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Learning how to build Lotus Seven replicas...together!
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PostPosted: Wed Jun 23, 2010 11:09 am 
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Location: Alberta, Canada
If one was really going to do an awd the one to use would be a Lada Niva. Really! I have one and its darn near perfect - everything looks pretty light weight. The diff is full time 4wd with the user selectable transfer case diff lock. On the Niva the front diff hangs off the oil pan but it looks like you could easily move it in front of the motor for a Locost and the driveshaft would run next the the oil pan. If you didn't like the 78hp or so the Lada motor puts out then a Fiat twin cam bolts up to the transmission. The rear axle is very similar to the British Ford as used in the orig book but with aluminum drum brakes. Its even got nice looking a-arms at the front that might be usable and 3 pot, progressive brakes on the front. Might be a hassle sourcing one in the US but still some kicking around Canada. Doesn't have rack and pinion though but close to an all in our donor.


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PostPosted: Wed Jun 23, 2010 12:39 pm 
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Location: san francisco bay area
krepus wrote:
So from what I'm gathering of the info given, you can use the same parts from a 4 wheel drive vehicle to make an all wheel drive vehicle? Using limited slip/open diffs instead of a posi/locker?
I think what I'm hearing is that, essentially, the systems are the same, but the diff(what's inside it) is what makes the difference... So a limited slip in the rear and an open diff or limited slip in the front would be all wheel drive?


at its most basic, sort of. the awd transfer case is another differential splitting the powerflow between front and rear instead of side to side and subject to the same requirements and constraints as a front or rear axle. the difference is the drive input is inline with the outputs instead of perpendicular. 4wd may but does not neccessarily have a center diff, aka 4wheel lock in jeep parlance, some of them are even all gear systems and ridiculously strong. problem is, with no center diff you have to rely on tire slip to make up for rotational speed differences front to rear and so its a lot harder on the drivetrain components as the torque gets shifted about twisting on things with nowhere else provided to absorb it. not something i recommend for hard surface driving. i've witnessed flamewars galore over this very subject so be warned opinions are like as$$$$$$ on what the exact differences are... but that front outside tire IS going to rotate at a different speed than the rear inside.

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PostPosted: Thu Jun 24, 2010 9:19 am 
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15 years ago there was a pretty radical hot rod called QuadraDeuce that had AWD.

http://www.ffcars.com/forums/showthread.php?t=94471

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PostPosted: Thu Jun 24, 2010 11:35 am 
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i had forgotten about that thing. zooom! 8)
having all 4 tires pulling means more surface area to transfer power to so your 60 foot times drop and cornering takes on a whole new meaning when your front wheels are pulling you around the corner vs being pushed around one by the rears. i can just imagine washing out all 4 due to averapplication of throttle :shock: i like the idea of awd and if you built front engine/primarily rear drive as a rhd vehicle you should have the room to run a front propshaft with a bump in the passengers floor. chevy makes a pretty nice 7.5" aluminum housing front axle for ifs, i imagine that you could cut down the right side housing and shaft pretty cheaply. heck it might even work for the rear if you can fit the short shaft and housing on both sides, i never checked.

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PostPosted: Fri Jun 25, 2010 9:31 am 
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oldejack wrote:
4472, borg warner?? you must really like the heavy stuff, the 1372 is lighter and its still a heavy pig.



From what I've researched, the 1372 and 4472 are essentially the same animal sharing most parts in common (the main difference being the output splines on the 4472 are 32 vs 27 in the 1372. The viscous coupler is also different giving different torque biases but is physically interchangeable.

It took me awhile to understand how it worked (not sure I do completely yet), but it appears that the planetaries in the 1372/4472 act much like a differential, but the torque is biased to the rear.

The viscous coupler acts much like a traction enhancing device in a differential (positraction, torsen, etc.) in that it will lock the front and back together when there is slippage between the two, but it isn't involved in the torque distribution.


There's an even heavier-duty (and likely heavier) NVG149 AWD case that is in Escalades and FS gm trucks/vans. Likely works on the same principles, but has been essentially bulletproof in large V8 applications in heavy vehicles.

The big benefit of the 1372/4472 is it supposedly bolts up to a 4x4 T5 (even though it never came that way from the factory). The front axle on AWD s-10/t-10/Astros where the 1372/4472 was used is essentially the same as the 4wd axle, but without the ability to disengage as it is not necessary on an AWD drivetrain (and would damage the viscous coupler if allowed).

If you wanted an AWD box that bolts up to a manual transmission and is going to handle a moderate amount of power in a relatively light vehicle, then the 1372/4472 with a T5 is probably the simplest and cheapest way to go about it - the parts are in salvage yards all over the U.S. and are common enough that they can be rebuilt with standard parts from multiple vendors. The T5 and the 4472 both have their shortcomings in heavy vehicles or high-power vehicles with sticky tires because they "see" more loads that way.

Cool as it would be, and I'm new to the Locost world, I don't know how easily it would work in that platform, mostly due to packaging constraints. You can "clock" the case off the back of the trans (within reason), but there's not a lot of room to go down in the locost and going up just makes packaging worse.


If you were building a "street" locost, it might be worth raising the seats up or raising the whole chassis height, and AWD is a nice thing to have on wet streets and the extra ground clearance would be practical,. Are there a lot of locosters driving regularly in the rain? Anyone driving in the snow?


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PostPosted: Fri Jun 25, 2010 10:44 am 
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interestingly enough, but not locost here in the states, i was looking for a price on some r33 front spindles (thanks for the lead chris, found 2 sets to email about already!) and it seems to me that the nissan awd transfer case used in the skyline/gt-r would work pretty darn well. hydraulically driven clutch packs, right side front propshaft, centered rear propshaft and and an oem "midcase". tone rings on the ring gears can be used for data source and a pwm can cycle the electrically driven solenoid to achieve a variable power distribution rate on the fly. large diameter but what do you expect, theres a chain drive in there. i wonder if the midcase could be swapped onto a tk-5 (nissan sourced) out of an rx7? 9k rpm 255 hp AND awd in 1500 lbs of car :headbang:


:?: why do i keep talking rotary power when i'm planning a ford v6? :?:

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