STS Miata - Project: Stronger Faster Lighter

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aMaff

High Speed Low Drag
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1992 Miata / 2003 Pathfinder
This evening I realized that over the course of this season, I'm taking nearly 100 lbs out of the car. ~ 60 lbs of roll bar, ~ 30 lbs of power steering, 6 lbs of wheels, a couple pounds per seat, uber light weight lug nuts... That's damn close to 100 lbs. When I set out to do these things, I really didn't think about the impact that would have. When I got it corner balanced at the outset of the 2008 season, it weighed in at respectable 2130 lbs. Doing a quick and dirty number crunch, taking 100 lbs out of the car is shaving about 4.7% of the weight at the beginning of the season. In a car with ~105 WHP (give or take), that's pretty darn significant.

Original power to weight: 2130 / 105 = 20.28 lbs / hp
New power to weight: 2030 / 105 = 19.33 lbs / hp

Given those 'goal' numbers, I really want to see what we're taking off the car. In an effort for accuracy, I will hopefully be picking up an accurate postage scale this week and weighing what has come off so far, and will continue to do so over the next couple months as the pounds drop. Once that's done, I can start on the engine rebuild and really see what this ol' girl can do!

~Andrew
 
I'm copying this post and the next from over in the miata section. I'm too lazy to re-write the whole thing, so... deal :p

Lost some weight today, and will lose a couple more pounds next week.
Installation was pretty simple once we had a plan. Problem with the 1st time you do it is that the plan goes through a few iterations before you finally settle on one that works. Part of the problem is that the seat isn't perfectly flat on the bottom. It's hard to describe the mounting, but long story short, these seats are about as low as you're ever going to get in a Miata with sliders. I love it! Seating position is lower, so the line of sight is no longer through the top of the windshield lol. The layback angle is the same as the Corbeaus, and as these aren't tube framed, they fit a ton better in the car. Unfortunately, I didn't think to take any pictures of the install, but we basically used 2 lengths of steel angle iron, and the seat is bolted down in 6 places along the bottom. VERY sturdy, and way sturdier than my Corbeau sliders that kept falling the F apart lol. The middle 2 holes we drilled directly into the top bracket of the slider and threaded those, and the 2 other pairs of holes (front and rear) are in the angle iron and use bolts, nuts and lock washers. Grade 8 hardware was used for everything.

Before:
IMG_0878.jpg


After:
IMG_1422.jpg


Look how much room there is in there now LOL
IMG_1424.jpg


This is what they look like with no covers:
IMG_1426.jpg


I'm kind of sad to see it go, but it was a lot of weight up high in the car. It's a beautiful piece that will likely be for sale soon. It was right around 60 lbs, so my car should be less than 2100 lbs now!!!! It's probably closer to 2070 or so based on what it weighed at the tour. Extra bonus is that the kirkeys + mounting hardware come out to be about 5 lbs less (at 26 lbs once ballasted) than the Corbeaus. I'm very happy with the results. I won't have time to work on the car this week (my folks will be in town), however I'll take s'more pics when we do the 2nd seat. Now that we know how to do it, installing the 2nd seat shouldn't take more than a couple hours.
 
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Ok, so I went ahead and put together an extremely technical drawing of what we did.

Please keep in mind that I haven't done the passenger side one yet, so it may be a little different.

The angle iron that we used was 1". It butts right up against the seat supporting the load on the front and rear very nicely. Anyway, the holes on the angle iron line up with the 2 stock holes on the ends of the sliders. We used 3/4" bolts on those. The 2 middle bolts go through threaded holes in the top of the slider. The front and back bolts have a washer on top of the seat, then use lock washers under the nut under the angle iron. I ended up using 2" bolts for those. The 1 1/2" could have worked, but was a bit skimpy on threads. 1 3/4" would have been ideal, but lowes didn't have any.. Note that the bolts holding the seats to the angle iron are inboard of the ones holding the angle iron to the sliders (towards the middle of the seat). That's the simplification I was talking about :p
 

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So today I actually went for a decent ride with the new seats today to Advance auto (30-ish minute round trip) to order a part for the Celica and I have to say I'm VERY happy with them. The seats have basically become a part of the chassis. It's no longer "riding ON a seat IN a Miata." No, now it's something different. Now it feels like your ass is bolted directly to the chassis of the car. The communication of what the car is doing is simply astonishing. I figured there'd be some difference, but it literally feels as though you have become part of the chassis of the car, it's amazing and I love it :D
 
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Good god that seat looks like it'd suck to sit in for longer than an autocross run.

Nice job losing weight. Is the driver keeping up with the slimming? ;)
 
Are you losing the power windows in your base package conversion, or are you keeping them under C&C?
 
khaosman said:
Good god that seat looks like it'd suck to sit in for longer than an autocross run.

Nice job losing weight. Is the driver keeping up with the slimming? ;)
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working on it. The goal's 20 lbs on that front. I would like to get down to 170.

Todd: I'm keeping the power windows.
 
khaosman said:
Good god that seat looks like it'd suck to sit in for longer than an autocross run.

Nice job losing weight. Is the driver keeping up with the slimming? ;)
Click to expand...

We have a Kirkey (Pro Drag) also in the ZX2...it's actually not bad.
 
TinmanMS6 said:
I don't think I've been 170 lbs since I hit puberty.

Lame.
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[mom]that's ok honey, you're just big boned[/mom]
Auto-Xer said:
We have a Kirkey (Pro Drag) also in the ZX2...it's actually not bad.
Click to expand...
Beat me to it. It's actually much more comfortable than it looks. For the record, having a convertible makes fitting the seats SO much easier ;). There was a lot of put the seat in, measure, drill, take everything out to make assembly easier, put it back in, tweak, take it back out, etc lol
 
aMaff said:
[mom]that's ok honey, you're just big boned[/mom]
Click to expand...

Last time I was in VERY good shape (a long time/60 lbs ago) I was still 205. :p

What sliders are you using? I don't see that tidbit anywhere above. Stock? Is there a lot of added thigh-wheel clearance? That's my primary issue in the Miata.
 
aMaff said:
For the record, having a convertible makes fitting the seats SO much easier ;). There was a lot of put the seat in, measure, drill, take everything out to make assembly easier, put it back in, tweak, take it back out, etc lol
Click to expand...

We really had no problems putting one in a coupe either; we used the Kirkey side mounts and bolted them to the OE sliders. It's very solid, and fits my 5'18" 230# frame much better than the OE seats--its the difference between fitting and really not fitting in the car for me.
ry%3D320
 
TinmanMS6 said:
What sliders are you using? I don't see that tidbit anywhere above. Stock? Is there a lot of added thigh-wheel clearance?
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Ah yes, sorry about that. They're the stock sliders, and there is a lot more added clearance. You may actually be semi-comfortable in my car now. Come by @ Points 8 and have a sit.
 
Auto-Xer said:
We really had no problems putting one in a coupe either; we used the Kirkey side mounts and bolted them to the OE sliders. It's very solid, and fits my 5'18" 230# frame much better than the OE seats--its the difference between fitting and really not fitting in the car for me.
ry%3D320
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Awww, you took the easy way out! I actually thought about using the kirkey side mounts, but that was another ~$70 or so that I really didn't want to spend if I could get away with $15 in angle iron that my co-driver already had laying around.

And dayum, 5'18"!? You'z a tall b****! :p
 
aMaff said:
And dayum, 5'18"!? You'z a tall b****! :p
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Nah...it's all smoke-n-mirrors. Heck--if I could get over my 'white-man-can't-jump' syndrome, I'd only be a shooting guard in the NBA.
 
I'll have to take you up on that test-sit.

Side mounts would get you a little lower as well, wouldn't they?
 
TinmanMS6 said:
I'll have to take you up on that test-sit.

Side mounts would get you a little lower as well, wouldn't they?
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I can't get any lower with sliders than it is. The bottom of the shell is flat on the slider.
 
So what is the layback on these? I know you said it was the same as the Corbeaus, but I don't know what that is either.

How are you ballasting to get up to 25#?
 
TinmanMS6 said:
So what is the layback on these? I know you said it was the same as the Corbeaus, but I don't know what that is either.
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18 degrees
http://www.jegs.com/SizeCharts/kirkey/570-41series.pdf
How are you ballasting to get up to 25#?
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lead? Honestly though I'm not sure. I'm getting a postage scale tonight so I'll know exactly how much I'll need to ballast it. I can probably get a couple 1 lb weights from play it again sports and just velcro them and put race tape over everything on the bottom of the seat. If it's much more than that, it will definitely need to be more securely mounted. I'll cross that bridge if and when I come to it.
 
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