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Discussion Starter #1
I took my bike in to have it dyno'ed and tuned because I just don't feel like I'm getting the power I paid for. Out of respect for all parties involved, I'm not getting on here to flame or bitch, so I'm gonna leave off some details. I had a factory decatted headpipe and a slip on muffler and the bike was pulling 87hp and 104 torque. After I upgraded the exhaust, I had a dyno'ed again and it dropped to 84hp and 95 torque, after being tuned and running a correct AFR.

Obviously, I left disappointed and pissed off. Here is my concern now after further review of the dyno chart. The first dyno, hp and torque are equal at 5252rpms. The second dyno chart, hp and torque are equal at around 4750rpms. Based on the formula of how hp is calculated, the second dyno is mathematically impossible. HP and Torque are always equal at 5252, right?

So, did I get a bad dyno? Is there anyway to translate the second dyno? Something just ain't right.

Thoughts?
 

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Good news is the last dyno sheet looks to be tuned ( lower peak tq) the first dyno sheet is not. However the 5250 thing is nothing more than a click of the mouse. ( force scaling) IF you look on the first sheet you will see the numbers are the same on both sides on the sheet at the same point, however the other is not

Now on new tune he started the pull very late. Odd ?? Hope you dont mind I re posted the sheets ,.. the twisting my head side ways to look was bugging me.

So understand that a peak number is one point and not the curve. You did not state if you changed other items with the next shop. I know that these are not the same shop( graph set up is a pain and no one swaps them around once set up) and that in itself can throw a wrench into them mix. The runs are over a year apart.. I have no dog in the fight but I am a tuner so I can explain what you have







This sheet is an example of how you would want to see testing back to back at the same shop. If that is not done you still need the runs to start and stop in the same area.. But dyno to dyno may give you a slight increase or decrease in power, engine temp, tire pressure what gear the pulls was made in. Not to mention air weather that day. SAE or STD all of this gets throw into the mix and some of the data you chopped off so its a guess if both are SAE pulls.

 

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HP = Torq times RPM divided by 5252 is formula to calculate HP.
knowing any 2 values in red you can calculate the 3rd.
Items to watch closely when comparing dyno reports are:
RPM: all data point must be compared at same RPM.
Scaling of HP and Torq axis will effect where graph line cross.
Correction factor, did the dyno operator change between runs.
If not all conditions should be the same.
Altitude, Humdity, Temperature, Fuel Temp, ect.
Dyno accuracy: +/- 1 - 3 % would not be alarming.

Hope this helps.
 

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Discussion Starter #4
Nothing changed from the first pull to the second pull other than the exhaust. The first run was made at the local harley dealer, the second at an independent. I've emailed both vendors (engine and exhaust) to ask what they think the issue could be, I haven't received a reply, but it is the weekend. I just don't want to come in slinging mud if its possible the dyno pull was either done or recorded incorrectly. Without revealing too terribly much, I've seen the exact set up pulling 100+ hp and 105+ torque by other members here on the forum.

I know all parties involved check this forum often and I don't want to be seen as dissing on their products when the issue could be on my end somehow? Make sense?
 

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Not looking at the paper work, can you tell any difference by the seat of the pants?
 

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Discussion Starter #6
I think so. Hate to say I think, but this whole project has kinda consumed me since last February building, tinkering, changing, tuning, re-tuning, auto-tuning, etc. I feel like it is running stronger since the pipe change, but maybe I'm just trying to convince myself?? The throttle lag it had is now gone since the tune but I haven't had much opportunity to ride with this crazy weather. I realize the dyno chart isn't nothing but paper and its all just bragging rights ultimately, I just wanna know if I'm getting what I paid for or not.
 

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2 different dynos.........no 2 are the same, and the results are HIGHLY variable just between operators, not to mention fuel in the tank, weather, engine temperature, tire pressure etc. It's tough enough to get back to back runs to match on the same dyno, when you change location, dyno and operators just to name the simple ones, it's a whole new ball game
 

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Stock cams 100 hp?.. That's is not going to happen. How about a list of the build then and now
 

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Discussion Starter #9
Well I don't guess listing the build could do anything but help right?

2010 Road Glide Custom
Fuel Moto 107 Big Bore Kit
Woods 777 cams
Screaming Eagle Ventilator intake
Dragos Dragula 2 into 1
Power Vision Tuner
Stock Heads
 

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Looks like neither one was tuned worth a crap .
The decat and freedom performance sheet looks like it was just a base .
And the 2-1 run was started in the late rpms . If dosent look very good either .
Your first exhaust and a good tune , would make the most peak numbers. The 2-1 will come in quicker but fall off quicker .
 

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95-100 hp avg and tq though should have been much higher. I see no reason why that kit should not be making 110+ tq with ease. As I already said from my earlier post the second run was was started late. You have the correct parts just needed to work on the tune. Is the PV tuner something tuner is comfortable using??
 

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Discussion Starter #12
95-100 hp avg and tq though should have been much higher. I see no reason why that kit should not be making 110+ tq with ease. As I already said from my earlier post the second run was was started late. You have the correct parts just needed to work on the tune. Is the PV tuner something tuner is comfortable using??

Said that he was, I really don't know. He's done some really good builds from what I've read. Pardon my ignorance, but what does that mean "the second run was started late"? Wrong gear?
 

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Discussion Starter #13
Looks like neither one was tuned worth a crap .
The decat and freedom performance sheet looks like it was just a base .
And the 2-1 run was started in the late rpms . If dosent look very good either .
Your first exhaust and a good tune , would make the most peak numbers. The 2-1 will come in quicker but fall off quicker .

So you're saying the decatted 2 into 1 headpipe with the freedom performance slip on should make better numbers than the Dragos 2 into 1? Why's that?

Thanks.
 

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Discussion Starter #14
Looks like neither one was tuned worth a crap .
The decat and freedom performance sheet looks like it was just a base .
And the 2-1 run was started in the late rpms . If dosent look very good either .
Your first exhaust and a good tune , would make the most peak numbers. The 2-1 will come in quicker but fall off quicker .

Also, are you saying neither was tuned worth a crap because of the numbers or because of something you see on the charts?
 

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Discussion Starter #15
discovered a leak between the breather and the throttle body, going to work on that tomorrow...still lean .
 

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I was informed yesterday afternoon on this. After looking at dyno sheets and talking with customer. Here is what I have to say.

First numbers are low period a typical 107 big bore kit with cams and no head work and descent exhaust and tune will make peak number around
99HP-103HP Easy.
113TQ- 116TQ Easy

As (Steve 124 Shark) said 110tq+ easy

As you can see it never got it. You can see it was a base map in the bike.
Per( Jim-Stroker post.)


A very good 2:1 will make a nice Radius mountain curve Vs a 2:1:2 where it makes more of a Nice Triangle curve.

With the new Dragula 2 exhaust design being that it has longer primary Mid range will be even better and carry out curve further.

Also as per my phone call with customer the map that was emailed to him was for 107 kit & D&D fat cat.. Not from me Sorry I do not have one for this build and cams for PV...

And when his dyno guy said he wasn't sure the Dragula 2 even had a baffle in it. That is your first sign get out and run the other way ask for money back..... My 2 Cents worth.......

As per my conversation with customer on this I suggested a few things.
1. Find a better tuner he had said Gary Williams was close to him.
Gary is very familiar with this 107 kit and 2:1 he would be a great place for this tune.

2. I suggest before taking the bike over to his shop for tune check compression and leak down etc., make sure bike is in tip top shape before you bring it for Gary W. to tune.

New Dragula 2 And Newer style Fat cat not even the same pipe. Only thing they share is the name 2:1..........


Its sad when you bring your bike to a shop and hope for a descent dyno tune and end up with a base map they really did not do anything with.

If I can further help Buddy just give me a call I will do what I can from my end here. Or better yet! Bring the bike up to me and Ill tune it for free to prove my points.


Here is a stock 103 95HP and 109/110 tq with Dragos 580 cam Dragula stock heads not my dyno... you can see it does better. And your kit should do even better than that.

Thanks FD.
 

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2010 Road Glide Custom
Fuel Moto 107 Big Bore Kit
Woods 777 cams
Screaming Eagle Ventilator intake
Dragos Dragula 2 into 1
Power Vision Tuner
Stock Heads
very similar build to what i had when fuelmoto did my 107. except i had a stock headpipe with a v&h twin slash muffler.

my dyno pull was 98hp/122 tq
 

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Keep in mind comparing dyno numbers from all these locations can bite in the rear. Look for the smooth curve and look for correct starting rpm points. and nothing more that a range in peak power.
 

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Here's an explanation of the convergence being different on the two charts:

The first chart is as expected, 5250.

On the second chart, you cannot see the scales on the left and the right in your picture., but I'd bet a million dollars they are different.

I dont know why tuners do this, but some do, the original tune I got from a dealer did. In my opinion its a sign of incompetence.
 
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