I get this question a lot! But honestly for me it’s an easy choice because of experience with so many different cars… Especially when dealing with import cars with these 6-speed t56 magnum transmissions.
Tremec calls the wide ratio “WIDE” because of the WIDER or BIGGER gear splits on 1-4 gears… So before I talk about this further, try to think of how a bigger gap in between gearing effects a car on shifts?
A larger gear split causes for a bigger RPM drop on shift, which results in bigger loss of boost, more lag on each shift. On a small displacement car, like most imports, this is of utmost importance! You want to minimize the car falling out of RPM and boost on shifts, which is inevitable, but the close ratio transmission will help a lot with this. Especially on the 3-4 shift.
I can tell you from experience, that I sell 99 close ratio boxes to every 1 wide. I try to talk to customers and ask why they want the wide ratio and normally after I talk to them about it they will change their thought process and go with the close ratio. Some guys are stuck on it because they want that shorter first gear. But you can not, and should not be picking a transmission based on first gear alone.
The proper way to do this is setup your rear gear to match the transmission. This will give you an ideal overall gearing setup and it will work beautifully. Normally something in the 3.70-4.30 range, depending on tire height with something around 4.10 usually being the sweet spot. If you are a V8 with lots of low end torque you may want to go with taller 3.73 gearing. If you have a small displacement motor like a rotary car or 4cyl with low torque you may want to go to something like a 4.30 gear.
Picking the proper gear depends on 3 things.
- your RPM limit
- tire size
You can use TREMEC’s calculator to fine tune your gearing choice!
If you want pricing on a complete transmission kit or any of the Tremec transmission offerings please fill out grannasracing.com/quote
Magnum-F Part numbers below:
Magnum Part numbers below:
Magnum XL part numbers below: