Changing gear ratio affect RWHP on a dyno?
04-09-2008, 07:43 PM
#1
Drifting
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Changing gear ratio affect RWHP on a dyno?
Going to a higher gear, say 2.73 up to 3.42, and then having the car dynoed, would RWHP or TQ show up on the graph. 
04-09-2008, 09:09 PM
#7
Team Owner
I think you should gain some torque. I'm sure I will be corrected if I'm wrong. 
04-09-2008, 09:29 PM
#11
Team Owner
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
04-09-2008, 09:42 PM
#12
Melting Slicks
It's kinda like this!
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
Higher final gear ratios reduce wheel horsepower because of increased friction loss
04-09-2008, 09:47 PM
#13
Team Owner
Much in the same way it loses HP too, that is in an illustrative way!
I would like you if you could give us an ILLUSTRATION to help us understand the loss, if that would be good for you
Please respond! So I wont make this mistake again
Thanks,Matt
04-10-2008, 12:47 AM
#15
Melting Slicks
3.42s are no good. You know you want 4.10s. So i have a question then. I dynoed at 424rwhp with 3.42s and now have upgraded to 4.10s what would my dyno numbers be now?
04-10-2008, 09:47 AM
#17
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St. Jude Donor '12-'13-'14-'15-'16-'17-'18-'19-'20-'21
It's kinda like this!
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
04-10-2008, 10:24 AM
#18
It's kinda like this!
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
When you try to remove your LUG NUTS with a 3/8" ratchet and socket it will take a ton of arm strength to remove them and if you had a dial gauge on your elbow the needle would move tremendously with the effort being used.
Now if you were to remove that same LUG NUT and used a long bar with the dial gauge on your elbow it would read less in the effort needed!
So to answer your question you will loose some dyno numbers because the 3.42 gears will make it easier to move the dyno, therefore the gears are utalizing what you already have and it takes less effort to get it going
In real world though it is ONLY a number but the results are better performance and quicker times and it takes lees to move your Vette from point A to B thus making it quicker
But the results are like adding 50 HP but it does not show up on the dyno just at the track and on the street!
I hope this helps
I don't really have a theory for why you lose power but it may have to do with engine load. Like maybe you have more power when the engine is under a higher load.
04-10-2008, 01:55 PM
#19
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This would be true if the percent decrease in hp/tq correlated with the gear reduction. Just like if went from a 1' breaker bar to a 2' breaker bar, The dial guage on your elbow would read exactly half of what the 1' breaker bar read given the same amount of tq at the lug nut. Going from a 3.42 to a 3.90 is a 14% difference which means you would loose 14% of your tq on the dyno and I don't think people lose that much.
I don't really have a theory for why you lose power but it may have to do with engine load. Like maybe you have more power when the engine is under a higher load.
I don't really have a theory for why you lose power but it may have to do with engine load. Like maybe you have more power when the engine is under a higher load.
Dynos #s are also affected by wheel/tire sizes and unsprung weight.
People seem to forget that Dynos are really a tuning tool and to some extent you can use the information for vehicle to vehicle comparisons but it is not 100% accurate.
