messing around with a frame design and with the required width for a horizontal honda engine is wider than i would want for a single seat car and I was wondering if the great minds here think something like one of these orientations could be possible to make a poor mans transaxle and save the 5-10 grand needed to buy (insert brand) used one vs 1000 dollars at the junkyard for the honda motor/tranny + a rear diff + me machining the connection parts...
The driveshaft/axle assembly is from another project and is longer than intended
Thoughts or has anyone seen something like this before?
The connection may need a reversing gear, i think how i have this model its going to be 6 back 1 forward but that could be addressed..
(this orientation may be backwards)
buzzboy
UltraDork
4/18/24 7:56 a.m.
Your plan involves two differentials and therefore a final drive ratio of probaly at least 6:1. That is the limiting factor of this idea.
In reply to buzzboy :
It has been done with reasonable success for mid engine dedicated rock crawlers over on Pirate 4x4, just not a good combo for the more street/race stuff here on GRM
like the others have said having double diffs really create too much gear ratio for decent street use unless you plan on running giant diameter tires. Just adapting the K20 to a rwd trans would accomplish your goal and save a lot of headache
No Time
UltraDork
4/18/24 11:19 a.m.
Probably lacking in strength, but aren't some of the rear diffs in fwd based awd systems a 1:1 ratio?
I think the real solution to this problem is an Audi transaxle. Or maybe Subaru. Porsche if you want the Audi one and like spending money.
cyow5
Reader
4/18/24 1:14 p.m.
It would take some fab, but I think there's room - what about 1:1 chain drive inside the transaction in lieu of the diff final drive? Essentially a transfer case?
kb58
UltraDork
4/18/24 1:28 p.m.
To the OP, what's the end use for the vehicle? Does it have to meet rules? Do you have a specific wheelbase and track width as a design requirement? If this is a "I wanna do what I want" car for trackday events - which I totally get - I suggest leaving the drivetrain as-is and using the wider underbody for downforce. Check out my signature for building a mid-engine "Seven".
kb58 said:
To the OP, what's the end use for the vehicle? Does it have to meet rules? Do you have a specific wheelbase and track width as a design requirement? If this is a "I wanna do what I want" car for trackday events - which I totally get - I suggest leaving the drivetrain as-is and using the wider underbody for downforce. Check out my signature for building a mid-engine "Seven".
Hey, it would just be a track day toy with no rules. Ive been working on car design and i was playing with the idea of drafting up a low budget/ low hp enviate type hypercar as a break. Bike engine is an option but the drive train is obviously a weakness, but transaxles kinda ruin the low budget aspect. Might as well just get the pdk/htg gcu combo and go for it at big dick bandit style
was curious if anyone had made something similar. The effort likely isnt worth it vs finding a good deal on a 3500 tranaxle on ebay or getting lucky at a junkyard and hoping it doesnt need another 2000 grand in parts
realistically i could make a little wider frame/ shorter wishbones considering the change in camber gains is pretty negligible if i wanted to go with a transverse setup
ill check it out your seven build!
Take a look at dpcars.net if you haven't already. Might be some interesting ideas for you.
kb58
UltraDork
4/20/24 9:52 a.m.
In reply to Keith Tanner :
I've met Dennis (the DP in DPcars.net) through his interest in my Kimini build. One time I told him, "You and I are at opposite ends of the budget pool; me being at the shallow end!"
To the OP, yes, the cost of a "real" transaxle sank my many ideas for crazy builds as well. While there are numerous units that kinda/sorta/maybe might work, being unable to romp on it occasionally without worry would be forever disappointing.
I often thought about this. How long would the differential in the transmission last if you just locked the unused output? That would effectively cut the gear reduction in half, so a 3.42 final drive would now be a 1.71. Paired with a smog-era highway ratio in the final drive like a 2.73, that gives you a 4.66 reduction overall.
In reply to Curtis73 (Forum Supporter) :
I can tell you that a G5M transmission will last about a quarter mile of spinning only one tire under load.
There are no bearings in the differential itself because they aren't meant to see much relative motion, and the inherent friction adds a small amount of limited slip effect.
To the OP, depending on your fab levels, you MAY be able to do something with a transverse trans that has a very tall final drive and a set of 2.21 gears from a Ford 9" or Chevy 10-bolt. You'll still have a final drive in the 5+ range. Alternatively, you could use a quick change setup (more $$$) to get the rear drive under 2:1 if you can find some 3.78 ring and pinion gears.
Personally I'd keep it transverse. There is a lot of heat generated in hypoid gears from all the friction, this means lost power. Also, it's cheaper this way 
A well engineered suspension link setup should be able to net you a good set of long lateral links with a transverse layout. The laterals can go behind the engine and trans, as can the toe links.
