blackmr2turbo

do stock FD's have 50/50 weight balance? how would one go about reducing the total weight while maintaing the balance?

i know everyone would add a downpipe and maybe a mid-pipe, that's about a 20lb weight reduction right?
then maybe a CF hood to replace the stock AL hood, that would be a few pounds lighter right? then what else could you do? a CF hatch? seems like most lightweight aftermarket parts are for the front, what abou the rear other than a CF hatch?

I think someone would like to see some accurate numbers, post whatever you engineers out there know about this perfect weight distribution.

pugg57

you can buy CF front bumper, front fenders, side skirts, rear fenders, hood, doors and rear bumper... not to mention spoiler, rear diffuser for more downforce front undertray, and front/side spliters. gut the interior (carpet etc.), ditch the seats and put in CF based momos... money is the limit. do a little research. all you have to do is google this crap and you can find it.

RX7Wishing

yes they have 50/50 balance. other then that i cant help you :p

DamonB

Take off all the extra weight or replace with all the lightweight parts you want. Weigh car. Add concrete blocks to the light end.

PandazRx-7

iTrader: (18)

Funny...I was thinking about this yesterday. I'm a little worried because I have a roll bar that ways 70lbs+ that I'm going to install and I have already relocated the battery to the rear compartment. Seems this is going to alter the 50/50 stock ratio?? I'm seriously considering getting a CF Hatch to offset this. Think that would be a good idea guys?

ttb

take out the spare

PandazRx-7

iTrader: (18)

Maybe not for a daily driver. But, I guess a high-flow cat and an aftermarket cat-back should help as well...

ijneb

Why are you so worried about 50/50 anyway? I thought I read somewhere that it was more like 46/54 (front/back) to begin with. Thats probabily done with an empty gas tank, and no driver.

You'd want more weight on the drive tires (REAR) anyway. So moving the battery, adding a roll cage, downpipe and midpipe all add that little bit of weight to the back tires.


Of coarse, this is all my thoughts.

r1dreamer

iTrader: (4)

i really dont think that carbon fiber will alter the weight that much, maybe

r1dreamer

iTrader: (4)

i really dont think that carbon fiber will alter the weight that much, maybe 5-10 pounds if you do the CF hood hatch and fenders, adn then you just spent thousands of dollars. mazda went crazy with the weight on these cars.
your not going to get much lighter unless you do single turbo exhaust battery no Ac Power steering, tings like that. al the body panels are lightweight aluminum. i honestly think CF is a waste on our cars. our hatch with the glass id say weighs about 15-20 pounds adn the hood weighs about 10. fenders are around 10 also.

does anyone know the actual weights of these parts?

i weighed in at 2620 with gas and the spare with nothing taken out of the car execpt the A/c becuase when i put the car back together after teh accident i didnt want to wait another day to get it on the road.

brandon

and this is a base model rx

TracyRX7

I asked on another thread about CF front fenders and CarbonCreations asked around the office and they weren't exactly sure but they thought about 5lbs less per fender.

The CF rear hatch (not sure if it is w/ lexan or stock glass window) was quoted as 60lbs less than the stock hatch.

I don't have any numbers for hoods, perhaps somebody else here does?

WaLieN

If you wanted to lose some weight in the rear, you could always take out the spare tire (20lbs), replace the stock cat-back with something much lighter (I don't know the exact weight of the stock cb, but I know it's pretty heavy). Right there, you would lose 50lbs. If you wanted to go further, you could remove the carpet and replace the hatch with a lexan/cf, which would probably drop another 50lbs.

tt2323

first you'll wanna look here good site:

http://www.mantissaracing.com/Mantis...eight_data.htm

you can save 60lbs with a full turbo back exhaust, gut the hatch with bose -50lbs remove airpump p/s a/c around 75 more pounds, lightweight battery -20 lbs

there thats over 200lbs already...carbon fiber isn't a cost effective way to lower the weight of an FD but removing all but whats necesary is!

TracyRX7

I believe the stock muffler is around 26lbs and the Dynomax Ultra Flo is around 9lbs.

I noticed on the FD of Andy and Teresa McKee (that is doing very well in SM2 on the Solo2 national tour) that all of the trunk and most of the interior panelling was replaced with CF. He said the car was down under 2500lbs. Thats pretty impressive weight loss since it still had a full functioning interior and I'm guessing gained some weight in the wheel/tire/brake combo over stock.

jimlab

Hands up... who can tell whether the car they're driving has 50/50 balance without a set of corner scales? That's what I thought.

People have been modifying these cars for years with impunity and having no trouble remaining competitive. I wouldn't worry about it or go to extreme lengths and expense to try to shave a few pounds with carbon fiber parts.

wingsfan

Yes, YOU would, if you thought it was a good idea But from a 50:50 standpoint, you're right, not worth the time/effort/expense.

My 50.2:49.8 distributed car seems to perform ok. It even comes with the Turbojeff endorsement

911GT2

Every body panel on our cars save the hood is sheet metal. Don't believe me? Take a magnet to your car, see which panels it sticks to.

maxcooper

Your car is basically 50/50. If you lighten the front and it ends up as 48/52, you aren't going to care. 50/50 isn't necessarily the ideal that we sometimes percieve it to be. For instance, many racecars are designed to be 40/60. 50/50 is much better than 60/40, but I wouldn't add weight to the front of a car to get it back to 50/50 if it was a little heavier in the rear.

You can tell big differences in weight distribution. I am pretty sure I could guess within 5% on most cars after a little spirited driving. I think what you feel is where the CG is -- in front or behind you -- and it is fairly obvious when the difference is large (60/40 versus 50/10 versus 40/60). The hard part of setting that test up would be hiding where the engine noise is coming from.

All the body panels are sheet metal. The hood is aluminum and the rest are steel. CF and FG hoods are NOT significantly lighter than the stock hood. I know at least a few of them are heavier than the stock hood. Buy a hood for vents; not to save weight.

You could save some weight with CF parts to replace the steel. I don't doubt the CF hatch is a good bit lighter than the stock one, but the 60 lbs that was quoted is surely mostly because of the glass rather than the CF part.

Another weight issue to keep in mind is the polar moment of inertia. If you have a lot of weight at the extreme ends of the car (bumpers), it makes the car harder to rotate. Move the weight toward the center of the car to reduce the polar moment.

-Max

Howard Coleman

iTrader: (6)

the more weight you take off the front the faster you go.

forget 50-50... that's close to stock. my car is 48 front 52 rear. it doesn't have a spec of carbon fiber except in the brake pads. you won't materially relocate weight by switching materials... you need to take all the unnecessary junk out of the front of the car. and there is alot.

battery goes to the compartment behind the passenger. power steering goes in the trash. ac goes in the same barrel - just roll down the windows and drive fast. factory exhaust ditto. abs is 15 pounds of useless weight. there is an insulation pad on the underside of the hood, junk it as it keeps the aluminum hood from soaking up and dissapating the engine heat. fog lights go. etc etc

rule one: light is fast
rule two: front weight is the enemy.

howard coleman

PandazRx-7

iTrader: (18)

Since were on the weight subject, I have a quick question... You know how the shop manuel says the front and rear height should be within 15 mm of each other, well I kinda like the more even look. So I dropped the rear about 10mm. Will 10mm make a big difference in the rear weight increasing or it's no big deal?

Rated R1

I have heard that a carbon fiber hood is actually a little heavier than the stock aluminum one. Anybody got any hard facts on that?

Howard Coleman

iTrader: (6)

no big deal. i run 25 inches front and rear measured at the top of the wheel wells.

btw, lowering the rear decreases rear weight. since you are talking a small amount it isn't an issue.

anytime you materially raise or lower your car your camber will need to be adjusted.

howard coleman

turbojeff

iTrader: (30)

The hood is sheetmetal also, it is just made with aluminum sheets instead of steel.

SpoolinRX

iTrader: (6)

^ yeah our hoods are light as hell

rynberg

The new Motor Trend (least favorite of the "big three" car mags but hey) shows some interesting weight bias data from Ferrari's research of their new Scaglietti. It was determined that 45/55 was the practical ideal for a front mid-engined car. Check it out.

Oh, and BTW, it fricking cracks me up that someone would spend significant coin to shave a few pounds. 90% of the forum wouldn't recognize a track (not strip) if it came up and bit them on the ***, let alone notice that the car is 3 lbs lighter from that new $1200 hatch...