4R70 guys lockup or not?

[JST4FN]

I'm getting ready to swap out the six speed for a 4R70. The trans is currently set up with a non locking converter. I know for all out strength this is the way to go. I was wondering at what point ,hp wise, lockup becomes an issue? I've gone thru a ton of threads on several forums looking at Cobra swaps etc... but I couldn't find a solid answer.
Thanks Mike

 

[Born To Run]

4R70

I'm getting ready to swap out the six speed for a 4R70. The trans is currently set up with a non locking converter. I know for all out strength this is the way to go. I was wondering at what point ,hp wise, lockup becomes an issue? I've gone thru a ton of threads on several forums looking at Cobra swaps etc... but I couldn't find a solid answer.
Thanks Mike

I know of some with a lockup at 800+ hp.He only drag races said vehicle.If you are racing only i would go non lockup.Lockup will give you a little better mpg & a few mph in the 1/4 mile.Ask your tranny builder & follow his advice.Good luck.

 

[94tbird]

I have a 4r70W with a lockup converter

They are a lot stronger than people seem to think.

FWIW I DO NOT USE the lockup at the track, although I do have the ability to. I had my converter stalled, and in combination with my shift points and redline, so I would not need to lock up to cross the line.

I just like that its there should i need it.

 

[MLC40]

I have had an FB 4R in the car for two years. When I was running 450 rwhp my trans temps were fine and I never used the lock-up unless I was on the highway. Now that I am running 640 rwhp the trans temps are higher and I use the lock-up on the street to keep them from getting over 190. FWIW, I lock-up after I shift into 3rd at the track.

 

[Fake_Snake]

FWIW, I lock-up after I shift into 3rd at the track.

mine is setup the same... i think mine is 3rd around 115 mph.. or something..

 

[94tbird]

I have had an FB 4R in the car for two years. When I was running 450 rwhp my trans temps were fine and I never used the lock-up unless I was on the highway. Now that I am running 640 rwhp the trans temps are higher and I use the lock-up on the street to keep them from getting over 190. FWIW, I lock-up after I shift into 3rd at the track.

What trans cooler are you using?

I changed my cooelr from the FB unit to a Derale one. When locked up i see about 120 on the highway

 

[JST4FN]

I have a 4r70W with a lockup converter

They are a lot stronger than people seem to think.

FWIW I DO NOT USE the lockup at the track, although I do have the ability to. I had my converter stalled, and in combination with my shift points and redline, so I would not need to lock up to cross the line.

I just like that its there should i need it.

I was thinking about doing the same. Is it the shaft or converter that's the week link? The converter I'll be getting with it is a 3600 non-lock. While performance will probably be fine I'm worried about temps on the street.
Thanks Mike

 

[05stroker]

I was thinking about doing the same. Is it the shaft or converter that's the week link? The converter I'll be getting with it is a 3600 non-lock. While performance will probably be fine I'm worried about temps on the street.
Thanks Mike

Is the trans you are getting a AVB or a MVB ?

 

[JST4FN]

It has a Lentech AVB with transbrake. I'm going to go with the optishift controller and put OD on a switch.
Thanks Mike

 

[05stroker]

It has a Lentech AVB with transbrake. I'm going to go with the optishift controller and put OD on a switch.
Thanks Mike

That is what I have. I seem to remember Len telling me if I wanted the AVB and TB the the lock up was not an option. I just dont remember if it was due to the power rating or fluid psi or supply or somthing like that. I would call hm Mon. (or maybe even tomorrow ) if I was you .

You can check mine out this weekend if you want. It is still on stands , so you can see where I had to "massage" the car to get it in there .

 

[JST4FN]

That is what I have. I seem to remember Len telling me if I wanted the AVB and TB the the lock up was not an option. I just dont remember if it was due to the power rating or fluid psi or supply or somthing like that. I would call hm Mon. (or maybe even tomorrow ) if I was you .

You can check mine out this weekend if you want. It is still on stands , so you can see where I had to "massage" the car to get it in there .

I have to work till noon and then I'm meeting the guy to get the trans. I'll probably try to swing by after that.

Thanks Mike

 

[MLC40]

What trans cooler are you using?

I changed my cooelr from the FB unit to a Derale one. When locked up i see about 120 on the highway

I am running the the biggest Derale stacked plate cooler with fan they make, I think the part number is 13670. The issue is I have mine mounted where the EVAP crap was so the air flow is not the best.

 

[94tbird]

I have the same unit. Mine is directly in front of the car, in front of the radiator. I got no AC stuff there so it fit perfectly. I didnt use the fan or the shroud that came with it.

 

[05stroker]

I am running the the biggest Derale stacked plate cooler with fan they make, I think the part number is 13670. The issue is I have mine mounted where the EVAP crap was so the air flow is not the best.

Do you have the unit with a fan or without ?

Edit: just noticed you said stacked plate . Is it the 12x13 ?

I have two of these installed in the same area whare the evap crap used to be .

http://www.jegs.com/i/Derale/259/15800/10002/-1

 

[MLC40]

Do you have the unit with a fan or without ?

Edit: just noticed you said stacked plate . Is it the 12x13 ?

I have two of these installed in the same area whare the evap crap used to be .

http://www.jegs.com/i/Derale/259/15800/10002/-1

Yes mine has the fan and the shroud. Here is the one I bought...

http://www.summitracing.com/parts/DER-13870/

Since you are running two of them you will be fine. I feel I am ok as long as I lock-up in 90+ days. If I ever thing it is too hot I will add another cooler.

 

[94tbird]

well im bringing this back from the dead with a new question

Why would you lockup in third instead of leaving it unlocked? What does this gain you?

At what point in third do you lock u? Immediately? Is there any RPM limit?

Im assuming when people say lockup converters are breaking, its because they are locking them up in a race situation vs leaving them unlocked?

 

[05mustang_TT_charged]

I had mine wired to Lock Up immediately when I shifted to 3rd. I never ran it unlocked so I am not sure of the difference between them but I was trapping 140 mph with it locked. I have a looser converter than you though and it wouldn't suck the rpm down that much.

 

[94tbird]

what converter are you running? I am a 3400 stall iirc

 

[fin1]

As soon as I hit third I lock it (PI stalled @ ~3600). You don't have to lock it. I didn't notice much ET change when I didn't lock it but the MPH will pick up some when you do. I do it simply to pull the RPMs down a bit so I that I trap at a lower RPM and closer to the power band.

 

[MLC40]

Once I shift to third I press a button and lock-up. There is a slight delay in me pressing the button so it gives the engine time to recover from the gear change. I have also not seen much of a ET difference if i don't lock-up.