desmo996

Does anybody know the weight difference between the Sport Package and the Grand Touring Package? Motorcyclists on the track estimate about 1HP per 7 lbs.

wakeech

depending on your options, it could be a few hundred pounds (ie: no-option base HiPower vs. All-Option Auto LoPower)... and that horsepower thing... *sigh* gross oversimplification. but yes, lighter is faster.

babylou

The extra doo-dads from Sport to GT and my weight increase estimates are:

Mirror doo-dads............~+0.5 lbs
Leather Seat Covers:......~+2.0 lbs
Power Driver's Seat:........~+4.0 lbs
Sunroof:.......................~+42.0 lbs
Bose Audio System:........~+3.5 lbs

Total Weight Gain:......~52.5 lbs

This is about 1.7% increase in weight which equates to ~4 hp. Of course, the biggest detriment to this increased weight is the sunroof way up top making the Cg significantly higher and therefore hurting handling. I posted on Edmunds a calculation I did on the RX-8 regarding the effect of the sunroof on Cg. I can't remember exactly but it was something like a 3.2% increase.

I want leather but am not willing to get a sunroof to get it. I don't care for DSC, Xenons or fog lights either. There goes another 9 lbs. Looks like a base model for me.

khoney

42 lbs for a sunroof? Sorry, I don't buy that. Don't forget, it you don't get a sunroof, you don't just have a hole in the roof! Seriously, how did you arrive at that number?

babylou

Don't forget I estimated the weights. I got the sunroof weight estimate from some other forum where some guy actually weighed his sunroof with motor, rails, switch and that little cover doohickey. He reported 50 lbs. I then calculated the weight of the steel and headliner in the "hole" and subtracted this from the 50 lbs.

I too have a feeling that 42 lbs is overstated but I am just passing along the best information I have. However, I would be surprised if the weight increase is less than 30 lbs.

desmo996

I agree with babylou regarding the sunroof, but I think your estimate for other items are a little bit conservative (i.e 2 lbs for the leather seats vs cloth). The added items in the GT, according to your calculations, would reflect a "loss" of about 7 HP due to weight. Good thing I ordered the SP.

rxtreme

iTrader: (1)

I thought a power drivers seat would wiegh considerably more after you added in motor's, all associated mechanicals, wiring, and switches.

MrWigggles

Desmo,

Your motorcycle analogy isn't correct. When people say pounds = horspower, they are really saying reduced pounds = better HP/weight ratio = equivalent horsepower gain.

For 3200 lb car (including driver,

250HP/3200lb = .07HP/lb

Taking the inverse:

1 HP for every 12.8 lb. So about 4 HP are lost due to the extra weight as Babylon described earlier.

-Mr. Wigggles

BRx8

i can see all your points but i, for one, am not gonna sacrifice luxury for some neglible speed increase...seriously, i'd much rather have the leather, navigation, 9 speaker system, power seats, and sunroof over a car with an insignificant speed increase...if you're adding a hundred lbs. or more like an extra passenger, then i'd say that's a big difference...but 50lbs. or less isn't gonna get the base or Sport a car length over the GT

so then, does it really come down to the few extra horsepower or does it come down to the fact that you just didn't want to pay for the GT? it's like saying, "Naw, don't give me top-of-the-line, i don't want it. Also, don't sit in my car, take your own ride. Also, I won't be doing any grocery shopping cuz groceries add weight. Also, I'm going on a diet"

sorry for the rant but it's just not that big a deal...and i'm not trying to pick on you, desmo996.

EDIT: this is of course my opinion as i will be using my car as a daily driver...i can see your hesitation on getting the GT if you were, in fact, gonna gut the RX and race it, where every little horsepower counts and the extra money going towards options would just be a waste...

ACRX8

A few hundred pounds? I don't think so!

desmo996

I understand what everyone is saying. I personally don't like weight on any of my vehicles. 30 lbs on the track on a motorcycle makes a lot difference and there is also to be said about inertia. Removing 30 pounds from a motorcycle feels like a 4.5 HP increase in power and it reflects on the lap times. I think a 50 lb on the RX8 between the SP and GT is a very conservative number. The real number is probably two fold. Time will tell. I drive my cars aggressively and every little bit counts. I don't talk on the phone when I'm driving, play with the radio or fiddle with the seat to get my b*tt warm. This car is designed to be driven hard and that's exactly what I intend to do. Remember, slower vehicles keep right. Peace.

wakeech

maybe not in this instance, but i've seen it on older RX-7 spec sheets.

babylou

It is funny how you consider 100 lbs "a big difference" while 50 lbs is "neglible". Not a bunch of room there for a "medium".

It is typical that you equate weight reduction to how much better the car will accelerate. Weight also affects handling, braking, fuel efficiency, emmissions, ride and crash safety. To preempt anyone don't say that heavy is safer. Yes, added weight, in the form of strength, in the structure improves safety. Weight in tacked on items, engines or power seats, reduce safety because they increase the energy load that the structure must absorb. Added unsprung weight actually hurts handling and makes for a rougher ride.

It seems to me that Mazda, of all companies, are commited to making cars light. It is no coincidence that Mazda cars (Miata, Protege, FD RX-7, RX-8) always seem to be at the top of the list in fun to drive ratings by the magazines. Look at the RX-8, it is 10% lighter than a similar sized BMW 3.

Basically I am sick of people cracking on others that want to "add lightness" and their response is it won't help performance much and they would prefer to have their luxury items. Well, if you prefer luxury items that is fine. There are tons of 4000 lb cars with loaded to the gills with "luxury" doo dads but are no fun to drive. Like a Mitsubishi 3000GT. Buy one of those. Oh wait you already have one. So why do you want an RX-8?

MaRX8

The Rx-8 for is all about Style and grace for me. I'm not going to be racing my car down at the track. If that's what I really wanted to do then, I probably wouldn't buy an Rx-8. I'd be better off with an EVO or STI. But those cars, just aren't my style. I want a car that's fast, great looking, and something I can drive with my friends and family in it. That's the RX-8. So having the GT package makes sense to me, why? Who cares about the weight, if I wanted to save weight while racing, well it wouldn't hurt me to loose about 50 lbs. myself. Hmm, I better take out all those speakers and amp, and maybe the passenger seat, oh yeah let's take off the A/C compressor because that adds a ton of weight, because that will make me a little bit faster...

If you obsessed with speed, I don't think the RX-8 is for you.

you'll never regret having the extra's down the road. It's only when you didn't get them that you might...

Alejandro8587

If you raced naked and fasted for a day you could shave off about 15 lbs, which would take care of everything except the moonroof :D