"A bit much" is somewhat the goal here, plus luckily I don't highway drive often at all. That is a good consideration too though, thanks
Question about re-gearing
- Thread starter tlord
- Start date
"A bit much" is somewhat the goal here, plus luckily I don't highway drive often at all. That is a good consideration too though, thanks
It really can’t hurt to regear to 5.13. That’s as deep as you can go in a non-Rubicon with factory axles.
The 42rle overdrive ratio 0.69 sucks, so for now just hit the OD button every time you shift out of Park and you’ll find it a bit peppier.
You can dismiss his suggestion. Anyone who argues against 3k rpm at 75mph has never had a TJ that can begin to get out of it's own way. The difficultly with the 42rle is getting that in the first place.
At the end of the day it is still limited by it's 190hp, 30% driveline losses, narrow 3200-4500 powerband and 5200 red line. In turn made worse by the 4 speed auto and it's excessively tall OD.
But put another way between 2750 and 3250, each 250 rpm is gaining about 10hp on tap taking you from 125hp at the crank to ~135hp at 3000 to around ~145hp at 3250. You lose 30% of that in the driveline, so 87 - 102 at the wheels.
If you want to make meaningful changes in the numbers on that power curve (I posted above), you've got to look at forced induction, increasing displacement by stroker crank, or swapping the motor. And you still might want or need the numerically higher gearing to have the power where you want it. For instance sizing a turbo on the smaller side might limit peak hp, but bring peak torque down to 2000rpm or lower making a wider power band and giving much better mid range power and response. Banks sidewinder was a good example of this. Increasing the hp number from 87 to 102 will have the same effect on acceleration whether you get there by gearing or power adders. Except the power adder route can mean you end up with much more than 190hp peak. It's going to be a bit more expensive when you factor tuning, but having someone install gears is not exactly cheap today. When you're putting $3k-$6k into a 20+ year old TJ without addressing all the age rotted suspension, leaking seals, etc... you've got to reality check yourself. You will never get that back at sale.
But put another way between 2750 and 3250, each 250 rpm is gaining about 10hp on tap taking you from 125hp at the crank to ~135hp at 3000 to around ~145hp at 3250. You lose 30% of that in the driveline, so 87 - 102 at the wheels.
If you want to make meaningful changes in the numbers on that power curve (I posted above), you've got to look at forced induction, increasing displacement by stroker crank, or swapping the motor. And you still might want or need the numerically higher gearing to have the power where you want it. For instance sizing a turbo on the smaller side might limit peak hp, but bring peak torque down to 2000rpm or lower making a wider power band and giving much better mid range power and response. Banks sidewinder was a good example of this. Increasing the hp number from 87 to 102 will have the same effect on acceleration whether you get there by gearing or power adders. Except the power adder route can mean you end up with much more than 190hp peak. It's going to be a bit more expensive when you factor tuning, but having someone install gears is not exactly cheap today. When you're putting $3k-$6k into a 20+ year old TJ without addressing all the age rotted suspension, leaking seals, etc... you've got to reality check yourself. You will never get that back at sale.
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