Topic: 38's on a 2.5l

[JeepGuyBill]

hey, has anyone run 38's with stock tcase and 2.5l...with 5.38 axles gears?  that is my limit since my front's a high pinion d60...i know it won't be back to stock...but will it be doable...i'm told that 38s with 5.38s is like 4.10s with 33s...doe sthis add up? cuz i can deal with the underpower of 4.10s and 33s...also...if i add the 4.0l throttle body and a tri-country inertia ring...would that bring 38's to stock with my gearing?

[kenny kustom]

i run 39.5's with 5.38's

[Jeffy]

Hi-Pinion D60 will limit you to 5.13's I believe.  You won't notice the difference offroad though.  Onroad, it will be a bit underpowered.  5.38's are recommended for 35's.  5.13's are good for 33's.  I don't think it will be any worse then 4.10's and 33's though.  I'm running 35's and 4.56's which should be comparable.  It's slow on the highways at speeds above 55mph.  The big issue is not having enough torque to keep the speed up with a wind.

[JeepGuyBill]

kenny, hoe does that treat you on and offroad?

[Jeffy]

I forgot, a friend of mine ran 38.5" with 5.13:1 gears for a few years.  He has a Tri-County Gear Inertia Ring as well...

[chrisfranklin]

i run 39.5's with 5.38's

Oh yeah!?  Well, I run 29s man.  And I'm saving for 27s!   

[kenny kustom]

I have hpd60 with 5.38's. That is the lowest you can go with a hpd60.
Works really good with the supercharger !

[Jeffy]

I have hpd60 with 5.38's. That is the lowest you can go with a hpd60.
Works really good with the supercharger !

5.13's aren't the lowest for the HP60 anymore?

[oldjeep]

5.13's aren't the lowest for the HP60 anymore?

As far as I know 5.38 has always been the limit on HP60's

[Jeffy]

As far as I know 5.38 has always been the limit on HP60's

It must be a more recent thing.  I have a few friends running Dynatrac HP60's and they were limited to 5.13's.  I'm wondering if it's an aftermarket only thing since I think Dana/Spicer is still at 5.13's.  I've seen Yukons at 5.38's though.

[JeepGuyBill]

I have hpd60 with 5.38's. That is the lowest you can go with a hpd60.
Works really good with the supercharger !

did you run this before you had a supercharger?

[oldjeep]

It must be a more recent thing.  I have a few friends running Dynatrac HP60's and they were limited to 5.13's.  I'm wondering if it's an aftermarket only thing since I think Dana/Spicer is still at 5.13's.  I've seen Yukons at 5.38's though.

Nope.
D60 5.38 Reverse rotation Gears
Dana Spicer part number 707475-5X

[Jeffy]

Nope.
D60 5.38 Reverse rotation Gears
Dana Spicer part number 707475-5X

Hmmm, strange.  I guess 5.38's are the limit then.

For offroad, I doubt you'd notice any difference though.  With a 4:1 in the transfer case it would seem downright peppy even with 39's.  Onroad though, the weight of the tires and the lack of lower gearing, you'd probably want to trailer it.  Although my friend always drove his up to the Rubicon.  He used to go up there almost every weekend at one point.  Now he's getting ready to install a 4.0L.  I'd wager that 7:1 would feel nice with 39's but that's portal country.  With a new engine or even a SC, you'd have a lot more torque to keep those tires turning.

[JeepGuyBill]

the engine swap is 2 or 3 years away for me...i'm building the drivetrain now to handle the power...hence the d60's...and the atlas 4:1 will go in in 2009...i figure by doing the swap this way, i'll be able to keep the jeep running with minimal downtime

[JeepGuyBill]

oh, and a side question...how much did the supercharger cost you? how much mpg do you get? and how much hp do you have now?