I can't speak from experience but I know that historically, the high altitude performance of the WWII's P-38's Allison engines improved significantly with the addition of forced induction! Even to the point where they went from a being relatively poor performing aircraft to becoming one of the most feared Allied warplanes in the Pacific theatre!

Without being an Engineer, common sense would conclude that increasing the air density into the engine using a turbo/supercharger would definitely increase hight altitude performance!!!

So to answer your question "Would a supercharger help with towing in the mountains?"
I'd have to say....yes! Is it worth the cost? ...that depends entirely on you and your financial situation!!

 

Reviving a dead thread.

Last year I upgraded the gears from 4.10 to 5.13 to pull my camper. About 3300-3400 lbs loaded. Awesome difference. The Jeep would get up to speed quickly and driving around the city was fine. On the highway, different story, the Jeep is constantly out of power, and 3rd or 4th gear at High rpms are required often. I live in the foothills and camp in the Rockies, so big long hills are a fact of life around here. Overall the gear upgrade was well worth the money.

1 year and 1 Christmas bonus later the Jeep is supercharged. I thought I would like to do something about the insane high rpms required to pull up hills and maybe some power to more easily maintain highway speed. Around town this thing is now amazing, the combination of the low gears and supercharger really gets the Jeep while towing up to speed; wasn’t really what I put it in for but that is ok. On the highway the result is marginal. I am able to use higher gears, so I did reduce the rpms required to tow, but overall the speed is only up slightly. I was disappointed and can only take comfort in the fact that while at highway speed I am at 3000-3500 instead of 4000-4500. You would think somehow that if you used lower gears (like 3-4th like I used to) instead of 5-6th like I do currently that it would result in more power up the hills. However it is not the case because if you shift down too much, the rpm is too high and the speed can not increase any further, and it is a speed that could have been reached without the supercharger.

So the verdict. I would not buy a supercharger simply for heavy towing, lowering your ring and pinion gear set is the best bang for your buck. It changes the low end, where you need the power to accelerate the vehicle from a stand still. You will drop your rpm but burn as much gas. Mileage before the SC 9.6 mpg, mileage after sc 9.5 mpg (mountain driving, 65 mph).

Although I bought the sc for towing, it is much more impressive when it is not towing. When combined with the low gears, the jeep feels like a v8. Would I buy it again? Not sure. Would I take it off now that I own it? never.

 

Update,

I had some trouble towing on the last trip out. Not much for hills just flat, windy and hot. 91 deg, and overheating issues. While under full power towing at highway speeds I was unable to run the ac, the engine temp would ramp up if I did. Luckily I was able to control the issue with the ac, but had it been a bit hotter out I bet that would not of been the case.

When I got home I unhooked the trailer and did some cruising no overheating issue. So I assume it was just at the limit of the cooling system. Here in Canada I likely will not repeat towing in those conditions anytime soon and it seems just a few degrees cooler I have never had an issue. However just a warning to anyone who frequently sees high temps, if you search there are others seeing some overheating problems once an sc is installed.

So towing at close to max load is definitely pushing the limits of the jeep, be it power or cooling. (thank god for a manual transmission or tranny and brakes as well!!!)

The jeep is much happy pulling my atv trailer, in the 2000# range than the travel trailer in the 3000# (weight and wind resistance area) range.

So like I said in the thread above for towing I would stop with the gear upgrade, then start saving for a v8 tow vehicle of some sort after that if you are not happy, the sc is not going to be the magic bullet.

 

seabass, that makes perfect sense. Why are diesels so great for pulling and towing? Torque. Lots of it. And the only gas engine that gets close is a V8.

I installed a Magnacharger on a F150 I used to have, and it was a blast. But even a Roots-style charger (which spins at lower RPM and gives a flatter HP increase) didn't make a lot of difference towing the pop-up I had. And that was on a V8.

I'm pretty sure Ripp is a centrifugal charger, which means it needs RPM to spin. It's closer to a turbo - more RPM means more power. Paxton and Vortech are two others for V8's that are similar, and while they make higher total HP numbers than a Roots-style, it's not as linear.

Personally, I wouldn't add an SC just for towing. Buy an old used diesel pickup, like an old Dodge with a 24 valve Cummins. It's cheaper than a Hemi and will tow your whole house.

 

Someone really needs to come out with a turbo kit for the JK. You could easily do a smaller quick-spooling turbo with 8-10lbs of boost that would help neutralize power losses at altitude and would make loads of low-end trailer towing torque. Would probably be less costly than the RIPP system too.

 

Someone is working on one (can't remember who) but it's stupidly placed by the oil pan if I remember correctly, waiting to get mashed up by a rock... Wish I knew more for ya