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Keith
Keith GRM+ Memberand SuperDork
1/18/12 10:37 p.m.

Thanks guys. Too bad it's gone out of print.

The black bike-engined car from the C&D article now belongs to a coworker. It's under 1000 lbs. I highly doubt a car engine would get down there.

alfadriver
alfadriver SuperDork
1/19/12 7:11 a.m.

There's a challenge....

The only powertrain I can think of is the Focus/3 front engine with the Duratec/MZR powertrain- it's an aluminum eninge, and a fairly simple 5 speed. that would eliminate the rear axle.

Other than that, the only powertrain idea I have is the Alfa Spider one- engine + trans is pretty light. Not bike light by any means. But very light. All aluminum structural construction.

What are some other super light powertrains?

One thing- lets say you were considering doing a challenge with this. And optimizing for the autocross- the lightness does decrease the need for tires AND power. So if there's a very light 1600.... (a bike engine would rule, I know).

carguy123
carguy123 SuperDork
1/19/12 9:59 a.m.

The new Chrylser 1.4 turbo engine is tiny!!

Graefin10
Graefin10 HalfDork
1/19/12 10:12 a.m.
Apexcarver wrote: Does this make me crazy? 1/8th scale balsa wood locost chassis in progress (cant start 1/1 in metal for awhile, so it sounded like fun) It sucks that the hobby/craft store is out of balsa in the size I need right now. Right now its a book chassis with SkinnyG's 3" change. I might cut out the "R" tube and try to get some good dimensions of Miata parts (try to make a scale approximation of the engine/trans/diff) and use it to spitball the rear diff mounts. If I go that route I'll have to decide how much detail I really want to do on the parts...

Yes, you are,but ain't it grand!

I've been saving cereal boxes and the like to build a 1/8 scale monocoque model that I want to get out of my head. I bought some super glue to stick it together with. I if you are I'm right in there with you. Keeps you going when circumstances stop you from doing what you really want to do.

Ranger50
Ranger50 Dork
1/19/12 7:02 p.m.

Is it wrong to want one in RHD???

EvanB
EvanB GRM+ Memberand SuperDork
1/19/12 7:18 p.m.

Not if it has a bike engine.

JamesMcD
JamesMcD Reader
1/19/12 7:43 p.m.

What about the Suzuki Swift DOHC motor (or even the 3 cylinder) plus a Sidekick/Tracker 5-speed? I think that combo is pretty light.

kevlarcorolla
kevlarcorolla Reader
1/19/12 8:06 p.m.

The swift engine is a great choice for a locost,light and very rev happy.Not exactly a power house at 100hp stock but the bottom end is tough as nails,I'd boost and rev it to the moon for a good time.I don't think they have great options for rwd trans though,I'm not sure how well suited the gearing of a tracker/sammy trans is nor how tough they are.

Ranger50
Ranger50 Dork
1/19/12 11:32 p.m.
EvanB wrote: Not if it has a bike engine.

But I don't want a bike engine.....

Teh E36 M3
Teh E36 M3 Dork
1/20/12 9:37 a.m.
kevlarcorolla wrote: There's no way a 4ag based locost is going to be 950lbs.My R1 powered scratch built track car was 927lbs in this pic,its much smaller than a locost and the engine and trans weighs 150lbs combined.

Yeah, but look at the tubing you're using- looks like 1.5" .083 at least? That E36 M3's heavy- strong, but heavy (very cool car by the way). I don't have anything to back up the guy's claim, and honestly can't remember where I saw his car, pictures, and his claim (maybe I should run for president with a memory like this), and have no frame of reference, as I haven't built a car like this.

I'd love to shoot for 500kg's with a car engine- something between a bike and car engine would be great- I love a frantic engine.

Keith
Keith GRM+ Memberand SuperDork
1/20/12 10:03 a.m.

That sub-1000 lb bike engined car owned by a coworker does not leave any easy/cheap ways to lose weight. When he got it, it even had carbon kart seats. Under 1k with a car engine is very, very ambitious. 500 kg (1100 lbs) - possibly. I might be able to get my car down there with some cash and effort.

I'm not even sure Caterham claims a car-engined Seven under 1000 lbs, and they're a little light on the weight claims.

Teh E36 M3
Teh E36 M3 Dork
1/20/12 10:16 a.m.

Interesting. That's good to know. Even 500kg is a bit ambitious eh? I'm curious, now that I think about it (and looking at kevlar's track car- what is lighter- a light walled square tube space/ladder frame, or a heavier tubed frame like the above (with fewer tubes) in an equivalent car?

I'm sure that locostusa has gone over this- along with the 4130 arguments.

alfadriver
alfadriver SuperDork
1/20/12 10:22 a.m.
Keith wrote: That sub-1000 lb bike engined car owned by a coworker does not leave any easy/cheap ways to lose weight. When he got it, it even had carbon kart seats. Under 1k with a car engine is very, very ambitious. 500 kg (1100 lbs) - possibly. I might be able to get my car down there with some cash and effort. I'm not even sure Caterham claims a car-engined Seven under 1000 lbs, and they're a little light on the weight claims.

Yours is Miata engine, right? Any idea how heavy is the power train?

kreb
kreb GRM+ Memberand SuperDork
1/20/12 10:29 a.m.
kevlarcorolla wrote: The swift engine is a great choice for a locost,light and very rev happy.Not exactly a power house at 100hp stock but the bottom end is tough as nails,I'd boost and rev it to the moon for a good time.I don't think they have great options for rwd trans though,I'm not sure how well suited the gearing of a tracker/sammy trans is nor how tough they are.

You got a build log link for that beauty?

alfadriver
alfadriver SuperDork
1/20/12 12:39 p.m.

Sorry about the short question- I was kind of interrupted.

But that's good information- comparing a 1600 Miata powertrain with a 2000 Alfa would be interesting- I'm pretty sure that the Alfa engine is considerably lighter, since it's all aluminum, outside of the basics and the liners. Gearbox- probably the same, Diff vs. axle- similar.

For wheels, I know the real magnesium Alfa wheels are super light..

It would be interesting to have a weight spreadsheet to make some changes....

Funny, too- I've got a spare single carb 1300, with a smaller tunnel case trans, Giuletta axle, and aluminum drums all around. All with nothing to go in.... If anyone wants a 85ish HP Alfa powered Locost, I've got to parts outside of the chassis to do it. That Sammimo body made me think that a locost chassis can be modified to fit the body.

93EXCivic
93EXCivic SuperDork
1/20/12 12:42 p.m.
alfadriver wrote: Funny, too- I've got a spare single carb 1300, with a smaller tunnel case trans, Giuletta axle, and aluminum drums all around. All with nothing to go in.... If anyone wants a 85ish HP Alfa powered Locost, I've got to parts outside of the chassis to do it. That Sammimo body made me think that a locost chassis can be modified to fit the body.

OH GOD. That Sammimo body plus an Alfa drivetrain sounds like sex on four wheels.

Keith
Keith GRM+ Memberand SuperDork
1/20/12 1:48 p.m.

Aluminum vs iron weight comparison: the LS1 aluminum block weighs 110 lbs. The equivalent iron block is 175 - numbers according to Car Craft. So on that big engine, there's a 65 lb advantage to an aluminum block.

I just weighed a bare iron 1.8 Miata block. 68 lbs (!). Assuming the same percentage of weight saving, you're looking at 43 lbs in aluminum. So you'd knock 25 lbs off with an aluminum block.

alfadriver
alfadriver SuperDork
1/20/12 1:58 p.m.

Well, one data page has the 1600 at 261lb. But I'll have to find a decent enough scale to weigh the engines that I have.

kevlarcorolla
kevlarcorolla Reader
1/20/12 4:44 p.m.
Teh E36 M3 wrote:
kevlarcorolla wrote: There's no way a 4ag based locost is going to be 950lbs.My R1 powered scratch built track car was 927lbs in this pic,its much smaller than a locost and the engine and trans weighs 150lbs combined.
Yeah, but look at the tubing you're using- looks like 1.5" .083 at least? That E36 M3's heavy- strong, but heavy (very cool car by the way). I don't have anything to back up the guy's claim, and honestly can't remember where I saw his car, pictures, and his claim (maybe I should run for president with a memory like this), and have no frame of reference, as I haven't built a car like this. I'd love to shoot for 500kg's with a car engine- something between a bike and car engine would be great- I love a frantic engine.

Your right its 1.5" tubing which I wanted to use mostly for my protection at track days,plus I hate the look of a square tube chassis.My car was built to a budget,so miata uprights and diff were used and no exotic bits.My car is alot smaller than a typical locost,uses a bike engine and nothing extra and it still barely makes it under the 1000lb mark.Building a 1000lb car engine based build WILL require some serious money to be spent unless you the ability to build everything yourself from lighweight materials. My car lost some weight over that pic with the keizers and slicks and could lose some more with wilwood calipers(which it seems are next to impossible to fit under 13" wheels it seems) but then I added some big 'ool wings front and rear so that weight went back on.

kevlarcorolla
kevlarcorolla Reader
1/20/12 4:45 p.m.

In reply to kreb:

The car or swift based engine??.

Keith
Keith GRM+ Memberand SuperDork
1/20/12 5:36 p.m.
alfadriver wrote: Well, one data page has the 1600 at 261lb. But I'll have to find a decent enough scale to weigh the engines that I have.

The difficulty with data pages is that they rarely measure the engines in the same form. Does the engine have a flywheel, accessories, throttle body, fuel system, crank damper, etc. That's why I concentrated on the one basic difference between similarly sized engines with blocks from different material. I figure most of the rest won't vary dramatically for a given displacement, as the parts will be similar materials and dimensions.

kreb
kreb GRM+ Memberand SuperDork
1/20/12 6:54 p.m.
kevlarcorolla wrote: In reply to kreb: The car or swift based engine??.

The car

kevlarcorolla
kevlarcorolla Reader
1/20/12 9:39 p.m.

Sorry can't seem to attach the link,Search "home built,bike engined autox toy".

geek49203
geek49203
1/20/12 11:43 p.m.

Just to lend some perspective here, the new 2012 Indycar will weigh about 1380 pounds total, of which at least 212 pounds will be in the motor (rumor has it that the current motors in testing are closer to 250). The new motors (2.2L) are supposed to be making about 575 hp.

Now... without getting into the typical flame wars that have surrounded Indycar for decades (or being accused of being off-topic on my first post here), let me suggest that perhaps trying for sub-1000 pounds with car motors (assuming 200 hp or more?) is a great engineering exercise, perhaps it won't be "locost" and maybe just a bit much for a fun drive?

Zomby woof
Zomby woof SuperDork
1/21/12 8:29 a.m.
kevlarcorolla wrote: Sorry can't seem to attach the link,Search "home built,bike engined autox toy".

Here's the link.

http://grassrootsmotorsports.com/forum/grm/home-builtbike-engined-autox-toy/39878/page1/

Kevlar, your car has me inspired. I've been looking at it for months.

My retirement project was going to be a tube chassis kit car, probably a Becks Spyder, but I like the look of your car so much, I might actually use the look for my own version. Probably Swift GT powered, of course.

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