dgeesaman

iTrader: (7)

Aluminum generally comes cast or wrought. Wrought means it comes in bar/rod and gets cut to shape, castings of course are poured to the shape and optionally cut afterward. Cast parts are usually more brittle than wrought, and wrought parts can be heat-treated for extra strength after being shaped.

If weight was really an issue with the pedals, consider how ceilings and floors are made. Since we can't find a 2" thick slab of wood to make a floor, we make trusses and beams to divide the area and put a thinner slab on to cover the gaps. For a pedal, you could probably skip filling the gaps altogether and cast a lighter, stronger structure. Like a basic bicycle pedal. That would be cost-effective, and probably be as strong and lighter than the current Mazda design. I think Mazda didn't get too aggressive in going this direction since it had to look like it would support the weight of your foot. Or it would have required a lot more engineering hours than the grams were worth (as in, hours spent on another component would have been more meaningful).

Mazda did do some suspension components using "squeeze forging" which I think is just a deluxe casting. Extra heat/pressure probably reduces brittleness and improves strength.

As for using wrought aluminum, you could cut/drill a plate into a rather airy-thin design. This is expensive for mass production, but can be done in a one-off manner. So you will see many home-built race-car parts made this way. But the cost doesnt' go down as you get into mass production.

The ultimate solution would probably involve one-piece titanium - higher strength/weight than aluminum. But expensive as all get-out.

I have to say, Mazda did a hell of a job for a car stickered at $35k. But it's no Enzo.

Dave

quicksilver_rx7

Here's another exception. Mine's an early 93 model (build date 8/92) and it had a black crossover pipe and a silver compression tube. Go figure. I always thought that people painted them silver to look like the efini pipe.


There's a reason Ford owns the controlling interest in Mazda now

Joe

FDNewbie

iTrader: (10)

Interesting.

So pretty much structurally reinforce a less dense object, huh? There would be gaps and areas not as thick/strong/dense as the rest (not structurally important areas however).

Nice. Thanks for breaking it down for me. That gave me an excellent mental image

You're saying to use wrought aluminum (a bar), shape it, then thin it out in areas, and drill it out in others etc...basically removing some of the material to lighten it? And that isn't feasible to be done via mass production? Gotta be done one at a time, which is why the cost won't go down?

Whoooowweee. Titanium sure is expensive alright. Hmmm. I'm wondering now if the Titanium Pedal Set I have (an accessory offered on the FD in Japan) is real titanium or just looks like it?

Isn't the Enzo chassis made entirely of CF and aluminum honeycomb sandwhich panels? I don't think such technology was anywhere near affordable in the RX-7's day, and it's not very affordable now. NSX's are all aluminum chassis (is that plural as well? lol) and look how expensive they are. I'm sure you're aware of how expensive the Enzo and Porsche GT are with their CF structure.

I think Mazda did an incredible job as well. I just wish it was as aerodynamically efficient as say, the new 911 Turbo, where it doesn't try and cut through the air; it actually promotes airflow through the chassis, enhancing downforce, cooling the brakes and motor, etc... amazing stuff. But again, you see the 911's pricetag, and you see the RX-7's pricetag. I think Mazda surpassed all expectations given their budget, and then some

Here's a post w/ more info re: the 911 Turbo's amazing aerodynamics: https://www.rx7club.com/showpost.php...6&postcount=98

LOL. There you go Joe. Yet another exception. Like I told ya...I'm just not surprised anymore.

I remember I was shocked when I found out about the red interiors on silver FD's. Then I found a black FD with red interior (you have one, right?). On ebay a week ago, there was a WHITE FD w/ red interior! It never stops man...

dgeesaman

iTrader: (7)

Yes. Since a pedal mostly has to transfer the pressure of your foot without collapsing, it's what we refer to as bending loading. In bending, making something thick truss-like works better than a solid slab.

Check out this battle-bot thing: http://www.teammadcow.com/construction_summer_2002.htm
and jump down to 25 July. That's exactly how they're building this - take a chunk, hog out pockets, and leave material where you need it. It just take a lot of time under the milling machine.

In mass production, cast parts have a high up-front cost and delay due to making the molds. So it's generally out of reach of prototype and low-volume projects. But once it's going, it'll pop out parts very quickly and cheaply. To keep up with an auto assembly line, this is a popular approach.

Just be sure it's not 'titanium look' or 'titanium coated' or something. I dunno about Japanese accessory parts, but a truly superior titanium pedal would probably cost $1000 here. Give or take a grand. For reference, I had some titanium D-rings made once, (D-rings like the ones that shoulder straps clip into on a dufflebag). They were 10g apiece and cost $150/ea. So Ti is very expensive, very.

I've seen little bits about it. I have a article from an auto trade magazine describing the latest GT's chassis, I will try to dig it up. It mentioned how they shifted the CG down like 0.1" and all the stuff they did to acheive it. That kind of development requires a very stable platform and a whole lot of wind tunnel time to prove it out.

Plus, the economy of scale applies here. If Ferrari were only making 100 of a particular car, they may hog out wrought material rather than casting, since they don't make these cars particularly fast, and the hassle of molds isn't worth it.

Dave

FDNewbie

iTrader: (10)

Bending loading, huh? I feel like I'm in a materials engineering class hehe. Good stuff Takin me back to my college days... (my roommate was an industrial engineering major).

Re: the titanium pedal, take a look at it, and tell me what you think. It clearly says "Titanium" (the name of the accessory), and the color/tint of the metal looks titanium gray to me (I was one of those 120 color Crayola guys ). Don't have a weight on 'em, but price was $200. Pic: http://img.villagephotos.com/p/2004-...6/IMG_2953.JPG

dgeesaman

iTrader: (7)

Oh I see, they are a thin titanium plate that is set on the existing pedals for cosmetics. I can see that being real Ti for $200, since it looks like it's only 1/16th or 1/8th thick, and it has no structural requirements.

I was talking about replacing the whole pedal and pedal arm with a single titanium part. That would be much more expensive than a cover plate.

Dave

FDNewbie

iTrader: (10)

A complete pedal set replacement in titanium?!?! What...do I look like I have money I don't know what to do with? lol. Besides...the .5 lbs I'd lose by such a mod (if it existed) would just KINDA be offset by the 30 lbs I picked up w/ the lambo door hinges haha

~Ramy

PS: FYI, Guru Motorsports makes a lightweight pedal box w/ removable Alloy Pedal Pads. It weights only 2.6 kg (5.73 lbs)!

dgeesaman

iTrader: (7)

I never it made sense

HDP

iTrader: (2)

dgeesaman

iTrader: (7)

I meant, "I made never sense said is".

Bah, forget it.

FDNewbie

iTrader: (10)

LOL Don, I saw it, and I thought eh...lemme let this one slide (even though Dave was quick to fault me on ONE misspelled word in a PM I wrote at like 4 am!! lol)

Nice one Dave haha

EDIT: On second read... What the??? Arruu?? I know what you meant the first try, but the second try...

Julian

iTrader: (14)

No its lighter

Julian

iTrader: (14)

Non-reinforce wheels were continued in production past '93. (Mine, I bought my 94 in 95 through Mazda Motorsport, had to wait for shipment from Japan and know that a dealer didn't have time to screw with it). 5 spds came with lightweight and automatics with heavier set. What seems to have changed is the supplier since wheels manufactured in 1992.

From reading the various service documents '94's A/C's came with either R12 or R134, there must either be a cutoff VIN number or differenece between factory installed vs at the US docks installation by MANA.

Now a '95 with a '96 ABS unit would be nice. For that matter I would prefer a 95 in my 94

FDNewbie

iTrader: (10)

Julian, re: the R12 vs. R134, there may very well be a VIN cutoff, BUT, I spoke w/ Mazda directly, and they told me they can't even tell what A/C system I had. So either the agent I spoke with is clueless, or Mazda doesn't keep track of it, and it was MANA at the docks. Who knows.

As for ABS, what's the difference between the 94 and 95 units? I know the 93 and 94 units are definitely different (back in the day, everyone at PFS used to always crowd around my car, looking at the ABS unit, because they pretty much saw 93s all day long).