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Login to post Forums » Grassroots Motorsports » 4wd Geo RallyCross Bad Idea

March 8, 2011 2:21 p.m. cghstang Reader

Some of my days are slow enough that I can get away with thinking bad ideas a bit farther through than I really should.

This particular bad idea involves the following: Yamaha R1 engine (with close ratio sequential 6 speed) Suzuki Samurai transfer case Miata rear and Sportage front differentials Long travel double wishbone suspension at all corners with miata rear uprights and sportage fronts and to top it off, a 95+ Geo metro shell with tubular chassis underneath, driving position moved nearly to center.

Like so...

Ideally built initially on a challenge budget with a cheapo superbike 4cylinder, 1500lbs max. Geared for a top speed around 90. Yes, it would have a locked center diff when in 4wd, but could also be driven in 2wd. Will I ever build it? Not likely. Would it be awesome if it worked? I think so.

So what do you think, is it even feasible? Would the R1 powerplant have the gusto to spin all four in the dirt? Would it's transmission puke its guts out?
March 8, 2011 2:25 p.m. pres589 HalfDork

Completely wrong engine, trans not up to what you want of it. The Suzuki G whatever 1.3 out of the Swift GTi seems like a good compromise and you don't have to recreate the wheel trying to connect this all mechanically.
March 8, 2011 2:25 p.m. Bobzilla Dork

why not just snatch an asian market Swift AWD setup?
March 8, 2011 2:29 p.m. pinchvalve SuperDork

Hayabusa + Samurai = Done.
March 8, 2011 2:31 p.m. cghstang Reader

The close ratio transmission and ability to put the whole shebang behind the driver is what makes this idea appealing in my head.

The transmissions hold up to some degree in locost 7s. Why not here?

pinchvalve wrote:

Hayabusa + Samurai = Done.

For a more crude version, yes I agree completely.
March 8, 2011 2:36 p.m. pres589 HalfDork

I can't see images here so if the mid-rear engine mounting was part of that, I apologize, work firewall stops that kind of stuff.

I think you're talking about a lot more driveline weight & inertia; when you drop throttle on an R1 you have a non-heavy wheel and tire, a light hub, and some chain to fight engine breaking. You're talking about a whole pile of parts beyond that. And you're talking about a lot of traction, at least in theory, this should stick like honey. I don't think the R1 trans is going to like any of this.
March 8, 2011 3:46 p.m. Zomby woof Dork

I don't think any bike motor would be best for that application.

Put a 4.3 in a Tracker/Sidekick, and smoke everybody.
March 8, 2011 3:53 p.m. Tom Heath Web Manager

cghstang wrote:

The close ratio transmission and ability to put the whole shebang behind the driver is what makes this idea appealing in my head.

The transmissions hold up to some degree in locost 7s. Why not here?

The stress of a heavier car (probably) combined with two additional driven wheels would be my concern. Not saying it's impossible, but it's sure to be more stressful on the driveline than a 7-type car.
March 8, 2011 3:55 p.m. pilotbraden HalfDork

At least put on a dry clutch kit so you can change clutches between runs.
March 8, 2011 4:05 p.m. mndsm SuperDork

^ that. A bike clutch would E36 M3 itself the minute it caught a whiff of a t-case and front and rear diffs in a car application. Though I wonder if using a modified 4-wheeler setup would work. I don't know what's on the market for those, but i've seen some silly things done to those and their side by side brethren, to make me think it might be possible if you used quad parts.
March 8, 2011 4:06 p.m. MrJoshua SuperDork

This has run through my mind many times. Here's a decent recipe:

-Complete Miata rear subframe/diff/axles/etc... in rear.
-flipped Miata or similar diff mounted up front with axles to mate to Geo hubs.
-1 600cc sportbike motor with driveshaft adapter on bike output shaft with driveshaft to rear diff.
-1 600cc sportbike motor with driveshaft adapter on bike output shaft with driveshaft to front diff.

Both motors fit where the back seat used to be with one aiming forwards and one aiming backwards. They are easy to convert to cable shift. Only issue is no reverse, but who cares.
March 8, 2011 6:54 p.m. kevlarcorolla New Reader

The only way to make this viable in my opinion is forget the engine behind you,looks like lots of room in your drawing but I have both a '96 geo and an R1 engine in my other car and I don't think it'll fit. Using complete car diffs will be way to heavy not mention way to wide for a geo track width.Toss the passenger seat,place the engine transverse in its place.Run a jackshaft off the countershaft using a hawk machine adapter to allow the use of a u-joint,run dual spockets outboard of the engine,build a couple chain driven diffs,mount as desired and feed chain to them. Presto,one awd swift.Run new yamaha friction plates and heavier springs from barnett and the clutch will last awhile as long as you don't abuse it.

2 engines don't make sense,too heavy combined so run use one with boost-bike engines love boost so have at it.
March 8, 2011 7:04 p.m. MrJoshua SuperDork

In reply to kevlarcorolla:

at 150'ish lbs each for bike motors and trans, I would hardly call 300lbs for ~250hp heavy. The bonus is that 600cc motors can be had for around $500 complete.

Yet another edit-It did just dawn on me that I may have different versions of light than a guy who made a tube frame Kevlar Corolla.
March 8, 2011 7:53 p.m. kevlarcorolla New Reader

In reply to MrJoshua:

Your right 300lbs for 2 engines and transmissions AND 250hp is very light.One engine and boost for the same 250hp will be over 100lbs lighter however.

My corolla was a cool car(bought by a drag racer-ack.....but apparently just bought for drifting so that at least involves corners)but my new car blows it away in every catagory.

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