Dyno Wheels
11-09-2005, 08:26 PM
#21
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Join Date: May 2005
Posts: 25
Originally Posted by kahren' post='770923' date='Oct 19 2005, 11:22 PM
many new cars, output diffrent amount of horsepower in diffrent gears, because they are tuned to run more conservative in the higher gears.
This topic > you
11-09-2005, 10:07 PM
#23
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Join Date: May 2005
Posts: 25
that you obviously haven't the faintest clue about how a dyno really works.
Come on man, I'm not a know-it-all, but..
I don't know how I can nicely say this, but you shouldn't have opened your mouth in this thread. 
Come on man, I'm not a know-it-all, but..
many new cars, output diffrent amount of horsepower in diffrent gears, because they are tuned to run more conservative in the higher gears.
11-09-2005, 11:51 PM
#24
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Join Date: Jan 2005
Location: Greenwood AR
Posts: 831
Kahren, you are getting pwned on this one, you have developed NO facts to what you are saying.
I disagree with you thinking that cars are tuned different in higher gears, that is a 100 % false statement. Most new cars run off of a MAP sensor which is load scaling, the higher the load, the more consecutive the fuel and timing settings become.
I disagree with you thinking that cars are tuned different in higher gears, that is a 100 % false statement. Most new cars run off of a MAP sensor which is load scaling, the higher the load, the more consecutive the fuel and timing settings become.
11-10-2005, 12:55 AM
#25
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Join Date: Jun 2004
Posts: 201
I remember hearing something to the effect that all gears (albeit transmission, differential, etc.) are torque multipliers. The wheels are also a form of gearing. I don't fully understand it so I won't go spouting off like I'm an expert. However I can tell you this: lower gear ratios yeild higher torque transfer. So a 3.55 gear will have less initial resistance than a 4.10. The same would hold true for tire gearing. I just try to imagine switching between two different tire sizes on a bicycle. The smaller wheels are easier to get going, but don't let you go as fast as the big ones. In the end, just dyno the car with whatever wheels you drive it with. Unless you are just trying to impress someone.
. . . . just a reminder that this entire thread probably means absolutely nothing to the guy that started it. It doesn't sound like he's even going to be using wheels to dyno his car.
As far as what gear to dyno in, that really is dependent on the car itself. If you have a large single turbo then you probably won't make full boost until late in first gear. However, you will be able to spool the turbo sooner in a higher gear. You don't want the engine to outrun the turbo do you?
. . . . just a reminder that this entire thread probably means absolutely nothing to the guy that started it. It doesn't sound like he's even going to be using wheels to dyno his car.
As far as what gear to dyno in, that really is dependent on the car itself. If you have a large single turbo then you probably won't make full boost until late in first gear. However, you will be able to spool the turbo sooner in a higher gear. You don't want the engine to outrun the turbo do you?
11-10-2005, 07:31 AM
#27
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Join Date: Aug 2001
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Originally Posted by kahren' post='777207' date='Nov 10 2005, 03:27 AM
i dont have the 1st or 2nd gear runs, they do look the same as the 3rd and 4th except with a lower speed. i will get them at some other time. what i have are 3rd and 4th gear runs.
same car, run after run
the right most pic in your sig is very nice....
11-14-2005, 02:19 AM
#30
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Join Date: May 2005
Posts: 25
One thing people overlook when they talk about different gears on the dyno is that the difference between 3rd and 4th gear won't be as pronounced on a car that makes 150 horsepower vs. one that makes 300+.
The difference between an average 1.25:1 3rd ratio and a 1.0:1 4th ratio is ~20% overdriven.
You want to select the gear that's closest to a 1:1 ratio.
When I dynoed my truck, it kicked down into 2nd gear when I made my pull and yielded a ~25whp higher peak torque number just from the gear change.
The difference between an average 1.25:1 3rd ratio and a 1.0:1 4th ratio is ~20% overdriven.
You want to select the gear that's closest to a 1:1 ratio.
When I dynoed my truck, it kicked down into 2nd gear when I made my pull and yielded a ~25whp higher peak torque number just from the gear change.