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 Post subject: Re: Offset differential
PostPosted: April 3, 2014, 3:53 am 
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Joined: March 23, 2014, 8:50 pm
Posts: 7
Location: Chicago Burbs
Miatav8,MstrASE,A&P,F wrote:
Cool project.

I suggest a centered irs because:

The tunnel won't need to be much larger than the driveshaft since the driveshaft won't be moving up and down in it.
This will allow more vertical travel without binding and weird angles on the rear driveshaft ujoint in right rear bump.
Less unsprung weight; important ratio for a decent ride on the street in a feather weight car.
Yup.A centered IRS would be my utopia given enough budget,design help,build time hours,and enough room to slide the motor left enough to get the transmission output shaft to the centerline of the car.


RoosterBooster:
Thanks for the Speedway link.That is one sweet looking unit!
I could not figure out how to reply to your post.Something about not allowing more than two quotes.


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 Post subject: Re: Offset differential
PostPosted: April 3, 2014, 4:18 am 
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Joined: March 23, 2014, 8:50 pm
Posts: 7
Location: Chicago Burbs
nsxguy7 wrote:
I built a very similar set-up a few years back. I used a CBR 900RR engine and a rear end from a Corolla GTS (AE86). I got it from a yard in Louisiana for a whopping $125 and it even came with a CUSCO limited slip installed. I shortened one side about 7 inches IIRC. Very pleased with the results..
That was quite a value at a buck and a quarter!

I did a little more rear end length estimating.
The overall drum to drum will need to be about 43"
The left drum to drive shaft center line works out to about 28"
The right drum to drive shaft center line will be about 15"


FastG wrote:
Berke 1, I just removed a Totoya 8 bolt rear end from my car and went to a 1st Gen RX7 to get a LSD. But this would be prefect for you, you could cheaply change it so a spool setup. Id a very clean axle complete from drum to drum, I removed the 4 link brackets and moved them to the new axle. And guess what I live in the Western Burbs of Chicago.

PM me if interested.

Graham
Thanks for the pic and dimensional info!

Shorting the right side may be a straight forward machine shop operation?
Stretching the left to about 28" drum to pinion c/l could be an issue.

From a book I have,the dwarf car guy's are (or were) using the 8 bolt Toyota rear ends,but they specify "S" in the model code saying that the 20 other codes are not suitable.(I think he's talking about 8 bolt?) I have more homework to do to see it the one you have ("s"?) can have it's axles modified (or new made) for a reasonable cost.


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 Post subject: Re: Offset differential
PostPosted: April 3, 2014, 6:40 am 
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Berke 1 wrote:
Miatav8,MstrASE,A&P,F wrote:
Cool project.

I suggest a centered irs because:

The tunnel won't need to be much larger than the driveshaft since the driveshaft won't be moving up and down in it.
This will allow more vertical travel without binding and weird angles on the rear driveshaft ujoint in right rear bump.
Less unsprung weight; important ratio for a decent ride on the street in a feather weight car.


Yup.A centered IRS would be my utopia given enough budget,design help,build time hours,and enough room to slide the motor left enough to get the transmission output shaft to the centerline of the car.


Not really a cost difference. Still need to shorten and respline one axle for non-centered irs.
As far as design, You'd buy the subframe with the irs and all the suspension points are there. The right side suspension pivots are brought closer to the centerline of the car.
What I didn't consider was the extra room required for a non-trailing arm irs, which you may not have (i.e. the uca needs to be in the drivers back to put the wheel in the center of the fender arc).

The S code is the lighter duty axle with 8 bolts and a 6.38 inch ring gear which comes in ratios from 3.5 to 4.1:1.
The T code has a 6.7 inch ring gear and comes in ratios from 3.36 to 4.3:1.
Consider that the 20 or so other toyota axles are probably not suitable because they are heavier duty and not competitive.
Second and third digits after T or S provide the ratio.
02=3.36
05=3.70
07=3.90
08=4.11
27=3.36
28=4.30
29=4.10
30-3.727
37=3.585
38=3.417

The fourth digit provides the number of pinions and if open or limited slip
2=2 pin, open
4=4 pin, open
3=2 pin, ls
5=4 pin, ls

They have had problems with splines on the shortened axle twisting due to the rigidity of the short axle (can't twist/give a little with peak load spikes). The solution is gun drilling the axle so it can twist but that costs more and since you are not racing, it may not be an issue.

You may need to use a wider axle from something else if the toyota axle is too narrow from the pinion to the left drum face, which may require a longer new axle on the left side.

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 Post subject: Re: Offset differential
PostPosted: April 8, 2014, 4:33 pm 
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Joined: September 3, 2012, 10:48 pm
Posts: 336
Location: Hamden CT.
one of the cars I own uses a winters quick change rear solid axel and the motor is mounted on the longitudinal axis mid engine .
no drive shaft !
good luck on finding the mini winters rears used . I have also installed them in many other cars they are a great rear to use how ever the cost of buying one new could be over budget if your looking to go the low cost route ?
how ever if you do buy new it's well worth the cost . you would then order it just as you would want it . winters will work with you every set of the way .
I run a gsxr 1000 motor when you turn the motor side ways it's best to also change to a baffled oil pan . rill tech offers some very good pans that will handle the G's . I have also installed there paddle shift kits and they are great !

I tend to try and sell my customers on IRS over a solid setup .
there are so many + to them over installing out dated solid axels is not really worth spending just about the same money and getting some thing that will never work as well as irs.
I have been doing quite a lot of them using mazda rears .
used parts are low cost and parts are every were .
I don't use the mazda rear x-members them selfs I weld the tabs on the chassis and just use the measurements off the cross member . the mazda cross members are way to heavy just to bolt on as is IMO .


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 Post subject: Re: Offset differential
PostPosted: June 7, 2014, 6:39 am 
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Joined: January 9, 2008, 9:55 am
Posts: 3
Location: Hong Kong
Perhaps a little like this??

Yamaha R1 - forged pistons and rods
Rotrex Supercharger
Emerald ECU
Methanol Injection
200hp at the wheels

I had this engine in another car with a 3.4 CWP but it was not tall enough for the bike engine, so when I put it into this car we pulled out the Ford English Axle (tallest CWP available is 3.54) and put in a Winters 7" Quick Change

Magnesium casings
Alloy Axle Tubes
Gundrilled axles with floating hubs

This is only available with either a Spool or a Locker . We have put a Spool in to see how it goes, if it understeers too much we are going to adapt the TranX Plate LSD from the original Ford English Axle to fit in the Winters housing.

This car has only just been finished, unfortunately I havent had a chance to run it yet, will be run in the next couple of weeks

It was fast when I had it in the other chassis (560kg with fluids but without driver)...... this one is 100kg lighter so I am expecting good things from this on the track.


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 Post subject: Re: Offset differential
PostPosted: June 23, 2014, 10:15 am 
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Location: Pittsburgh, PA
Have you had a chance to try it?

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 Post subject: Re: Offset differential
PostPosted: November 12, 2014, 2:14 pm 
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Joined: December 11, 2013, 11:37 pm
Posts: 12
Location: Colorado
I used a 3 series BMW rear end and equal length live axles. Engine is an old gsxr 1100. The drive shaft runs at about a 6 degree angle. This is in a little roadster that used to be a Dwarf car. The old configuration had the drive shaft running along the right side of the car with a short shaft at the end of the drive shaft that was suported by pillow blocks. This final shaft was set paralell to the differential input shaft. The final drive then was with sprockets and a roller chain. I did it this way so that I could place the seat as low as possible in the car. Low CG you know. The pinion shaft sprocked was right behind the back of the seat. It was OK for racing but chain life was short. In the current configuration I'm sitting over the driveshaft. The seating position is now about 7" higher.


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