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View Full Version : Tuning your 4.0 for PULP and extra HP????????????

RockhamptonTJ
29-08-2003, 02:00 PM
I highly skilled machanically minded friend suggested to me that to get more horsepower from my "detuned" 4.0l i should run it on PULP (premium) and rotate my distributor until it pings, then with the use of a timing light back it off 4 degrees. And always use premium.

He has done this to several of his past vehicles and described the extra power as often astonishing.

Has anyone done this? And how does it go?

Tony
Steve F
29-08-2003, 02:54 PM
This is pretty much how I tune my old 62 Beetle but not sure if I'd try it on the jeep. Id actually be more interested in retarding the timing slightly so it will run better on ULP with less pinging (pinking... whatever), isn't the Jeep a little smarter than this though, does it have a knock sensor and automatically retard the ignition if it detects knocking or is the old 4.0lt too noisey for this to work/be reliable.

Cheers
Steve
Gojeep
29-08-2003, 05:30 PM
Doesn't work on most EFI vehicles I have been told as the computer over rides it anyway. Thats the trick I used to do in the carburetor days that I have no wish to go back to!
wrench
29-08-2003, 07:52 PM
Tony.
Unfortunately the 4.0 has a crank angle sensor on the flywheel. so rotating the distributor only puts the CAS (flywheel) & the CKP. (distributor) out of synch.
Dont do it, but do run PULP if your budget allows. Better quality, higher octane = smoother, cleaner running & maybe even better economy.
I always ran my XJ & now my WJ on PULP when possible.
David
TJPete
30-08-2003, 09:13 AM
I highly skilled machanically minded friend suggested to me that to get more horsepower from my "detuned" 4.0l i should run it on PULP (premium) and rotate my distributor until it pings, then with the use of a timing light back it off 4 degrees. And always use premium.

He has done this to several of his past vehicles and described the extra power as often astonishing.

Has anyone done this? And how does it go?

Tony

You cannot "rotate" the dizzy on this motor. It is indexed for TDC. If you "rotate" it you will certainly detune it! :wink: