I have been thinking of eventually getting a supercharger and my question is do you think the stock 6-speed would be able to handle it? I have read that the manufacturer's maximum rating for the NSG-370 is about 272 ft-lbs. With superchargers running 5 - 6 PSI boost this will equate to a torque output of about 320 to 330 ft-lbs. It's only about 20% over the manufacturer's rating, but the last thing I want to do is spend more money repairing my transmission after spending money for the blower... Insight from anyone who has used the NSG-370 over its recommended rating would be greatly appreciated

 

The manufacturers maximum torque input rating for the NSG-370 is 272ft lbs.

Now, that doesnt mean it will break with 273ft lbs. Thats just the mfg rating. Meaning it will never be put behind an engine with more than that in an OEM application. There have been V8 conversions in plenty of TJ's that retain the stock NSG-370.

Also, that torque rating is kind of deceiving in a real world application. As the engine is only going to generate that torque for a given rpm range. I would think that so long as you don't do wide open throttle clutch drops, you should be fine.

Although if you are going to run larger than stock tires, be sure to regear. As this will remove a lot of stress from the rest of the drive train.

 

Sweet, thanks, that makes sense that it will just never be put behind an engine with higher torque from the factory. I mostly worried because it looks like the 3.8 has peak torque from about 2300 to about 3700 RPMs. I mostly want the SC so I can leave in 5th or 6th and be able to accelerate and pass on hills. Currently if I have to pass on a hill I need to go down to 4th gear. I just worried at highway speeds the engine would have very close to peak torque and if I floored it in 6th to pass up a hill I would be putting over the recommended rating through it for more than a few seconds.

 

Your described scenario will not over stress the transmission. The only time you could risk damage is if you are rock crawling or pulling a very large vehicle or object while in 1st gear from a dead stop. Once your Jeep is moving on the road, you won't be able to induce enough torque and stress on the transmission to break it.

Where are you getting a supercharger? How much are they?

 

I'm looking at getting an Avenger SC system. I can't post any links or anything since they aren't a sponsor of the forum but if you google it you should be able to find them. It's a twin-screw (roots) style system that gives boost from way down low (1200 - 1500 RPM) and according to the owner gives over 80 HP and close to a 50% increase in torque throughout the RPM range. It sounds like it would be just like having a 4.7L V-8 (from the grand cherokees) under the hood which is just what I'm looking for. Their kit is $4500. The only catch with their kit is that it requires either cutting your stock hood or using an aftermarket hood with more clearance for the blower...

 

please review the forum rules obviously you have not. You can post links. They just can not be clickable,

 

This is a sound description of how things work…

The second it how we build power which is direct contention with the way the Naturally Aspirated engine builds it.

RIPP supercharger kits come equipped with a centrifugal blower because they deliver liner manageable boost at precisely the correct RPM and exactly when the engine can handle it. Vortech Superchargers build boost based on volumetric efficiency. Meaning as the engine goes up in RPM it increases its ability to move air. As it moves air it build boost increasing the power band by a nominal amount, in our case 100-120 rear when HP and 80lbs or torque. The best thing about this is its efficiency, it takes a mathematical 7-11 crank HP to deliver that meaning it’s the most efficient belt driven blower on the market. Also by being so liner the ECU deems it a consistent and works with the additional air. ECU cooperation means all the OEM safety systems are still present and all fuel trimming and ecological trimming at part throttle are 100% active. This delivers both better than stock fuel mileage and reduces your carbon foot print (for what its worth).

A roots unit will build boost real early in the RPM band, in fact below the 2200rpm we deliver at, however by experience the consequences (when it matters) far outweigh the pros. Given the narrow angle and lack of volume at lower RPM, cramming 4-6psi at 1500-2500 rpm causes havoc. Firstly it builds a tone of cylinder pressure the engine cannot displace, often leading to bent rods, blow head gaskets and a host of other pressure related issues including cracked ring landings. Secondly while the boost has been built as you go up in RPM the blower loses its efficiency,( which is ironically counterproductive) it actually starts to take more crank HP to power it – as much as 30hp to produce 4-6 psi – so the efficiency simply not there. Additionally throwing boost at lower RPM also requires much more tuning. You need a lot more fuel and timing control correction to make it smooth which leads us to our most important point the tuning.

Lastly and more to the point of this thread – transmission will suffer because it pours on power where the trans was not equipped to handle it. Most of these question aare completely valid and the points need to be addressed. We put a lot of thought into the day to day use of a JK and how it would be used off road as well. A centrifugal is just a well rounded performer and delivers exactly what you need safely and problem free.

Question welcome.
RIPPTECH

 

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