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The Dyno RoomA special room dedicated for Dyno tuning products, troubleshooting and results. All Gearheads and Dyno Operators are welcome here as well as the guys that are new to tuning. Please see the special rules for this section before posting.
I have some questions and I hope that dyno tuners can answer , for me to learn and understand. AND I'm sure lots of other people who will read will learn something also.
OK. I'll start with what I THINK I know. I had my bike on a dyno for just a power run. No tuning was done. I just wanted to see where I was at for now. I have one more item and then time for a FULL DYNO TUNE.
My bike is a 2017/107. Stock numbers are 81 HP and 104 tq. After doing my upgrades, my dyno power run only, NO tuning... I'm making 103 HP and 121 tq.
So, What I know about dyno, is that either in 5 or 6th gear, the rpm are slightly run up, and then crack the throttle WFO until hit rev limiter. Do that several times to get multiple run readings. Then the chart shows the MAX power and the MAX Tq at a certain RPM.
Now , in every day riding, HOW much of that is actually being used? SURE, that MUCH is there,,,but realistically not being used.
I use a V&H FP3 which is connected to my phone app. I can start the app and see real data on 22 items. Recently I was curious about how much HP and Tq is being used.
IN a safe roadway, I did a hard acceleration in 5th gear from about 40mph up to 90. the MAX torque is was using was 90. The MAX HP I was using was 60.
And just cruising in 6th, 75mph its about 18hp and 36tq. Tq is always about 1.5x higher than HP.
So unless I was doing a drag race, I'll never hit the max HP or Torque?
WHY is MORE better?
Next, If my MAX torque is at 3,900 is it better to shift at 3900 in the lower gears, and then when the HP kicks in at 5000 for the higher gears.
It's been said that torque is how fast it gets you to the wall, and HP is how deep it drives you INTO the wall...
Excellent question!
While I don't have much dyno experience, I've wondered this myself. I DO think what you are inquiring about is what separates a GOOD dyno tech from a "pay-n-pray" dude who just relies on selling the big number. Don't get me wrong, I'm all for big numbers! But as you asked, how often do we really use them?
I believe there's a lot of information about a tuner's caliber in WHERE he/she touches the tune. Always exceptions, so take that for what it's worth. As I said, I'm not a dyno guy, but there are several here. I hope they chime in with their input. Always good info!
I remember during the late-70s through the 80s, when GM focused on torque -- to a fault. They were learning a LOT about how to make "clean power," with all the regulations and stuff. I think they've figured it out pretty well since then. VVT and all. Best of both worlds.
I have some questions and I hope that dyno tuners can answer , for me to learn and understand. AND I'm sure lots of other people who will read will learn something also.
OK. I'll start with what I THINK I know. I had my bike on a dyno for just a power run. No tuning was done. I just wanted to see where I was at for now. I have one more item and then time for a FULL DYNO TUNE.
My bike is a 2017/107. Stock numbers are 81 HP and 104 tq. After doing my upgrades, my dyno power run only, NO tuning... I'm making 103 HP and 121 tq.
So, What I know about dyno, is that either in 5 or 6th gear, the rpm are slightly run up, and then crack the throttle WFO until hit rev limiter. Do that several times to get multiple run readings. Then the chart shows the MAX power and the MAX Tq at a certain RPM.
Now , in every day riding, HOW much of that is actually being used? SURE, that MUCH is there,,,but realistically not being used.
I use a V&H FP3 which is connected to my phone app. I can start the app and see real data on 22 items. Recently I was curious about how much HP and Tq is being used.
IN a safe roadway, I did a hard acceleration in 5th gear from about 40mph up to 90. the MAX torque is was using was 90. The MAX HP I was using was 60.
And just cruising in 6th, 75mph its about 18hp and 36tq. Tq is always about 1.5x higher than HP.
So unless I was doing a drag race, I'll never hit the max HP or Torque?
WHY is MORE better?
Next, If my MAX torque is at 3,900 is it better to shift at 3900 in the lower gears, and then when the HP kicks in at 5000 for the higher gears.
It's been said that torque is how fast it gets you to the wall, and HP is how deep it drives you INTO the wall...
starting to slow down at 45 mph
You got the saying bass ackwards.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you
Last edited by Buelligan666; Apr 11, 2026 at 08:32 AM.
An example of torque and hp:
torque is the force you apply to a wrench, and horse power is the bolt turning. Another way to look at it is hp is time and distance while torque is the force to get you moving..
Horse power increases as your rpms increase that time and distance again. So the lower your rpms the lower your HP. Increasing torque makes your acceleration faster, if makes the bike feel more lively, its not about getting to top speed.
in fact 90 present of your ridding will be ~2500. -2700 rpms. You would be surprised at how little you go above this on an average ride.
Thats the Short version
A dyno sheet only shows whats happening at wide open throttle. Nothing else. 95 percent of a proper tune is spent at part throttle settings dyno sheet doesnt show any of that.
Now, a fact it takes x amount of horsepower/ torque to move x amount of weight at a fixed speed (level ground). That amount of horsepower doesnt change whether its a stock engine or full performance build. But, the properly tuned performance engine will require less throttle opening to achieve the same fixed speed. And of course available power is much greater than the stock engine to accelerate that same weight at a much higher rate. Helpful???
As far as using the FP3 for useful performance data- I wouldnt put to much faith in the reported numbers.
A (proper) tune simply calibrates the ECM tables to the components installed.
The basic tuning process starts with ensuring the displacement/injector settings ( all constants) are accurate.
Check/set MAP Normalization Gain table so airflow can be accurately modeled.
Measure/set IVO/IVC.
Run the bike through all reachable TP/RPM/MAP cells for both cylinders while recording data. Edit the VE look up tables so the AFR achieved = the AFR requested.
Once that's satisfactory, start editing the timing tables for best power while continuing to measure/edit VE to maintain the AFR.
When that's all good, and the EGR effect tables have been edited, if the bike + product you're using has the capability, perform requested torque control tuning.
Print sheet (The sheet is a snapshot of WOT.)
Torque is the ability to do work.
Horsepower is how fast the work is getting done.
This is a snapshot of the 2% to 100% runs looks like.
No pie in the sky, the above is the real math behind it all. So let's give an example that many do not understand but it's worth learning. We are going to use a fixed amount of torque at 2 different RPM points.
1.904 = (10 * 1000)/5252 So here we have 10 ft lbs @ 1000 RPM and this equates to 1.904 HP
11.424 = (10 * 6000)/5252 Now we again have the same 10 ft lbs but this time @ 6000 RPM and this equates to 11.424 HP
So what do you want 11.424 HP or 1.904 HP?
Last edited by Steve Cole; Apr 11, 2026 at 12:29 PM.
A dyno sheet only shows whats happening at wide open throttle. Nothing else. 95 percent of a proper tune is spent at part throttle settings dyno sheet doesnt show any of that.
Now, a fact it takes x amount of horsepower/ torque to move x amount of weight at a fixed speed (level ground). That amount of horsepower doesnt change whether its a stock engine or full performance build. But, the properly tuned performance engine will require less throttle opening to achieve the same fixed speed. And of course available power is much greater than the stock engine to accelerate that same weight at a much higher rate. Helpful???
As far as using the FP3 for useful performance data- I wouldnt put to much faith in the reported numbers.
Thanks,
A very good explanation .
Up until the bash on V&H FP3. I'm sure they will disagree... @vanceandhines
Thanks for the answers. I guess I was hoping for more (less techno) rational behind NOT building bigger, if most of the time its 2500-3200 rpm... that's hardly much effort.
Oh don't get me wrong... I LOVE the faster acceleration. the ability to pass better and faster with 2up. On a hill. only dropping down 1 gear, NOT WFO...
A riding buddy spent $15k rebuilding his motor. He makes 125 HP and 137 tq... We've "raced"... I win up to 5th gear at 75mph and then he pulls away.
When I rebuild my bike I will just put new parts, better parts, but not gonna worry about BIG HP.
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