Race car dyno video, and invitiation to our first race this season
04-23-2015, 01:19 PM
#1
Developer
Thread Starter
Race car dyno video, and invitiation to our first race this season
Video from yesterday. I needed to heat-cycle the new ring and pinion gears we installed (4.10:1) and just do a general performance run-in of the drive train before we leave for The Autobahn in Joliet IL this weekend.
You can see me count up from 1st into 4th gear for the camera and let her rip. We had wheel spin at about 5500 rpm, lighting up the tires on the dyno rollers.... You can hear it when the rate of acceleration suddenly increases.
If your in the Joliet area, stop in! It'd be nice to see you and you really need to hear this 928 bark. The forecast is for rain on Saturday, but Sunday is supposed to be nice.
We are in the GTS (German Touring Sedan) series.
You can see me count up from 1st into 4th gear for the camera and let her rip. We had wheel spin at about 5500 rpm, lighting up the tires on the dyno rollers.... You can hear it when the rate of acceleration suddenly increases.
If your in the Joliet area, stop in! It'd be nice to see you and you really need to hear this 928 bark. The forecast is for rain on Saturday, but Sunday is supposed to be nice.
We are in the GTS (German Touring Sedan) series.
04-23-2015, 04:39 PM
#5
Rennlist Member
I didnt mean the dyno is a reflection of you or the car... its is funny, because those little dual rollers are hardly any match for the "real" dynos with the large drums......and better grip and stability. it was based on your comments that you saw wheels spin in the lower gears. why wouldnt you, right? Im sure it gets the job done in the end, but with your kind of power, its near the limit of those " smaller " type dynos.
04-23-2015, 05:41 PM
#7
Developer
Thread Starter
It's OK. A Mustang Dyno is an eddy-current dyno, and the Dyno-jet dynos are inertial. So yes, the DynoJets have the large heavy drum. And the drums here are smaller.
What they cannot do so well is maintain a load in mid throttle. On an inertial dynanometer, once you get the drum spinning it takes very little power to keep it spinning.
I prefer the eddy current dyno's like this one for some things.... tuning, bedding piston rings, heat-cycling a ring gear, "driving" a car on the rolling road as it were. This kind of dyno can spend as long as you like in each rpm cell and continue to maintain the load. Gives you longer amounts of time at each rpm to get your tune just right.
I know newer DynoJets have dded an eddy-current feature just so they can also offer this capability.
If your goal is the highest dyno number to impress people, a inertial drum dyno like a DynoJet is your boy. But I have to say, as of late the newer Mustangs and the newer DynoJets keep getting better and more accurate and I've noticed the delta between the two is closing. That difference we used to see between those two brands/types is narrowing.
What they cannot do so well is maintain a load in mid throttle. On an inertial dynanometer, once you get the drum spinning it takes very little power to keep it spinning.
I prefer the eddy current dyno's like this one for some things.... tuning, bedding piston rings, heat-cycling a ring gear, "driving" a car on the rolling road as it were. This kind of dyno can spend as long as you like in each rpm cell and continue to maintain the load. Gives you longer amounts of time at each rpm to get your tune just right.
I know newer DynoJets have dded an eddy-current feature just so they can also offer this capability.
If your goal is the highest dyno number to impress people, a inertial drum dyno like a DynoJet is your boy. But I have to say, as of late the newer Mustangs and the newer DynoJets keep getting better and more accurate and I've noticed the delta between the two is closing. That difference we used to see between those two brands/types is narrowing.
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04-23-2015, 05:43 PM
#8
Developer
Thread Starter
A larger drum would provide a larger contact patch, true, but only one. Here there are two rollers and two contact patches per tire.
I think my wheel spin was more likely a factor of my -2 degrees of rear Camber. We lowered the pressure int he tires to 25 psi (it was 35) and that helped, but the tires still broke loose well before redline.
I think my wheel spin was more likely a factor of my -2 degrees of rear Camber. We lowered the pressure int he tires to 25 psi (it was 35) and that helped, but the tires still broke loose well before redline.
04-23-2015, 06:21 PM
#9
Rennlist Member
A larger drum would provide a larger contact patch, true, but only one. Here there are two rollers and two contact patches per tire.
I think my wheel spin was more likely a factor of my -2 degrees of rear Camber. We lowered the pressure int he tires to 25 psi (it was 35) and that helped, but the tires still broke loose well before redline.
I think my wheel spin was more likely a factor of my -2 degrees of rear Camber. We lowered the pressure int he tires to 25 psi (it was 35) and that helped, but the tires still broke loose well before redline.
.... and yes, breaking the tires loose would happen well before redline... actually at max torque... It's OK. A Mustang Dyno is an eddy-current dyno, and the Dyno-jet dynos are inertial. So yes, the DynoJets have the large heavy drum. And the drums here are smaller.
What they cannot do so well is maintain a load in mid throttle. On an inertial dynanometer, once you get the drum spinning it takes very little power to keep it spinning.
I prefer the eddy current dyno's like this one for some things.... tuning, bedding piston rings, heat-cycling a ring gear, "driving" a car on the rolling road as it were. This kind of dyno can spend as long as you like in each rpm cell and continue to maintain the load. Gives you longer amounts of time at each rpm to get your tune just right.
I know newer DynoJets have dded an eddy-current feature just so they can also offer this capability.
If your goal is the highest dyno number to impress people, a inertial drum dyno like a DynoJet is your boy. But I have to say, as of late the newer Mustangs and the newer DynoJets keep getting better and more accurate and I've noticed the delta between the two is closing. That difference we used to see between those two brands/types is narrowing.
What they cannot do so well is maintain a load in mid throttle. On an inertial dynanometer, once you get the drum spinning it takes very little power to keep it spinning.
I prefer the eddy current dyno's like this one for some things.... tuning, bedding piston rings, heat-cycling a ring gear, "driving" a car on the rolling road as it were. This kind of dyno can spend as long as you like in each rpm cell and continue to maintain the load. Gives you longer amounts of time at each rpm to get your tune just right.
I know newer DynoJets have dded an eddy-current feature just so they can also offer this capability.
If your goal is the highest dyno number to impress people, a inertial drum dyno like a DynoJet is your boy. But I have to say, as of late the newer Mustangs and the newer DynoJets keep getting better and more accurate and I've noticed the delta between the two is closing. That difference we used to see between those two brands/types is narrowing.
better for break in , because you can simulate a load and leave it running likes its on a road. BUT, it doesnt allow for the realistic acceleration effects of running an engne to redline as it is done on the road or track. sometimes any issues that come about from a 80 to 150mph run, over 7-8 seconds , might not be seen by the mustang and might be seen on the dynojet. sometimes the mustang during the hold rpm and max load can give unusual heat generation and show problems that might not be present in a normal acceleration. both are fine, but different.
as far as ego numbers, thats not exactly true of the dyno jet.... if you accelerate that drum, you accelerate that drum, PERIOD. the work it does over time, is power (rate of change of KE) its easy to measure and quantify. mustang eddy current dyno is a much more processor intensive calculation that can vary for a number of reasons. last i ran both, they were within 5 hp of each other, and that could have been due to all sorts of variables.
04-24-2015, 08:43 AM
#11
Nordschleife Master
There was thread earlier about the engine dyno results in terms of the power and torque. What were the rear wheel power and torque results? I am curious about the losses in the drivetrain. It would be to nice to see what the loss percentage is at each rpm for this setup.
04-24-2015, 10:30 AM
#13
Developer
Thread Starter
ptuomov: that was one of my objectives. We had engine dyno numbers, I wanted chassis dyno numbers so I could learn what my drive-train loss was through the T56. Alas, it was not to be. We had the wheel slip on the dyno, and not enough time for me to effort the correction and get the chassis dyno number. It was a shame - I would have liked to know that.
04-24-2015, 10:38 AM
#14
Developer
Thread Starter
What time are you running on Sunday?
On Sunday I have practice at 8:35, qualifying race at 10:30, and the race at 2:30
schedule here: http://nasamidwest.com/season/?page=...&eventid=28819