When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Door sticker:
GVW=== 4118 LBS.
Pass Wt.= -525 LBS. Car only=3593 LBS.
Driver Wt=+260 LBS. Total Wt=3853 lbs.
I have weigh the car on a +/- 20 lb. calibrated truck scale w/full tank & 260 lb. driver = 3860 lbs. (Porky Pig)
I have removed my Stage 1 front splitter (see pic) 'but' added side skirts, chrome wheels (silver before) and a transparent top. If I could cut some weight maybe I could improve my 'marginal' track times. Light weight wheels/tires would help.
Check out your weight sticker!
Last pic taken 11/12/17 at track below:
Last edited by C7/Z06 Man; 11-16-2017 at 08:09 PM.
I had my 2015 M7 3LZ weighed on the official scales at an SCCA club race event. It was 3556 lbs with stock wheels and tires and AP Racing brakes. Full fuel tank.
Door sticker:
GVW=== 4118 LBS.
Pass Wt.= -525 LBS. Car only=3593 LBS.
Driver Wt=+260 LBS. Total Wt=3853 lbs.
I have weigh the car on a +/- 20 lb. calibrated truck scale w/full tank & 260 lb. driver = 3860 lbs. (Porky Pig)
I have removed my Stage 1 front splitter (see pic) 'but' added side skirts, chrome wheels (silver before) and a transparent top. If I could cut some weight maybe I could improve my 'marginal' track times. Light weight wheels/tires would help.
Check out your weight sticker!
Last pic taken 11/12/17 at track below:
Thanks
Originally Posted by Poor-sha
I had my 2015 M7 3LZ weighed on the official scales at an SCCA club race event. It was 3556 lbs with stock wheels and tires and AP Racing brakes.
With 'other' race car, corner weights were measured/set-up with sand bag weight in drivers seat for balance. Without sand bags, L side should be a little less.
With 'other' race car, corner weights were measured/set-up with sand bag weight in drivers seat for balance. Without sand bags, L side should be a little less.
My 1lz A8 with replica 19" rims and nitto tires which are 8lbs heavier then stock each and non run flats in the front and a procharger and meth kit and about a 1/4 tank of gas with AR headers no cats weigh 3475lbs at the track
So let’s start with the assumption of a stock LT4. How much of a performance gain or loss would one expect to see with a change of 50#, 100# etc in either direction? Is he 50# increase in weight change the performance for the worse the same degree as a gain of 50# for the better? I hope that makes sense. How much weight would you need to shed to drop .1 sec in the 1/4mile? I ride bike a lot and cyclists are chasing grams on a road bike but that has to do with long term endurance with a lighter bike.
Follow up question. Is all car related weight loss the same? Meaning if I shed 50# in wheel/tire weight, is that the same as lightening body/engine components?
Thanks in advance.
So let’s start with the assumption of a stock LT4. How much of a performance gain or loss would one expect to see with a change of 50#, 100# etc in either direction? Is he 50# increase in weight change the performance for the worse the same degree as a gain of 50# for the better? I hope that makes sense. How much weight would you need to shed to drop .1 sec in the 1/4mile? I ride bike a lot and cyclists are chasing grams on a road bike but that has to do with long term endurance with a lighter bike.
Follow up question. Is all car related weight loss the same? Meaning if I shed 50# in wheel/tire weight, is that the same as lightening body/engine components?
Thanks in advance.
They say (old school) that 10 lbs. of rotating weight i.e. wheels, tires, rotors, etc. is equal to approx. 100 lbs. of sprung weight i.e. car body, engine, etc.
Now I don't know if it's really a 10 to 1 ratio in the 'real world' or not but also as the rotating weight moves out from the center line of the axle it has more of an effect on acceleration (slower) from what I have read.
Example: Spin a small round metal rod or large nut in your fingers than try spinning it at the end of a short string/wire. Same object just a little harder to get it going or stopping.
Bottom Line: Yes, 50# of rotating weight will slow you down or speed you up more than 50# of sprung weight.
PS: I've heard a vendor on here say that once they replaced the heavier set-up with lighter wheels and tires the car felt lighter from behind the wheel and also picked up a few tenths in the 1/4 too.
Last edited by C7/Z06 Man; 01-11-2018 at 12:20 PM.
Just to be clear the vendor's car was hooking before the lighter wheel/tire set-up. Most people who replace a heavier set-up with lighter wheels & tires, usually with skinnies up front (less rolling resistance) will reduce their ET in the 1/4. Your results will vary!
PS: As with my original post I agree that the further away from the axle center line i.e. tires, a weight reduction will have a larger effect.
Last edited by C7/Z06 Man; 01-11-2018 at 12:27 PM.
It’s a challenge to get a true comparison on changes. I would bet that most owners who change wheels also change or upgrade tires depending on their needs. I could not see someone buying a nice set of rims and put their old rubber back on. Hard to say what percentage the change in wheels/tires contribute to reduced ETs.
I see the value in road racing for sure and a lighter combo is easier to accelerate and stop. I would assume that once the rotating mass of a tire reaches a certain RPM, the energy needed to continue accelerating would decrease.
I recently changed to CF wheels that weighed at 16lb front and 17lb rear. At the same time I also switched to non-ZP Cup 2s. It did seem noticeably different (quicker and VERY smooth) from behind the wheel.
Unfortunately, nothing scientific (track times) to back that up. Maybe when I am home next trip.
I recently changed to CF wheels that weighed at 16lb front and 17lb rear. At the same time I also switched to non-ZP Cup 2s. It did seem noticeably different (quicker and VERY smooth) from behind the wheel.
Unfortunately, nothing scientific (track times) to back that up. Maybe when I am home next trip.
What kind of GF wheels and where did you get them ?
Thanks
11-16-2017, 06:32 PM
2015 Coupe, 1LZ, Stage 1, A8 trans, full tank.
