Porch951
NAXJA Forum User
- Location
- Albuquerque, NM
Here you go:
http://jeephorizons.com/tech/rpmchart.html
http://jeephorizons.com/tech/rpmchart.html
i think 4.56 for me to but then again my 33's are getting old 35's have been on my mind but not in the budget for a while
the killer in MPG isnt RPMs. the 4.0 likes running between 2250 and 2750. the killer is load.
example:
with 3.07s (AX-15) and 32s i get better highway mileage (speedo says 70mph, GPS says 76mph) in 4th gear than i do 5th even though im running 3000 RPMs in 4th and 2200 in 5th. the key is load. instead of the throttle being wide open and the vehicle struggling to maintain RPMs, its more responsive in 4th and under half throttle when the load isnt as heavy.
I have 30's and 3.55's right now, and i'm averaging 13.5mpg with my Cherokee. I used to get 19mpg before i put on the 30's, and it was a lot more "peppy".
whats the best way to get an accurate reading assuming your speed is correct? full tanks at a time?
I had an interesting discussion with a materials engineer about cryo treatment. He told me that cryo treating a ring and pinion is a bad idea because of the properties the process imparts on the metal. He said that cryo is great for things like axle shafts and u-joint crosses but it actually gives a ring and pinion the wrong kind of properties. It gives the metal a sort of flex ability that will contribute to failure on a R&P due to the tooth contact. It was a very interesting discussion.just get them cryo treated if youre that worried about 4.88's being a little weak for the D30
the shafts from the 96 and 99 D30's will be exactly the same.
I had an interesting discussion with a materials engineer about cryo treatment. He told me that cryo treating a ring and pinion is a bad idea because of the properties the process imparts on the metal. He said that cryo is great for things like axle shafts and u-joint crosses but it actually gives a ring and pinion the wrong kind of properties. It gives the metal a sort of flex ability that will contribute to failure on a R&P due to the tooth contact. It was a very interesting discussion.
Yeah, might have been just one guy's opinion but it made sense to me.that is interesting. i was just suggesting it due to growing popularity on boards like pirate and what not so it seemed like it was something beneficial. that is surprising though. sounds like you got the real ins and outs of the process.
check your motor mountswell firs im sorry for my response about that glug lug thing. i was sound asleep seconds later....
When moving slow like backing into a spot or after the clutch engages i hear a noise coming from the rear floorish area. it has a lug glug sound to it and seems to be the rear. just did the shoes drums and springs n things but dont think its that(happened before).
Also the play i as talking about is in the rear only. with the rear on jack stands you can feel a small abount of play pulling outward
also w/ the rear on stands and turning the wheel forward and backward there is play between the other wheel. i know some is fine but it almost seems like a lot.
and about the original question.... NO MATTER what gearing i go with (anybody's recommendation) prob 4.56 i will be looking at much better mpg than i get now?
and although a dd i like to wheel the hell out of it when i can