RX-8 Race Weight
 

Hey guys,

I did a search for RX-8 weight in race trim and couldn't find what I was looking for. Has anybody checked the weight of their full race, stripped and caged RX-8s? I'm trying to make a decision on roll cage tubing size. Thanks!

There are a few threads in the racing section that list various weights of different trimmed cars, some stripped, some full interior, etc.

Example from a trustworthy source.

I need to improve my search skills. Thanks 9k, you're the man!

I'd look at what minimum weight you'd need to hit for your classing anyway and go from there (unless it's unachieveably light - see also SCCA E Prod weight and similar).

Most of us end up getting the easy weight reduction stuff out of the way until we're a bit under minimum, then add ballast to meet the minimum spot-on. It's not like the RX8 needs a ton of weight relocation to handle well.

Thanks for the tip! I was a little worried about the weight because I want to build a rollcage with 1.5"/0.120" wall DOM tubing. Per NASA regulations, the car must weight less then 3000 lbs for that size tubing. I believe that this easily achievable now. There's a catch though, the car's original balance is going to be a little off due to an LSX swap. I'm trying my best to mount the engine as far back and as low as possible without cutting the crossmember, firewall or trans tunnel (I don't want to go TTU). The car has been stripped down to the bones and I'm eliminating any weight I can from the front and moving it towards the back. I will corner weight the car and see what I can do to keep the proper weight bias.

Down to 2434 dry now...

That's pretty good!

My PWC car weighs 2500lbs sans driver and fuel, could weigh less but since the move to TCA has us weighing 2950 w driver theres no point...

2419... :ylsuper:

we are 2348 with full tank but our car has no roof or windshield lol we over killed on our cage could have been under 2200 but id rather live on a roll over

I searched but could not find an answer, what is the top 10 heaviest things to loose on to save weight, I have base 04 already swapped out the driver seat for fixed back and a 6 point. Thank you.

Weight
 

How much exactly does the 8 weigh ?

3,107.433333 lbs

My RX8 is approx. 2,620 wet (full tank of gas + roll cage)

^That's awesome

#renesislivesmatter

lmao.......

Ouch. I'm tracking my DD, a 2005 Base 6MT, and it weighed 3082 with 10 gallons of gas and me in it, almost stock (U1 battery, HKS hi power as far as weight reduction). at 185 pounds driver, that puts my car DRY at 2834 mostly stock.

The car is DD, 2004 EU HP (170kW)
1242kg all fluids (including 1.5L of oil for the Sohn), half tank of gas.
60kg welded roll-cage, and some modifications to windows, auto-fire extinguisher, no AC, Battery Deka for Harley, OZ Ultraleggera, AD08r 245/40 R18...etc.
Interiors looks like in the pics.

There are ways to improve but the car will be no street legal then...

Best regards

In Spain we have a running timeattack rx8 is in 1.180kg with cage, but carries carbon fiber roof , doors, fiber , fiber gate , polycarbonate windows all ...

My rx8 is in process, still used by the street , so it has almost all the airbag , radio , speakers and even several panels, with a quarter tank weighs 1.320kg

Rules have a lot to do with how much you can remove and heavily limits you, most classes I know of here in the states are quite restrictive in terms of stock based classes compared to what I've experienced overseas in Asia and in Europe so more difficult to find the weight savings within the rules.

1260kg in metric. That's about 2777 lbs

The 2004 - 2005 Base model (no DSC) RX-8 6-spd were the lightest around low-mid 29xx lbs as delivered from Mazda. EDIT: A link to stock parts weight is listed in my next post down below this one.

Still waiting for someone to build a Titanium power plant frame (PPF) :D:




.

I am going to have to get my white 2005 Sport model under the knife soon to see where we're going to end up on the scales. This is all great information though!

For the S1 model this is probably the most comprehensive thread on OE part weights though some of the later posts aren't updated on the front page

https://www.rx8club.com/series-i-tec...8-parts-81791/



.

:hahano:

it'd probably be cheaper and more weight savings to just get rid of it by adding a trans mount and custom fabbing a new rear subframe to mount the diff, or buy the one from V8Roadsters

Assumes any of that is allowed by whatever rules apply

Would ovular tubular aluminum help much you think? Of course I'm offsetting the weight savings with the 20b though...

EDIT:
I'm thinking of the front sub frame... not the PPF...

You have a whole other set of issues with a 20B fitment and an aluminum subframe isn't your solution.

Only commercial kit I know of, just fyi and proceed at your own risk, not an endorsement etc.

RX-8

Interesting. That simplifies some of the process anyway. I'll weigh my options.

I have this model: 2005 base 6MT no DSC/TCS

• 3008 on NASA Dominion scale with ⅓ tank and me (17.4# wheels and 235/40 R888)
• 2982 on NASA VIR scale w/ ⅓ tank and me (21# wheels and 255 street tires)
• 2976 on NASA Summit scale w/ ~¼ tank and me (17.4# wheels and 235/40 R888)

NASA scales don't seem very consistent. I weight about 190# with gear on. That puts my car as light as 2786#.


I have full interior, A/C. The only weight major reduction is a HKS hi power exhaust, fortune auto 500 coilovers, U1R tractor battery (19#), lighter wheels, AEM intake, RB DR midpipe (not even sure this is a reduction). I have a larger CSF radiator which added weight back in, too.

Dude.

The inconsistency I was referring to was the back to back NASA scale weights. I don't have faith that they have been consistent between events (they may even be changing scales).

You're talking factory weight; I knew that. However, this thread is called "race weight". So I don't think my feedback has been off topic. I'm hoping it helps for people with similar mods to guesstimate their weight, but wanted to qualify by starting the NASA scales may lack accuracy and repeatability.

i know how to set them up for max negative camber; the idea was to position them to have less static camber but more camber gain. But since I also don't know how good it is to run the UCAs at such a step angle I've decided to play safe and just position the way they were probably intended.

But at 13.5" front ride height it seems like I could've gotten enough just with the oem eccentrics, so I wouldn't recommend those bushings to anyone unless they are looking for more camber at higher ride heights.

I have an 05 sport (no traction control, no sunroof). We are at ~2,730 in DSP (autocross) trim. That's full interior minus speakers, AC. Race seats, lightweight battery, single exit exhaust (oem headers still). The rest of the weight loss gets expensive (brakes, lighter wheels, headers).












The car was 2,830 in stock trim with the same single exit exhaust (but with cat instead of resonator). 1/4 tank of fuel in both trims.

Since I was able to get under 2700# in STX trim I'm hoping for low 26xx in DSP trim. A lot of OE parts are so light that you don't gain much plus I'm adding some weight back with the splitter/spoiler setup and bigger wheels/tires.

That's really impressive! Our weight is with wide wheels/tires and aero.


I used the thread where you posted the weight of the OEM parts to estimate most of our weight loss, and weighed the before and after of the replacement parts, and my math showed 2,730. SCCA scales confirmed it although I know they aren't the most reliable.


hmm, how could we get down to low 26xx.... I bet we could save 12-15lbs on crazy nice wheels, not sure on the header? 5lbs?, probably 15lbs on brakes? We could lose the sliders on the driver seat (passenger seat doesn't have any) and drop 3 or 4lbs, but that's not practical since we have multiple drivers. The driver's seat is lighter than the STX limit anyway so there isn't more than a few lbs to lose. Maybe a little more in the exhaust if we did titanium or something. The clutch can't go any smaller/lighter or we won't be able to launch at pros. Battery is already about as light as you can go at just a few lbs. Now that I really think about it, I have no idea how we could drop another 100lbs in DSP trim. I see 40ish with a bunch of $$.


In fact, I'm impressed you got below 2700 in STX trim - how is that even possible with the AC system weighing 18lbs and your seats had to be around 15lbs heavier than mine, combined?


Less fuel maybe, but then you risk starving.


You don't have to answer, I'm just brainstorming/curious.

It takes custom parts built for that purpose rather than the usual off the shelf stuff plus some rare stuff like sub-14# 17x9 wheels etc.

Man I wish we were allowed under 3000. I am running T4 in SCCA and our min weight with driver was just upped another 50lbs to 3175! (oh and we have to run a 60mm intake restriction) I am a larger driver at 260lbs and I still have over 160lbs in ballast to make weight with a half tank of gas.

It's any wonder that the RX-8 does any better than it does in T4, jeesh

I'm a bit late to the party, but the RB midpipe is nearly five lb lighter than the full cat. Still 1.5 lb lighter than a gutted cat. I weighed them all on a calibrated scale.

That off the shelf stuff is still heavy. Use 20 Ga stainless tube with slip flanges and you'll double that reduction.

Finally finished and got to weight my car. This is not super accurate because it's a truck scale, I'll have more accurate numbers when I do the corner balancing. The car has an LS1 (aluminum, not a truck engine), T56 transmission, and very stout roll cage. Full tank and 150lb driver in it.https://cimg3.ibsrv.net/gimg/www.rx8...fd3f0fcf2b.jpg

Yah, that's going to be near the bottom of the calibration curve of scales rated for 20-30 times that weight. Most calibration methods are designed to have the greatest accuracy in the middle 75% of the range. When you get to either extreme, accuracy often starts falling off significantly.

The LS is probably 100-200 lb heavier than the Renesis and the roll cage is probably another 100+ lbs.

Keep in mind that the car is gutted to an extreme. No glass at the front doors. Custom wiring harness with just the very basics, custom brake lines, no ABS or anything. I was actually expecting it to be a bit lighter.

I don't know that all those parts are worth upwards of 450lbs but I could be wrong.

Like you said, you'll have a better idea when it's corner balanced.

Have you seen how much wiring (including huge caddies, computers, etc.) can come out these cars? I bet that was 450lb alone 😜 J/k. But seriously, it's a lot. Other heavy things that come to mind are, exhaust system, PPF and EPS rack that were all replaced with much lighter counterparts. These cars also have a ton in carpet, sound deadening material, airbags everywhere... but yeah, I'll provide a more accurate number when I get it. To be honest I don't think it will change much and as is the front/rear weight bias doesn't seem too terrible (F52.7% R47.3%).

Sorry, forgot what forum area I was in and thought of it as otherwise stock rather than as a race/track car. Yeah, I can see that as being a good weight then. Good job!

The wiring harness from the dash to the headlights weighs almost 50lbs. Was SO happy to get that out of the damn car!

We weighed in at 2745 at Nationals this year - only 100 lbs heavier than the winning BRZ, who also is from our region.

2396 dry, no driver.

Almost ready for the Runoffs.