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02-02-2020, 10:00 PM | #1 |
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Do light wheels make a measurable power difference?
Hi all,
I have some new forged wheels on the way (Advan RS-DF) and I am wondering if I should dyno the car before fitting them (rolling-road style dyno, not a hub dyno, obviously) to see what power difference they make at the wheels... if any. I think there should be a difference but happy to be corrected if physics says otherwise. On the Superstreetonline project Z4M they made an additional 13hp and 10ft-lb by fitting wheels that are 4lb lighter each. Has anyone ever dyno tested lightweight wheels? Will I see a measurable difference? |
02-03-2020, 09:46 AM | #2 |
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My OZ Ultraleggera 18 in rms were weighed vs the stock rims and the OZ's weight savings is an incredible 42.4 lbs....the rotating or spinning mass of reducing over 10 lbs at each wheel positively affects corner turn-in and reduces braking mass and unsprung weight.
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Last edited by racerbruce; 02-03-2020 at 12:06 PM.. |
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02-04-2020, 02:57 AM | #3 |
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Thanks, racerbruce.
Did you measure power before and after fitting your wheels? I’ve had lightweight wheels on pretty much all my cars and love the performance benefits but I have never done pre- and post-install dyno runs to see if there is a measurable power difference. |
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02-04-2020, 08:07 AM | #4 | |
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Testing
Quote:
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02-05-2020, 03:17 AM | #5 |
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Okay, thanks.
We’ll see if someone else has experience. I’m quite curious about this given how common it is to fit lightweight wheels. |
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02-06-2020, 03:25 AM | #6 |
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Yesterday I stumbled on an old discussion about this on m3forum and the superstreet article was referenced. There was a bit of debate and consensus wasn’t reached (it’s an online forum, after all) but it was interesting to read. Still no first hand, dyno-proven results though.
http://www.m3forum.net/m3forum/showt...=218821&page=6 |
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02-16-2020, 04:15 PM | #7 |
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BHP measured at the engine, no. WHP measured steady-state, no. WHP measured while accelerating, yes, because you will have less power losses from spinning up the rotational mass of the wheels. Lightweight flywheels work on the same principle.
http://www.uucmotorwerks.com/flywhee...heel_works.htm Whether this power gain will show on a dyno depends on the type of dyno and how it measures HP. An inertial dyno would theoretically see a difference but I'm not sure if it's large enough of a difference to show up. https://en.wikipedia.org/wiki/Dynamo...of_sweep_tests |
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02-17-2020, 03:52 AM | #8 |
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Thanks, filtercoffee - great information.
I think load dynos (e.g. Dyno Dynamics) should also see a difference (theoretically at least)? |
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02-20-2020, 11:40 PM | #10 |
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04-24-2024, 08:43 AM | #11 |
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https://www.audizine.com/forum/showt...eel-horsepower
everything is described here, the guys took measurements on 3 types of wheels on a dyno |
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04-24-2024, 02:57 PM | #12 |
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i bought MBANS wheels a few months back.... BY FAR the highest quality wheel ive ever had the fortune to own, and so light they genuinely feel like they'd snap at the first sign of stress, lol. Of course they wont but man ive never picked up a lighter 18" wheel. In contrast my old 260M m3 wheels literally felt like boat anchors in comparison.
The change to the drive for me has been night and day, every moment felt better immediately but these dropped some serious weight from the previous 260m setup (nearly 40lbs) did i mention how freaking beautiful they look? https://youtube.com/shorts/ECEahK7ru...4F3CQV6pqM-V7E
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04-25-2024, 11:32 PM | #13 |
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Glad you’re still liking them 🙂 my new wheels are not exactly heavy, but still 1kg heavier per wheel and I really do think I can tell the difference in ride quality in comparison to those Advans.
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04-27-2024, 03:26 PM | #14 | |
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Most of all, these wheels are super rare now, and ADVAN discontinued them in BMW sizing making them pretty special , thanks again for working so hard to get these over to me! means ALOT. How some up to date pics of your car with the new wheels on
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05-03-2024, 12:00 AM | #15 |
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I’m not sure why, but I reckon these wheels look better on a roadster than they did on my coupe.
So many wheels are NLA in sizes for our cars. As far as I can tell, I got the last pair of silver 18 x 10 +25 RG-Rs in North America, and I don’t know if they’re even available in other markets (they’re not in Japan or Australia). I’ll post a couple of pictures of tho new wheels when I get home 👍 |
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