Michiana Jeep Club

Hey Gang,
Anyone have any experiences good or bad with these performance chip kits? There seams to be a couple of company’s producing them. They say there is a boost of 60-80 HP and a increase of gas mileage from 4-8 MPG. Please give us your feedback and we will keep you posted if we go with a specific one and how it turns out.

The Sand Man

I don't have any experience with them on the Jeep, but I used to build and tune race cars and performance diesel trucks. 60-80 HP out of a stock gas powered engine is almost completely unheard of. With a very high performance engine, that's more than possible, but on a stock 4.0 I would doubt it (I've been wrong before). I definitely don't intend to rain on any parades, but I would say that something along the lines of 10-20 hp and an 1-2 mpg are more reasonable expectations. Are you looking for more torque, horsepower, mileage, or just have an itch to do some improvements to the Jeep?

There's no possible way a plug and play chip could produce 60-80 HP gas. With that kind of gain . You would need a better fuel system deliver , injectors throttle body. Then comes hard parts . Head to flow the extra air and fuel needed. And I'd bet a different cam to allow valves to open more to again account for extra air and fuel. Then comes distributor. Needs to upgraded to a hotter spark and plug wires also would need upgrade. . And there's more I've not included .
I'd say one may gain 3-5 real horses. And possible 1 mpg. Real world numbers.

An easy way to gain 3-4 HP .is to eliminate the stock clutched cooling fan . And go electric. And also rid that problem a jeep has with high under hood temps and over heating the 4.0 Pron to. As far as. Mpg. Really!!! Its a jeep not made for mpg.....

i agree with troy, the fastest cheapest 5-10 comes from getting rid of that mechanical fan.
and i also agree with the really low numbers on a gas engine from a chip, and really i would expect ANY increase in mileage, most likely a 1-5 mpg loss....sad but true.
the fan you will be able to "feel" in the seat of your pants when you "get some"..... IMHO.(what ever its worth)

With 33s your best bet is going to be to change your axle gears to get back to close to stock gearing with the bigger tires.
Prob 4.56s-4.88s.

I managed to increase my jeep's fuel economy from about 9 mpg to 16 mpg by loading it on the trailer and hauling it to the trail with my truck!!! LOL

Roger...