Grassroots Motorsports

Register Log in to GRM
- Community

Birthdays
Recently on the Classic Motorsports forums

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Login to post Forums » Grassroots Motorsports » straight axle locost, why not?

1 2

Oct. 19, 2009 4:10 p.m. oldopelguy Dork

So staring at a defunct Samurai chassis the other day got me wondering about just how bad would a straight axle Locost really be. Particularly when the axles are reasonably light, can be coil spring suspended, and allow the option of AWD.

Thought process goes like this:

-Samurai axles at both ends, deep gears (pretty common) and pinions offset on both axles to the passenger's side of center about 8" as standard -Standard 40" Locost frame, tranny tunnel offest to the passenger's side to line up with axles and allow for big guy driver (me) -Motorcycle engine and trans installed centerline of car, chain over to a differential mounted between the front and rear driveshafts to allow for AWD. -Probably suspension on both ends with an A-arm to the center bottom of the axle and a couple of parallel arms up top. Forced low roll center and easy to set up. -No need for much body work past the axles, not structural anyway, so easy light construction.

Pretty much an AWD midget racer, bodied stylisticly like a Locost. Any reason not to try it?
Oct. 19, 2009 4:29 p.m. Brust Reader

Yes. No.

Do it!

Dpcars.net for the DP1 design process- chain driven AWD lightweight for some inspiration- for track use I think the solid axles will be fine. Think about cushman axles for super light weight.
Oct. 19, 2009 4:36 p.m. Appleseed Dork

Wouldn't a strait axle LoCost be a lakes modified? Not a bad thing. You can have a hot rod and a sports car all in one.

See?
Oct. 19, 2009 5:28 p.m. Toyman01 HalfDork

Build it!!! Must also have a build thread with lots of pictures. Then write a book and become famously wealthy! Please keep the book price low enough for us mere mortals can afford to buy one. Thanks in advance.

Seriously does sound cool. Doesn't the Sammy use solid axles on both ends? Might be a problem with getting the camber set on the front. How about a Suby drive train. 300hp + AWD + Locost = awsome!! Build it!!
Oct. 19, 2009 5:38 p.m. Dr. Hess PowerDork

The Lotus Mark II was straight axle in front. Elevens were still solid rear axle.
Oct. 19, 2009 5:40 p.m. donalson UltraDork

stretched sammy frame with an MGB body sitting on top... and body covered with denim (yes jean material)...
Oct. 19, 2009 6:36 p.m. RossD HalfDork

This comes up on Locostusa.com all the time; people want an AWD locost. I for one would love to see it and would love to see how you get around the different inherent problems. So go ahead and build one!

On the other hand, do you really need AWD? Wheres one of our resident locost drivers to chime in?
Oct. 19, 2009 7:16 p.m. Keith PowerDork

This is too hard to do with AWD

It would be fun to do for a problem solving exercise. It's not quite in the whole "add lightness" realm, but I'd love to see it done.
Oct. 19, 2009 7:25 p.m. dyintorace Dork

I'll admit upfront that I don't know what I'm talking about, but here goes.

Could you start with a complete 323 GTX and use it as the basis for a Locost?
Oct. 19, 2009 7:31 p.m. Ian F HalfDork

Umm... a locost with a solid front axle... isn't that an old Jeep?
Oct. 19, 2009 7:51 p.m. JoeyM Reader

Dr. Hess wrote:

The Lotus Mark II was straight axle in front. Elevens were still solid rear axle.
I think stalkers are solid rear axle...
Oct. 19, 2009 8:00 p.m. cghstang New Reader

In reply to Ian F:

"...Enzo Ferrari later described the Jeep as 'America's only real sports car'...

from: http://ww2db.com/vehicle_spec.php?q=243 and http://www.4wheeloffroad.com/featuredvehicles/off_road_review/index.html
Oct. 20, 2009 12:16 a.m. mainlandboy New Reader

Given how narrow the Samurai axles are, you'd likely have to stick to a "book" sized chassis which is 40" from inside to inside. Assuming your tranny tunnel is about 6" wide and offset to the passenger side 8" to line up with the offset differential, that only leaves room for a 9" wide passenger seat, so I'm assuming that this will be a single seater!

As the Locost chassis tapers towards the front, things get pretty tight for space and it would be quite difficult to package a differential/transfer case in there.

With a solid axle at both ends, I wouldn't expect any miracles in the handling department!

My 2 cents, Mark
Oct. 20, 2009 12:23 a.m. SkinnyG Reader

mainlandboy wrote: With a solid axle at both ends, I wouldn't expect any miracles in the handling department!

Me neither - I'd be counting on them.
Oct. 20, 2009 7:28 a.m. Ian F HalfDork

cghstang wrote:

In reply to Ian F:

"...Enzo Ferrari later described the Jeep as 'America's only real sports car'...

And... ?

My point is by the time you add the transfer case & front drive axle and lift the chassis high enough to clear said components, you will basically have an old Jeep... only probably not as good... Sure, you can slap wide, low profile tires on it (...and early 90's memories of Samurai's running around with 13" 50 series tires come to mind... screaming down the hwy at 50 mph when the speedo probably said they were doing 80...), but it's still going to have a rather high center of gravity... and handle like poop.

I'm no stranger to silly ideas (my head is full of them), but I really don't see the point of this one... unless you're building a rock-crawler...
Oct. 20, 2009 8:21 a.m. klipless New Reader

Keith wrote:

This is too hard to do with AWD

How'd you know? That's not even you driving!
Oct. 20, 2009 9:10 a.m. mw Reader

If anything, I would use the front diff and shafts from a sidekick so you can have ifs. I still don't know that it would be something you would be happy with once it was finished.
Oct. 20, 2009 9:16 a.m. kreb Dork

LocostUSA has a huge thread about AWD locosts. The subbie has the engine ahead of the front axle. There are a few cars whose layout facilitates AWD - the BMW 325ix, Toyota Previa, the british Sierra....all hard to find. i don't know enough about the Samurai to lend an opinion on that specific model, but would suggest two things:

-The traction benefits of AWD in a high speed car are questionable relative to the added weight and complexity till you get over 200 HP or more.

-If you stretched the chasis a bit, you could position yourself so that the rear wheels are in back of you, not next to you. This will allow added width in the passenger compartment - possibly enough to allow for a transfer case.
Oct. 20, 2009 9:31 a.m. MrJoshua UltraDork

E36 325iX prices are low right now! I like the Sammy idea if you are looking for a single seater. Does the transfer case go straight out or slightly down?
Oct. 20, 2009 5:23 p.m. thatsnowinnebago Dork

What if you just put the chassis below the axles? Sorta like a body lift, just in reverse. That way you can keep the low center of gravity. I'm sure it would look ridiculous with the super tall shock towers but that's the price you pay for something as cool as that.
Oct. 20, 2009 6:50 p.m. oldopelguy Dork

Of course the body will hang below the axles, actually between them as well for the most part. Built like a Locost where the driveshaft goes through a tunnel, just with another one going to the front axle. The offset tunnel allows the weight of the engine to be more centered in the chassis instead of all the engine weight on the same side as the driver.

I actually wasn't going to run a transfer case, just a differential between the front and rear driveshafts with a chain drive to it off a sideways mounted motorcycle engine. Think Bezerkley diff and engine turned sideways.
Oct. 20, 2009 6:56 p.m. MrJoshua UltraDork

Do you have a diff in mind? I think all of my calcs for a center diff like I think you are describing had something like a 60mph top speed.
Oct. 20, 2009 7:19 p.m. Appleseed Dork

thatsnowinnebago wrote:

What if you just put the chassis below the axles? Sorta like a body lift, just in reverse. That way you can keep the low center of gravity. I'm sure it would look ridiculous with the super tall shock towers but that's the price you pay for something as cool as that.

Google "underslung." It does exist.
Oct. 20, 2009 7:31 p.m. oldopelguy Dork

My first cut at the dif was to use a VW air-cooled one, unbolting the ring gear and replacing it with a chain sprocket. Since the dif mounts to a case via side plates on both sides, all I really need to do to locate the bearings and such is provide two parallel surfaces with the appriate bolt holes. Pretty much a box with holes drilled in the end for the chain to come ou of and go back in through and a couple big holes on each side to bolt the VW side plates to. I figure I can either pack it with grease or just seal the chain path and fill it with oil.

I can't think of any reason it wouldn't hold up to any speed the drive shafts hold up to. The tapered roller bearings aren't really any different on the pinion than they are on the sides.

Altenately, it might be as easy or easier to use a chain driven full-time 4WD differential from the output part of a transfer case. Something like the full-time 4WD full-sized Wagoneer. Already driven by a chain and set-up for the speeds and loads, it would just require building the right kind of housing.
Oct. 20, 2009 7:59 p.m. MrJoshua UltraDork

2 bike motors , one aiming forward, one aiming back, driveshaft coming off of each motor. No center diff needed!

1 2

You'll need to log in to post.