I just lifted my JKU and put her on 35's. I have notice my RPM's have dropped about 400 to 500 from where they were stock. My question is has anyone installed a Ripp's supercharger with out regearing first? Did it help with the bogged down feeling? I currently have 4.10's and was thinking of jumping to either 4.56 or 4.88 or just going with the Ripp's supercharger. Is there a chart that tells you how much your rpm's will increase with a change in size of gears? If anyone can help me out that would be great.

Thanks

 

I installed the RIPP supercharger before regearing my Rubi to get a feel for what gear I would need. The lift and the 35's were installed a several months before the SC so I got a good feel for the difference the wheel size made. The terrian around the house is light to moderate hills and before the lift the transmission would down shift on about sixty percent of them to stay at seventy. After the lift the transmission down shifted on every hill and on the steeper ones went all the way into second. The superchager improved acceleration from a stop as long as you were reving above the 2600 rpm mark. The transmission still downshifts when going up a hill but no longer into second and the aceleration after down shifting is much improved. You feel the super charger start to kick in at 2500 rpm but it really is quite noticable at 2800 to 3000 rpm. On flat to light hills such as over passes the supercharger keeps up just fine even for accelerating around some one with no down shifting unless get on it. If you do not have too steep of hills where you drive you could probable get away with 4.88 gears. I am opting to put in 5.13 instead to eliminate all down shifting going up the hills around the house.
Here is a link to a gear / rpm table
https://www.jk-forum.com/forums/show...hlight=gearing

 

Thanks for the chart. That is actually what I was looking for.

 

RIPP will even tell you to regear first..

 

Actually RIPP said it would not be an issue to regear afterwords and it has not been. I have a 2011 so it is a piggyback system.

 

true not a issue at all.. but better to get your rig all setup first ...then supercharge.. but you dont have to .. you just get better results from the start with the supercharger if your gear ratios are correct.

 

I talked to Ripp's about this. They are telling me I should put 5.13's in which to mean seems really small. By the chart my RPM's would be really high. I don't really want my RPM's in the 3000 range while doing 110 km/hr. I was thinking max 4.88's even with that they are almost RPM's 2800, if the chart is correct. I find this really confusing.

 

I assume you have a standard transmission to be at that rpm range at 110 km/hr and that would put you where the supercharger really kicks in well. An automatic would be at about 2450 rpm. They are running 4.88 where the land is flat with little undulation. From driving mine at 4.10 I do not believe that the 4.88 would be enough at elevation and with inclines. Maybe someone with a SC with 4.88s can chime in.

 

I'm still running my 4.10s with my SC. Mainly because there is not a got shop around here to install my 5.13 Yukons sitting in a box in the kitchen. I just run with my overdrive off and it works out great. At 70mph I'm pushing 2800rpm and that is a nice sweet spot. Lots of power. And my MPGs are hanging at 15mpg mixed driving. Hills are not an issue at all. Eventually I'll get these gears in.

 

for me 5:38s 37"tires and ripp supercharger = perfect match if you have 35s 5:13's are perfect .