Can you do Lexan in place of glass?
Glass is *heavy*
Can you do Lexan in place of glass?
Glass is *heavy*
Rodan said:
If your ruleset allows the removal of the interior, there's gains to be made but you'll be sacrificing streetability to get anything serious. A race seat, will save a few pounds, and you can leave the pax seat in the paddock if the rules allow.
Most of the interior gutting allowed is behind the B-pillar. Which means you are SOL in a Miata, although you can chop down or modifiy the dashboard. Race seats is definitely a direction I'm leaning in, as not only will they cut weight, they'll hold me in place so that I'm not trying to hold myself upright and drive.
You don't have to pull the dashboard to get the evaporator out. Take the glove box out and it drops out the bottom.
It's really hard to take significant weight out of a Miata. I had my street car awfully close to 2000 lbs wet at one point, but it had no HVAC.
Here's some of my work over the years: http://targamiata.com/tags.php?tag=weight%20loss
I agree that the big low hanging fruit is the roll bar. We have a removable roll bar for sale at FM - it won't fit your car, but you can see how it's implemented.
Pull the soft top, get a hardtop. Remove the hardtop for competition.
Next easiest is a battery.
If it's got a 1994-97 dash, the 1990-93 is a fair bit lighter.
Stock doors are 32.45 lbs. Just a door skin is 14 lbs, but it won't support its own weight and you can forget about windows. Removing the crash bars is a dumb idea if this is a track car and not a cone dodger.
Pulling unnecessary wiring out goes a long way.
The V8R stuff in particular is prone to cracking. I would stay away unless you're going to maintain this thing like a racecar with frequent inspections. It's also going to have mobile suspension pickup points which may not be what you want. If you go with tubular control arms, make sure they're strong (not always a strong point) and that they don't limit compression travel in the rear.
You're not going to save massive weight with an engine swap. Do that for other reasons, don't try to convince yourself it's a weight loss target. The BP is not the boat anchor everyone says it is.
Brett_Murphy said:Can you do Lexan in place of glass?
Glass is *heavy*
Replacing the rear window in my hardtop saved about 5 lbs. A windshield would have to be thicker and the stock windshield is 20.9 lbs, so the potential weight savings there is hard-won. Side windows - no side windows are lighter than lexan side windows. You can get clips to put glass in temporarily.
The Targa Miata was right about 2100 lbs with a full tank of gas in race trim. That's fully weatherproof and street legal with a cage. No HVAC, no interior to speak of, pins on the trunk.
Miata batteries are already small. But a diy capacitor could be all you need. Saving 20ish lbs?
How much of your 2250 was spare tire and Jack and toolkit?
Next I'd look at the exhaust system, sometimes some fairly heavy components can be swapped out for little other compromise.
Headlight motors? Maybe make the lights work with a cable from inside?
Do you have an oil cooler that isn't really necessary? Big brake kit? Hitch or luggage rack or trunk props?
Heck, speakers are heavy. Make them so they can pop out if needed.
Do all that and you'll be down say 50 lbs.
Keith Tanner said:The Targa Miata was right about 2100 lbs with a full tank of gas in race trim. That's fully weatherproof and street legal with a cage. No HVAC, no interior to speak of, pins on the trunk.
That's with the V8 drivetrain? That's pretty darn light!
It's XS. The point of the class isn't to build to the absolute limit of the rules. It's to take the street legal, built the way you like it car you car you already have and go out and have fun while also having a place to compete against like minded competitors and cars. Your car meets the weight requirements, run it as is. If you're talking about swapping in a set of lightweight doors...you've missed the point of the class.
That all said, for autocross use, the rollbar is nothing more than dead weight mounted way up high. I'd ditch that if it can be made to be easily swap-able for track use.
That was when it was a four. It got some cage upgrades and more skid protection with the V8, I think it's about 2300 now. I don't have those numbers in front of me.
Miata battery is 26 lbs. Going to an Odyssey PC680 will save you 10 lbs and requires no special care and feeding. Lithium batteries can be lighter and fiddlier.
Headlight lids, oddly, are really heavy. The motors aren't all that light either. Going to a DIY fixed light setup will likely look terrible but might save significant weight.
Wilwood brakes will save weight by going to aluminum calipers. Otherwise, the early 1.6 brakes are your lightest setup. Drill the rotors as you dare and upgrade the pads to stop better.
Seats can make a big difference, you'll net more speed just by being in control of the car instead of flopping around on the stock seat. Slider can be eliminated from the passenger side, it's heavy.
As everyone has already said, lightweight battery. If you relocate it to the front you can eliminate the heavy cable running all the way to the rear of the car.
Run less gas. Bring a 5 gallon jug with you and fill as needed but if you're autocrossing on more than 1/8th of a tank you're doing it wrong.
Top hats. NA top hat are heavy. NB hats are lighter. Aluminum ones are even lighter.
Ditch the soft top and get a hard top. If you want to leave it home you can get a snap-on bikini top to protect from the occasional shower going to and from events.
Smog control stuff like the charcoal canister under hood. If it can be eliminated, take it out. Any steel brackets you can fabricate aluminum ones to replace them? Now is the time to get creative.
If you do race seats with a harness you can eliminate the seat belts with their reals and retractor mechanism.
Replace headlights with LED units.
codrus said:You don't have to pull the dashboard to get the evaporator out. Take the glove box out and it drops out the bottom.
Oh, I guess I'm used to every other car that I've ever worked on the HVAC system. That's convenient.
I mean, the good news is, most of the other Miatas I've raced with that were SSM-ish, were in similar trims as mine as far as lightening. And if 2100lbs is difficult to hit, then seems unlikely they'll be weighing that much either. And I've blatantly outpowered every other boosted Miata I've raced against.
I have also considered going to a fixed-headlight, as others have suggested, because I have the Jass low-pros and they don't illuminate E36 M3, so I need to change things up anyways.
Something kind of like the Jet Stream fixed headlights.
KyAllroad (Jeremy) said:Wilwood brakes will save weight by going to aluminum calipers. Otherwise, the early 1.6 brakes are your lightest setup. Drill the rotors as you dare and upgrade the pads to stop better.
Top hats. NA top hat are heavy. NB hats are lighter. Aluminum ones are even lighter.
Replace headlights with LED units.
That's the thinking behind our Little Big Brake Kit - light Wilwood calipers on stock rotors. They were developed after seeing the brake setup on Bill Schenker's CSP car. We have a 9" variant, but it fits very few wheels because the caliper is so close to the mounting pad of the wheel.
Top hats - that's an interesting one! I wouldn't assume aluminum ones are lighter, as they tend to incorporate a spherical bearing. I'd go with function over weight here as the potential savings are small. You might save more weight with an aluminum bodied shock like a Fox versus a steel one like a Koni or Bilstein. Foxes are 40% lighter. If you have MaxPeedingRods, you've already lost this battle badly :)
The weight of the actual headlights isn't too bad. It's the mechanisms that have the mass.
NickD said:I have also considered going to a fixed-headlight, as others have suggested, because I have the Jass low-pros and they don't illuminate E36 M3, so I need to change things up anyways.
Something kind of like the Jet Stream fixed headlights.
Problem is it's really hard to improve on 7" reflectors. They're already in a very good place optically speaking. I have yet to see a set of low-pros or fixed lights that I think are an improvement over stock lights. Part of the problem is that you have very little height to work with. I'd start by prioritizing just what you want out of your headlights and where you drive. You may do better by sinking a couple of 5" units in the front bumper cover.
Keith Tanner said:Top hats - that's an interesting one! I wouldn't assume aluminum ones are lighter, as they tend to incorporate a spherical bearing. I'd go with function over weight here as the potential savings are small. You might save more weight with an aluminum bodied shock like a Fox versus a steel one like a Koni or Bilstein. Foxes are 40% lighter. If you have MaxPeedingRods, you've already lost this battle badly :)
I have Xidas on hand, ready to go in, so those are aluminum body. Those are probably going to help the cars performance more than any weight loss though. It'll be nice to have much more appropriate spring rates.
NickD said:I have also considered going to a fixed-headlight, as others have suggested, because I have the Jass low-pros and they don't illuminate E36 M3, so I need to change things up anyways.
Something kind of like the Jet Stream fixed headlights.
Thanks for the picture. That helps my thoughts on doing my own fixed headlights.
1722lb's is where mine ended up on the dump scales. 94 R completely stripped, with the 91 interior dash, straight door panels, no top, no interior no sound deading and everything light weight that you can do easily.
Street legal yes, no blower so I think 1900lb's is doable with some creature comforts plus the blower
Do not underestimate the value of lightweight calipers.
Keith Tanner said:KyAllroad (Jeremy) said:Replace headlights with LED units.
The weight of the actual headlights isn't too bad. It's the mechanisms that have the mass.
What about fabbing something that you could keep the stock 7" headlights, in the factory position, but remove the guts and make something that you could pin them up or down?
Would LED replacement 7" housings be lighter than the standard housings and bulbs?
I second the electric rack/column conversion if you want to keep PS. Lose the potential leaks, reduce clutter in the engine bay and potentially drop some weight.
Another thing to look at is trimming or drilling fasteners. Anything that is too long should be trimmed back to a safe length. Anything that can be drilled should be (basically nothing critical, but I'm sure there are several that could be). Titanium and aluminum fasteners can be used, just watch for dissimilar metal issues and strength.
Wheels are another spot that could be relatively easy to drop some weight, they just won't be cheap and can reduce the streetability of the car as they could be a little more delicate.
AWSX1686 said:Keith Tanner said:KyAllroad (Jeremy) said:Replace headlights with LED units.
The weight of the actual headlights isn't too bad. It's the mechanisms that have the mass.
What about fabbing something that you could keep the stock 7" headlights, in the factory position, but remove the guts and make something that you could pin them up or down?
That's an interesting though. I have a second set of headlight mechanisms I could bastardize to try and make work.
NickD said:AWSX1686 said:Keith Tanner said:KyAllroad (Jeremy) said:Replace headlights with LED units.
The weight of the actual headlights isn't too bad. It's the mechanisms that have the mass.
What about fabbing something that you could keep the stock 7" headlights, in the factory position, but remove the guts and make something that you could pin them up or down?
That's an interesting though. I have a second set of headlight mechanisms I could bastardize to try and make work.
Friend of mine has a 240SX with pop ups and he removed the motor/mechanism in favor of a prop rod. He has to lift the headlights by hand now but the rod pops into it's slot when you lift the lights and lowering them just involves poking the rod back out of it's slot. He said it was good for 10 pounds off the front of his DSP car.
Stefan said:Would LED replacement 7" housings be lighter than the standard housings and bulbs?
Yes, I believe so. The LED housings tend to be plastic instead of glass.
We had a customer who gun-drilled his front upper control arm bolts. There aren't many people that give light weight numbers that I completely believe, but I do believe him.
A coworker did an EPAS conversion. I'll ask him about weight savings. Motors aren't weightless.
It's worth noting that I always give weights "full wet" with a full tank of fuel. That's because there are only two repeatable amounts of fuel, completely empty and completely full. Others will weigh with some random amount of fuel or will do some math to compensate. Just be aware if your'e trying to compare.
Keith Tanner said:Stefan said:Would LED replacement 7" housings be lighter than the standard housings and bulbs?
Yes, I believe so. The LED housings tend to be plastic instead of glass.
Unless of course you use the Truck-Lite bulb/lights. They weight a good bit, as you know. ;)
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