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.
_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS
viewtopic.php?f=5&t=13225&p=134742Simple Spring select
viewtopic.php?f=5&t=11815LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12