blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
I beat the snot out of 4.56's in a D30, they were beat on prior to me owning them and the current owner is beating on them harder than I did.
4.56's in a D30 is just fine.
4.56's in a D44 is not even a question.
Yea, all the crying about 4.56 destroying a d30/44 didn't make sense to me. I'm sure that you might run into issues with a bigger power plant and 37+, but 33 and the 4.0L or even a 4.7L I6 I can't imagine causing a lot of stress.
That said, either this will be my first attempt at setting up gears, or I'll be paying some alcoholic redneck to do the setup for me (he charges $150 per axle, which seems both expensive and cheap at the same time), so I've no idea how confident I'll be with the resulting install/setup.
Anyone in Vancouver, BC want a LOT of beer for an install ?
Not quite completely off the subject but...
If you do decide to re-gear, I can attest to the combination of 33" (P285/75R16) tires and the 4.56:1 gear set. The combination gives a 10% mechanical advantage over stock which is to say that the engine will be turning 10% faster for any given road speed.
This 10% is not a calculated value, it is a measured value.
As I run a Supercharger, I had to install a F/IC to manage the larger injectors and to retard the ignition under boost. I use an AEM F/IC 8 which provides the capability to calibrate the speedometer by altering the VSS signal.
The correction required to get the speedometer to a less than .5% error is, -10.1%. thus, the 33" tire and 4.56:12 gear combination results in a 10% advantage. Whilst not exactly accurate, I am willing to live with the 1/2 percent error... Yes, this is sarcasm alright.
My fuel economy is not a good one to use for reference as it heavily depends on just how many times I get frisky on the skinny pedal. If I keep it out of boost (yah, right...) the Heep gets about 16 to 17 in town.
In boost, it gets 12. But..... It is a very fun 12......
IMO, this tire/gear combination is just about the optimal selection as it still allows for highway speeds. Also IMO, you need the mechanical advantage as soon as the rig is lifted and larger tires fitted. I know this is obvious but, larger tires take more torque to turn and lifted rigs suck aerodynamically...
The XJ is a Brick On Wheels to begin with and then, we lift them to create Brick Walls on Wheels....
Yea, I did the same calculations. I'm coming from 4.10, so not as huge an upgrade in torque, but should at least restore a little pedal power and hopefully make driving on the highway less embarrassing. (As it stands now, I have to pull over to let grandma and grandpa pass on a regular basis, and went from 20mpg with the 31's to avg. 16-17mpg with the 33's).