After we wrote our story "a Day On The Dyno" in the June '07 issue, we decided that we weren't quite happy with how we did things.
If some testing is good, then more testing must be better, so we contacted as many coldair, high-flow intake manufacturers as we could to take our testing to the next level.
The test mule, once again, was our '01 Wrangler. This time around, we had 138,000 miles on it, with a stock engine, transmission and transfer case, a brand new JE reel rear driveshaft, 4.56 gears, a rear Detroit Trutrac, a Gibson cat-back exhaust system, and 315/75r16 (35-inch) pro Comp Extreme aTs.
Sometime between the last test and this one, we had formed a working theory that it wasn't so much the air filter as the air tube that makes the power in these kits. With most, if not all, aftermarket air intakes, the air filter itself can flow more air than the Jeep can use. Sure, there are varying degrees of restriction from one filter to the next, but on a stock 4.0l engine we just aren't convinced that a significant result will be seen at the wheels from the air filter alone.
For our money, our butt-dyno can't tell the difference if one Jeep has 2 more horsepower than another, and really, any number of things can lead up to a variance of 5 horsepower or lb-ft of torque. Now, 10 horsepower is another story, and we think that is significant.
For the testing this time around, we ran each kit for three dyno pulls using a rear wheel dynameter. in our results listing, we have taken an average of the three maximum horsepower and three maximum torque numbersfor a quick comparison. look, before you fire up the hate-mail generators, we know that peak horsepower and torque numbers aren't going to tell the whole story, but all the intakes we tested were very close and improved drivability over stock. For the whole power story, check out jpmagazine.com, where you will find the dyno pulls in their entirety, as well as a video of each pull.
Of course, we put the stock intake, with a new filter in it on for a baseline, but then we also went ahead and pulled off all of the stock filtration just to see what we'd get power-wise. The summary of our testing can be found below, including the stock and stripped-ofeverything tests.
Below, we give a brief description of our impressions of the kit, list the Manufacturer's Suggested retail price, and rate the difficulty of the installation from a low of 1 (most difficult) to a high of 10 (easy as pie). if the install was a slam dunk, with no hammers required, went quickly, and didn't have a million parts, it got a 10; if we hit snags, or it had a ton of parts, and thus took longer, the install rating started going down. We note the type of filtering element below in case you've got a preference there. We provide a quick view of the average max power produced with each kit and list a few pros and cons of each.
At the end of the day, we still feel that we should be buying these intake kits based on how well they filter, how easy they install, how it compliments the Jeep, which one fits our budget, or simply which company we like the best. They are all great kits, and any pros and cons we list are really minimal grievances with them that wouldn't stop us from buying any of these kits in the future.
Stock Intake And Filter
First, we ran the stock intake and filter setup. it is made of plastic and rubber, with a few hose clamps to hold it all together, and we had no problems installing it because it was already there.
Msrp: $21,000 as tested (came attached to '01 Wrangler)
Install 1-10: 10 (bolted on just like stock)
Filtering Element: paper and foam
Average Peak Torque:188 lb-ft
Average Peak Horsepower:142.3 hp
Pros:
installs great
filters really well
high resistance to water intrusion into engine
Cons:
paper element falls apart when wet
doesn't flow that well
it is a stock part.