Rolling Road Results - Need advice! :-(
08-11-14, 08:01 AM
#16
Lexus Test Driver
iTrader: (2)
Join Date: Mar 2011
Location: Alberta
Posts: 878
Likes: 0
Received 0 Likes
on
0 Posts
You would have to assume a drivetrain loss in order to get a representative flywheel estimate.
380.4hp for a nearly stock run is impressive; but as mentioned before means absolutely nothing. I'd be more pissed if I was car number 3, and put up lower numbers than car number 2.
08-11-14, 08:08 AM
#17
Forum Administrator
iTrader: (2)
08-11-14, 08:39 AM
#19
Forum Administrator
iTrader: (2)
Mazdaspeed is pretty easy to tune. Wouldn't be surprised if it was tweaked and either the owner wasn't saying or done before he bought it.
http://www.mazdaspeedforums.org/forum/f338/
http://www.mazdaspeedforums.org/forum/f338/
08-11-14, 11:55 AM
#21
So the plot thickens!
Had an email back from AMD (the dyno guys) saying the figures are at the flywheel.
He also confirmed the dyno itself is a Dimsport Dyno Race Rolling road.
That supports Stu saying the other cars were spot on power wise, but means our cars were down on power.
The tuner is still suggesting its due to the autoboxes.
Hopefully the other dyno will give us a better idea.
Had an email back from AMD (the dyno guys) saying the figures are at the flywheel.
He also confirmed the dyno itself is a Dimsport Dyno Race Rolling road.
That supports Stu saying the other cars were spot on power wise, but means our cars were down on power.
The tuner is still suggesting its due to the autoboxes.
Hopefully the other dyno will give us a better idea.
08-11-14, 04:46 PM
#28
Tech Info Resource
iTrader: (2)
For example, Oleg Kozenutsov tested his bone stock Supra at Supras Invade Los Vegas in 1999. BONE STOCK down to the air filter. He put 340 hp to the wheels if you believe Dynojet. No one ever put even 300 to the wheels with a bone stock Supra. People accused him of lying, cheating, stealing, making a deal with the devil and all sorts of awful things.
In 2000 Bryce Dana put down 2 less horsepower than the full race RPS Supra on "pump gas" and everyone was amazed at Bryce's car. Guess what? I was at the gas station with Bryce. Yup the gas came from the pump, but it sure wasn't the 91 octane premium everyone thought it was.
So, if you really think dyno testing is "fair' and a good measure, dream on. The only thing it is good for it seeing a large power change after a modification. Heck, I can put a lighter set of wheels on a car and Dynojet says I'm making more power despite the fact nothing has changed in the entire power train but the rotational inertia. That's not making more power.
So when you can measure coolant temp, oil temp, fuel temp, air temp, exhaust temp, humidity, barometric pressure, AND CONTROL all these parameters, you might possibly get a fair representation of what your engine will do. If you can't, it's anybody's guess what your numbers will look like.
08-11-14, 05:04 PM
#29
Test:
Davenport Motorsports (www.davenportmotorsports.com) of Canada, wanted to see the dyno effects of running different wheels on cars. They took a factory 2012 Camaro SS and ran 3 dyno runs. They ran the first run with a set of aftermarket wheels, the 2nd run with a set of stock factory wheels and the 3rd run with a set of HRE P45S wheels, all in 20” sizes.
These results highlight the effects of rotational inertia on drive-train losses (the hp lost between the engine crank and the ground). Wheels and tires contribute to drive-train losses as energy is used to spin up the wheels (and decelerate the wheels under braking). From the dyno chart you can see the effect of replacing factory wheels with lighter HRE wheels and see the negative effects of installing heavier aftermarket wheels.
Results:
1. (Blue curve) Factory wheels: 20”x9.0” with Pirelli 275/40-20 tires weighing 68 lbs combined per rear wheel. – Max hp: 371 hp, Max Torque: 375 ftlbs - (Baseline)
2. (Red curve) Aftermarket wheels: 20”x9.0” with Pirelli 275/40-20 tires weighing 72 lbs combined per rear wheel – Max hp: 369 hp, Max Torque: 373 ftlbs - (A [-] loss of 2 hp and 2 ftlbs)
3. (Green curve) HRE wheels: 20”x11.0” with Nitto 315/35-20 tires weighing 60 lbs combined per rear wheel – Max hp: 380hp, Max Torque: 384 ftlbs - (A [+] gain of 8 hp and 9 ftlbs and that is running a 2” wider wheel/tire combo)
Conclusion:
The engine obviously still cranks out the same amount of hp and torque, the lighter HREs simply waste less of it before it gets to the ground. Also interesting to note is that the gains are not just peak gains, but gains across the entire rev range. If they had done a braking test, we would have seen similar results as the rotational inertia effects also have a significant effect on how much energy is used to stop the wheel/tire combo vs. stopping the car. We talk about these effects all the time and focus on designing lightweight wheels with low rotational inertia, but it isn’t every day that you get to see real hard data showing the true effects.
[/URL]
.
Davenport Motorsports (www.davenportmotorsports.com) of Canada, wanted to see the dyno effects of running different wheels on cars. They took a factory 2012 Camaro SS and ran 3 dyno runs. They ran the first run with a set of aftermarket wheels, the 2nd run with a set of stock factory wheels and the 3rd run with a set of HRE P45S wheels, all in 20” sizes.
These results highlight the effects of rotational inertia on drive-train losses (the hp lost between the engine crank and the ground). Wheels and tires contribute to drive-train losses as energy is used to spin up the wheels (and decelerate the wheels under braking). From the dyno chart you can see the effect of replacing factory wheels with lighter HRE wheels and see the negative effects of installing heavier aftermarket wheels.
Results:
1. (Blue curve) Factory wheels: 20”x9.0” with Pirelli 275/40-20 tires weighing 68 lbs combined per rear wheel. – Max hp: 371 hp, Max Torque: 375 ftlbs - (Baseline)
2. (Red curve) Aftermarket wheels: 20”x9.0” with Pirelli 275/40-20 tires weighing 72 lbs combined per rear wheel – Max hp: 369 hp, Max Torque: 373 ftlbs - (A [-] loss of 2 hp and 2 ftlbs)
3. (Green curve) HRE wheels: 20”x11.0” with Nitto 315/35-20 tires weighing 60 lbs combined per rear wheel – Max hp: 380hp, Max Torque: 384 ftlbs - (A [+] gain of 8 hp and 9 ftlbs and that is running a 2” wider wheel/tire combo)
Conclusion:
The engine obviously still cranks out the same amount of hp and torque, the lighter HREs simply waste less of it before it gets to the ground. Also interesting to note is that the gains are not just peak gains, but gains across the entire rev range. If they had done a braking test, we would have seen similar results as the rotational inertia effects also have a significant effect on how much energy is used to stop the wheel/tire combo vs. stopping the car. We talk about these effects all the time and focus on designing lightweight wheels with low rotational inertia, but it isn’t every day that you get to see real hard data showing the true effects.
.
Last edited by MK4Sup_isF; 08-11-14 at 05:09 PM.
08-11-14, 06:19 PM
#30
Lou