr and owner.

Chippitt68

I too had a very good experience there. I didn't use my fatshotz. They recommended the stock head pipe(minus converter) and my 4" slip ons. I had the bike tuned previously and it had a dip in the range I ride the most. I took Bevons word and I'm very happy with how it turned out. He explained the jackpot 2-1-2 head pipe would give higher numbers, but more to the right. He was spot on.

kd

Quote from: BadHabit on April 28, 2019, 04:09:06 PM
See more confusion....From supertrapp's site "NOTE: When tuning an exhaust system, start with fewer discs and add. Never start with a lot of discs and subtract."


I just looked and I see that.  I have another set of instructions saying the opposite.  I agree with the add to theory more.  You can watch the torque drop off and the power come on and stop before the torque goes away.   
KD

Durwood

Quote from: BadHabit on April 28, 2019, 02:25:21 PM
Ohio I understand that. I'm saying if 20 discs are good why not 30?  If I only had 8 discs installed and the pipe came with 12 I can see where running all the discs I HAD would be preferred. But I'm way over that and I asked them if I could have to many and they said emphatically NO!  More is ALWAYS better
Like I posted earlier, it's a balancing act. I try to get the best early torque that I can without choking it with too few discs causing a mid range dip. I start with a certain amount of discs depending on the build, then tune to the graph by either removing or adding discs until the curve is to my liking.

Complete tune of the entire map is not needed on every disc change, only wide open throttle tuning until the correct count is found.

That's the way I do it. It's not hard, just time consuming.

BVHOG

Ok, so if it doesn't make a difference then why would they need to restart from scratch?  From my experience with the disc pipes a couple discs can make a huge difference.
If you don't have a sense of humor you probably have no sense at all.

BadHabit

April 29, 2019, 09:01:58 AM #24 Last Edit: April 29, 2019, 09:06:50 AM by BadHabit
The way it was explained to me from tech support at fuel moto and supertrapp was exactly as durwood explained it. Several other posts from tuners seemed to agree. But because they are highly respected who am I to tell them how to tune right? When they finally agreed to "remove a few discs and see if it does anything" they insisted I tell them do I want maximum torque or maximum hp. I said I wanted a balance the owner told me it HAD to be one or the other...I told him if it had to be one or the other torque...I tried calling this morning but for some reason they are closed for the day.