Rotating mass questions.
03-30-2009, 09:33 PM
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Rotating mass questions.
I recently installed a set of UR pulleys. (Crank, PS, and alt.) and even though I haven't had them on for long, I noticed I'm getting about 10% better mileage. I don't think we've gone back to summer gas yet so I don't think that's it. That increase in mileage seems pretty darn high to me for such a small change. Is that what people usually get, or did someone mess with my gas?
If that's a normal gain for such a decrease in rotational mass, would going to a set of lightweight wheels (about 14 pounds each) have a similar impact on fuel economy since it's a similar reduction in rotating mass? I also noticed that my throttle seems far more responsive. Would lightweight wheels also increase throttle response?
If that's a normal gain for such a decrease in rotational mass, would going to a set of lightweight wheels (about 14 pounds each) have a similar impact on fuel economy since it's a similar reduction in rotating mass? I also noticed that my throttle seems far more responsive. Would lightweight wheels also increase throttle response?
03-30-2009, 10:21 PM
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hey, mate !
I also got UR pulleys and my MPG also grew by 8-10% per tank, no joke. It used to be 270-290 or so per tank with my driving style, but now I hit 300-330 without breaking a sweat (of patience from slow driving) My throttle response and best of all low end TQ have increased dramatically. I am not sure about how profound the effect of the light wheels would affect your car, but I only hear positive things. How much do stockies weigh BTW ?
I also got UR pulleys and my MPG also grew by 8-10% per tank, no joke. It used to be 270-290 or so per tank with my driving style, but now I hit 300-330 without breaking a sweat (of patience from slow driving) My throttle response and best of all low end TQ have increased dramatically. I am not sure about how profound the effect of the light wheels would affect your car, but I only hear positive things. How much do stockies weigh BTW ?
03-30-2009, 11:05 PM
#5
I noticed that when I started to mod about 18 months ago, my milage went from 19.5 mixed to 26.5-27.5 mpg mixed w/ just CAI, Header, Test-pipe, Pulleys and eventually reflash. I'm looking forward to lightweight rims for the decrease in un-sprung weight, but clutch, LW flywheel & LSD have got next big chunk of change.
03-30-2009, 11:07 PM
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Wow, a 10% increase from simply changing pulleys? That sounds very interesting to me. What are the potential downsides of changing your pulleys? Alternator being under powered?
Your question about wheels. What you would probably experience is more horse power to the wheel. Even though the horse power at the crank will stay the same regardless of wheel weight, the less weight you have on the wheels the more power efficiently power can be transferred.
I dunno how accurate this info is, but i have heard that for every pound that is gained at the wheel, that is like gaining 10 lbs on the car, so if your wheels are losing a total of 10 lbs (2.5 lbs per wheel), you essentially lost 100 lbs of weight on the car. Again, i don't know how accurate that is, but the general concepts are what matters here.
Your question about wheels. What you would probably experience is more horse power to the wheel. Even though the horse power at the crank will stay the same regardless of wheel weight, the less weight you have on the wheels the more power efficiently power can be transferred.
I dunno how accurate this info is, but i have heard that for every pound that is gained at the wheel, that is like gaining 10 lbs on the car, so if your wheels are losing a total of 10 lbs (2.5 lbs per wheel), you essentially lost 100 lbs of weight on the car. Again, i don't know how accurate that is, but the general concepts are what matters here.
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03-31-2009, 01:27 AM
#10
Stock wheel and tire for an 05 came to about 45 lbs.
My aftermarket wheel and tire comes to about 38 pounds and I noticed no change in gas mileage. However, I think my habits changed since acceleration and braking were markedly better.
My aftermarket wheel and tire comes to about 38 pounds and I noticed no change in gas mileage. However, I think my habits changed since acceleration and braking were markedly better.
03-31-2009, 04:23 PM
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Wow, a 10% increase from simply changing pulleys? That sounds very interesting to me. What are the potential downsides of changing your pulleys? Alternator being under powered?
I dunno how accurate this info is, but i have heard that for every pound that is gained at the wheel, that is like gaining 10 lbs on the car, so if your wheels are losing a total of 10 lbs (2.5 lbs per wheel), you essentially lost 100 lbs of weight on the car. Again, i don't know how accurate that is, but the general concepts are what matters here.
I dunno how accurate this info is, but i have heard that for every pound that is gained at the wheel, that is like gaining 10 lbs on the car, so if your wheels are losing a total of 10 lbs (2.5 lbs per wheel), you essentially lost 100 lbs of weight on the car. Again, i don't know how accurate that is, but the general concepts are what matters here.
It is "possible" to run the stock belt with UR pulleys, but it is a little too long. that is why when I revved the engine up, it made clopping sound,- the belt slipped. it made the same sound when AC was on, car was idling and I turned the wheels at the same time bc that put more load on the accessories. What u need is a belt from CR-V
04-01-2009, 09:43 AM
#15
No room in
Where would one get this new belt/what would you recommend? Pulleys is on my list of things to do eventually, and talk of 10% fuel economy increase bumps it up a notch or two. Plus my current belt has a small fray in it and will need replaced...
04-01-2009, 01:34 PM
#17
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Somehow I missed that post but read every other post in the thread. Thanks. 
EDIT: Is there a particular year range I need or are they all the same? I'm not up on my CR-Vs.
Last edited by Takran; 04-01-2009 at 01:39 PM.
04-01-2009, 02:06 PM
#18
04-01-2009, 02:44 PM
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The T1R is not true stock size as the NST is. Since it would be slightly underdriven, you would need a different belt with and nobody knows what size is correct. I almost went that route before Marcus at Heeltoe told me this. I can say that the NST fit and finish is outstanding
Stock layout pulley sure is a good bang for the buck, but installation..... 
04-01-2009, 05:09 PM
#20
Here's the UR pulley thread from almost 3 years ago.
https://acurazine.com/forums/1g-tsx-performance-parts-modifications-126/jtsos-ur-underdrive-pulleys-installation-666337/
https://acurazine.com/forums/1g-tsx-performance-parts-modifications-126/jtsos-ur-underdrive-pulleys-installation-666337/
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