SoCal Dyno / TUNING Day with MM and CRH
05-15-2008, 06:35 PM
#676
TroublemakrExtraordinaire
Where is this coming from? I am not sure that anyone knows how low the dyno was reading. We could pull any arbitrary number to multiply. I never made any claim of what the real HP readings "should" have been. My point is simply that they were consistent across the board.
In all honesty I don't really even care if my HP was higher or lower than anyone else. I am only interested in understanding the readings so that I know if I have improved my car (and by how much) when I make changes in the future. At the end of the day, who gives a rip if someone elses car performs differently other than to understand what changes will effect performance on your own car?
In all honesty I don't really even care if my HP was higher or lower than anyone else. I am only interested in understanding the readings so that I know if I have improved my car (and by how much) when I make changes in the future. At the end of the day, who gives a rip if someone elses car performs differently other than to understand what changes will effect performance on your own car?
05-17-2008, 04:43 AM
#679
TroublemakrExtraordinaire
lol @ Brettus
I liked the tag in someone else’s Sig ... the RX-8 is not the fastest car on the road, just the most fun. If having massive HP is the only goal, buy a Mercedes-Benz SLR McLaren Roadster. 641 HP stock and you won't have reliability issues
But seriously, what difference does it make if someone has more HP than you? The question is, do you like your car? If so, great. If not, change it or buy a new one.
Jeff, can you explain the relative wheel speed to run time setting? I understand torque and HP. What I don't understand is how the dyno's are configured. The load they exert on the car should be constant but the wheel size would change the ratio of the dyno wheel to the car wheel. The transmission does not make the reading more or less accurate. That in itself would be irrelevant since the RWHP is a function of how much load is applied to how fast the car's wheel can change the speed (acceleration). It does not matter what is in between the engine and the wheel as far as RWHP is concerned. Obviously it does matter for the transfer efficiency but that is a whole different topic (that MT guys like to focus on).
Oh, and for the numbers the Turbo guys were posting ... they are fairly meaningless. The Turbos rely on the air force which is not constant when changing speeds. On the dyno the air flow is only whatever the external fan is blowing at. That fan speed/air pressure is not changing at all. This means they are not getting the real effect of the turbo in comparison to what it would when the car is actually driving. I would expect that every turbo would have had low numbers simply based on that fact unless there were really strong fans blowing that would emulate the same volume of air as if they were driving.
For Phil's SC I would not think that to be the same. I would really love to know what his numbers were. Guess I should not have waited at the BBQ.
I liked the tag in someone else’s Sig ... the RX-8 is not the fastest car on the road, just the most fun. If having massive HP is the only goal, buy a Mercedes-Benz SLR McLaren Roadster. 641 HP stock and you won't have reliability issues
But seriously, what difference does it make if someone has more HP than you? The question is, do you like your car? If so, great. If not, change it or buy a new one.
Jeff, can you explain the relative wheel speed to run time setting? I understand torque and HP. What I don't understand is how the dyno's are configured. The load they exert on the car should be constant but the wheel size would change the ratio of the dyno wheel to the car wheel. The transmission does not make the reading more or less accurate. That in itself would be irrelevant since the RWHP is a function of how much load is applied to how fast the car's wheel can change the speed (acceleration). It does not matter what is in between the engine and the wheel as far as RWHP is concerned. Obviously it does matter for the transfer efficiency but that is a whole different topic (that MT guys like to focus on).
Oh, and for the numbers the Turbo guys were posting ... they are fairly meaningless. The Turbos rely on the air force which is not constant when changing speeds. On the dyno the air flow is only whatever the external fan is blowing at. That fan speed/air pressure is not changing at all. This means they are not getting the real effect of the turbo in comparison to what it would when the car is actually driving. I would expect that every turbo would have had low numbers simply based on that fact unless there were really strong fans blowing that would emulate the same volume of air as if they were driving.
For Phil's SC I would not think that to be the same. I would really love to know what his numbers were. Guess I should not have waited at the BBQ.
Last edited by BlueKnight; 05-17-2008 at 04:48 AM.
05-17-2008, 09:35 AM
#680
Administrator
Thread Starter
iTrader: (7)
I'm considering doing yet ANOTHER DynoDay this summer and I'm curious to see who would be interested.
the Dyno will be at a different location and will cost roughly the same. (give or take a few bucks)
If there's enough interest I will pick a date and negotiate a price for us...
the Dyno will be at a different location and will cost roughly the same. (give or take a few bucks)
If there's enough interest I will pick a date and negotiate a price for us...
05-17-2008, 11:09 AM
#681
The dyno has to be set up to understand the effective gear ratio of the car being tested so that it knows the engine RPM from the drum speed.
It also is set to load the drums based on how long you want the run to be.
Since the dyno was expecting t lower gear ratio of a M/T 4th, it didn't load the drums as heavily fo the A/T 3rd and calculated the motor to be spinning way faster than it was.
Air Force?
Huh? Turbos make their own air pressure. They don't care if the car is moving.
It also is set to load the drums based on how long you want the run to be.
Since the dyno was expecting t lower gear ratio of a M/T 4th, it didn't load the drums as heavily fo the A/T 3rd and calculated the motor to be spinning way faster than it was.
Oh, and for the numbers the Turbo guys were posting ... they are fairly meaningless. The Turbos rely on the air force which is not constant when changing speeds. On the dyno the air flow is only whatever the external fan is blowing at. That fan speed/air pressure is not changing at all. This means they are not getting the real effect of the turbo in comparison to what it would when the car is actually driving. I would expect that every turbo would have had low numbers simply based on that fact unless there were really strong fans blowing that would emulate the same volume of air as if they were driving.
Huh? Turbos make their own air pressure. They don't care if the car is moving.
05-18-2008, 02:03 PM
#683
TroublemakrExtraordinaire
Yep, that certainly does sound likely. And Jeff's explanation makes sense.
I do think it is a bit strange that they would want to use the engine's RPM to calculate RWHP since it would be way more accurate and consistent to use the actual Dyno wheel RPM to calculate it.
And Jeff, air force is probablly a bad term for me to use. I have heard that the air pressure generated from the car movement has an additional effect on turbos and that you can alter the dyno read of a turboed car by increasing or decreasing the air flow generated infront of the car. I do not know if that is true or not but assumed that as a possible reason that the turbos could have performed lower.
Jedi, I would be up for another dyno. All I wanted it for in the first place was to have a baseline to compare mods to. If my last one was flawed then I basically dynoed last time for nothing :-(
I do think it is a bit strange that they would want to use the engine's RPM to calculate RWHP since it would be way more accurate and consistent to use the actual Dyno wheel RPM to calculate it.
And Jeff, air force is probablly a bad term for me to use. I have heard that the air pressure generated from the car movement has an additional effect on turbos and that you can alter the dyno read of a turboed car by increasing or decreasing the air flow generated infront of the car. I do not know if that is true or not but assumed that as a possible reason that the turbos could have performed lower.
Jedi, I would be up for another dyno. All I wanted it for in the first place was to have a baseline to compare mods to. If my last one was flawed then I basically dynoed last time for nothing :-(
05-19-2008, 12:33 AM
#688
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iTrader: (7)
we'll take care of you Jeff, I won't let you lose money on a deal, not on my watch. 
05-19-2008, 08:43 AM
#689
Boost Junkie
Join Date: Nov 2003
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And to be honest, if you want to come early, I will pay to have you hang out in my Garage for a little bit and shake down the car. I hear it is pretty hot in the AZ right now.... its a mild 86 in my garage right now.
05-19-2008, 01:33 PM
#690
never mind all this SoCal BS . NZ is where you want to come MM . I have a big garage (bigger than Slavearms) with central heating (i'll put a fan heater in the middle ) and a beautiful epoxy coated floor that is really comfortable to lie on . Waddayasay MM ?
05-19-2008, 02:04 PM
#693
Destroying Threads
Ray...........help me sell the fidanza and exedy clutch
and I will buy your clutch and flywheel damn it T.T
(shouldn't have ordered it at that time, damn mee!!)
and I will buy your clutch and flywheel damn it T.T
(shouldn't have ordered it at that time, damn mee!!)
05-20-2008, 11:36 PM
#700
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