Brentis

This link is crazy. I rather figure out how to make more HP than figure out that the front engine eye hook w/ both bolts weighs 0.73lbs.

Nonetheless these people thought it was worthwhile to find out and much more.

http://www.purplemantis.com/Mantissa..._reduction.htm

Mr. Stock

That is Gene Felber's site.
I have posted that link here on the forum whenever someone asks about stripping weight off the FD3S.
Check the current thread Dropping some weight in an RX7

BTW, there are two ways to make your car go faster
1)Make more horsepower
2)get rid of unnecessary weight

Which way do you think is better?

If you said 1)Make more HP, you are wrong.
It's always better to shed weight. Now, guess why.

the_glass_man

iTrader: (2)

Just because these cars don't way much to start, does not mean you shouldn't look for ways to shed a few pounds.
Reducing weight aids acceleration, braking, cornering, gas consumption.
The less weight the better if you ask me.
Thats why I don't have PS, A/C, etc...

Brentis

Well both approaches reach their limits - it is just which one hits it first.

I also subscribe to the thought of not thinking of ways to save $$$ but ways to make more $$$

And finally I think that HP is like watts, bandwidth, real estate, $$$, and women.

Flyrx7

iTrader: (1)

[QUOTEIt's always better to shed weight. Now, guess why. [/B][/QUOTE]

Ooh, could it be because it's cheaper?
Here I go, but it seems to me I "read" somewhere that for every hundred pounds you drop you gain 1/10th in the quarter. One of the reason why the "commitee's" made Mazda add balast to make them more inline with the other cars in their class (eventually making Mazda unable to compete in their class, whole other story, but I digress). Actually, if you read Yamaguchi's book, they were on a "gram" shaving quest just to get the 3rd gen into the HP to weight ratio that was their target goal from the beginning. A little here, a little there can add up.

Regards,
Frank

Mr. Stock

Too many damn 1/4 milers here.
This is the RX7FORUM, isn't it? Where are all the road racers?
Sigh...

Flyrx7

iTrader: (1)

Not sure if this reply is directed at my post, but what's good for the goose is good for the gander.
I use the quarter mile analogy that my autoshop teacher taught us to make a point, his context, not mine. I'm sure that if you shave weight and it makes you faster in the quarter it will make you faster on the track, auto-x, slalom, parking lot, driveway, whatever
The point I was trying to make is even Oprah could run a 5 second 40 if she shed like 60 pounds..... (or a 5 minute mile for you track guys

Frank

Mr. Stock

Operation Zero.

Mr. Stock

It was directed at the goose.

Less weight=better handling. Of course, better acceleration is a given.

maxcooper

Reducing weight increases performance in every way (not ride, but I mean the fun kind of performance). The RX-7 would be much less interesting if it weighed 3200-3800 lbs like the other cars in its class. I like HP, too, but light weight is a very key element of the RX-7 design and making it even lighter generally makes it even better.

Reducing unsprung weight (wheels, tires, suspension) makes the suspension work better (more grip). Reducing rotating weight (wheels, tires, flywheel, driveshaft) increases dynamic drive power (RWHP on a DynoJet), especially in low gears. It also improves throttle response and makes downshifting a lot easier. Reducing the polar moment (by reducing weight or just moving it in toward the center from the ends of the car) makes the car easier to turn for faster lap times. Weight removed from anywhere improves acceleration, braking, and handling.

The Mosler MT900 has a Z-06 drivetrain but only weighs 2200 lbs. It goes 0-60 in 3.5 seconds and can get 28 MPG with the air conditioning on.

I realize this is all a bit obsessive, but reducing weight really pays off.

-Max

M5150

i guess in operation zero they didnt care for doors that closed nicely

adam c

iTrader: (2)

So, if you really want your car to accelerate faster and handle better, get your body fat down to 8%. No sense dropping 50 lbs of car weight if you are super-sizing at Burger King.

tubbinator

"Where are the road racers?" you say? I'm here :-)

I just saw the thread about the LS1 engine in the FD and was equally offended because I'm a rotor-head, but hey, to each his own :-) Besides, I pull my FD to the races with a 350-powered Suburban. Looking for a diesel-powered dually though :-) At least that way my pull vehicle will have a turbo LOL

CCarlisi

Here here. (or is it hear hear?.....har har :-p)

For anybody that doesn't see the benefit of weight reduction take a look at the performance numbers a Lotus Elise produces with a NA rover 4 banger.

jimlab

If there are parts you can do without, why not take them off the car to improve performance? As stated previously, it's "free", assuming you're willing to live without them. It's only when you start replacing all your fasteners with Titanium that it becomes an obsessive/compulsive disorder...

I've been weighing almost everything lately. That's why I know I saved 5.6 lbs. by going with an aluminum '03 Cobra 8.8" differential, despite every internal part (differential assembly, ring and pinion, caps, bolts, inner axle stubs) being bigger, heavier, and stronger. That was a fringe benefit, however. The original goal was to gain a wide range of gear ratios at a reasonable cost while improving strength.

You don't have to be obsessive about it, but it never hurts to be aware of what you could save by dropping your A/C or P/S, for example. Gene has just compiled a list of what other people (for the most part) have observed. Some through curiosity, some through an overpowering psychosis to shave every last ounce that isn't absolutely necessary. I wouldn't know anything about that...

tt2323

why can't i open that link?

jimlab

Try this one...
http://www.mantissaracing.com/Mantis...eight_data.htm

tt2323

that'll do it. thank you!

Tim Benton

iTrader: (1)

Gene's site is down. I can't even get the one Jim posted to load either.

Tim

gfelber

Guys,

I switched ISPs and domains for more space and better service. I've been uploading some new stuff, so the site may have been down for a bit.

Here ya go:
http://www.mantissaracing.com/Mantis.../RX-7/RX-7.htm


The link for weights is: http://www.mantissaracing.com/Mantis.../RX-7/RX-7.htm

Regards,

Gene

APEXL8T

There you go! I've been road racingsince 92' and I see a lot of fat asses who do everything for a few ounces in their cars but not miss that McBreakfast or two.

Mr. Stock

But I noticed that those overweight guys are pretty good racers. Maybe it is nature's way of giving the good drivers a weight penalty. Instead of a ballast for the car, they have to deal with the extra blubber

the_glass_man

iTrader: (2)

Always take a healthy poop before you get in the car!

dices7

i cant get on to any of those sites. help

Sgtblue

iTrader: (16)

She'd have to shed the weight of BOTH ***-cheeks.