The Weight Reduction Thread

[dr_sharp]

I've lost almost 20lbs since this thread started Pretty soon I am going to have to start looking at car parts for weight loss

 

Added LosAngelesLGT diet program to list.

[BennnGeee]

Its all about weight placement, take all that stuff you tore out and put it in your passenger seat and you will get a better time than with just you in the car guaranteed.

[dr_sharp]

Added a tire! Can't wait to drive with these Advans!

[ClimberDHexMods]

Have you seen this yet? http://www.iwsti.com/forums/gd-members-journals/65805-anorexicsti-05-sti-lightweight-w-full-interior-2660lbs-62-lbs-2598-a.html

 

I think his idea of removing ounces at a time makes total sense, as it has added up to over a hundred pounds in weight reduction if you pull off hundreds of individual little things from the car. Add that to removal of the big things, and swapping lighter aftermarket parts and you are in serious business

[ClimberDHexMods]

More links:

http://forums.nasioc.com/forums/showthread.php?t=1400175

http://www.fastener-express.com/m6-x-1-x-14mm-socket-head-cap-screw-gold-anodized-qty-100.aspx

http://www.iwsti.com/forums/gd-members-journals/106006-richardcranium419-04-sti-journal-mod-list-update-12-jun08.html

[07spec_b]

i thought stock spec b weights 3525lbs

[ClimberDHexMods]

stock glove box is very heavy due to a weight inside it to make it lower on its own when opened. I think the glove box door can be opened, and the weight can be removed.

[ClimberDHexMods]

driver side metal crash plate at knees: 2lbs 7oz. I see no need for it to go back on. I can't see how it would do anything in a crash or otherwise.

[lightweight14]

Interesting, iwsti has extensive threads on weight reduction. Out of curiosity, are there certain reasons why someone would not time attack a LGT and rather a STI??

 

The LGT imo is more aerodynamic for one.

[lightweight14]

Sound deadening material: trunk liner, hood, against wall that leads down to transmission, and I believe there are some metal pieces underneath the backseat.

 

Has anyone considered removing the bumper beams and front subframe???

 

I know on the sti the front subframe which is there for U.S. saftey regulations weighs approximately 27lbs(removing helps with the understeer). Bumper beams weigh well over 50lbs combined, and as mentioned the lightweight battery will help with the understeer as well. Windshield washer fluid can be emptied/ removed as well, much easier to do on a sti.

 

Too bad no one makes lightweight bumper beams and other parts for our cars.

[ClimberDHexMods]

Sound deadening material: trunk liner, hood, against wall that leads down to transmission, and I believe there are some metal pieces underneath the backseat.

 

Has anyone considered removing the bumper beams and front subframe???

 

I know on the sti the front subframe which is there for U.S. saftey regulations weighs approximately 27lbs(removing helps with the understeer). Bumper beams weigh well over 50lbs combined, and as mentioned the lightweight battery will help with the understeer as well. Windshield washer fluid can be emptied/ removed as well, much easier to do on a sti.

 

Too bad no one makes lightweight bumper beams and other parts for our cars.

 

I have considered all of the above, and will likely remove almost everything. Looking at a 12lb Deka. Might have a stabilizer bar fabricated to bring back some front end stiffness. Maybe. Need to get a closer look at the subframe. Not worried about understeer anymore, but can you explain how more front end flex would create less understeer? As I imagine it with what little I know, more weight would transfer to inside, which would this act like a bigger sway bar and cause the front end to slide out easier. Or do I have it backwards.

 

Time attack: STi has a bigger variety of aftermarket support, allows for wider tires, is lighter, comes with a drivetrain good for the track almost out of the box (6mt, helical front and rear, R180, bigger hubs/bearings, etc). It's just a lot easier to work with. Wind resistance, what are the drag coefficients of each?

[Cossey]

Awesome thread, as I'm classing my car right now for NASA's TT rules lol.

 

As far as tracking an STi vs. LGT: Look at the aftermarkets for each car and compare. It's so much easier and usually cheaper to get parts for an STi. Right now I'm in the process of getting a very custom set of very high end coilovers for my LGT, and it's a pain in the ass. The LGT looks a little more aerodynamic, but I don't know if anyone has actually tested both cars' drag coefficient. I prefer the longer wheelbase of the LGT, and I feel it helps the car more stable on the longer, sweeping turns. There's a reason SOA and Phoenix Racing used the LGT before going to the new STI's for a race car, but I'm not quite sure what the reason was lol.

[lightweight14]

I have yet to get under my LGT, but I imagine the subframe looks identical. The piece is completely for safety, not sure which model it is but there is another model sti( type r, spec b, something of the sort ) which does not have the front subframe from factory. As for flex, you might experience some but it would be very minute. The only drawback is safety. According to the Sti forums, if a front end collision were to occur the subframe would act as a carrier for the engine. Others have mentioned that it creates more exposure for dirt, grime, etc to get on the underbody. Either way, the JDM sti ( something model ) does not have it from factory. I think its safe to say that it is there for the sole purpose to meet U.S. saftey regulations.

 

I do not know enough yet to comment on the weight transfer of the LGT, I do know on the sti that removal of the subframe results in little to zero flex. This would create a better turn in.

[ClimberDHexMods]

I have read similar versions of this as well, regarding the front end.

It is known that US crash standards call for additional low speed protections that are not seen in foreign markets.

The JDM front bumper beam is thinner.

 

One issue I see with weight reduction is it further biases the weight to the front if a traditional path is followed. Would be great to pull as much as possible from the front ( very difficult) and put it in back. Windshield washer reservoir and pumps comes to mind.

 

Discussions of center of gravity and the distance of weight from center rotation point are fun.

 

For the critics, this is all for fun, so don't freak out.

 

I want to put the deka under the passenger seat. Perfect place for it per this topic. Hope it starts E85 at 30* F.

[Cossey]

I wouldn't worry too much about proper weight balancing on the cars. If you take weight off, wherever it may be, you're still going to get a better response out of the car than if you stayed the same weight, just more balanced (ex. taking the battery out entirely, rather than moving it to the trunk).

 

No matter what, removing weight is going to benefit the car as long as YOU can adapt to it.

[ClimberDHexMods]

I wouldn't worry too much about proper weight balancing on the cars. If you take weight off, wherever it may be, you're still going to get a better response out of the car than if you stayed the same weight, just more balanced (ex. taking the battery out entirely, rather than moving it to the trunk).

 

No matter what, removing weight is going to benefit the car as long as YOU can adapt to it.

 

You are right, but two comments:

1) it's just as much--if not more--about the fun of the project than the outcome

2) I get that I don't know how to drive and all... for now I'm more interested in ways to beat other cars in a straight line without over-straining my drive system.

[Cossey]

I wasn't saying you don't know how to drive at all, I was just saying in general. I know a lot of people think they need to make the car adapt to them in order to be fast (I thought like that before I started tracking), so they change things on the car to suit them.

 

I'm prolly the only "car guy" that hates working on cars. Or at least I have lately. I look forward more to seeing the "fruits of my labor" rather than the labor itself lol.

[ClimberDHexMods]

^^^^ I'm the opposite, just want to turn wrenches and build increasingly difficult things all day.

[dr_sharp]

OEM STi clutch, pressure plate, and flywheel went on today. Will weigh the stock items tomorrow when I get the car back.

[dr_sharp]

OEM 6-spd clutch components added. Sti clutch is significantly stiffer, but not undriveable. I really wish I would have measured the diameter of the contact surfaces on the STi flywheel and clutch. The STi components weight about the same as the spec.B comopnents, they (the spec.B components) are just marginally lighter. But I know that the STi components can handle a significant amount more torque.

[dr_sharp]

Does anyone have a lightweight battery that could provide input? Weight? Reliability? My stock one is about to go.

[dr_sharp]

Lithium Ion options:

 

http://ossom.com/Applications%20Starter%20Battery.html

 

http://www.voltphreaks.com/products_street.php

 

http://www.braillebattery.com/index.php/batteries/ml9c/

 

[edit] one more:

http://www.tekbattery.com/battery_prices.html

[TRSCobra]

http://www.braillebattery.com/index.php/batteries/ml9c/

 

$950?! :shocked:

[ClimberDHexMods]

What does the deka version cost? Braille is just an intermediary brand that does no manufacturing or R&D AFAICT.

[dr_sharp]

The Braille technical specs are superior to the Deka tech specs. I agree that they do look like the same package; they likely just source their casing from the same company. The casing is where the similarities end.

 

Deka:

http://www.dekabatteries.com/assets/base/0278(6.10).pdf

Weight: 17lbs (looks basically identical to the Braille battery below)

325 Cold Cranking Amps

19 A-hr @ 10hr

This is all of the tech specs that are listed, which is generally not a good sign.

Note the flimsy terminals

 

Braille:

http://www.braillebattery.com/index.php/batteries/b2317/#

17 lbs

475 Cold cranking amps

641 Cranking amps

1191 Pulse cranking amps

23 A-hr @ 20 hr

Note the solid terminals