Did you have 2 guys lifting the car at each end?

 

lol, no trickery - the car had about 3/8 of a tank of gas in it. Noone was more surprised than I was when we rolled the car onto the scales. I thought about it a fair bit and attribute the weight to a few key things.

1) starting with the lightest possible car (no sunroof JDM R2)
2) single turbo
3) light exhaust
4) no emissions stuff
5) lighter bucket seat
6) big one - not putting tons of **** back in the car. no bigass bodykit, BBK, roll bar, subwoofer, heavy *** rims, billet sway bar mounts, etc etc. Mazda tried very, very hard to make the car as light as possible. Most aftermarket stuff is heavier than OE parts
7) tons of little things - PFC lighter than stock ECU, rear wiper delete, tool kit, air pump bracket cut off, very short IC piping, plastic BOVs, it all adds up

I'm putting the new engine in over the next couple of days and have taken some more junk out - spare tire, smaller battery, P/S stuff, lighter flywheel, lighter suspension. I'd like to see a weight around 2550 lbs.

 

Danny do you remember the weight of the stock gas tank ? Wich model ATL did you use? Was it the largest that could fit and are you able to still users stock location to gas up ?

 

Stock Component Difference Est Car Weight Modification
Air Conditioning -30 2759 Remove Compressor/Condensor/Heater core and all piping
Air Pump -12 2747 Remove
Down Pipe Cats -15 2732 Strait Pipe any
Mid pipe Cats -15 2717 Resonated Pipe any
Muffler -5 2712 Aftermarket any
Emissions piping -5 2707 Remove/block
Twin Turbo plumbing -5 2702 Remove/non Seq
Pulley Kit -3 2699 Unorthodox Racing
Power Steering -20 2679 Mavil Manual Rack
Headlights -10 2669 Evo R/RE-A
Fog Lights -5 2664 Remove
Carpet -30 2634 Remove
Dash -36 2598 Single Panel 3/32 alum
Battery -15 2583 Oddessy
Seats -40 2543 Recaro Profi SPG
Windscreen -15 2528 Lexan - any
Rear Glass -10 2518 Lexan - FAL
Side Glass -20 2498 Remove
Hood -1 2497 Chargespeed
Hatch -10 2487 Chargespeed
Doors -25 2462 Gut/Remove interior panel Power Locks/Windows
Fenders -2 2460 Chargespeed/Any Carbon
Steering Wheel -8 2452 Momo 330mm alcantra + quick release
Air Bag Sensors -10 2442 Remove
Front Bumper Reinforcement -10 2432 Hole Saw (50% of area removed)
Rear Bumper Reinforcement -10 2422 Hole Saw (50% of area removed)
Sound Deadening -25 2397 Dry Ice + Rubber Mallet/Scraper
Gas Tank -20 2377 ATL Aluminum enclosed fuel cell
Spare Tire/Toolkit/jack -20 2357 Remove
Interior pipe threading and brackets -5 2352 Drill/Angle grinder/Sawzall all mounts for interor panels/speakers/etc
Aluminum Panel Bolts -2 2350 Fastner express - 43% weight savings on all heatshield/body panel bolts
Hole Saw to non stressed interior panels -15 2335 front of strut towers, rear of strut towers, speaker surrounds
Clutch -3 2332 Aftermarket any
Flywheel -5 2327 Aftermarket any
Driveshaft -4 2323 ACPT Carbon Fiber Driveshaft
Sunroof -17 2306 Ronin Speedworks - Carbon/Carbon
TI Lug Nuts -1 2305 Aftermarket any - very expensive
Headliner -5 2300 Remove
Sun Visors -3 2297 Remove
Wiring Harness -8 2289 Simplify - Single turbo
Windshield Wiper/Coolant resevior -5 2284 Remove
Interior Plastic -35 2249 Remove
Side Mirrors -6 2243 APR GT3
Radio/Antenna/Wiring/Speakers -20 2223 Remove
Undercoating -4 2219 Remove - Heat gun + Scraper + sanding and lightly re-coat with Rhino Liner or Linex for about 30% reduction in weight.


When I get a chance I'll post a list of most of these parts with actual weights.

 

The big one on your list is what really matters or the not putting things back in list

However most folks take things out to reduce weight for track use and therefore need to put lots of things back in.

My track car is a gutted R1 single turbo car with an m2 roll bar (light weight about 50lbs) and still weighs over 2600lbs.

 

I just weighed my car for a military move.
-full tank of gas
-interior delete bins back.
-no emissions
-no ps
-no ac
-stock twins
-unknown dp, stock cat, rb dual cat back

2620 lbs... ohhh yeah

 

It must be made compulsory for anyone who starts a weight reduction thread to post their pics and stats first.

 

NYRX7,

The weights I have on the fuel cell are based on a generic cube type 22 gallon ATL cell in an aluminum enclosure, and you cannot use the stock filler location as it is not high enough above the top of the 22 gallon enclosure which is a top fill to give you the right gravity feed.

You can, if you're good with body work move it to sheet metal behind the drivers side window like you'll see on Super GT cars.

I wouldn't go below 20 gallons on a track car ... I know my car only gets around 4-5 mpg on track and I don't like to go below 1/4 tank just to keep the pumps submerged, so 22 gallons is only around 65-70 miles/fill. Plus, the car tends to be slightly front heavy anyway, so skimping on a fuel cell for another 7-8lbs (22-15gallon) really isn't worth much.

Even though this is a weight thread, the weight loss from a fuel cell is really just a positive side effect. The real reason to do the conversion is to improve reliability and fuel delivery, the stock tank can clear the pump during very hard cornering for people using R compounds.

Ideally, I'd LIKE to do a custom 22-25gallon fuel cell with a bottom panel that's angled up at around 12-14* to create a diffuser effect, but that gets into aero...

For reference, here are the part numbers for the ATL units I've mentioned.

Fuel Cell(bladder): SA122B. (22 Gallon- 25" x 17" x 14", -8AN Outlet )
Aluminum Enclosure: AC122B ATL told me this would be around 2/3 the steel container weight which is 19 lbs, netting around 12.5lbs for a total weight of 35lbs

The weight of the sheet metal removed in the rear hatch is offset by the steel framing that must be welded in to support the tank, and fuel pumps and hosing should stay the same so your weight difference is just the cell/enclosure vs the stock cell/enclosure. I have in my spreadsheeet that the stock tank weighs in at 55-60lbs, but I don't have a picture of it on a scale and that's most likely an educated guess :-) I'm a very, very slow project person but I will be removing a stock gas tank ( and everything else ) from a FD that's going to be getting a roll cage installed some time next year and I plan on forcing myself to take tons of pictures and weigh everything individually as it comes off.

Regards,

Danny Gamble

 

Why not get the 30 Gallon Carbon Fiber fuel tank that's a direct fit replacement for the stock tank?

 

I started eating right and exercising.

The car isn't that heavy.

 

*No emmissions (air-pump) = 20 lbs. + maybe 5 or 6 more lbs. for EGR, split-air bypass, double-throttle, AWS etc.

*PS and AC, including brackets and pulleys = 36 lbs.

*Stock pre-cat = 22.5 lbs.

*Rear bins, lids and touring/PEP carpet = 18 lbs.

Source: Mantissa Racing

I'm only seeing maybe a 100 lbs. of reduction give or take. No offense, but considering you had a full tank I'm thinking the scale was pretty generous. Especially when compared to the weight of a 'gutted' car like Fritz Flynn's.


For a street car, and even for the occasional track session, radical weight reduction seems silly to me. You loose confort, what little refinement there was and re-sale value. I suspect at least some remove the stuff because it breaks and they're too lazy or don't have the money. I'm with gracer, I've got a little around my waist I could loose first.

 

Thanks for the detailed reply Danny.
Glass man, I've searched for that tank a few times and have only come across is being offered in the SP cars.

 

You can get the carbon tank here. http://www.smb.net.au/mazdarx7zone.htm. Or by directly getting a hold of Carbon Man here.

 

For a dose of realism (a "normal" streetcar) I recently had my car corner balanced:

Total weight with me (a svelt 180lbs ) in the car, full tank of fuel, spare tire and tools, and fitted were my heavy Kinesis street wheels = 3096lbs

My car still has full AC, PS, and a working sound system. Also a rather heavy 4 point roll bar. and bunch of "other" performance mods.

Sometimes performance and reliability DOES have a weight penalty - BBK's and wider (larger) wheels and tires for example.

Just for the record.

Regards,
Crispy

 

So far...

items deleted:
* spare tire and tools
* radio/antenna/speakers and related wiring
* a/c, emissions
* seat belts (in favor of straps)
* simplified sequential

lightweight replacements:
* intake
* battery

other substitutions:
* 17x9.5 wheels with 275/40 tires (~50lb/corner)
* smic
* dp/mp/cb

Last weigh-in: 2700 w/ sunroof and 1/2 tank gas (SCCA National Tour scales)

Planned mods (goal is low 2600 if not better):
* fuel cell w/ surge tank
* flywheel
* lighter wheels
* delete p/s
* delete front washer tank

 

great info

 

so far i've removed tonsils, wisdom teeth, spleen, kidney, and all body hair. every track day i trim my nails (fingers AND toes) and take out my fillings. the day before i take a double dose of a good laxative and really flush my system. also don't forget to take off your wedding ring or other jewelry.


all kidding aside, i was actually thinking about this the other day. i'm wanting to replace the oem sound deadening material with some aftermarket sound deadening/heat barrier material and i was curious about how much weight it'd be to redo the whole interior floor. i don't see it being much really but i am curious.

most enthusiast forums do have a weight redux how-to or sticky somewhere. although the rx7 is a light car, it could always weigh less. if nothing else, seeing the parts weight is interesting and informative.

 

- Spare tire (never came with one )
- Light weight rims.
- Carbon/Kevlar single layer bonnet.
- Removed air pump
- Removed cat.
- Smaller Muffler. (straight flow)
- Driving with no stuff in the rear (which i don't need tho)

Soon:
- Delete A/C
- Carbon rear hatch

Don't know what else to do - i COULD swap my auto for an manual gearbox. But i don't know if it's going to be. As it's a daily driven car.

 

^Why are you doing a radical weight reduction on a streeted auto? Seems more of a re-sale value reduction.

 

Sgtblue:

I'm not thinkin about selling my car but keeping it for a pretty long time (maybe the A/C will be kept, i don't know)

But the plans for winter is also a raceported 13B with a T88 or a GT35R turbo, which should produce ~ 500 BHP.

EDIT: I wouldn't call it a radical weight reduction but a smaller one.

 

I had put mine on a weighbridge and came out with 1220kg/2689lb.

Automatic, 18" wheels (not light) with air con removed- (pump, all lines, front radiator cooler and under dash radiator block all torn out)
No spare, no insulation in rear hatch area under carpet.

Thats with 1/4 tank of fuel. Fuel weighing about 0.7kg per litre from memory (less dense than equivalent water) and without driver.

JDM RHD model, no sunroof, base options, cloth seats, Type-S car with a fiberglass front nose and side skirts, and copious amounts of fiberglass filler in the rear quarters (by the looks of it- courtesy of Japanese owner)

Not bad for a mostly stock twin turbo auto trans daily driven car? (considering the auto trans+fluid is heavier than a manual box)

 

Ok
Mine was 1224k
Single turbo
Rotary work exhaust
17" wheels
No AC
No air pump
Bigger brakes at 4 wheels
Etc

 

AutoX build....2510 without driver
Auto-X FD SSM Build - RX7Club.com - Mazda RX7 Forum

 

I seem to remember my car was measured as 1080 kg (2376 pounds) with an empty tank, 16" wheels (with skinny winter tires), and no wing/cage, but in hindsight I wonder if maybe their scales weren't just off.
My friend thinks there's no way it was that light.

 

Mine is also an autox build, but not quite so light. 2650 without driver the last time I checked.

2510 by @tomsn16 - better make sure the SCCA scales are calibrated.

In XA believe my car would be too light for national tour. I think that is 2900 lbs with driver,