TurboCity’s Rock-It Tube and K&N Conversion

author’s note: After running the TurboCity kit for a while, I decided to swap it out for the K&N cone conversion kit offered by Rusty’s OffRoad. I really haven’t noticed any performance difference in the kits, other than it’s easier to check my oil now (see note about clearance issues below). Also, Rusty’s kit costs less than half of what the TurboCity kit does and uses a larger air filter, so Rusty’s kit probably gives you a bit more power over the TC kit. While I still think the TC kit is good, Rusty’s kit is a better choice for most applications (XJ and TJ).

Installation date: 12/15/98.

I’d been running an AMSOIL foam air filter for a while now with no real complaints, but I couldn’t say I’d noticed any gains from it either. So, after hearing a lot of good things about TurboCity’s new Rock-It Tube and K&N cone filter conversion, I decided to give it a try. I called up TurboCity and placed my order, and within a few days I had a new toy for my Jeep sitting on my front door step.

A K&N cone airfilter conversion is a rather simple engine mod, and both Cherokee America and Grand Cherokee Unlimited have run articles on how to do the conversion yourself for very little money. So why didn’t I just do it myself and save a bunch of money? Good question…I guess I just wanted to see what all the fuss about the TurboCity conversion was about.

The TurboCity kit is pretty basic: a steel “Rock-It” intake tube, K&N cone airfilter (#RU-0960), a piece of black PVC tubing with a t-connector stuck in one end, and some stickers. No instructions are provided, but the installation is pretty straight forward.

The first thing to do is remove the factory air intake from the intake manifold. There is a clip that attaches the factory intake tube to the throttle body, I just used a flathead screwdriver to pop the clip open, then the tube just slips off the throttle body. The inside of my throttle body was pretty dirty, so if you’re rig is more than a couple of years old, you might want a can of carb cleaner and a tooth brush handy at this point so you can clean out the throttle body. Also, be sure to disconnect the two hoses from the factory air tube. Now just remove the airbox itself, mine was attached with 3 1/2″ bolts in the bottom of the box.

Then all you do is clamp the Rock-It tube to the throttle body, connect the hoses (the two hoses you pulled off the factory air tube just plug into the t-connector), and clamp on the K&N filter.

The filter rubbed against the insulation on the bottom of the hood, so I just cut a whole in the insulation where the filter rubbed. There seems to be adequate clearance between the tube and filter and the actual hood itself though. The black PVC tubing TurboCity provided with the kit was too short by about 4″, well, it fit (the pics show the tubing TC sent me) but was too short for my preferences, so I just ran to the hardware store and bought 2′ of high-temp. hosing to use instead. The new tubing is is the color of the K&N filter and gives the kit a kinda wild look. The only real drawback to the TurboCity kit is that now the K&N filter blocks my engine oil dipstick, so to check my oil I have to move the Rock-It Tube.

So was it all worth the $125 I paid to get it to my door? Well, I’m not sure yet. I expected the fit to be a little better, but then it was really designed around a slightly different engine layout. Oh, and the Rock-It Tube does have a support brace that goes against the valve cover (it’s that little hook-like thing on the bottom of the tube in the first picture), so the tube isn’t just hanging out in space. I don’t think it would be possible to turn the Rock-It tube so that it ran to the factory airbox location, you’d have clearance problems with the hood.

One thing I’m not sure about yet though is the fact that the metal tube heats up to a very high temperature due to the fact that it sits right on top of the engine, I imagine this heats the incoming air, and I’ve always heard you want cold air coming into your engine…I need to ask around about what the deal with the incoming air temp is. Guess I’ll have to wait to see what kind of mileage gains I get from the conversion. After I’ve been running the conversion for a whlie I’ll add a “long-term review” to this write-up.

One advantage to the Rock-It tube is that it raises the intake level by a few inches, so you could go through deeper water than with the stock intake, assuming you don’t short your electrical system first…

Overall I’m pretty happy with the kit so far, it looks cool, and now I have this huge empty space to work with…I’m thinking maybe a small York… And you should hear the engine now, sounds like a jet turbine when you first fire it up. The TurboCity Rock-It Tube kit is only available for ’91 or newer 4.0L Jeeps. According to TurboCity’s website, the Rock-It tube itself is good for a 3-6hp increase, and the K&N cone airfilter is good for another 4-7hp gain. So theoretically, you’re looking at an increase of 7-13hp with the whole kit. TurboCity also now offers an “auxiliary mounting base” for mounting compressors, tools, etc. in that big empty spot left by the airbox.

TurboCity can be contacted at:

1137 W. Katella
Orange, CA 92867
Email: turbocty@sprynet.com

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