Upgraded diff

[gmvf6l]

Hey everyone,

2 days until I upgrade my current 2.92 stock diff gears to tru trac 3.45 or 3.73. I'm really stuck between these two gear ratios. As I know 1st gear will be pointless with the 3.7s but not sure 3.4s will be punchy enough off the line for myself personally.

I own vf calais 6.0 auto and already have cnc heads, cam, otr, headers, full 3" and even evcX throttle controller set to launch control and that isn't enough.

Just looking to those who has had similar experiences maybe with both gear ratios or ones you have now from the standard row boat 2.92 stock ratio.


Thanks

 

[hjtrbo]

Did you replace the converter with a high stall unit?

 

[gmvf6l]

Did you replace the converter with a high stall unit?

Not yet, only done cam, heads, otr, headers, exhaust. Now diff in 2 days after that I was considering 3500 hi stall

 

[RevNev]

2 days until I upgrade my current 2.92 stock diff gears to tru trac 3.45 or 3.73. I'm really stuck between these two gear ratios

I think for general road use, 3.73's are too low and 3.45 is the better choice with a cammed auto.

 

[daves8]

I have a Calais with 6.0.

I have smaller sized cam (219/224/115) and all bolt ones and went with 3.45 diff gearing.

Happy with result

 

[daves8]

Not yet, only done cam, heads, otr, headers, exhaust. Now diff in 2 days after that I was considering 3500 hi stall

What size cam did you choose?

You might not need a stall if it’s small enough and doesn’t push on breaks with a 3.45 diff

 

[gmvf6l]

What size cam did you choose?

You might not need a stall if it’s small enough and doesn’t push on breaks with a 3.45 diff

223/228 but looking at going bigger soon aswell.

 

[gmvf6l]

I have a Calais with 6.0.

I have smaller sized cam (219/224/115) and all bolt ones and went with 3.45 diff gearing.

Hap

I have a Calais with 6.0.

I have smaller sized cam (219/224/115) and all bolt ones and went with 3.45 diff gearing.

Happy with result

Obviously a massive change to take off? How's it feel at 100kmh

 

[gmvf6l]

I think for general road use, 3.73's are too low and 3.45 is the better choice with a cammed auto.

It's only a baby cam at the moment. I'm just greedy and want the best punchiness off the line I can get without going to overboard with say 3.9s or 4.11s lol

 

[Ginger Beer]

You need to look at it holistically

Your converter stall should be based of your cam, diff gears, engine power, and importantly what you use your car for, street? drags? 90% street 10% drags, this bit matters alot

If you mess this up you will have issues and the car will not perform optimally for what you mainly use the car for

Then, once you know what stall you require for your cam and diff gears, get the transmission tuned

It isn't as simple as just bolting random stuff in, but, if you do your research and speak to a "good" automatic transmission shop that does alot of performance stuff you will be fine

And then, if you add boost later on, especially PD, you may need to revisit the cam and stall

#science