http://www.evoxforums.com/forums/sho...=1#post1054494

Back Seat Delete, but keeping the back seat.
25 pounds.

 

hate to necro bump this but since the front end is pretty heavy and i know the hood is light so going carbon isnt needed but would going with the carbon front fenders cut weight a good bit. I dont really know if its worth it but looking to cut weight on the front for now and do suspension stuff until my warranty runs out then ill go crazy with bolt ons.

 

Not sure on the weight savings with the fenders but here is some mods you can do to cut weight down on the front...

AMS A/C Delete (20lbs)
AMS Crossmember (3lbs)
Fog Delete (~2lbs)
JDM crash beam (4lbs)
SSP Crash beam brackets (4lbs)
CF hood
CF fenders
lightweight flywheel (1.5lbs for the streetlite)
manley 94mm crankshaft (2lbs)

 

ok cool thanks. Im also thinking of doing the lightwieght 2pc rotors like giro disc, wheels, and driveshaft. As well as the fenders. Ill probably get rid of the seats and un needed crap. Not my daily driver but a fun weekend car.

 

Yea forgot to mention the rotors. But me personally if im going to touch the front, ill do the rear. I'm planning on doing 2 piece rotors and lightweight driveshaft this summer. Although i wont get my engine back until Sept from AMS..lol.

 

The back you say? I thought the evo was nose heavy. I thought about doing the rear too but then i was worried that it would mess up the weight distribution to much. I was hoping to get to a more of a 50/50 balance. I know it wouldn't be that exactly but closer.

 

You also gotta think of your braking bias. Now i dont think it effects it to much since the handling package comes with 2 piece in the front and 1 piece in the rear. However the girodisc 2 piece are lighter then the oem's. So if you go girodisc 2 piece in the front and leave the rear alone you may upset the braking bias abit to much. Someone please correct me if im wrong. Like i said i dont see rotors doing to much but if you did pads as well and left the rear ones alone. You will screw your braking bias up horribly.

But in all honesty, I doubt you will notice a difference either or, but if you did. You would notice a difference by going 2 piece on all 4 corners (due to less rotational mass) then you would by only doing the front so it keeps the weight distribution even.

 

The pads govern the braking bias more than the rotors. So a two piece in front and one piece in the rear will be ok from a brake bias standpoint. You are correct regarding the rotational mass though, and having all four on 2 piece rotors will really help. You'll feel it.

 

It is. Certainly getting weight out of the front is best but getting the rest of the car lighter is good too. Then just corner balance the car using scales to rebalance the car for the weight change.

With each tire on an electronic scale you then adjust your coil over height to shift the pressure (weight) on each tire. This balances your car for your weight changes and makes a big difference in handling. Any good race shop can help you, we do it all the time.

 

To add to the above, lighter rotors and driveshafts are really more about reducing the rotational inertia of the drivetrain, not weight-reduction per se. After all, when doing weight reduction, you start up high and work down, since CG height is as important as mass (since it's the product of the two that sets weight transfer).

I can't remember which site it was on, but I recently saw a thread about reducing the weight of the OE gas-tank. It was going to be a ton of work and only save something like 10-20#. Well, that would be a colossal waste of time and money, since the gas-tank is in the least important location for weight; in fact, it's where you add ballast if the rules force you to. Ignoring rotational intertia, the same goes for the driveshaft.

 

well the driveshaft, rotors and wheels is for rotational mass which is one of my biggest weight reduction points. I started to do that in my sit before i got rid of it and man did it make a difference. the lightweight trunk, hood, and removing the interior was hardly felt if at all. but the the rotation weight reduction was huge.

After read some of your post ill probably delete the trunk and put a small battery and get a cf trunk.

 

Yes, we have two posts welded at the right trunk corner for weights. You are correct, of course, as to the difference of rotational mass/ inertia and weight reduction. I was speaking to "feel" and performance impact more than anything else. Rotors you can feel. I'll assert that, once any lightening is complete (and that includes rotors and such) corner balancing the car will really help and will produce handling benefits by taking advantage of the weight saving efforts.

 

Oh, I totally agree about rotor mass affecting all aspects of feel, probably because it's both rotational and unsprung, even if not that high. Have I mentioned how much I love my little brakes in the last five minutes?

 

Bringing this thread back a bit

I did a few modifications to my personal Evo X GSR with factory aero kit as I want to get it as light as possible and figured I would share what I could.

My friend has a set of scales so I can weigh my car every once in a while just to see where it is at.

I removed the spare and tools out of the trunk, all of the trunk carpet and plastic as well, I have the follow mods that I will work on weights at some point.

Ohlins Coilovers (Need to weigh vs my stock suspension), Tomei TI Titanium Test Pipe and Catback (Weights about 12lbs total need to weigh the stock for comparison), Tomei Down Pipe, Ray 57 Xtreme wheels 18x10.5 +22 with Falken RT615K tires 275/35R18, half tank of gas and everything not part of the car removed (Glove box empty, center console etc.) other than that car is still stock under the engine bay.

Car was at 3400lbs even I believe these things are suppose to be around 3550~lbs with a full tank of gas?



I need to still weigh my stock wheels with stock size tires on them, but I did weight my daily driven wheels.

18x10.5+22 offset Rays 57 Xtremes with 275/35R18 Falken RT615K: 50.45lbs each.



I went to a track day this weekend and I want to get a bit more weight out of the car. I would like to someday get the car down to under 3200lbs with a bit more power Right now I am right around 300whp and 300wtq and only have the turbo back exhaust and OTS COBB Stage 2 tune.

When I race I use my TE37 18x9.5 wheels with 245/40R18 BFG R1's: 41.80lbs each.



This saves me roughly 9lbs per corner when I race from my street wheel and tire combo.

I also this weekend removed my rear back seat and honestly though it would only be like 25 to maybe 30lbs. To my amazement the back seat is over 40lbs!!

Cloth Evo X Rear back seat bottom: 12.50lbs.



Cloth Rear Back seat back part: 28lbs.



All 3 rear head rest together was just over 3lbs. They are roughly 1.2-1.4lbs each.







This weekend I should have had my car to roughly 3325~lbs with the race wheels/ tire combo and removal of stock rear seat at a 1/2 tank of gas

How my car currently sits.



One of my next mods will be a Mini batter and removal of the stock big heavy Battery. I am hoping to save at least 25~lbs there and then I will weigh the car and see if I can get it to under 3300lbs soon

I will try to keep updating this thread with info I find off my personal car

-Dallin

 

So, for comparison purposes, the race car is currently 3085 with five gallons of gas in the tank.



Gutted, of course. And there's probably another 80 lbs there somewhere:

Driveshaft
Heater
some metal tabs
Lexan for glass

I will say weight reduction gets expensive pretty fast.

Our problem became, as we pulled weight out we had to reduce power to meet class rules. Turning the boost down (along with timing and such) took the power out but killed torque faster. This required a different turbo to spool faster (was a FP Red now Blouch) and find us some lost torque. The faster spool introduced some throttle tip in overboost problems... it's a long road.