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Old 12-07-2007, 11:33 PM   #1
soslow
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Subaru Stars Total weight reduction or F/R weight distribution more valuable?

First let me say that I'm not sure if this belongs in interior & exterior modification forum, or here.. I suppose I'll let the mods decide for me.

Secondly, I HAVE SEARCHED.

After doing a lot of searching I have found a few weight reduction threads but I can't seem to find anything about weight distribution for the Impreza in regards to handling. While it is apparent that you can remove a considerable amount of weight from the car my question is might it be more effective from a handling standpoint to remove weight from the front of the car and selectively relocate weight towards the rear to improve weight distribution? Obviously from a acceleration standpoint it makes no difference where the car loses weight (excepting rotating mass) but from a handling standpoint might it be better to try and achieve as closely as possible a 50/50 balance over simply removing weight any way you can?

I'm certain that the Impreza would never achieve a 50/50 weight distribution without ballast weight but it does seem that by removing weight from the front (lightweight bumper beams, etc.) but not the back and relocating components (such as the battery) to the rear of the vehicle handling might be improved over just simply removing weight..

Am I completely off base here? and if this has been covered please link to it.
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Old 12-08-2007, 03:13 AM   #2
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....it is always going to be a 'combined' effort.

The vast majority of the mechanicals to remove/relocate/reduce weight are in the front of the car.

There is a good bit of easily removed overall weight to dispose of, and depending on your budget and attitude toward comfort and safety......a LOT of possible weight reduction, most of it shifting balance rearward
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Old 12-08-2007, 06:44 AM   #3
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Quote:
my question is might it be more effective from a handling standpoint to remove weight from the front of the car and selectively relocate weight towards the rear to improve weight distribution?
In theory, you should shoot for 50/50 weight distribution, but there is a practical limit to how close you need to get to that ideal. You also need to keep in mind that ideal weight distribution varies depending on which quality you are trying to improve. For example a Porsche with rear biased weight balance has much better dynamic weight distribution under hard braking than a car that is 50/50 or front biased. On the opposite, a front biased AWD car like the WRX will have an advantage during hard acceleration, as the weight transfer under acceleration will modify the static weight balance to shift weight onto the rear wheels.

To answer your question, you need to decide what charateristic is most important. "good handleing" is such a broad term it is nearly meaningless as each driver will put different emphasis on different characteristics.

At some point you get "close enough" to ideal weight balance, at which point you can get the car to do just about anything you want it to do with other means. Uneven weight balance is only a practical problem when it creates a handling effect that you can not overcome with typical chassis setup tweaks.

It is something that in my opinion should not be stressed to the point of obsession. Yes if you need to move a component for some other mechanical reason, relocate it with weight balance in mind. But the efforts to achieve ideal weight balance can chew up a bunch of time, effort and money better spent some place else. It is a matter of value received for effort invested, in which case I would say, make reasonable efforts to improve weight balance if you want spectacular handling (quick and easy mods like relocating the battery for example -- you gets lots of weight movement for a single relatively simple modification).

Larry
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Old 12-08-2007, 10:58 AM   #4
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Specifically what compenents can be removed, replaced or moved to achieve as closely as possibly a 50/50 balance (without compromising comfort; i.e. not removing the air conditiong, I don't mind extra noise)? The car I have in mind is the 2002-2003 WRX so if a compenent isn't avalaible let me know..

lightwieght front bumper beam
relocate battery to trunk
carbon fiber front fenders (Are these paintable?)
alumanim a-arms
remove fog lights
carbon fiber front door skins
replace roof skin with alumanim or carbon fiber

Anythings else?
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Old 12-08-2007, 12:18 PM   #5
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Quote:
Originally Posted by soslow View Post
Specifically what compenents can be removed, replaced or moved to achieve as closely as possibly a 50/50 balance (without compromising comfort; i.e. not removing the air conditiong, I don't mind extra noise)? The car I have in mind is the 2002-2003 WRX so if a compenent isn't avalaible let me know..

lightwieght front bumper beam
relocate battery to trunk
carbon fiber front fenders (Are these paintable?)
alumanim a-arms
remove fog lights
carbon fiber front door skins
replace roof skin with alumanim or carbon fiber

Anythings else?
....d0000000000000000d...you are barking up the wrong CF tree here

there is VERY-VERY little(other than to make you poor and someone else rich) to be gained---if ANYTHING....from CF anything on the car......the fenders weight almost nothing and door skins waste of all that applies.

The roof skin is an idea, but $$$$$.

Threre are LOTS and LOTS of MUCH cheaper and easier ways to remove a whole ****pot more weight than any CF anything.

....keep lookin
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Old 12-08-2007, 12:18 PM   #6
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what is your ultimate goal for the car?
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Old 12-08-2007, 12:22 PM   #7
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best/easiest wieght loss is to swap to lightwieght racing seats and ditch the carpet. that will easly drop 40-50 pounds out of the car.
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Old 12-08-2007, 01:19 PM   #8
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Old 12-08-2007, 03:14 PM   #9
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Quote:
Originally Posted by waktasz View Post


Thanks for the link, like I said I have searched and I already read this..

Uncle scotty.. I know that CF hoods are a waste of money from a weight perspective, but also the fenders and door skins? I have taken off subaru fenders before and while they're not heavy it would seem that between both fenders and front door skins there would be some weight loss (is alumanim an option here?). Just wondering how much though..

The ultimate goal for the car to have a daily driver that is dirt road and city street friendly, provides great handling on the curvy backroads and is fun to drive; I don't at all mind extra noise or a stiff suspension. Something like the effect of an BMW M3; except with AWD.. Nice enough for passengers who could give two sh**s less about 0-60 times and cornering G's, but fun and extremely capable when the occasion arises; including track time. Eventually I will be going for some form of an STi drivetrain swap. Whether it's a JDM 2.0l or USDM I havn't decided yet as that is down the road.

Basically I want the performance modifications to be more or less transparent to a passenger (excepting NVH levels) Not looking for a CF adorned I'm a street racer give me a ticket look. I will put a wing on it though *shrug* Anyone know if the rally wing from the 2001 impreza rally car is sold anywhere?
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Old 12-08-2007, 03:31 PM   #10
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Quote:
Originally Posted by soslow View Post
Thanks for the link, like I said I have searched and I already read this..

Uncle scotty.. I know that CF hoods are a waste of money from a weight perspective, but also the fenders and door skins? I have taken off subaru fenders before and while they're not heavy it would seem that between both fenders and front door skins there would be some weight loss (is alumanim an option here?). Just wondering how much though..

The ultimate goal for the car to have a daily driver that is dirt road and city street friendly, provides great handling on the curvy backroads and is fun to drive; I don't at all mind extra noise or a stiff suspension. Something like the effect of an BMW M3; except with AWD.. Nice enough for passengers who could give two sh**s less about 0-60 times and cornering G's, but fun and extremely capable when the occasion arises; including track time. Eventually I will be going for some form of an STi drivetrain swap. Whether it's a JDM 2.0l or USDM I havn't decided yet as that is down the road.

Basically I want the performance modifications to be more or less transparent to a passenger (excepting NVH levels) Not looking for a CF adorned I'm a street racer give me a ticket look. I will put a wing on it though *shrug* Anyone know if the rally wing from the 2001 impreza rally car is sold anywhere?

...stop stying to spend $$$$....spend more mind
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Old 12-10-2007, 06:46 AM   #11
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Bump for more opinions or ideas..
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Old 12-10-2007, 07:47 AM   #12
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Lightweight battery in the trunk. Removes 35 or so pounds fron the front corner (in front of the wheel no less) and adds ~ 15 lbs behind the rear seat (but in front of the rear axle). I recommend the Oddysey PC680 (ask Uncle Scotty about his )
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Old 12-10-2007, 11:25 AM   #13
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Quote:
Originally Posted by soslow View Post
Bump for more opinions or ideas..
....d000000000000000d.....some of us have been around a while and read ALL of these threads before.

ya got it all answered......do some research and stop wantin ta be spoon fed

and ya still barkin up the wrong CF tree, here
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Old 12-10-2007, 12:00 PM   #14
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soslow,

Please state the use of your car.

For a street car, you will want to do far less than you would for a track car. As an example, take my racecar:



This is obviously a track-only, never any chance of being on the street car. It started life very nose heavy. I have lightened the car over the years that I have owned it. Easy things like moving the battery from the engine compartment to behind the pass seat made sense for 3 reasons. It freed up engine compartment area, it moved weight back and it moved weight down. An added bonus was that the batt kill switch is right inside the pass side near where the mirror goes. The wire that went back to the battery from the switch reached to the spot it was placed behind the seat. Net zero added weight.

On the more radical side, the hood on the car is a home made, fully aluminum piece. It's held with 5 hood pins and weighs 5 pounds. It's functional and reduces front weight at no real downside for the track. It would not really make sense on a street car as it's not overly secure (easy to steal your engine stuff) and it does flap around in spots where it's not supported on the sides. Again, on a racecar, that doesn't matter, but it's not much for fit and finish.

It really also depends how serious you are about reduction of weight or redistribution. Lots of components, wires and accessories can be moved down in the car. Lower CG will help you. I personally don't do this if weight has to be added to make the change. But if it can be done at a relocation, only....go for it. Everything from horns to vacuum controls to wire routing can move down without removing any of it.

With enough sweat equity, you can do some really good redistribution and reduction. Don't start with door skins and fenders and hoods. The door bars are the biggest weight out of all that stuff and unless you're building a cage anyways, you won't be doing any removal there. Scrape off all the sound deadening/undercoating. We're talking at least 50 pounds over the entire car. If it's a street car, you'll have to be a bit more diligent about keeping rust from starting under there.

Have at it, but have fun and don't spend money.

jack
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Old 12-10-2007, 08:09 PM   #15
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I think with what you've said you want for the car, your better off starting with an STI.
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Old 12-10-2007, 10:07 PM   #16
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Quote:
Originally Posted by CGMDan View Post
I think with what you've said you want for the car, your better off starting with an STI.
This is true, but there are several reasons I don't
1. I don't quite have enough money for a decent STi I can on the other hand afford a nice 02-03 WRX; not to mention lower insurance over the STi (not that my insurance won't be high anyway!)

2. Not ready for an STi yet, more power and lower gas mileage than I really want for right now, and I like the bugeye's better.. Is it just me or do the 04-05 headlights look like they came off a corolla imo?

Seeing as largely despise most every new car I've driven or seen for one reason or another be it styling, to many electro nannies etc. I've more or less decided to get something I really love and keep it rather than continually buying cars.. for me the 02-03 WRX is it; very good part availability and aftermarket support and it's completely upgradeable under the hood and inside to at least the 2007 model year.. Eventually I'll have an STi (or better) in a bugeye body; more expensive in the long run but upfront cost (I have to eat now principle) and getting the exact car I want is more important to me.

for Uncle Scotty: I have searched this forums many times looking for information and opinions on this; I've not found it.. I'm not asking to be spoon fed I'm trying to ask for opinions and input on whther people think it's better to just lighten their car up as much as possible anywhere you can (and yes you can find plenty of good threads on this) or would it be better to be more selective in the weight dropping process to aid handling balance? I have yet to see this covered. I'm not saying it has or hasn't been covered before, but I can't find it. If everything has already been covered before then hell why even have an active forum at all? Just archive everything and get a better search feature..

EDIT: thanks jack

and yes I'll stay away from CF, not a big fan of it anyway.. (excepting the roof skin, I'll use alumanim if I can find it)
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Old 12-10-2007, 11:15 PM   #17
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A header is a good way to get weight off the front end of the car too.

Whether it makes sense for you is a separate question... just sayin'.

john
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Old 12-11-2007, 12:40 AM   #18
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Quote:
Originally Posted by soslow View Post
This is true, but there are several reasons I don't
1. I don't quite have enough money for a decent STi I can on the other hand afford a nice 02-03 WRX; not to mention lower insurance over the STi (not that my insurance won't be high anyway!)

2. Not ready for an STi yet, more power and lower gas mileage than I really want for right now, and I like the bugeye's better.. Is it just me or do the 04-05 headlights look like they came off a corolla imo?

Seeing as largely despise most every new car I've driven or seen for one reason or another be it styling, to many electro nannies etc. I've more or less decided to get something I really love and keep it rather than continually buying cars.. for me the 02-03 WRX is it; very good part availability and aftermarket support and it's completely upgradeable under the hood and inside to at least the 2007 model year.. Eventually I'll have an STi (or better) in a bugeye body; more expensive in the long run but upfront cost (I have to eat now principle) and getting the exact car I want is more important to me.

for Uncle Scotty: I have searched this forums many times looking for information and opinions on this; I've not found it.. I'm not asking to be spoon fed I'm trying to ask for opinions and input on whther people think it's better to just lighten their car up as much as possible anywhere you can (and yes you can find plenty of good threads on this) or would it be better to be more selective in the weight dropping process to aid handling balance? I have yet to see this covered. I'm not saying it has or hasn't been covered before, but I can't find it. If everything has already been covered before then hell why even have an active forum at all? Just archive everything and get a better search feature..

EDIT: thanks jack

and yes I'll stay away from CF, not a big fan of it anyway.. (excepting the roof skin, I'll use alumanim if I can find it)

I pm'd you......and the thread, below, is long....but covers things pretty well

http://forums.nasioc.com/forums/show...ight+reduction
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