What, if any, have your MPG gains been with your 4.0 under drive pullies?

 

I did an e-fan a underdrive at the same time. Gained me about 1 to 1.5 mpg on avg. I datalogged a 9hp and 11TQ gain too.

And just so you know.. I data logged the e-fan by itself. It gained nearly nothing in the cold weather when I was testing.

IMO it's worth it. Everytime you hit the throttle you can tell it's got more punch.

Rich

 

best bolt on mod for a 4.0 by far....

 

Thanks for the info Rich.

$300 is steep thus why I'm looking for MPG numbers not just opinions.

 

didn't pay that much for mine and a new Gatorback belt.....

 

Thanks for the helpful information.

Care to share where you bought yours?

 

http://www.stuffforyourranger.com/st...d613f96aa7c2c5

 

$250 for the pullies, $32 for the belt, $10 for shipping. I rounded up the extra $8 to get $300 =)

 

Are pullies are really pain to install. On average with decent mechanic skills how long would it take a person to install a pully?

 

I took off my fan at the same time which helps... but with a $15 three winged puller it took me about 1.5 hours. It's not hard. Not too sure about leaving the fan on and trying to do it though?

Rich

 

Thanks, something to look forward to.

So just out of curiosity with the pully and a tuner your lookin at about a 30hp and 35+tq gains.

 

Both products would probably be in the 7-12 HP range each. Your estimate is probably too high.

 

What can I expect in regards to MPG gains?

 

What I have found on the pulley. Say over 4 fill ups you get 17.2, 18.5, 17.9, 18.5. After installing the pulley I would get solid high 18's and never dip back in the 17's at all after consecutive fill ups. Thats the best real world data I can give. Driving conditions, driving styles, and a/c effect it from tank to tank. At least with me. One tank I'm towing, another tank I'm not. Then it gets hot and the a/c goes on.

 

If you drive it daily... at some point it will pay back the cost in mileage alone. But you know.. having that tip in torque improvement is nice too. No kidding.. you can feel it everytime you hit the gas.

The *only* downside I've seen is that at extended idling my a/c gets 1/2way warm. So I set it on max if I'm sitting in a long line of traffic. Otherwise it's a good mod and well worth the money.

IMO it's money better spent that was the K&N or the Magnaflow exhaust. My new x-cal 2 has yet to be determined as how it'll stack up (mpg average not yet complete). But it too has made a very noticable improvement in power & mileage.

Rich