# Help! Warp 9, sub 2100lbs car, ??Direct Drive??



## madderscience (Jun 28, 2008)

I would start by fixing the design you have, and then seeing how you like it. I personally would love to do something similar to what you have done with a 4wd toyota hilux at some point. Keeping the xfer case is a good compromise between full-on direct drive and retaining the main gearbox as well, and could be handy in a vehicle that might sometimes get used offroad or for pulling something.

Once you fix the design, you can monitor motor temperature as you are driving normally, and if you are seeing excess temperature you can then adjust the diff ratio, or depending on the transfer case you have you may even be able to change the ratios within it. 

Instead of going to 2 motors if you can't get a single warp 9 to run cool enough, upgrading to a single warp 11 would probably do it and would probably be less effort and similar cost (presuming you sell the warp 9 to recoup some cost) vs. going to dual motors.

As for computing ideal diff ratio, Figure what your maximum typical speed will be, and work backwards from tire diameter and raio to a number somewhat under the warp 9's max rpm value. For example if you want no more than 5000 motor rpm at 65mph, and you have 24" tires, you would want a diff ratio no higher than about 5.5:1. That is a pretty high ratio, but you can find 4wd diffs for some vehicles, like toyotas, in that ballpark. The diffs you have now are likely 4:1 or so. It is very likely there is a 4.7:1 ratio available, if nothing else, for your samurai.

Another thing you could do to combat motor heating issues if it is not too severe is add forced air ventilation to the motor.

Once everything else is sorted out, change to full synthetic, NON-llmited slip gear oil, such as redline superlight, in the xfer case, and also in the diffs (unless it is a limited slip, in which case use LSD compatible synthetic gear oil in there. If it is a part-tiime 4wd system hopefully it has locking/freewheeling hubs on the front axle, that will improve efficiency a lot when you don't need 4wd.


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## mizlplix (May 1, 2011)

I am running direct drive in my 1,900# car, but it is an AC system. I have a 6.14 rear gear and sufficient top RPM to go 65 MPH. All is happy. (I could go as low as low as 9:1 and still do my job due to my top RPM.)

Now, your system is DC: you do not have the RPM like I do but the principle is the same.

Figure out what top speed you can get by with.....Tire and gear the car for that and that only. It will give you the best power gear you can get and still get up to speed. You might think about a forced air blower through the motor to help brush temps.....Just a thought. It is going to depend a lot on your terrain and how flat it is.....flatter is good.

Miz


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