[rami335i]

Guys, can a 40 lbs reduction in unsprung weight make a big difference in a drag race?
The reduction is coming from lighter wheels and moving to non-RFTs.
Is the difference noticeable in a drag race to justify around $2,000?
I am already FBO

[hemi to e90]

Originally Posted by rami335i

Guys, can a 40 lbs reduction in unsprung weight make a big difference in a drag race?
The reduction is coming from lighter wheels and moving to non-RFTs.
Is the difference noticeable in a drag race to justify around $2,000?
I am already FBO

idk bout drag racing cause its not my thing, but id imagine it would help.

but the difference in ride, handling, braking, and acceleration is fucking fantastical.

[E90SoFlo]

got yelled at by a mod so i edited this, forever alone =p

Mod adds: Mea culpa -- I am not a mean guy. Plz accept apology.
Stressdoc aka yelling mod

[Syndicategt]

Unsprung weight is HUGE! You will feel it instantly, especially with 40 lbs. I felt an amazing difference when I switched from CSL wheels to forged light weight rims. 1 lb of unsprung = 2 lbs of static weight in performance gains.

80 lb subs are not unspung weight.....

[stressdoc]

Originally Posted by E90SoFlo

I have subs and they're about 80 pounds.. Not a single f&*( is given.

Unless you have your subs mounted on your wheels you don't know what the f&^* you are talking about. The OP is interested in unsprung weight.

To the OP: he!! yes 40 lbs makes a huge difference in performance -- not so much for drag racing (at our levels, it is all about more power and traction), as for handling. Acceleration will be faster as the rotational mass of the wheels you are turning is lighter. But more significantly, your suspension has so much less momentum to control with that much weight loss. That said 2k is a lot of $.

[BMWsky]

Unsprung weight is most obvious in regards to handling. I don't know if you'd notice it much in a drag race, but you'd really feel the difference on the track or street. 40lbs is still 40lbs so you'd probably shave a thousandth on a dragstrip, but I think other variables would be more of a factor.

[themyst]

There was an article on tire rack about the effects of unsprung weight on straight line acceleration. Dropping 9 lbs per corner net the test car 1 mph in the quarter mile. Do a search for the article on Tirerack. Difficult to do it on a phone.

[hemi to e90]

Originally Posted by E90SoFlo

I have subs and they're about 80 pounds.. Not a single fuck is given.

google "unsprung weight" please.

[E90SoFlo]

Jesus you guys are so fucking serious about everything, calm down. I didn't even read the OP's entire post. CALM DOWN.

To the OP: Yes 40 pounds are noticeable.. You will prefer the non RFT also.

[jippii ensio]

Originally Posted by Syndicategt

Unsprung weight is HUGE! You will feel it instantly, especially with 40 lbs. I felt an amazing difference when I switched from CSL wheels to forged light weight rims. 1 lb of unsprung = 2 lbs of static weight in performance gains.

80 lb subs are not unspung weight.....

He is using your equation, so that is why he got it to be exactly the same

1lb = 2lb ->
40lbs = 80lbs

[jippii ensio]

Originally Posted by stressdoc

Unless you have your subs mounted on your wheels you don't know what the f&^* you are talking about. The OP is interested in unsprung weight.

Not really. He is interested in rotational (or rotating) weight (or mass), but he , and everybody...?? are talking about unsprung weight. which is wrong. When accelerating, the unsprung mass is no worse than sprung mass. But rotational is worse than static.

Wheels and tires just happen to belong to both rotational and unsprung categories.

[rami335i]

Originally Posted by E90SoFlo

Jesus you guys are so fucking serious about everything, calm down. I didn't even read the OP's entire post. CALM DOWN.

To the OP: Yes 40 pounds are noticeable.. You will prefer the non RFT also.

i read somewhere that 1 lbs unsprung weight reduction can equal to 10 lbs sprung weight and that each 10 unsprung lbs reduction equals 10 whp or 0.1 sec in the quarter mile.
i thought to myself if i can spend 2 grand and save 40 lbs to make my car much faster why the he11 not??!! but again if that is true, everyone would have done it.. what do you guys think?

[jippii ensio]

OP, if you value 0.1s at $2k, your life has a lot of value.
There are cheaper ways to be as quick, despite of being FBO already.

[eric@helix]

A rule-of-thumb for adding power or dropping weight is that you need to gain about 8-10 WHP, or lose the equivalent weight to feel a difference in performance from the driver's seat. Losing the equivalent of 80lbs (40 unsprung) should make a noticeable difference in the car's performance.

[rami335i]

Originally Posted by jippii ensio

OP, if you value 0.1s at $2k, your life has a lot of value.
There are cheaper ways to be as quick, despite of being FBO already.

maybe i was hoping 0.5 sec for the 40 lbs unsprung reduction.
yeah you are right, i am better adding meth for less than $500 and get the 30-40 whp !!!

[jippii ensio]

Originally Posted by rami335i

i read somewhere that 1 lbs unsprung weight reduction can equal to 10 lbs sprung weight and that each 10 unsprung lbs reduction equals 10 whp or 0.1 sec in the quarter mile.
i thought to myself if i can spend 2 grand and save 40 lbs to make my car much faster why the he11 not??!! but again if that is true, everyone would have done it.. what do you guys think?

It's not 1:10 but close to 1:2 depending on several factors such as how the weight is distributed.

Rotating mass

[bigdaddycane]

I didn't even read the OP's entire post.

there-in lies the problem with so many reponse posts on this forum...

[GeorgiaTech335coupe]

For $2k its not worth it, from a drag racing perspective. You would be lucky to lose 0.1s off your time and maybe gain 1mph. If you are a manual transmission and the tires you are switching to are not drag radials, you will probably never see that gain as it is EXTREMELY hard to be consistent on your launches with street tires.

My opinion, get rid of the run flats and go with a non run flat performance tire. They are cheaper than run flats and will give you better traction. Only get the rims if you really like them. Spend the rest of the money on a meth kit. It is the second best thing to making your car faster, right behind a tune. You will easily gain a minimum of 2 mph with meth.

[Proper Motion LLC]

I think it makes a significant difference in all these 60-130 times.

You can lose 15 lbs per wheel/tire if u go with super light 17-18 lb wheels, and light tires like Continental DW and Pilot Super Sports.

[turb0mik3]

Yes. Lighter wheels = less rotational mass. That is very good.

[achien]

$2k and you get 40lbs reduction? you got a lot of value there.

I am looking at BBS RGR rims and it will net me 48lbs in savings, but the rims costs $4k.

I doubt your rims are forged and they provide that much weight savings for only $2k. At your price point, you will only get cast-aluminum rims, which will be around 20lbs (5lbs per corner) in weight savings.

Originally Posted by rami335i

Guys, can a 40 lbs reduction in unsprung weight make a big difference in a drag race?
The reduction is coming from lighter wheels and moving to non-RFTs.
Is the difference noticeable in a drag race to justify around $2,000?
I am already FBO

Originally Posted by stressdoc

Unless you have your subs mounted on your wheels you don't know what the f&^* you are talking about. The OP is interested in unsprung weight.

To the OP: he!! yes 40 lbs makes a huge difference in performance -- not so much for drag racing (at our levels, it is all about more power and traction), as for handling. Acceleration will be faster as the mass of the wheels you are turning is lighter. But more significantly, your suspension has so much less momentum to control with that much weight loss. That said 2k is a lot of $.

Originally Posted by rami335i

i read somewhere that 1 lbs unsprung weight reduction can equal to 10 lbs sprung weight and that each 10 unsprung lbs reduction equals 10 whp or 0.1 sec in the quarter mile.
i thought to myself if i can spend 2 grand and save 40 lbs to make my car much faster why the he11 not??!! but again if that is true, everyone would have done it.. what do you guys think?

Originally Posted by jippii ensio

OP, if you value 0.1s at $2k, your life has a lot of value.
There are cheaper ways to be as quick, despite of being FBO already.

[ExpensiveTaste]

Originally Posted by achien

$2k and you get 40lbs reduction? you got a lot of value there.

I am looking at BBS RGR rims and it will net me 48lbs in savings, but the rims costs $4k.

I doubt your rims are forged and they provide that much weight savings for only $2k. At your price point, you will only get cast-aluminum rims, which will be around 20lbs (5lbs per corner) in weight savings.

Not necessarily so. The apex arc-8's are just under 18.45 lbs per wheel in an 18x8.5(Roll Forged) and 18.85 lbs per wheel in an 18x9.5. Now let's say you also went with Continental DW's. You would save 63.4lbs in unsprung weight over factory 162's with Potenza RFT's:

162 F: 30lbs
162 R: 32lbs
Apex F: 18.45lbs
Apex R: 18.85lbs
Wheel Savings: 49.4lbs

Bridgestone RFT F: 25lbs
Bridgestone RFT R: 26lbs
Conti DW F: 21lbs
Conti DW R: 23lbs
Tire Savings: 14lbs

Total Price $1966.00 plus shipping

That's the setup I'm going with anyway...