4.6 stroker torque converter for 42re

98zjstroker

98zjstroker

Well-Known Member
Joined
Oct 14, 2009
Location
concord nc
So now is the time to install the motor but before I do I want to replace the original torque converter. I have the 42re transmission. There are a lot of options out there like lock-up converters and stall converter. Haven't found much on what people have been using for the jeep stroker.

Not sure if the stock converter is a lock-up but if not I was thinking about getting one that was to help reduce heat. Any thoughts on this for a stroker set-up? Is it best to go with a stock converter? I would assume not because of the HP and torque changes along with the use being more for power and offroad then what the original one was.

Second comes a stall converter. I know this depends on my RPM range, HP & torque, along with the weight of ZJ. Because of this I assume there is a range of differences between what people might be using so I am putting in specs of cam and estimates of HP and torque.

Cam lift int- .443, exh- .443

duration @ .050 .209 .213

duration .263 .267

RPM range per manufacture for the cam is 1000-5300RPMs

HP range from what I can find on a conservative estimate was 260hp and around 300ftlbs of torque. (unable to find out RPM at time of peak HP and torque) and a gross weight of 5300lbs

Without knowing RPMs at time of peak power is it possible to still get a torque converter that will work? And any ideas on where to go/order from for aftermarket torque converters?
 
so I was a little delayed in getting a hold of them but was finally able to yesterday. the guy I spoke with said that they do not have any that I can order but that they would rebuild mine if I sent it out and add "a little stall" to it.

Can someone tell me what the stock stall is on the 42RE? Is it in the 800rpm range?

And is there a benefit to low stall?

My knowledge on transmissions and torque converts isn't much other then a lot of magic happens that makes your car move. from what I understand that stall of the torque converter sets the RPM range in which power gets sent to the transmission (might not be right). Race motors are build to launch at higher RPM which is why you put a stall converter in them. So if I am correct in that why would a low stall be good for a built stroker motor with more power?
 
Stall speed is the rpm the converter pushes through the brakes, if holding the brakes as hard as possible.

Has more to do with cam specs

Race cars generally have higher stalls bc they have longer duration cams, that need to get up in the rpm range where overlap time isn’t as much of an issue and the power starts coming on.

Higher stalls in Offroad can be bad bc of the extra heat added to the fluid while the Rpm’s are increasing yet the vehicle isn’t moving.

Too high of a stall speed and you waste a bunch of rpm range if the motor and cam aren’t selected and built for a high stall.

Personally I wouldn’t go much above stock stall speed, just enough to not push thru the brakes in low range.

In our PTC converter, on 502 BBC, we tried several off the shelf converters before getting the one from ptc.

The first couple had too high of stalls bc it just wasted rpm range and built way too much heat. The buggy is super light, and has stupid torque. So even the v6 “factory” Chevy stall converter was advertised as 1700, was pushing thru the brakes at 1100.

PTC was able to build us a converter that doesn’t push thru the brakes at idle, but also doesn’t have a higher than 1500-1700 stall speed. It also doesn’t flash as high with light load and big throttle as a newer LS style converter.

I understand they won’t build you one, but the trans catalogs I used to have listed 3 converters for “stock” applications with 3 different stall speeds.

Idea is to get one that doesn’t push in low range, but doesn’t have a much higher stall either.
 
@Mac5005 thanks! totally not how it was explained to me in the past. I knew it was normally tuned for the cam you are using. So how I understand what you are saying I should stay away from the 1600-1900 heavy duty high stall lock up torque converter I as also looking at? And stay away from a low stall because it would push power through to soon? just want to make sure I understand correctly.

Sounds like I need to just sent PTC my converter then
 
84jimmy said:
@Mac5005 thanks! totally not how it was explained to me in the past. I knew it was normally tuned for the cam you are using. So how I understand what you are saying I should stay away from the 1600-1900 heavy duty high stall lock up torque converter I as also looking at? And stay away from a low stall because it would push power through to soon? just want to make sure I understand correctly.

Sounds like I need to just sent PTC my converter then
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Honestly, if it were me personally, I would try a stock replacement converter first, see how it behaves. Aren’t too expensive.

Then if it doesn’t behave as you wish, take detailed notes about how it behaves, Rpm, load, throttle, gear range etc,

Then talk to PTC and send them yours.

As far as picking which stock converter, find a trans parts catalog, on inter web, and see what stock converters are available.

I’m guessing some model Grand Cherokee with towing package on I6 would be my choice.


Transmission Parts Online 500 500 Transmission Parts
 
Mac5005 said:
Honestly, if it were me personally, I would try a stock replacement converter first, see how it behaves.
Click to expand...

So if you recommend getting a stock one first do you even think its worth it to order a new one or just use my old one? I didn't have any issues with it before I took the motor out. This way I can save some money up front and if that point I dont like the way it performs do the same thing. Or do you think it should be replaced given the amount of miles that are on it and the stroker motor install?
 
@Mac5005 ? do you think I should just use my old one or get a new stock one? no known issues with the old one. I went on the link you posted (thanks for that) saw the stock replacement for mine which is a code 596. It doesn't show the stall rpms for it and I didn't see anything on a torque converters for a ZJ with a towing package. Everything I have found about stall for those was around 2000-2200rpms but nothing specific to mine.
 
I'd run it. The stroker motor doesn't have much of an effect on it. If you put a 4:1 case in it, you'll probably be looking for a new converter.
 
84jimmy said:
4:1 case? As in transfer case? And if so is that the chain and gear set in the transfer case?
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Yes, the lower gear ratio will allow the torque converter to walk through the brakes in low range. If you're asking, you probably don't need to worry about it.
 
shawn said:
Yes, the lower gear ratio will allow the torque converter to walk through the brakes in low range. If you're asking, you probably don't need to worry about it.
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you are right I dont......but now that I looked at it I am interested. this will have to be something I look back at later. one thing at a time
 
84jimmy said:
@Mac5005 ? do you think I should just use my old one or get a new stock one? no known issues with the old one. I went on the link you posted (thanks for that) saw the stock replacement for mine which is a code 596. It doesn't show the stall rpms for it and I didn't see anything on a torque converters for a ZJ with a towing package. Everything I have found about stall for those was around 2000-2200rpms but nothing specific to mine.
Click to expand...

If nothing was wrong with your stock one and worked fine, I’d run it.
 
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