Weight reduction

OK, I know we have a 3600+ lb car so small weight savings take a while to add up. However, the relatively minor changes I've made (especially for track days) seem to have made an arguably significant dent.

Enkei PF01 wheels/Hoosier R6 295/315:
Front 60 street vs 45 - 15 lbs each x 2 = -30 lbs
Rear 58 street vs 49.2 - 9 lbs each x 2 = -18 lbs
Corsa Extreme axle backs (pair) 54 lbs stock vs 24 lbs = -30 lbs
Kooks Off-Road H-pipe 32 lbs stock vs 17 lbs = -15 lbs
Side pipe delete 5.5 lbs each = -11 lbs
Kooks LT headers vs stock manifolds = + 3lbs
Roll bar, mounts & harness bar +69 lbs.
Rear seat delete kit +12 lbs.
Remove rear seats and belts and factory mounts -54 lbs
Swap to the Tiger Hood -17 lbs
Remove washer bottle incl fluid -8 lbs
Remove flat repair kit -5 lbs
Sparco race seat 35lbs versus stock seat 46lbs = -11 lbs
302S tow hooks +2 lbs
FRPP air-to-oil cooler +8 lbs
1-pc DSS aluminum driveshaft vs stock -21 lbs
DS saftey loop +10 lbs
Trunk liner -7 lbs
Passenger seat -46 lbs (track only)
Watts link versus panhard bar +15 lbs
Rear axle weights -5 lbs
Battery relocation kit +25 lbs
Remove A/C condenser, compressor, lines and belt -21 lbs.

Total weight savings so far is 116 lbs with passenger seat and 162 without it.

With a curb weight of 3630, I'm at 3514 to 3468 with or without the passenger seat.

 

[ArizonaBOSS]

That's damn good for a non-adjustable setup.

 

[cloud9]

That's damn good for a non-adjustable setup.

Thanks that's what I thought too. Definitely happy with the results. I should also mention this was with the factory passenger seat removed. My main goal was to see what happened to the cross weights with it out to make sure it still made sense to pull it. It only moved the cross weight split 0.19% the wrong direction by pulling it, so out it goes for track days It weighs about 50 lbs.

 

[PeteInCT]

You should take out both seats :

 

[boss man]

Nope. I'd consider moving the battery to the rear but not going to spend a ton to do it so not in any hurry.

I'm shocked to hear that with everything that you have invested already.

 

[cloud9]

I'm shocked to hear that with everything that you have invested already.

LOL you have to draw the line somewhere at some point. There's really no end to what you can do and it all comes down to cost/benefit. Before you know it the 2015 will be out and it all starts over again ;D

 

[patrickshelby]

Anyone taking the A/C off?
I know taking the condenser away improves the cooling A LOT.
What about the weight of the compressor...?

 

[cosm3os]

Its the first thing I do to a racecar, but anything I'm driving on the street has to have that.

 

[Fabman]

removing fuel tank evaporative system under spare tire well is worth 20lbs.
I am told that this will not create code errors if the vents are re-connected instead of running through the evap unit but have not tried it yet myself.
(good place to remove weight)

Would love the see some details on this mod.

 

[302 Hi Pro]

Anyone taking the A/C off?
I know taking the condenser away improves the cooling A LOT.
What about the weight of the compressor...?

IMO, removal of the complete A/C system would save a significant amount of weight save for the evaporator, which I would leave in place and seal the hose connections. Plus removal of the A/C lines, Compressor, Rec/Dryer, etc., removes weight from the front of the vehicle which should help with improved weight distribution.

The A/C condenser removal will improve air flow for the cooling system, especially if you have stacked an external oil cooler core.

Good luck with your mods,
302 Hi Pro

 

[ford20]

Would love the see some details on this mod.

Same here.

 

[ArizonaBOSS]

The Evap delete is probably more like 8-10 lbs. I've done it on my car.

I did it the "dirty" way without reconnecting any of the lines etc so I do get some codes but they do not seem to have any effect on performance.

 

[302FAM]

I did not have my car built but I was told by Jonathan Blevins of Chicane23 that it weighed no more than 3400 pounds as is when I bought it. I removed the stock boss Recaro passenger seat and made some other adjustments to the interior over the winter, removing more than 55 pounds for sure. Now, CAT scale minus my weight and gas has the car at no more than 3335 pounds dry (could be a bit less), which seems very close to expectations based on both independent estimates. That includes a fairly heavy duty fire suppression unit, substantial roll cage, relocated contained battery, etc.

 

[TeeLew]

weight loss is secondary to weight balance. lightening the battery by 18lbs up front doesn't effect the weight bias percentages by any measurable amount. by moving the weight to the rear (and adding a few pounds for the cables and box), i was able to shift 1% of the weight to the rear (on paper). i think it may have a greater impact though, so i am working on procuring a corner scale to verify. the reason i think it will have a greater impact is because the 32lb battery sits just behind the front axle, which means part of its weight is shared with the rear. i moved it to the back of the spare tire well, which moves that 32lbs to the rear axle only. another benefit is a lower CG from that weight sitting nearly 2ft closer to the ground.

The overall difference in vertical CG will be small, but shifting the weight balance 1% to the rear is a fk'n chunk. It's not appreciated nearly enough.

 

[TeeLew]

Weight Weeny report.

Cast iron rear housing with Torsen diff is 32# heavier than AL rear housing with Trac-Lok diff. It's kind of the worst place to remove weight (low and in the back), and most people want to run the Torsen, but it's a data point.

 

[TeeLew]

Nope. I'd consider moving the battery to the rear but not going to spend a ton to do it so not in any hurry.

You don't have to spend a ton. You start with 1 g or 1/0 battery cable and a plastic marine battery box. A couple U-bolts through the floor (use large washers) and a tie-down strap. Done well, it looks nice and is very secure.

When you do this, you shift about 1/2% of car weight off the nose and add it to the rear. A 1% weight distribution change is massive on track. People agonize over this or that bar or spring, but tend to snooze on weight distribution. This is actually a fundamental change which is more powerful than most other tuning tools we're likely to use.

Start here: https://www.batterycablesusa.com/extreme-battery-cable-bulk

 

[JDee]

That's all true, but there's a net weight gain since you need to run a long positive line and it has to be upsized due to the length. Battery cable is heavy and it's expensive these days. But for sure you do move weight rearward and you can center it if you want. I did this with my '16 and TBH the car handled no differently and the lap times were not noticeably any better. I was pretty disappointed and ended up taking the whole thing out, the added weight just wasn't worth it. In a racing application for sure you'd do it but for lapping I think there's more bang for the buck with other mods given the time and cost to do it.

You can dump a ton of weight just by going to a lightweight battery, like a Braille and it's a simple thing to do. There is a downside to doing that also, I found them to be marginal with starting a hot engine so I always looked for a sloped spot in the paddock which was easy at Mosport but not so easy at most other tracks. So then I started carrying a big spare battery to jump start the car when the little battery couldn't do it, which was about 50% of the time on a hot engine. I tried 2 small batteries, the Braille and some other one the name of which escapes me at the moment, and they both were hit and miss. I ended up going back to a big battery up front and life was good again.

Nothing is ever simple and there really is no free lunch it seems.

 

[TeeLew]

If you put the battery in the back, the car handling changed. That's a fact. It might not be a change that you prefer or one that worked well with the rest of your setup or one that you even felt. But, the car did not handle the same with the battery in the back and the battery in the front. It just didn't.

Li-ion batteries seem to be a little hit/miss with whether they want to play with the rest of your electronics. I know guys that have gotten random limp modes on the S550 cars with Braille batteries. It is a nice little drop in weight, but, most of the time, people only use them for competition when you can't drop weight another way.

 

[armphoenix]

I have 1000whp and my QA1 CF drive shaft has no issues with it.

How about the antigravity battery swap? Supposed to drop some weight with that too..

 

[JDee]

I think the other small battery I tried was antigravity? It was no better than the braille. You can likely lose a lot more weight by doing stuff like taking the carpet underpad and maybe the entire carpet out, remove the rear seats, get lightweight racing seats and stuff like that.

 

[Mad Hatter]

I found this Braille battery http://www.braillebattery.com/index.php/braille/product_batteries/gu1r, which is light, I think strong enough also for DD and not to expensive (at Jegs for 499.--). What do you guys think?

I went through two Braile battery's. But its was probably my fault for not giving it more love. You need to get a battery tender as they are sensitive and only lasted a couple of races each.
I would not really consider it for a DD. Charging your cel phone can leave it dead.