Posted by Desoto61 [138.162.0.43] on Friday, March 27, 2015 at 06:32:42 :
In Reply to: Re: Increase road speed posted by Dean [75.54.236.188] on Thursday, March 26, 2015 at 23:39:00 :
It's all a tradeoff, gearing just allows you to trade speed and torque. The problem is most small diesels are stuck with gas transmissions, which just aren't designed well for the way a diesel makes power.
The best way to get more road speed is to have more gears, and they can be taller than in a gas engine because you have more torque low in the power band to turn them. I.e. your gas engine probably wants a normal cruising speed around 2200 RPM, while most diesels will want to be at least a few hundred RPM lower.
Problem is since gas engines are so much more common most transmissions are designed around their power band for light duty vehicles. That's why an 18 wheeler can do the same speeds you can, they just need about 3 times the number of gears to make it happen.
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