Hello! I have a Infiniti G35 Coupe, that I daily, so I want to keep the car decent as a daily, and for track use the same, but because I daily it I would like to get a bit better gas milage and I know lightening the car can really help with that, so I was wondering what you guys think the best way to go about that is? And then if you suggest something, maybe a link to the item that will fix that... I already have some aftermarket wheels/tires on it so I have that done, but not sure what else you guys suggest... Any help is appreciated thanks!

 

You can fill your tires with helium. 😁

 

Are your aftermarket wheels forged? If not they are likely quite a bit heavier than the stock wheels.

When doing weight reduction, there’s very few pieces that you can replace with another piece that is going to be significantly lighter, and make enough difference to justify the cost other than like a titanium exhaust which is a lot lighter than stock. Exhaust Lightening is all about removing items.

I would start by removing the spare, jack, and basically stripping the trunk. Than the back seats. Then racing seats for the front will be a big difference in weight. Then sound deadening and carpets, radio, panels, and on and on. But something to keep in mind, almost everything you remove will increase the noise level inside the car, especially once you remove the carpet and sound deadening.

if your main goal is better gas mileage, then weight reduction is really not the direction to go. Your driving behavior will affect the mileage far more than weight reduction. And weight reduction will only impact the mileage when accelerating, it will have almost zero impact on mileage when cruising down the road. Even doing a ton of weight reduction would have very little affect on the mpg.

weight reduction is not great for a daily. It’s more for a track car, or somebody that is a dedicated track person, but has to daily their track car. For an occasional day at the track for fun it’s not worth “wrecking” the car and suffering with the noise and lack of creature comforts everyday.

 

^agree with the above....gut the trunk and install bucket seats first and foremost. I shed ~100 lbs by doing those easy things. Wheels and exhaust also saved some lbs, albeit not as substantial as the interior mods. None of this stuff increased my mileage though. It did make for a better handling, more fun car.

 

IIRC you can save some pounds with an aluminum or carbon driveshaft. Will also reduce rotational weight.

 

Remove spare tire + jack
Replace front seats
Replace OEM flywheel (if 6MT) and driveshaft with lightweight versions

For the mileage you're going to want a 5/16 plenum spacer (with an MREV2 lower plenum if you have the rev-up engine) and an Uprev tune. Plus it will get you a pretty significant increase in power and driveability.

 

Thanks so much! Greatly Apreciated, all of the help.

 

Lighter 2 piece brake rotors and forged wheels made noticeable on my car.
Other suggestions:
lighter battery (stock one is pretty heavy)
Aluminum batwing and W chassis braces (stock steel ones are quite heavy)

 

where do you get the aluminum chassis braces from?

 

where do you get the aluminum chassis braces from?

 

fd raceshop and gk tech each make aluminum chassis braces.

 

I have so many questions here.

1) What brand of bucket/racing seats to use ? I got the Planted brackets but am struggling to pick the seats. I see many use Braum reclining seats (which are $800-$1000) with the stock seatbelts being used on Youtube or Instagram, but some also use the cheaper Amazon/eBay clone brand ones for $300 or so.
2) Is the better seat a FIA rated seat ? or a used/expired FIA rated seat like a Sparco/Corbeau/Bride replica is fine for daily use and two-track-days-a-year use ?
3) are these comfortable for 200 mile drives ?
4) I am guessing the heated seats are a dead option if you remove the stock seats. So what do you do with those heating on/off buttons ? do you reuse those switches for something else ?

I understand that seats have tons of posts but what is the current day best seat choice for someone between 165lb-200lb medium waist (34"), that's comfortable for the drives but also makes the car look cool.

 

I'll give my input on the Corbeau A4 seats which are very popular as a dual-purpose seat.
- weigh 26 lbs each according to the manufacturer. My stock sedan seats weighed 64 lbs each.
- retains the heater. The heating element in your stock seats can be swapped over to these. This is an option.
- they recline
-ample room for a 34" waist
-shoulder bolsters are not too wide so fitment is no problem
- option of lumbar support
- I paid $1535 for both seats which are full leather and have both heaters. Can be had for $900/pair with black cloth and no options.

https://corbeau.com/a4/
https://g35driver.com/forums/v36-interior-exterior-lighting/471912-corbeau-a4-seats-short-review.html

 

Another seat option is the 370z nismo half-recaros. They are about half the weight (42#’s +\-) of the coupe seats and have integrated airbags and are fully (manually) adjustable. I say “half-recaros” because they are the recaro cs back and the 370z oem bottoms.

 

Don't bother with FIA rating unless you're in a bracket that REQUIRES it. If they meet the spec and you find ones for a good price that's fine but it's not something you need to be specifically searching for.

I'm guessing most rated seats that are expired aren't new and thus have been pretty abused, I've never seen a race car that people were gentle with, it's usually a matter of exiting the car as fast as humanly possible post-race so you can get that sweaty ****ing race suit off so you don't really care if you're hard on the upholstery

If you want the lightest possible then you're looking for a set of Kirkeys, good luck daily driving them though. Maybe just delete the seats for race day and bolt in a Kirkey?

Honestly though as long as the seats weigh less than like 50 lbs you're doing good, the factory 370Z recaros can fit if you modify the bracket substantially and will still work with the SRS system.

It's one of those things though where you're going to be spending quite a bit of money for a VERY VERY small performance upgrade.

For road course you're better off spending the money on a track dedicated set of pads/rotors to swap out on those track weekends.

For straight line you're better off spending the money on a set of wheels/slicks and the 370Z rear axle/hub conversion so you can get a better 60' time.

If you have all the other bolt ons taken care of (plenum spacer, MREV2 if rev-up engine, headers, test pipes, exhaust, 3.5" intake, 75mm throttle body, tune. Also lightweight flywheel if 6MT, single piece aluminum driveshaft for both 6MT and 5AT) then shaving weight is the next step, if you don't have the basic bolt-ons already then there's a lot of low hanging fruit to be spending money on before you are worrying too much about shaving weight.