GR seats are a little lighter than previous gen. Washer fluid is definitely the cheapest way to reduce weight. I’d like to reduce weight as well but it’s difficult to lose a significant amount. I would want to lose it where it matters most which is at the extremities of the car and in the front. Lightweight battery for summer conditions might be a relatively cheap weight reduction. Lightweight header might give some more net power as well as weight reduction. I’d be interested in other ideas as well!

 

Yeah, I get the sentiment to save weight primarily at the front, since the car is already heavier at the front by default and decreasing weight at the rear might make the car more tail-happy. Maybe lightweight wheels are a good option. You have 4 of them, so if each wheel loses 5 lbs, that's already significant.

 

Keto. 🤪 Seriously though, the cheapest and healthiest way would be if I dropped 30 lbs.

 

A/C is worth 40 lbs.

 

What's your purpose? Primarily daily driver, weekend canyons, track? How much amenities do you want? Do you need back seats?

Oh, and sound generator can go of course! 😁

 

Well, if you want to save weight by replacing OEM parts with high quality aftermarket options… TWS T66-F in 18x8 +44 with the stock 215/40/R18 tyres will save you about 7lbs per corner. (Total 28lbs)

Then an AP Racing BBK with 298mm size rotors will save you 20lbs

Then add a Fujitsubo Authorise RM+c single outlet titanium exhaust to save another 25lbs

73 pounds saved and all it took was a lot of money… but no sacrifice to comfort… add some nice bucket seats and you are over 100lbs saved quite easily

 

I am planning to remove the back seats - no idea how much weight that will reduce.

 

You're ignoring the weight of the seat rails.

My Kawai Works rails are maybe 15-20lbs. My Recaro RSGK is 10lbs. So we are talking 25-30lbs for a very lightweight setup. A smaller savings although still substantial if both seats are replaced.

 

You're ignoring the weight of the seat rails.

My Kawai Works rails are maybe 15-20lbs. My Recaro RSGK is 10lbs. So we are talking 25-30lbs for a very lightweight setup. A smaller savings although still substantial if both seats are replaced.

View attachment 3629

I was going to point that out and everyone always forgot about the rails.
Racing seat is better in every way to an oem seats in a sportscar, unless you have chosen a wrong size for your body type. The only issue would be the in/outgress of the car.

My question to you is if anyone look into incoporating the one button slide forward rail into any race seats?
or, if the stock Oem can be retained and bolting the fixed seat mount on top of it?

 

looks likes there's plenty of room for those seats to - good fit

 

Just make sure you don't have a waist size larger than 33. I'm a 33 and these are tight. My Bride Zieg in my other car is the same. Given the RSGK is a Recaro made for the Japanese market (not actively sold in the U.S unless imported), my assertion is that Japanese seats are built to a maximum 33 waist lol.

 

Lighter wheels are the best. You could also get a lightweight battery. I suppose you could remove quite a lot by various means but would you not then have to adjust the suspension to compensate?

 

Wheels and battery are easiest.

 

I decided to go to the gym

 

diet and exercise.

 

Light weight pulley's...take the manual out of the glove box. Remove the special module and speaker for the fake sound

 

...take the manual out of the glove box.

Seriously, this. 2 lbs. 14.5 oz

1.318 kg

 

What is the purpose of wanting to remove weight? Sure, if you're going to build a full-on race car, then start ripping out unneeded amenities. Just remember, there are ways to reduce weight while leaving the comfort features of the car.

Removing Unsprung Weight should be first and foremost. Lightweight wheels such as; Rays Engineering Volk Racing TE37, ZE40, etc, or Wedsports TC105N, are all good light weight choices. A competition brake kit can reduce unsprung weight. Additionally, a 1-piece carbon driveshaft, lightweight flywheel, and lightweight pulleys can have a great affect on driving feel and engine stress.

For every Pound of Unsprung Weight removed, it is equivalent to 10 Pounds of Sprung weight.

 

The fake speaker, battery and exhaust should all be easy to live with, assuming you spend enough to get decent quality.

Weight loss makes every aspect of the car better performing so I'd say it's worth more than say just power or just brakes.

 

One of them Max Orido batteries

 

The mounting bracket looks nice, not sure if $100 makes sense but it's nice. If it works for the lfx36 battery as well and the new car I might go that route.

 

Sorry for the late reply

I believe Orido-san has alluded a while back the bracket would be for the LFX36, though the Japanese use the A3 instead of the L3. Don't know if that would be an issue.

Also, I am also tempting to get a Li ion battery as a mid-early mod for my incoming GR86, but I've never dealt with batteries before. Could you give me some advice on changing to and maintaining a Li ion battery? Thank you~

 

Thanks @apex2apex , I wasn't aware of the difference between sprung and unsprung weight yet. It makes sense though if you think about it.

The important key takeaway (as I understood it) is that unsprung weight (weight that's not supported by the springs) has an exponential effect on acceleration (instead of a linear effect as sprung weight has) because most components that make up unsprung weight are also rotating mass. And according to my research, rotating mass is around 3x times harder to accelerate or decelerate per kg than a non rotating mass.

The other benfit of reducing unsprung weight is that the springs have a much easier job to keep the tires planted on the road, because they have to push less weight downwards whenever the wheels get pushed upwards due to bumps on the road. That translates to better grip and more ability to put the available horsepower down on the road.

 

Thanks @apex2apex , I wasn't aware of the difference between sprung and unsprung weight yet. It makes sense though if you think about it.

The important key takeaway (as I understood it) is that unsprung weight (weight that's not supported by the springs) has an exponential effect on acceleration (instead of a linear effect as sprung weight has) because most components that make up unsprung weight are also rotating mass. And according to my research, rotating mass is around 3x times harder to accelerate or decelerate per kg than a non rotating mass.

The other benfit of reducing unsprung weight is that the springs have a much easier job to keep the tires planted on the road, because they have to push less weight downwards whenever the wheels get pushed upwards due to bumps on the road. That translates to better grip and more ability to put the available horsepower down on the road.

What will you choose to focus on first?

 

I don't know about an ideal size.
Disadvantages are that you will either change gearing or add sidewall which will make turn in less sharp and negate weight savings.

You also need to ensure that brakes will clear.

 

Lighter = better.

Curious how the car would drive with 15x9" vs 17x9" - it would be a large sidewall though, as stated above, so it would likely feel sloppy. I am curious the average lap time differences though.

 

How much lighter is the rubber sidewall than a forged aluminum wheel section?
Now if you kept the sidewall close and just lowered and geared the car lower that would be faster in most instances.

I'd assume a 17x7.5 or 7x8 on 225 or 235s with the shortest sidewalls would be the fastest. Width adds weight as well.

 

It would be interesting to test and find out.

 

Has anyone had experience with using billet aluminium/titanium components for like say the suspension area? I'm guessing not only that they tend to be more stronger than the OEM stamped steel components, but they also are lighter too?

Speaking of billet components, I saw a video of the Alfaholics GTAR-290 (on a tight twisting winding road, bare in mind) keeping up well with the M2 Competition. The spec on that car meant that it had 290hp per ton from its 830kg weight with a 240hp engine. The 5kg reduction in suspension components made that car absorb the bumps much more efficiently (rebound better). No doubt, its an expensive modification to do, but it pays dividends to the way the car behaves.

 

For your reading pleasure. The Hows And Whys of Battery Relocation - Garage Tech. I’m still researching battery options, but have used an Odyssey PC680 in the past on my E46 M3. I’m also wondering if I need to run a full length negative cable or just short runs to chassis ground on both ends (trunk and engine bay). I will create a specific thread when I sort some details.

 

I'd assume you'd be able to run short cables but theory and practice are probably why Japanese cars work and German cars all have electrical gremlins lol 😆

 

I did a relocation in a Taurus SHO and only ran a full cable for the positive side. No issues, but that was 30 years ago and cars are rolling compuynow and likely more temperamental

 

I did a battery relocation to the trunk of a1964 Falcon (back in the eighties) and had some grief until I ran a -ve cable from the battery to a starter bolt, problem solved. Grounds are tempermental. You practically need to be an electrical engineer and metallurgist to know what will work.

Looking at what I just typed I realize that it was no help.