Making more usable power in a day
We have been beefing up our ’01 WJ Grand Cherokee Laredo in the pages of Jp by adding suspension lift and bigger tires, a winch and bumper, and swapping T-cases and driveshafts. Despite all of this, we have not yet spent any significant time trying to get the 4.7L V-8 engine to make more power. Well, it’s about time isn’t it? The fact is that the ol’ WJ is pretty powerful, and while we have contemplated re-gearing the axles to pick up what little power and mileage the larger tires have sapped, it has not been one of our priorities…yet. Despite this we do believe that there is no such thing as too much power, and to that end we finally decided it might be time to see what a few simple mods could do for the Grand’s gasoline-burning mill. To show the results rather than just feel them, we got in touch with our pals over at Airaid Filter Company. Airaid graciously offered up not only a few goodies to help the Grand make power and torque (via one of its intake systems and throttle body spacers), but also some time testing parts on their all-wheel Mustang dyno. We also got to test out a spankin’ new TrailDash Jeep Tuner from Superchips to see what kind of horsepower and torque we could make with the 4.7L V-8. We made more power and significantly more torque lower in the rpm range. We also discovered a few more benefits with the installation of these parts. To see extra photos of the parts and a video of the WJ at speed on the dyno check out jpmagazine.com/wj_performance_extras.
Cost vs. Benefit
Making power and torque is generally pretty expensive and difficult. Our experience with making more power in our WJ was not too expensive, but at just over $1,000, not necessarily cheap either. We will benefit in many ways from our upgrades, not only in the gain in power. The Jeep does seem to be getting slightly better mileage since the upgrades despite our giddy I’ve-got-more-power lead foot. This should be much better when we get time to really try the Economy Tune and Economy Mileage Coach of the TrailDash. Also, keeping an eye on transmission temperature (as an example) could help save us a large chunk of change in a vehicle such as this that is sometimes used for towing and could overheat the tranny.
|Airaid Intake System with SynthaMax filter (PN 311-148)||$318.90|
|Airaid PowerAid Throttle Body Spacer (PN 310-515)||$114.95|
|Airaid Pre-Filter (PN 799-440)||$26.95|
|Superchips TrailDash (PN TKTK 438753)||$589.00|
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Dyno Run Results
The chart above shows the results of our three different set-ups.
Purple = Stock
Blue = Poweraid throttle body spacer, Airaid Intake System
Red = Poweraid throttle body spacer, Airaid Intake System, Superchips TrialDash with 87-octane performance tune.
Overall, we made 40 lb-ft of torque between 3,000-3,400 rpm and about 8 hp at about 4,200 rpm. That’s the kind of grunt that the ol’ butt dyno can really feel and the added power along with the improved shift points makes on-road driving much more enjoyable—all on 87-octane gas. Wow, 40 lb-ft! That’s a really solid improvement for a gas engine. Makes you wonder what would happen if we were not too cheap to spring for the high-test fuel.