Author Topic: Dyno Tune & Cam question  (Read 1464 times)

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Online mickblues

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Dyno Tune & Cam question
« on: April 10, 2019, 12:23:11 PM »
Im trying to get some advice from pros here.  I recently upgraded my 09 street bob to SS 110 kit.  Heads ported/machined by Dave Mackie compression 10.7   I already had Woods TW-8-6 cams in my bike and left them.  HPI 55mm TB w/ 5.3 injectors and new Thrashin AR 2-1 exhaust.   My builder tuned with Power Vision and I thought numbers would be better not that they are bad.  122/121   Id like the torque to come on sooner and thought it would and pull harder than it does. See the dyno sheet.   

I posted this over at HD forums and got some feedback, just trying to some more digging on this.

I spoke with a known tts mastertuner who said bring it after breaking in the engine.  He said could be my cam.  Id like to get some input on what others think here.  Thanks!

Offline scott7d

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Re: Dyno Tune & Cam question
« Reply #1 on: April 10, 2019, 08:10:12 PM »
I've never heard of that exhaust. It is a full length system? Sometimes the stubby little two into ones can hit the curve hard like that on the low/mid range.

Offline Hillside Motorcycle

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Re: Dyno Tune & Cam question
« Reply #2 on: April 11, 2019, 04:16:16 AM »
Good money that pipe is the problem.


















Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Offline Nastytls

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Re: Dyno Tune & Cam question
« Reply #3 on: April 11, 2019, 06:33:20 AM »
That's not a typical TW8 torque curve; it's nothing like mine was.

Nothing wrong with the TW8 or the PV and no need to replace it with a TTS. Dump that exhaust. A lot of these companies coming up and just welding some pipe together without doing any testing or having any concept of what makes an exhaust work. If you want that custom stainless look, have Burns design an exhaust for you and then have someone weld it up for you.

Offline tdrglide

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Re: Dyno Tune & Cam question
« Reply #4 on: April 11, 2019, 06:57:13 AM »
I just looked at the exhaust website. Looks like they have several baffle options. Don't know which one you have. Maybe a different one might help.

Online Rsw

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Re: Dyno Tune & Cam question
« Reply #5 on: April 11, 2019, 07:14:55 AM »
That's not a typical TW8 torque curve; it's nothing like mine was.

Nothing wrong with the TW8 or the PV and no need to replace it with a TTS. Dump that exhaust. A lot of these companies coming up and just welding some pipe together without doing any testing or having any concept of what makes an exhaust work. If you want that custom stainless look, have Burns design an exhaust for you and then have someone weld it up for you.
Agreed I have essentially the same set up except I have GMR heads it made 134/125 with a short RB LSR pipe slight torque dip down low but that 8 pulls all the way out the back door   Guess I agree itís the pipe

Offline kd

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Re: Dyno Tune & Cam question
« Reply #6 on: April 11, 2019, 07:17:05 AM »
I looked up the pipe and it appears they did some sort of testing with Fueling.  It has a familiar look to it.  There are several baffle / options available with that pipe.  It may need an experienced Dyno tuner to straighten it out or to find the problem with the combination of pipe components.  Maybe one of the FXR guys on the site have some experience with the pipe and will be willing to offer some helpful insight.

https://www.thrashinsupply.com/products/thrashin-ar-system-exhaust-fxr
KD

Offline SOCS

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Re: Dyno Tune & Cam question
« Reply #7 on: April 11, 2019, 09:54:39 AM »
A local dealer uses that pipe a lot with the M8 Softails, I just bought a Fat Bob there. The Dyno guy was trying to sell me on a build and offered a lot of Dyno charts for me to view. Most of the charts had similar dips though not as bad. I did notice the pipes with the " dog ball baffle" had a better looking curve.
« Last Edit: April 11, 2019, 10:06:48 AM by SOCS »

Offline speedzter

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Re: Dyno Tune & Cam question
« Reply #8 on: April 11, 2019, 05:15:41 PM »
Whenever I see a cheap pressed 2-1 collector as oposed to a decent fabricated merge collector, I question the quality.

Info on the "AR chambers"

https://patents.google.com/patent/US6336471

Offline Hilly13

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Re: Dyno Tune & Cam question
« Reply #9 on: April 11, 2019, 06:34:21 PM »
Regardless of patents and reversion theory that is still a big dip, similar to V&H big radius 2 into 1 sheets I've seen, maybe pipe alone or pipe and components, any of you dyno chaps seen this pipe?
Just because its said don't make it so

Offline BVHOG

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Re: Dyno Tune & Cam question
« Reply #10 on: April 12, 2019, 06:27:04 AM »
Well, Dave knows what's going on with heads so I would rule that out, secondly that cam at 10.7 to 1 is probably one of the best power producing cams available if you don't mind a little associated sound from the valvetrain. So that leaves the pipe which I have never heard of and likely the problem. Even with the pipe not being the best I would be willing to bet it is VERY lean in that dip area as well.
If you don't have a sense of humor you probably have no sense at all.

Offline harpwrench

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Re: Dyno Tune & Cam question
« Reply #11 on: April 12, 2019, 06:32:06 AM »
I'd put a supermeg on it, keep the PV

Offline George W

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Re: Dyno Tune & Cam question
« Reply #12 on: April 12, 2019, 09:02:37 AM »
I'd put a supermeg on it, keep the PV
If you live to be a 100 you won't get better advice than that!!!

Offline Yo_Boss

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Re: Dyno Tune & Cam question
« Reply #13 on: April 12, 2019, 05:10:11 PM »
Just listen to what everybody here and hdforums has told you. Your exhaust sucks.

Online mickblues

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Re: Dyno Tune & Cam question
« Reply #14 on: April 12, 2019, 11:04:05 PM »
Lot of advice and appreciate all the feedback.  I do have the dog baffle in this pipe. Is it possible if went with different baffle would make that much difference?

I spoke to a local tuner who has tuned with this exhaust and did say the dip is this exhaust. But would the pipe alone cause torque coming on late? 

Anyone recommend good pipes for my set up to get more torque?

Online mickblues

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Re: Dyno Tune & Cam question
« Reply #15 on: April 12, 2019, 11:08:34 PM »
I looked up the pipe and it appears they did some sort of testing with Fueling.  It has a familiar look to it.  There are several baffle / options available with that pipe.  It may need an experienced Dyno tuner to straighten it out or to find the problem with the combination of pipe components.  Maybe one of the FXR guys on the site have some experience with the pipe and will be willing to offer some helpful insight.

https://www.thrashinsupply.com/products/thrashin-ar-system-exhaust-fxr

Yes i have the more aggressive dog baffle in there. Im going to call Thrashin and aee what they say.  I was hoping a good tuner could make it better

Online mickblues

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Re: Dyno Tune & Cam question
« Reply #16 on: April 12, 2019, 11:15:47 PM »
I'd put a supermeg on it, keep the PV
This pipe you think is better than thunderheader? Will it add more torque ?

Offline Yo_Boss

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Re: Dyno Tune & Cam question
« Reply #17 on: April 12, 2019, 11:34:24 PM »
Dragula 2

Offline Hilly13

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Re: Dyno Tune & Cam question
« Reply #18 on: April 12, 2019, 11:36:19 PM »
I looked up the pipe and it appears they did some sort of testing with Fueling.  It has a familiar look to it.  There are several baffle / options available with that pipe.  It may need an experienced Dyno tuner to straighten it out or to find the problem with the combination of pipe components.  Maybe one of the FXR guys on the site have some experience with the pipe and will be willing to offer some helpful insight.

https://www.thrashinsupply.com/products/thrashin-ar-system-exhaust-fxr

Yes i have the more aggressive dog baffle in there. Im going to call Thrashin and aee what they say.  I was hoping a good tuner could make it better
A few posts up BVHOG chimed in, he can tune, a good tuner could probably lessen that dip, but without spending the coin to find out there is no way to know for sure cause of the pipes unknown characteristics, at least around here. It might be a good pipe  :nix:
Supermeg is a good pipe, tunable, not all like the sound.
Just because its said don't make it so

Offline rigidthumper

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Re: Dyno Tune & Cam question
« Reply #19 on: April 13, 2019, 05:55:25 AM »
W8 works well 3K-6K. This is why sometimes they start their runs at 2500. Makes it look better.

Offline tdrglide

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Re: Dyno Tune & Cam question
« Reply #20 on: April 13, 2019, 07:04:18 AM »
If you really are at 10.7:1 compression and everything was assembled properly your cold cranking compression should be about 200 psi at near sea level according to Big Boyz calculator. I would at least start there before spending  $$$ on new pipes.

Online mickblues

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Re: Dyno Tune & Cam question
« Reply #21 on: April 13, 2019, 03:04:20 PM »
Well, Dave knows what's going on with heads so I would rule that out, secondly that cam at 10.7 to 1 is probably one of the best power producing cams available if you don't mind a little associated sound from the valvetrain. So that leaves the pipe which I have never heard of and likely the problem. Even with the pipe not being the best I would be willing to bet it is VERY lean in that dip area as well.

Was hoping a good tuner can fix the dip and torque curve. Does the pipe need a certain amount of back pressure

Online mickblues

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Re: Dyno Tune & Cam question
« Reply #22 on: April 13, 2019, 03:08:11 PM »
If you really are at 10.7:1 compression and everything was assembled properly your cold cranking compression should be about 200 psi at near sea level according to Big Boyz calculator. I would at least start there before spending  $$$ on new pipes.

I donít think ill be changing that exhaust I just got it so Iíll have to get the tuner to look at and see if he smooth out the curve and hopefully get more tq earlier on.

Offline Hillside Motorcycle

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Re: Dyno Tune & Cam question
« Reply #23 on: April 15, 2019, 03:55:10 AM »
Unfortunately, folks spend their money on a pipe prior to realizing what actually works.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Offline kd

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Re: Dyno Tune & Cam question
« Reply #24 on: April 15, 2019, 06:10:56 AM »
If you really are at 10.7:1 compression and everything was assembled properly your cold cranking compression should be about 200 psi at near sea level according to Big Boyz calculator. I would at least start there before spending  $$$ on new pipes.

I donít think ill be changing that exhaust I just got it so Iíll have to get the tuner to look at and see if he smooth out the curve and hopefully get more tq earlier on.


If it was me, the first person that expressed an interest in the pipe would get to make an offer.   :nix:  You could spend more in dyno time than the difference on a new pipe.  You may be able to recoup most of what you paid while the pipe is newer and then get into a known performer.   If you are after performance your selection is more limited.
KD