For those who autox there seems to be some discrepancy on what the true weights of the different option packages are. Well my buddy just invested in a set of scales and we brought over two RX8s to weigh. Before any modications we wanted to get base weights.

The first one is a brand new 2005 6-speed base car. This car is going to be built for BS and you will see it running at Texas region events as well as a few Pros, Tours, and at Nationals.

Here are the numbers:
2005 Mazda RX8
53.5% front, 46.5% rear
2866 lbs w/o driver

This is totally bone stock + sat receiver, stock 18x8" cast wheels/stock tires, stock exhaust, and 4 gallons of gas (1/4 of a tank). We removed loose change, the factory jack, fix-a-flat compressor and lug wrench (there is no spare tire), otherwise it's "As delivered".

Next we put on our new-to-us 2004 GT. This car will be built for STU and will run at the same events. Here are the results:

2004 Mazda RX8
53.6% front, 46.4% rear
2914 lbs* w/o driver
*The car weighed 2939 with 8 gallons of fuel (1/2 a tank) and using 6.25lbs per gallon, this reduction should put it on par with the base car fuel-wise.

Now this car has the Grand Touring package which includes: Sunroof, leather seats with power driver's, and the Bose sound system. This car also has the aero package which includes a front spoiler, rear spoiler, and rear side skirts. Also, the same as the 05, it has stock 18x8" cast wheels/stock tires, stock exhaust, removed loose stuff, factory jack, fix-a-flat compressor and lug wrench, otherwise it's "As delivered" as well. So being just ~50lbs more, I don't think that is too bad at all. From here, STU weight reduction will begin!

 

My 05' 6spd base with rear wing, SSR comps, 245-35-18 V710s, 1/4 tank fuel and single sided exhaust was 2830lbs.

 

What type of scales did he get? I'm looking to buy some.

 

I was 2830# at Peru last year with around 3/8 tank, the problem is the gas gauge on these cars is so flakey you have no real idea what is actually in there unless you run it empty and then add a specific amount (which I did for Nats, but never weighed the car there), there wasn't much more to be had legally had out of my car.

You could just put a turndown on the catpipe exit rather than an exhaust (8# deduct on my car), Hoosier tires are a bit lighter but you'll get creamed by the Kumho V710 drivers, a couple of pounds with aluminum body shocks, maybe a pound per wheel off the SSR weight if you're willing to pay the piper, there might be another 15# or so, not sure it's worth the cost though (and eardrum pain of unmuffled exhaust under the car, yikes).

 

Longacre 15" Accuset. Works great. I think he got them here: http://www.saferacer.com/co15ac.html

Here's a pic of the weighing:


I already have the 18x9.5 Enkei RP-F1's which should lose me some weight. I also plan on changing seats, battery, exhaust, and a few other odds and ends and hopefully I can get down in the 2750lb range for STU. To me it was just interesting to see that all those GT options really didn't add that much weight.

 

you'll gain most of what you lost in wheel weight back in tire weight

you'll have to do more than that to get down there, most of the parts that are readily available aren't built with minimum weight in mind ...

 

Yep, the 275's are probably a bit heavier. Trust me, I'll weight both when I get a chance.

As far as the parts, I'm beginning to realize that. I think for STU purposes, I'm going to have to blaze a new trail so to speak and find or build my own stuff.

 

thanks for the weigh-in information, subscribed for future reference

 

I was looking at tire weights for the 275-35s that fit the Enkei RP-F1s. When all calculated, and assuming OEM wheel weight is ~22lbs and then taking into account OEM Dunlop's weight, I think I figured you'd save ~4.5-5lbs. per corner.

 

I just got my new Falken 615 tires mounted up on the Enkei's and will weight those along with the stock wheels/Dunlops next week. I'll post up the results here.

 

The problem with the weight of the GT versus the base is that a lot of it is on top of the car. Still, it is amazing how light these cars are. In STU, you can switch out the seats, can't you? That has to save you some weight. Still, getting down to 2750 seems very hopeful. Good luck.

 

My OE wheel and tire complete was 49lbs. My SSR's with V710s are 39lbs. This was with a digital bathroom scale so I would guess those numbers could be off by +/- 1lb.

 

I got 17"x8 enkei rp 2 with a shaved Toyo RA 1 size 235/40/17 and with centercaps and lugnuts weigt is 39lbs. I vavent tried them yet but I am itching to do that. My enkei rpf 1 with stock o40 wgt was 44.5 lbs.
olddragger

 

oh yea I forgot to say that my 17" package total cost was approx $750- how about that for wheeling and dealing. The tires have one run on them and 75% of thread left
OD

 

I'm shaking in my boots already ....

 

hehe, thanks...I think

Yea, I know some of that weight is in the sunroof and yes it's too high but it was the compromise I had to make with the wife so it is what it is.

And yes you can change seats and yes I will be. I have a set of Sparcos sitting in the attic and will swap those in for big events. Of course I will weigh both and see what the savings is.

Interesting info on the differences on wheel/tire packages. I'll try and get my STU set-up weighed as soon as I can get access to a scale.

 

at the top of the tech section is a post on weight of various stock components. feel free to pass on to me anyhting i don't have listed and i'll add it.

 

Yes, my 18 x 9.5 Enkei RPF1's mounted with shaved Yokohama Advan Neova A007 tires weigh weigh 44.5 lbs each, but it's not just weight that counts with a wheel/tire assembly, it's also inertia, which is weight concentration vs radius position squared. Most of the weight you lost was off the wheel which is the shorter radius positions, while the weight of the wider tire treadcap is more focused on a larger radius position. In the end it's a wash at best, but more likely a small performance negative in terms of inertia. However, whatever small impact that may have on accel/decel performance will be more than offset by the higher cornering speed that the larger wheel/tire package will provide.

 

FYI, throw a cat in it and knock off some weight:

https://www.rx8club.com/showthread.php?t=82286