Gear ratios? V8 conversion

Jake Weso

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Sep 22, 2016
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Hi all, new to the forum. I have an 01 TJ. I'm doing a ford 5.0L swap. I'm using an AX15 trans. And np231 transfer case. I'm have a Dana 44 in the rear. Not sure what I'm doing in the front yet. Prob gonna run 35" tires. Is there was anybody out there with a V8 conversion? and what gears did you go with?


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Welcome to the forum Jake!
 
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Buddy of mine did an ls swap, but with a 4l60e auto. He's on 35's with 4.56 gears and likes it.
 
You'll have to post some photos as you go. I've never seen anyone do a Ford 5.0 swap, that should be cool!

@Stinger is on here and he has a V8 swap. Maybe he'll chime in with what gears he's running.

Although the engine being a V8 versus the factory I6 isn't really going to determine gear ratio I don't think. That's going to be determined by your transmission and your tire size.
 
Although the engine being a V8 versus the factory I6 isn't really going to determine gear ratio I don't think.
Engine size definitely affects it which is why we gear differently for the 2.5L vs. the 4.0L. Which is why I was planning to stay out of this particular thread, I don't know what ratios would work well for a healthy V8. I'd guess one ratio higher (a lower number) for any given transmission final drive ratio. :)
 
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Sounds like an awesome project. Running 35's with the ax15 I would recommend 4.56. You'd be running 2450ish at 70, no problem for the 5.0. Say you average around 45 mph, you are only running around 2000 rpm in 4th, where the 5.0 can easily squirt out of traffic if need be.
 
4.56 is the way I'd go as well. I have a few V8 buddies wth Chevy engines (not sure of the power comparison to the 5.0) but they have 4.10 and 35's and are not a fan. I would go with 4.56 for a solid daily driver I think.
 
Hi all, new to the forum. I have an 01 TJ. I'm doing a ford 5.0L swap. I'm using an AX15 trans. And np231 transfer case. I'm have a Dana 44 in the rear. Not sure what I'm doing in the front yet. Prob gonna run 35" tires. Is there was anybody out there with a V8 conversion? and what gears did you go with?


Sent from my iPhone using Tapatalk
Hi all, new to the forum. I have an 01 TJ. I'm doing a ford 5.0L swap. I'm using an AX15 trans. And np231 transfer case. I'm have a Dana 44 in the rear. Not sure what I'm doing in the front yet. Prob gonna run 35" tires. Is there was anybody out there with a V8 conversion? and what gears did you go with?


Sent from my iPhone using Tapatalk
Just wondering... What gears did u go with? My v8 has stock so far which is 3.07 gears. And they are way to high. Top speed is about 135 with 35's.
 
My applause for doing this project! I want to see pictures on progress and when it is finished I run LR4, 35's, 4.88, but I have NV3550 which has a 1:1 in 4th and .78 in 5th, perfect gearing. Paired with 241or have crawl of 78:1. Still running 30 in front with 4340 axles. At 70 in 5th I am below 3000 rpm. Welcome to the forum!
 
I'm with @motomick76 on the welcome and I am also a V-8 owner.

I have a Dodge magnum V-8 5.2 in my TJ with a 44RE transmission & 5.13 gears in the axles. I have a Ford HP44 narrowed to Waggy width and a TeraLow CRD60 rear.
I started on 35" tires and was turning about 2500 RPM's in 4th(OD) 0.69 and then went to a 38" Swamper that measured about 37" and was turning about 2300 RPM's both at 70 MPH.

Use this to see what your RPM's will be with different gear ratios: Gear Ratio Calculator (grimmjeeper.com)

And while I agree that a more powerful engine is more forgiving as to what gear ratio we choose to use with our V-8's I would still say it is important to gear it properly as to not either smoke the clutch or burn up your auto tranny.

Know what the peak torque & HP numbers are and where for your engine and then gear accordingly.
 
My applause for doing this project! I want to see pictures on progress and when it is finished I run LR4, 35's, 4.88, but I have NV3550 which has a 1:1 in 4th and .78 in 5th, perfect gearing. Paired with 241or have crawl of 78:1. Still running 30 in front with 4340 axles. At 70 in 5th I am below 3000 rpm. Welcome to the forum!
Thanks for the welcome. I just got this yj a few months ago. I havnt even got it in 5th gear yet. I'm running 70-75 in 4th gear. Its insane, top speeds gotta be 130mph and I'm on 35's. I think I need at least 3.55 gears. Its pushing about 370 hp.