Lighter BRZ without tuning
 

Hi Guys,



I dont have access to a tune and all so my mods will be limited to reducing weight/dynamics. I'd rather steer away from mods that will change airflow, odometer reading, sensor readings etc. while keeping the car looking generally stock



Heres what i plan to do, please chime in each item!



1. CF Driveshaft - In general, everything seems positive about this mod

2. Lightweight Wheel/Tire combo retaining 17x7.5 215/45 sizes

3. Lightweight Flywheel and Pulley Combo - seems ok at first but i realized it also carries some problems some people are sharing with it like idle problems, dying down fast because it also stops faster. I will have to make adjustments but.. (not something id want to change esp for a traffic daily driver)

4. I want to retain batteries because i hear small batteries need to be charged if unused much. Greater risk of discharge.

5. Retain seats of course.







So there you go. Basically 2 of 3 mods that I wanna do sans a tune.

1. Can't comment on the effectiveness of CF 1-piece driveshafts other than to say they're expensive.
2. 245's will be pinched on 17x7.5. You want at least an 8, if not 8.5 or 9. They're also heavier. If you're going primarily for weight, stay with 215's. That said, there are some lightweight 17x7s out there, so you can cut weight on wheels. If you have copious amounts of money, there are brake kits with lighter calipers and rotors that will save a fair amount of unsprung weight too.
3. Flywheel, yes. Your shifting will need to be on point, because your RPM will drop faster. Pulley, no. You're not saving a ton of weight there and enough people have reported engine problems associated with lightweight pulleys that I would pass.
4. You can save pounds with a lightweight battery, but I'd want a garage or some place where I could leave it on a tender.

Look into exhaust. The OEM exhaust is freaking heavy. Aftermarket exhaust can be significantly lighter. Titanium exhaust can be tremendously lighter. Also tremendously louder.

Read Anthony's 4 Step Diet Program for a lot more ideas on where to cut weight.

Why can't you do a tune? Premade tunes are as easy as flashing your ECU. I wouldn't get a catless header without a tune anyways; it won't run correctly.

for lightweight ideas start here.

It also depends on what you want to do with your car. If it is a dd that won't see much if any track, then 245 are real overkill and 215's or 205's will be much more entertaining. Also, a cf driveshaft is good, but the aluminum is 80% as good and half the price.

Ignore what people say about lightweight pulley's. They still think we're in 1950 and every car has a massive v8 that needs to be externally balanced. A lightweight flywheel is a good mod, but it doesn't really cause much problems in this car.

As for lightweight batteries it really depends. A stock battery usually weighs 40 lbs. You can now buy all sorts of lighter batteries, to the point where even auto parts stores are selling them. As long as they have 400+ cranking amps and you don't let them sit forever, you should be fine. But if you have a garage it is always good to have a trickle charger installed. There is so many different options now it really is amazing.

Also, buy and install a drop in filter. The computers can adjust enough for that to have an effect. Supposedly brand isn't that important.

I've been thinking of alt mods as well, as I'm not looking to squeeze every bit of power out if I can get 90% of the power for less.

Been looking at changing to lighter overpipe and catted front pipe first and axle back. Trying to lower the weight in the front and middle of car first, plus cat backs dont change the power enough to spend the extra on it.

Also, looking to swap FD prior to header and tune as well.

Hey gram, whats a good lightweight exhaust that doesnt make the car loud? I want to retain close to stock sound levels. Thanks!

Why can't you tune the car? The mods you're talking about will cost thousands and still be less effective than tuning.

I'm a big fan of light weight. But you'll spend hundreds/thousands to save 5s/10s of pounds, and performance will not be improved by any perceptible amount. Lightweight flywheel is the only thing you'd really notice, and that would be due to revs changing more rapidly during shifting, not from any actual performance improvement.

IMO, enjoy car and save yer $$$.

I'm sure lightweight wheels would make a noticeable difference as well.

Between wheels, spare tire removal, lightweight battery, and lightweight exhaust you should be getting close to 26XX pounds.

The car won't be drastically faster, but it should acclerate/handle/brake better all without making the car harsher to drive on a daily basis.

Good thread, interesting to hear about weight mods, not oft discussed around here. Like others have said, I think your biggest savings would be around:

• Lightweight wheel/tire
• Lightweight exhaust
• AGM battery (better cranking performance, better lifetime, lighter for the same capacity, better charge retention)
• Lightweight (fixed?) front seat(s)

You could really get some decent savings out of these pieces I'd think. Not sure how much difference it would make in acceleration, but would be interesting to compare.

Seems foolish IMO to upsize to 245 width tires, especially if you're leaving power output alone. All you're getting with 245 tires is increased unsprung weight and aero drag. Stay with the stock 215 width.

Honest mistake! Edited now to 215/45 :)


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There are a lot of build threads dedicated to adding lightness. Some people have removed hundreds of pounds

Lightweight flywheel + CF driveshaft + bucket seats + removal of trunk items + light, single exit exhaust + lightweight 17" wheels and tires + lightweight battery + remove factory crash beam/replace with aftermarket.

Those are simple things that can be done without completely ruining the daily practicality of the vehicle by stripping everything out. It can add up in cost quickly, though:

Corbeau seats/brackets = $800 (~50lbs)
CF Driveshaft = $900 (~15lbs)
Flywheel = $450 (~15lbs)
Removing tools/spare/etc = FREE (30lbs)
Nameless single exit axle back = $300 (~30lbs)
17x8 RPF1s with 215/45 tires = $1600 (15lbs)
Lightweight Battery = $250 (25lbs)
Aftermarket crash beam = $150 (~15lbs)

$4300 and you're looking at ~190lbs removed from the vehicle, while retaining pretty much all of the interior in the original configuration and keeping the features/comforts.

Easiest and most cost effective method is ditching everything in the trunk and going to a Nameless single exit axleback. Those two alone will save you well over 60lbs and cost you ~$300.

The stock battery weights around 12kg. You can replace it with a 7-8kg battery and don't have any issues. In fact, a deep cycle battery will be better than the OEM one.