Ken,
1. On a chassis dyno (where your car is strapped in), you are SUPPOSED to use whatever tranny gear is your 1:1 ratio. For our W58 5-speeds, this would be 4th gear. For those w/ Automatics, it would be 3rd (you lockout the 4th gear OD). For the MKIV guys, they are SUPPOSED to be using 5th gear on their Getrag 6-speeds. For some reason, the majority of them don't, they use 4th gear, which I know for a fact is not their 1:1 ratio.
2. Gearing is already factored in. Does not matter what you have for a rear diff ratio.
3. You can't measure actual crank hp on a chassis dyno, you will have to pull your motor & put it on a bench dyno that will properly measure the crank hp. On our Supra's for a chassis dyno (we will use a Dynojet as a example), they say take your rwhp & add 15 - 18% (numbers may vary, depending on who you talk to) & that will get your crank hp. For those w/ 4wd (like DSM's or possibly Nissan Skyline's) the numbers can really be different...
Don't forget, the rollers on a chassis dyno are under a load, it's supposed to simulate actual driving conditions. The rollers don't spin that freely. Everytime I dyno a manual tranny, I have to remember to give it more gas/slip the clutch more, when I first get the wheels moving. Yep I've easily stalled the motor before.
Have you ever dyno'd the MKII or any car for that matter before?? Just curious...
(Redpra has been dyno'd at least a dozen times over the last 4 years, the Silver Slug got dyno'd this past Spring).
artm: all of our 1:1 ratios are exactly that!!! The gear ratio's are 1.000
1. On a chassis dyno (where your car is strapped in), you are SUPPOSED to use whatever tranny gear is your 1:1 ratio. For our W58 5-speeds, this would be 4th gear. For those w/ Automatics, it would be 3rd (you lockout the 4th gear OD). For the MKIV guys, they are SUPPOSED to be using 5th gear on their Getrag 6-speeds. For some reason, the majority of them don't, they use 4th gear, which I know for a fact is not their 1:1 ratio.
2. Gearing is already factored in. Does not matter what you have for a rear diff ratio.
3. You can't measure actual crank hp on a chassis dyno, you will have to pull your motor & put it on a bench dyno that will properly measure the crank hp. On our Supra's for a chassis dyno (we will use a Dynojet as a example), they say take your rwhp & add 15 - 18% (numbers may vary, depending on who you talk to) & that will get your crank hp. For those w/ 4wd (like DSM's or possibly Nissan Skyline's) the numbers can really be different...
Don't forget, the rollers on a chassis dyno are under a load, it's supposed to simulate actual driving conditions. The rollers don't spin that freely. Everytime I dyno a manual tranny, I have to remember to give it more gas/slip the clutch more, when I first get the wheels moving. Yep I've easily stalled the motor before.
Have you ever dyno'd the MKII or any car for that matter before?? Just curious...
(Redpra has been dyno'd at least a dozen times over the last 4 years, the Silver Slug got dyno'd this past Spring).
artm: all of our 1:1 ratios are exactly that!!! The gear ratio's are 1.000