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Discussion Starter · #1 ·
So I did the 4x4 calculater and it looks like with the automatic tranny and 5.13 gears and a 4:1 tcase the best I can come with is like 50-60:1 final crawl ratio. Can that be correct? That seems awfull crappy! :darn:

Is making me think of a manual swap. I did the calc. with some of the manual tranny info on there and came up with something like 128:1.

What is a good Tranny swap int an Xj. anybody done this and what kind of experience was it? and how did it wheel?:drive:
 

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If you are at 60:1 with an auto you can about double it with the torque converter. I have a ratio about there and with the auto it seems much lower. It will also be smoother. Ask Shane at HBRK about it.
 

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Wrench Wench
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This is correct, although the 2:1 ratio isnt entirely acurate, but it is a good rule of thumb. A stock converter actually is around 1.8:1, but that decreases as you get closer to the stall spead, and then it is 1:1.

Depending on the size of tire, weight of the vehicle and the power of the engine and last but not least the type of wheeling you do will dictate the correct crawl ratio.

For example, the Deliverance buggy was sitting at about 3500#'s with water in the tires. The motor pushed out ~225-240hp with around 300 ftlb's. It was on 40" tires. I played with gear sets in the axles (sometimes not by choice :D ) and the ratio that I liked best was around 50:1 using a stock Powerglide converter. This was great for both trail and comps. But I didnt have enough gear choices for cruising the sand dunes.

In todds new buggy, it will be around 2200#'s and will have around 150 HP and ftlbs and we are setting it up to be around 65:1. If this was a trail rig about 3000#'s we would have opted to go to about 75-80:1.


For your XJ, 50-60:1 is probably in the right ball park with 35-37" tires, as long as you have at least a 6cyl in there. But im not sure if any XJ's even came with the 4 banger.
I believe you can get a 904 tranny to bolt to your motor, if so, a lot of people are taking the guts from a 999 and putting it into a 904 and making a pretty tough tranny out of it.


Some cool tech is that Art Carr has developed a new converter for the rock crawling guys. We have one of their new converters for Todd's buggy. Basically they have taken a super small 9" shelled converter and put a different configuration together for the fins inside.
What does this due?
The torque multiplication goes all the way up to almost 3:1 which is nice for crawling. But the small converter makes it spin up fast and with a stall of around 2500rpm the motor can spin up fast into its powerband and launch you if needed :D

I hope this helps.
 

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Discussion Starter · #6 ·
That clears up things somewhat. I don't really understand how a torque converter works, but it sounds like it should be fine. thanks!

So this new torue converter, can you get it without the stall? I do some daily driving and don't think I want to have to ref to 2500 to start from a stop light, Or is that evan how it works?:confused: :confused: :confused:
 

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Listen to these guys. Chris and Shane are probably the most knowledgeable about the auto trans.

I have a C6 (2.46 first) with 5.13s and a 4.3 that puts me at 54.27. I run 42" tires and the crawl ratio is just about perfect! A little shorter tire like a 39.5 and it would be spot on. I ran a manual for years. The np435 had a 6.69:1 first which was nice but after going to an auto I will never go back!:thumb:
 

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That clears up things somewhat. I don't really understand how a torque converter works, but it sounds like it should be fine. thanks!

So this new torue converter, can you get it without the stall? I do some daily driving and don't think I want to have to ref to 2500 to start from a stop light, Or is that evan how it works?:confused: :confused: :confused:
FYI, most stock converters for 6cyl are around the 1500rpm range. You want that, you dont want to get rid of it :D
 

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Wrench Wench
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Yeah, I would run a stock stall converter. My XJ has a factory 2200 stall converter behind the 4.3, and although it is nice sometimes, in the slow crawling stuff I wish it was just a bit lower.
But in a crawling situation, it would be nicer to be lower than 37:1, and you would like that stall @2200 rpm.


For instance, if you have a stall around 1200 RPM with a low crawl ratio, even 37:1, you might have a problem driving through the brakes.

On my old Razor chassis, using the same drivetrain as the Deliverance, I first set it up at about 60:1.....Way too low with a stock stall, and it would constantly try to drive through the brakes.
 

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Discussion Starter · #11 ·
So if I understand it correctly, the stall doesnt meen, it doesn't go at all untill ....., it is just inhibited untill it reaches stall rpm. Is that correct?
 

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The problem I have now is that I when up against a load, I have to rev the engine up a bit to get it to go, and the vortec likes to rev quick, so sometimes I go from no tire movement to spinning very quickly, I have thought many times of running a V8 converter to drop the stall a bit. I ran a 4.3 converter behind the LT1 in my caprice and really liked it, but that's because the engine would rev more before hooking so my launches were much better, but I lost the creeping I used to have at idle. It is the same problem I have with the jeep.

Although, the higher stall converter is much more fun when I am practicing for Jeepspeed!



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Actually chris, you would enjoy a lower crawl ratio!

Like my buggy was, I could come up to a wall or waterfall, and with very little effort and a tiny push on the throttle, I could crawl right up.

I think it would be worse if you dropped the stall speed.


TTT was worried about the crawl ratio thing, and we got him setup with gears now where he has a ton of control crawling through the rocks. When he first went out, he was very quick over the rocks and had to power through stuff.....Not now!
 

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Given my 4-runner with a 4.3 v6 shooting at about 260-280 hp and 300ish pound feet of torque, what converter would would be my target in front of a 700 R4 or 350, keeping in mind I will have a toyota doubler behind the works?
this isn't a DD, but some road to trail use is anticipated, hence the desire for a 700.
 

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Doubler with what gears? and What gears in the axles? What size tire?

Im guessing a 2.2x 2.2 in the cases, probably 4.10's in the axle?

The 700 with that configuration will put you at about 60:1
With the 350 you are about 50:1.

I would think that a stock converter would be nice. I would use a converter from a 6cyl though, it has a little bit higher stall than the v8's do. With that being said, I believe that the 700 will have a higher stall than the 350 will.

I used a v8 converter in the Deliverance, Even with the engine at idle, the car would lunge when you would stick it in gear unless you were hard on the brakes. So the higher stall of the v6 converter would have been alot nicer there.
 

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the 96 and newer with the smog stuff removed, an open air system and an open exhaust....You can get 225-240. There are a couple of other parts you can stick on it to get some more horses, but I think about 260 is it with out tearing into the motor.

I was told that my v8 converter with a v6 in front of it was really close to about 1300RPM stall.


I wish they had made an aluminum block 4.3 or at least heads for it...I think it is an amazing motor if you can lighten it up a little!
 

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the 96 and newer with the smog stuff removed, an open air system and an open exhaust....You can get 225-240. There are a couple of other parts you can stick on it to get some more horses, but I think about 260 is it with out tearing into the motor.

I was told that my v8 converter with a v6 in front of it was really close to about 1300RPM stall.


I wish they had made an aluminum block 4.3 or at least heads for it...I think it is an amazing motor if you can lighten it up a little!
Thats pretty much what I did with mine... bumped the compression up a bit too, and am using a different cam.. tell ya what, finding a cam for post 93's is a bit of a bitch! I'll be running either stock gears or 4.88's and 2.2's in the cases with 36" tires.. Wonder if i end up running 4.88's if I would want a higher than 2200 stall converter? or would that be getting into the counter-productive range...
On a side note, i'm looking into lowering the compression agan and putting a turbo on it for more power in the dunes.. It has pleanty of power for trails and rocks, but you can never have too much in the sand...
 

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AJ, i would leave it with the stock 2200 converter.

And I would try it with the stock gears first, I dont think you will like the lower gears of a 4.88, I think that may be too low for that v6...they are torque monsters!
 
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