From me to mike @ www.f150lightning.com

"How does the Independent Rear Suspension on the lightning do during launch at the drag strip? I like the idea of the IRS for handling but don't want to sacrifice traction at the drag strip.

thanks for the info
joe santana"

From mike to me

"Joe...I have not meant to put off your e-mail...I have been giving your question some thought.
With F-1s there is no noticeable difference. The rear squats more, which transfers more weight. It does this smoothly. However when the rear squats with this type of rear suspension it has a tendency to lift the outside edge of the tire. I am pretty sure that if this proved to be a negative thing that it could be adjusted out, for the drags...Just my guess.
This unit costs around 6000 so you need to be sure where your priorities lay, in case it is not the best of both worlds.....Mike....Lightning Performance"

 

An IRS can not transfer more or less weight. This is a function of rate of acceleration, center of gravity height and wheelbase. An independent will change camber with squat (assuming the upper a frames ar shorter than the bottoms and the tops are leaned down on the inboard end) This can all be designed out if you want to give up handling. The independent will always give both tires equel traction in all acceleration and braking. This is somthing that NO Ox cart rear suspension can do. The only reason that all drag cars use Ox cart or no suspension at all is a huge IRS capable of handling 5000 hp is at least a challange with u joints. Detroit uses them because they are cheep to produce. Remember that NO real racing Indy/F1/Pro Rally/Desert racing car with a huge budget and no rule problems uses Ox cart suspensions. Even rails give up and just weld the rearend to the chassis. Remember with 500 ft-lbs at the crank times somthing like 3 in first gear times 2 for the torque converter and you get somthing like 3000 ft-lbs of twist going down the driveshaft that the frame and springs are reacting to. Then the rear dif multiplyes by 3.6 or so and now you get around 10000 ft lbs at the axles and poof instant smoke.

Hope this helps

 

The ground torque from my recent Super-Flow dyno run was a little over 1700 lb-ft

 

J15Big

That is in third gear 1:1 ratio and the torque converter is locked up so you get 500 ft-lbs times 3.73 gears times .88 for drive trane loss = 1650 give or take a little

 

I have heard a few horror stories of Cobra's -n- slicks snapping halfshafts when launching hard. And we make alot more TQ then them.

I was always told that IRS is for handling and for very comfortable rides, not 1/4 mile racing.

 

captain, I have the same feelings. I hope it has some stout, chromemoly halfshafts. It's going to need them.

The problem with sqatting on the launch can be dialed out, but will need to be tailored, depending upon weight, available traction, and tire type.

It should be awesome for the road racers.

 

Then there are those of us who don't care about 1/4mi times but rather cornering in a twistie.

Daniel