Whipple/Roush 5.0: 3.31 vs. 3.55 (vs. 3.73)? RWD vs. 4WD?
 

I've owned 3 Ford F-150s in a row with the 3.73 rear end. And I've already read in the archives that because of gearing, first gear on a 10R80 with a 3.73 is really more like first gear when running a 4.19 rear end on 6R80.

https://cimg7.ibsrv.net/gimg/www.f15...302700c50a.jpg


That being said, what gear set does everybody recommend for a supercharged 2018 5.0 crew cab F-150? And does everybody fall into the "with this much torque, 4x4 is a must" camp, or are there some of you with RWD trucks? In case it matters, here are my own specific needs:

• Want a reliable daily driver. If the most aggressive gearing will immediately exceed the engineering limits of components, I'm not interested if it will leave me stranded on the side of the road with my family.

• Not going racing. Don't even care about bragging rights.

• Not towing (but will haul stuff in the bed occasionally)

• Will not install oversize tires (but will replace stock wheels with 22" ones and better rubber with same rolling diameter).

• Will probably install traction bars. I may not care about racing, but I don't like axle hop either.

• Don't care about MPG, at least at current fuel prices (I drive a 6.2 right now, so anything will be an improvement). I will take long distance road trips though, so I don't want too much cabin drone from cruising at excessively high RPM.

• I don't need 4WD where I live, and I actually prefer the simplicity (and rake, less weight, and no risk of IWE/transfer problems?) of 2WD. But I would consider a 4x4 if that's the only way to put all the power to the ground (seems like most folks recommend launching in 4-HI?). Or if from a safety/reliability standpoint, it's better to have 4WD because that's less strain per axle. But again, I could care less about 60-foot times, and got used to rolling on the throttle in my modified Gen 2 Lightning (RWD only).

So what does everybody recommend for my application?

Is there a particular combination or setup to avoid?

With your "wants"...... 2WD and 3.31s - the close and steep gearing of the 10R80 wont have you missing the 3.55's

4X4 is cool for hard launches, but you wont use it much and just more crap to break in the long run. If you were big into racing or stomping on Vets and Hellcats off the line at a red line, then 4x4 would be worth it, if you just want the kick in the pants acceleration flooring going up the freeway on ramp, then dont waste the money on it.

I can't make sense of why you are considering supercharging a truck from your post? If you don't race and don't want bragging rights, I don't follow.

Not trying to pick you apart, but taller gears are harder on a drive train. 3.73 will stress driveline components less, not more.

4wd 3.31 gears for a Whipple or Roush. Once you add one of those superchargers it will be equivalent to a Lightning with a stock engine and all the mods you can throw at it including an aftermarket supercharger if that gives you a reference point. It will light the right rear at 60 mph in 2wd. 4WD with this setup is worth every penny. Anytime you want to launch hard on the street it is no problem and the launch is amazing. You won't regret buying this setup.

I remember you from some of the old Lightning forums.

My truck is pretty mild compared to some on this board, 2016 5.0 Roush 2.3, 75mm pulley, and a custom tune, probably around 560whp (dyno soon) with 3.73 gears. Its a regular cab shortbed 4x4 with 295 section width summer tires and an E-locker axle, and from a dig in 2wd if I roll onto the throttle hard (no launching) it will completely shred my tires through 1st and 2nd. If I romp on it from a low speed roll it will shred the tires in second and will continue to spin them on the 2-3 shift. I've even spin tires on the 3-4 shift. I have the 6r80, so I can only imagine shorter gearing with the 10r80 would be even worse.

There is simply not enough weight at the back for any sort of traction, and these trucks are so light the performance level is really high. I was hard on the upgrade path and had it all planed out for the rest of year, but after going with the 75mm pulley and finalizing my tune with Matt at ID Motorsports I discovered its too fast for the tires and can be a little hairy on the street in 2wd if I'm not careful with the throttle.

All that said, 4x4 launches are a religious experience that can only be compared to Dr. Brown and Marty taking a ride in the DeLorean. I've been in and driven faster cars, but this is a truck and going that fast and pulling that hard, while sitting up so high off the ground, cannot be compared to anything else. So don't deny yourself the experience of a 4x4 launch, even if you only use it a few times a year.

So my answer to you is 3.31's with 10r80, and 4wd for the times when you want to peel your eyelids back. With 3x31's you'll do a better job of putting the power down in 2wd, and the gearing of the 10r80 means you are not really giving up the gearing advantage.

I'm a bit surprised that guys aren't choosing stickier rubber to help with the traction issue rather opting for taller gearing. Sounds backward to me.

Me too