Converter Blow Through

[ZC-DMAX-LMM]

I have done Mike L 30 mph test looking for 1:1 ratio of tach to mph to see how my coupling efficiency was. Granted I have a 1600 stall that was installed before I had my current turbo. During the test i noticed about 1000-1400 rpm increase before it really starts to hook and pickup. I know this showing it is not efficient. My biggest question/ concern, is this bad for the converter or trans life? Figuring on gettin it restalled higher or possibly goin to another tc down the road once funds allow...but if it is doin damage I would rather bite the bullet now..sorry for the long post. Revmax converter btw...

 

[Chevy1925]

you need to log the slip difference of the coverter to see just how bad you are blowing through it. restalling it higher will make coupling worse.

 

[ZC-DMAX-LMM]

you need to log the slip difference of the coverter to see just how bad you are blowing through it. restalling it higher will make coupling worse.

Is that a PID i would already have? I remember there might be something like that in my cts2, is that the same/ reliable?

 

[JoshH]

With a converter unlocked, you will have to flash the RPM to where it stalls before you start accelerating. This does not damage anything in the transmission or torque converter; it is just part of the fluid coupling and how a converter operates. If the converter is locked and you notice an increase in RPM without an increase in speed, that is not good. When the converter is unlocked, what RPM does the engine jump to before it starts accelerating? If you floor it from a stop, what RPM does it flash to immediately before it takes off? If you foot brake it and try to build boost, how high does the RPM climb before it stops increasing or it pushes through the brakes?

 

[ZC-DMAX-LMM]

With a converter unlocked, you will have to flash the RPM to where it stalls before you start accelerating. This does not damage anything in the transmission or torque converter; it is just part of the fluid coupling and how a converter operates. If the converter is locked and you notice an increase in RPM without an increase in speed, that is not good. When the converter is unlocked, what RPM does the engine jump to before it starts accelerating? Its goes to about 2200-2400 and thats from the 30-35 roll. If you floor it from a stop, what RPM does it flash to immediately before it takes off? If you foot brake it and try to build boost, how high does the RPM climb before it stops increasing or it pushes through the brakes?

I understand that the coupling has slip but when Mike L said its should follow the tac and be about 500 diiference got me concerned since mine was soo much more than that. I will get the answers to the other questions today on my lunch break. When the tc locks though it locks and takes off.

 

[Mike L.]

You can have a higher stall with great coupling. You need a good converter builder that can dial in your converter to what YOUR truck needs. Also remember you do not need to use all the stall your converter is capable of. Use what you need for the best launch. Stall is for launch and it's finished 50 feet out of the hole. It should start coupling right after that. The key is to have the correct stall to get your rpm's up so that you can instantly take advantage of the coupling. You want a smooth transition.

 

[JoshH]

I understand that the coupling has slip but when Mike L said its should follow the tac and be about 500 diiference got me concerned since mine was soo much more than that. I will get the answers to the other questions today on my lunch break. When the tc locks though it locks and takes off.

Every converter is different. A higher stall converter will allow the engine to flash to a higher RPM before it starts to couple which is good to help get larger turbos spooled up. If you have a way to datalog you should be able to see converter slip spike and then start to pull down at the top of each gear. Engine RPM will drop some on the shift, but you will likely see the slip go back up a little immediately after a shift. There is no rule on exactly how your setup should behave since there are so many variables that affect converter stall speed.

If your 1000-1400 RPM estimate is accurate, it sounds like your converter stall speed is a little higher than a 1600 RPM.

 

[ZC-DMAX-LMM]

Every converter is different. A higher stall converter will allow the engine to flash to a higher RPM before it starts to couple which is good to help get larger turbos spooled up. If you have a way to datalog you should be able to see converter slip spike and then start to pull down at the top of each gear. Engine RPM will drop some on the shift, but you will likely see the slip go back up a little immediately after a shift. There is no rule on exactly how your setup should behave since there are so many variables that affect converter stall speed.

If your 1000-1400 RPM estimate is accurate, it sounds like your converter stall speed is a little higher than a 1600 RPM.

Does my autocal have the capability to read that since I dont have a v2?

 

[ZC-DMAX-LMM]

When the converter is unlocked, what RPM does the engine jump to before it starts accelerating? Its goes to about 2200-2400 and thats from the 30-35 roll.
If you floor it from a stop, what RPM does it flash to immediately before it takes off? 1600
If you foot brake it and try to build boost, how high does the RPM climb before it stops increasing or it pushes through the brakes? Standing on the brake I got it to around 2100 rpm and 15 psi.
And on my cts2 the highest tc slip i saw was 1100.
I got a couple videos if that would help.

https://drive.google.com/open?id=12Cd9HvGinjYyvmLuscOJGbULV0M8c5US

https://drive.google.com/open?id=1zAFtIZ6LAxKgiGkuPkx81TBG8v-HXXLU

 

[ZC-DMAX-LMM]

Weekend bump


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