What is the most ridiculous aftermarket product? Hands down, it's the "little intake fans" and the "throttle body spacers" with the bore grooves. Right there on the list has to be those "underhood exposed filters" that suck in 200° underhood air instead of ambient (70°-100° air from the fenderwell). 10° air temp rise is -1% HP. That's how dynos are calibrated for temperature changes. Does anyone really believe that all those OEM manufacturers designed expensive plastic inlet systems - for the last 20 years - that pull cool air from the fenderwell, hood or grill because they didn't have anything else to spend their money on? Then there's those "factory calibrated" mass air meters that do not use a chip or re-calibrated processor with oversize injectors. They unwittingly reduce the voltage signal to the mass air meter to compensate for the larger injectors at WOT but they neglect all the driveability issues. The result is over advancing timing, lean mixtures, detonation, surging, bucking etc.

The TBS won't help you. You can use a drop in K&N for the same slight increase as a cone setup, but don't bother with a cone setup unless your willing to spend some money. The solution to getting tons of cold air to a cone filter setup is pretty simple, however it's costly. It increased my highway milage from 20 to 24 mpg. It actually made at least as much difference in performance as the Borla exhaust too. Unfortunately I dropped back to 20 mpg when I went to the 4.10's.

KYLiberty, your hood is without a doubt the coolest of all in this community, but I dont think anyone else would spend the amount you did to get one, even for that guaranteed cold air.


As for throttle body spacers, I remember reading something on the AEM website that says AEM doesn't make a TBS for the KJ because in their R&D period of making our intake, they realized a TBS would do absolutely nothing to increase the performance of the 3.7L.

I trust AEM.

The Fastman throttle body works well on the 3.7, especially if you've made other upgrades to it already. The AEM and K&N cone help a little, as well as the K&N drop in. The cone setups work very well combined with the throttle body if you add a hood, or do a "$4 cold air intake modification."

The Fastman throttle body works well on the 3.7, especially if you've made other upgrades to it already. The AEM and K&N cone help a little, as well as the K&N drop in. The cone setups work very well combined with the throttle body if you add a hood, or do a "$4 cold air intake modification."