The stock stall on a 2004.5 5AT G35 is 2600-2900 rpms per the service manual. The torque multiplication ratio is 2.0.

Those are pretty darn good specs for a torque converter (usually abbreviated "TC", not "TQ" which just stands for torque).

For FI, the TC is usually upgraded with a *lower* stall speed to help traction at launch with all of the added engine torque that FI provides.

For NA, some have gone higher (greater than 3k stall) to increase off-the-line torque. The torque multiplication that occurs at launch (2 X) rapidly diminishes to (1:1) which makes sense once the TC is locked up. The higher the stall speed, the easier the engine will rev to that rpm before the car begins to move (because the wheels are fluid coupled via the TC to the engine but the TC is not locked and the two halves of the TC spin freely). When you raise the stall speed, it allows you to get the engine into the power band before applying the torque to the wheels (reducing bog).

Follow Sharif's advice -> go with the VB.

 

Will the VB help u in the quarter mile? I understand the VB helps u with firm shifts but what does that amount to for performance? Is the VB just needed to save the trannys' life?

 

With the VB and TC I was gaining 1/2 a car length per shift,that's about 0.05 sec and that's an approximation...but yes

 

Thats mostly bc u have a tc installed. U were able to get a good start.

 

I believe you asked on the shifts not off the start and shifts is what I responded to,TC came aboout six months after the VB and was a trmendous help but we are heavy and AWD

 

It will help in just about every way. You can wait to do the TC at a later date, as the tranny does not have to be removed for the install of the VB. Anyone going FI on a 5AT should have a VB upgrade as a manditory step. It will save you alot of headaches in the future...

-Mark

 

Thinking of going FI with an auto, so is the best to do a valve body upgrade and tranny cooler?...anyone know the cost of the vb upgrade?

 

I believe they start with Stillen at $700 and Level 10 at a bit more and then theere are 2 versions one about this level and another around 1200 from memory.Close enough for correction,add install
I thought I would add my piece on complete trans build
http://www.infinitifx.org/phpBB2/viewtopic.php?t=11010

 

http://www.forgedperformance.com/sto...cat=261&page=1

 

& will be moving 5+ @ 750.00.... I will try to let everyone know if I hear from the them again OR someone just get it together...

-Mark