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Old 09-15-2007, 01:52 PM
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Weight loss programs...

I was wondering what could be done to the car to drop its weight? It ways just over 3000 lbs and I want it more around 2200. I don't use nav, I will be replacing the back seats with air, and removing "Confort" eletronics like the AC, wiring that is for "in case you want" products, etc. What else could be done to strip this car of its massive shell? No carbon fiber anything please. We are talking about weight loss, not replacements.
Old 09-15-2007, 01:55 PM
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Remove the engine and transmission.
Old 09-15-2007, 02:50 PM
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apart from the obvious removal items - I got rid of a lot of weight by fitting the smallest automotive baterry I could find and replacing my exhaust with a Ti catback system. The the stock exhaust system weighs a friggin ton .
Old 09-15-2007, 03:00 PM
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You want to loose 1000 pounds? Why didnt you just buy the body from Mazda, then go with a tubular frame? I dont see loosing a 1000 lbs, but good luck.
Old 09-15-2007, 03:34 PM
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A couple hundred pounds is doable. 800lbs is next to impossible, unless you're gonna gut the entire car, and replace stuff.
Old 09-15-2007, 03:40 PM
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you'll never get to 2200 my friend, set a better goal of around 2600 (which is pretty freakin hard too)
Old 09-15-2007, 04:02 PM
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The best way to cut weight out of the car is for the driver to go on a diet.
Old 09-15-2007, 04:10 PM
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Too bad you dont want CF cuz carbon fiber rims are a huge weight loss option (on both the car and your wallet)

Do you want to just remove items? Is cutting and putting in aluminum an option?

Otherwise gut the interior of all carpet/plastic, the console, dash, get rid of all the airbags too. (they're heavy). Remove the speakers, headliner and that should be good for a few hundred pounds im sure.
Old 09-15-2007, 08:22 PM
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this thread sucks
Old 09-15-2007, 09:16 PM
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You'll never make it to that weight. Lose the rear seats, swap out the stock exhaust for a lighter exhaust, and replace your front seat with a lighter aftermarket seat. If you can lose the front passenger seat, get rid of it. Strip down the interior - plastics, carpeting, etc. If you don't use the nav, get rid of it. Stripping down the interior will help lose plenty of weight. Usually aftermarket a carbon fiber hood may help a bit, but the 8's stock hood isn't ridiculously heavy.

Also, any stock parts you remove for weight should be sold so you can buy lighter aftermarket parts for the parts you need to make the car work.
Old 09-15-2007, 11:07 PM
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Lose all interior panels, carpet, sound deadening, remove all seats and replace driver with a light weight "racing seat", replace all windows with lexans, ditch all spare items (like wheel, jack, etc), ditch radio, ditch a/c and heating components, remove all engine bay plastics, strip the trunk, remove air bags, strip dash off and create a "custom" instrument display(one STACK display should be enough, LOL), and get some Enkei RPF1 wheels... That should lower your weight quite a bit, probably close to 2400 if not less lol (just assuming).

Last edited by SayNoToPistons; 09-15-2007 at 11:12 PM.
Old 09-15-2007, 11:23 PM
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Sell your car and go buy an Elise.
Old 09-15-2007, 11:24 PM
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damn, those enkei rpf1s weigh less than 10 pounds each.

what do the stock rims weigh, like 22-23lbs? and to make it even better, afaik, each 1lb of rotational mass eliminated is similar to removing 4 pounds of dead weight in the car. so thats removing more 130lbs off the car. holy crap. http://www.good-win-racing.com/Mazda...-1051bRX8.html

only downside is the $279x4 price tag. and the fact that they look ugly.
Old 09-16-2007, 03:42 AM
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Thumbs down

Originally Posted by AkinaGod
I was wondering what could be done to the car to drop its weight? It ways just over 3000 lbs and I want it more around 2200. I don't use nav, I will be replacing the back seats with air, and removing "Confort" eletronics like the AC, wiring that is for "in case you want" products, etc. What else could be done to strip this car of its massive shell? No carbon fiber anything please. We are talking about weight loss, not replacements.
Doing this will not help much unless your doing atuox events.
I have an old super street mag. They got 2 350 Z's gut one and removed everything they could. The other was stock. The only thing that was different was the stoping dis. The 0-60 was the same and the 1/24 mile was about 2sec faster.

If you realy want to drop weight strip the car and rebuild it useing light weight screws and what not like in NASCAR ect, and remove all the safty things on the car with a air saw. Then put the car back together and see how much weight from all the stupid little parts you shaved off is vs stock
Old 09-16-2007, 11:04 AM
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Originally Posted by DOMINION
Doing this will not help much unless your doing atuox events.
I have an old super street mag. They got 2 350 Z's gut one and removed everything they could. The other was stock. The only thing that was different was the stoping dis. The 0-60 was the same and the 1/24 mile was about 2sec faster.

If you realy want to drop weight strip the car and rebuild it useing light weight screws and what not like in NASCAR ect, and remove all the safty things on the car with a air saw. Then put the car back together and see how much weight from all the stupid little parts you shaved off is vs stock
Yea, because so far all I really got is removing some completely useless components in the dash, remove the back seats, center console in the back, maybe put some nice lightweight seats in for the front with 4 points, and of corse some lightweight performance parts, but other than that I am kinda lost to what to do.
I can kind of see that with the Z's. I mean the engines they have are pretty beefy and they can handle the stock weight pretty well. But the RX8 isn't as strong as the Z. Plus its torque is considerably less. I think the weight loss would be quite beneficial even if it is by .5 of a second. But I won't know till it happens. *Shrug*
Old 09-16-2007, 11:05 AM
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Originally Posted by The RX-8
Remove the engine and transmission.
Well considering you couldn't replace the engine with any other engine as lightweight as the rotary I think that would be working quite backwards. Plus rotary power is unique and just for me. Tranny I actually agree with. A nice RX7 tranny would be a nice touch.
Old 09-16-2007, 11:06 AM
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Originally Posted by Brettus
apart from the obvious removal items - I got rid of a lot of weight by fitting the smallest automotive baterry I could find and replacing my exhaust with a Ti catback system. The the stock exhaust system weighs a friggin ton .
Thanks.
About the battery how much did it weigh before and how much does it way now? Do you have any starting issues? Or is the rotary uneffected by loss in battery power? I was always told a bigger battery is better for the engine. Is it harder to start? Feel like there are any probs?
Old 09-16-2007, 11:09 AM
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Originally Posted by WoodsOfGreenRx8
You want to loose 1000 pounds? Why didnt you just buy the body from Mazda, then go with a tubular frame? I dont see loosing a 1000 lbs, but good luck.
800 lbs. And I heard of it being done but I couldn't talk to the guy who did it so I don't know what he did. I doubt very much he used a tubular frame. His car looked modified but almost exactly the same. The interior was gutted except the vitals, which I know would help considerably. But I want to keep as much as possible the interior look - the back.
Old 09-16-2007, 11:09 AM
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Originally Posted by lone_wolf025
A couple hundred pounds is doable. 800lbs is next to impossible, unless you're gonna gut the entire car, and replace stuff.
I may have to. I kinda assumed I would have to actually. I just want to know what I could start with.
Old 09-16-2007, 11:16 AM
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Originally Posted by champi0n
Too bad you dont want CF cuz carbon fiber rims are a huge weight loss option (on both the car and your wallet)

Do you want to just remove items? Is cutting and putting in aluminum an option?

Otherwise gut the interior of all carpet/plastic, the console, dash, get rid of all the airbags too. (they're heavy). Remove the speakers, headliner and that should be good for a few hundred pounds im sure.
When I get better at driving track I will be switching to CF rims but only on the track. I agree. I was thinking about the aluminum replacements but I don't have the money for that. Seeing what I can do at home and with minimal professional help first. I would like to keep (At least in the front two seats) a driving car interior. I want to replace a few parts there and remove a few things like some extras in the dash I won't use. A/C will be gone. If I can get to the air bags without blowing off my face I will. Never did that before and one guy said it is a bit difficult. But ill take a look thanks for the input.
Old 09-16-2007, 11:17 AM
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Originally Posted by Mugatu
this thread sucks
So does your mom but you don't hear too many of us bitching about it. Don't post unless your going to say or do something useful towards the thread.
Old 09-16-2007, 11:18 AM
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Originally Posted by SlayerRX8
You'll never make it to that weight. Lose the rear seats, swap out the stock exhaust for a lighter exhaust, and replace your front seat with a lighter aftermarket seat. If you can lose the front passenger seat, get rid of it. Strip down the interior - plastics, carpeting, etc. If you don't use the nav, get rid of it. Stripping down the interior will help lose plenty of weight. Usually aftermarket a carbon fiber hood may help a bit, but the 8's stock hood isn't ridiculously heavy.

Also, any stock parts you remove for weight should be sold so you can buy lighter aftermarket parts for the parts you need to make the car work.
Thanks for the input. WIll do.
Old 09-16-2007, 11:22 AM
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Originally Posted by kersh4w
damn, those enkei rpf1s weigh less than 10 pounds each.

what do the stock rims weigh, like 22-23lbs? and to make it even better, afaik, each 1lb of rotational mass eliminated is similar to removing 4 pounds of dead weight in the car. so thats removing more 130lbs off the car. holy crap. http://www.good-win-racing.com/Mazda...-1051bRX8.html

only downside is the $279x4 price tag. and the fact that they look ugly.
Yea I will be doing that for the track. ******* costs are hard on the wallet, though. Be a bit before I got money for that.
Old 09-16-2007, 11:39 AM
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I just helped a friend strip a 2 year old EVO for track use. I don't remember the specifics on before and after curb weight but we freaking GUTTED this car of everything non-essential. Here's a "more or less" list of everything we took out:

- all seats
- all carpet (the carpet is surprisingly heavy, by the way)
- all headliner and insulation
- all interior door panels
- window motors (replaced with manual crank mechanisms)
- power locks
- entire ac system - compressor off the engine, condenser at the front, hoses, coil in the AC box, etc.
- console
- entire stereo including amps, head unit, speakers, etc.
- airbags (surprisingly easy to remove, actually - helps to have a shop manual, but job 1 is to just disconnect the main wiring cable from the control unit behind the dash (easy to find - everything is bright yellow by law), then after that's done, the bag units are "safed" and you can safely remove their covers, remove retaining clips, lift them out and disconnect them - and airbag wiring and control unit
- trunk liner, spare, jack, hardware, etc.
- glovebox
- miscellaneous guards, heat shields, liners, insulation and a lot of little **** and fasterners, clips, etc. that wasn't necessary.

We weighed the entire lot of **** that came off the car - it totalled up to about 450 lbs of gear. Not as much as you think.

When we were done the entire car was completely stripped out to basically a rolling shell with operating doors and windows.

Additional savings will come from:
- replacement wheels and tires with lower-weight, racing-only rolling stock
- replace cast-iron brake rotors with ceramic rotors
- replace stock radiator with a higher-effiencicy, lighter weight unit.
- replace battery with racing unit
- replace exhaust "cat back" with lighter-weight, free-er flowing design. The tracks he runs at require catalysts on cars that came equipped with them, and mufflers.

Now that the car is "essence of EVO" though, he has already added back weight in terms of either racing parts that are heavier/stouter than stock items:

- Full roll cage inside (about 120 lbs of mild steel tubing and welds)
- Sparco racing seat "system" (about 65 lbs)
- Sparco racing belt set (about 15 lbs)
- Welded-in-place frame gusseting and rear strut bars (about 30 lbs of metal)
- Racing fuel cell
- firebottle system including piping to the engine bay and trunk/fuel cell
- Dry sump oiling system and high-output oil pump and tank
- High-output racing fuel system
- High-output racing ignition system

Like someone above said, what surprised us both is how little the straight-line performance was affected - the amount is easily covered up in driver inconsistency.

That said, the HANDLING is greatly improved - less weight to shift, roll around, transfer, etc. This car handled like a dream already, and with all this weight stripped out, it feels positively light on its feet. My perception of EVOs has always been that they feel heavy and blunt - they accomplish great handling through massive tires, big contact patches, stiffer than hell suspension and structure. But after the weight loss, and the seat was installed, the car feels very "light on its feet" and tossable - like a dance partner rather than a linebacker. Like the difference between an Elise and a Corvette. I just drove it again yesterday on a private track (this guy is a member of the racing "country club" south of Chicago) and now that the cage, fire system, and additional frame bracing is in, the car is hyper stiff, and handles beautifully, and hasn't lost that "tossable" feeling.

Great fun.

I'd love to turn one of these into a race car sometime (an RX-8 that is).

You won't find 800 lbs to strip away, but it does make a differrence.

Last edited by StewC625; 09-16-2007 at 11:42 AM.
Old 09-16-2007, 03:54 PM
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Originally Posted by AkinaGod
Thanks.
About the battery how much did it weigh before and how much does it way now? Do you have any starting issues? Or is the rotary uneffected by loss in battery power? I was always told a bigger battery is better for the engine. Is it harder to start? Feel like there are any probs?
old battery was 16 kgs new one 9 kgs . so 7kg saving (15.2lbs)
I originally was just going to use it for track days because the CCAs were about 1/2 what the old one was (430cca vs 7**cca) .
It is winter here now and although my car is always garaged it gets close to freezing in there . I have had absolutely no issues with starting and it turns over just as fast . Mind you my car always starts instantly anyway .


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