Questions about final drive ratio

[TurboTurismo]

Hi all, Just wondering if using an a413 tranny from a 89 2.5 turbo mini would work in my Turismo as far as the final drive, the car will have the matching 89 turbo engine installed aswell....... should I go with a tranny from a turbo car instead? the current 91 tbi setup and an 87 auto and has good around town getup and go but I still want good hiway rpms aswell when I put the turbo in.....suggestions please

I run 195/50/15s http://www.cardomain.com/ride/2291434

Thanks

Robb

[TurboGLH]

I'm sure Simon will correct me if I'm wrong, but I believe that all turbo boxes got 3.02 as a F/D. So the van auto will work just as well as a car one.

On a side note, you may find that the 2.5 in a light car like a turismo may drive better with 2.93 or 2.74's instead. If this is going to be a decently built 2.5, changing the F/D now would be easiest vs doing it in the car later.

[TurboTurismo]

Well the engine is a 89 2.5 T1 out of a mini as stated and the final drive 3.02 I think....Simon....where are you?.... seriously, with the Turismo@ 2300 lbs or so will the 3.02 gearing make me too slow in town and what if any are the issues at hiways speeds... I am still learning about the turbo setups. The engine and tranny combo are from a 89 shorty mini that really has only 65 k , whats that in miles?.... like 40 thou or something, My MoPar book says it has 180 ft lbs torque and 150 hp stock, I have been dealing with Carbs and tbi stuff and maxed out all I can do to get them fast and still have good drivabilty.....I gave em up for now, so now its turbo time for fun and probably more headaches..LOL....

Robb

[turbovanman²]

Yeah, most turbo's if not all turbo cars/vans got the 3.02, this is a great gear for around town but makes for a brutally high rpm on the highway.

You need to go lower, IE 2.50, with a light car like you have, you can get away with that. I changed out my transfer gears to .91's and dropped 3-400 rpm on the highway and noticed no ill effects around town, and thats with my 3600lb van,

I'll post up the link when I get home that shows all the tranny final drive and transfer gear ratio's.

[Vigo]

yeh with your setup definitely go with lower numeric final drive. my aries with about the same tire size as you and a 3.5fd 520 i.e. 2.5:1 in 5th was perfect, and thats as low as the gearing gets for these cars unless you dig up some fairly rare 525 crap. 3.02 was never fun in any car i owned. 2.78 auto was decent. but 2.5 effective top gear ratio from the 3.5FD 520 was the best.

you can build a 2.6FD 413 with common parts, get a 3.5 fd 520 or 523 or build a 3.5fd 555 hybrid. since you got low weight and high torque id just build a cheap, easy-to-find/fix-everything 2.6fd auto.

also, if you do go auto but arent sure what gearing you may end up wanting, look at the different gearing combos and figure out primarily which ring and pinion you want. transfer gears are easily swapped from the driver wheelwell. doing the ring and pinion in the car is much more annoying.

ring and pinions:


2.86:1

3.05:1




transfer gearsets:


0.91:1

1.06:1

there are others but these are very common.






combos:


2.86/.91 = 2.60:1 FD


3.05/.91 = 2.78:1 FD


2.86/1.06 = 3.02:1 FD


3.05/1.06 = 3.23:1 FD



A413/670 ratios
2.69
1.55
1.0
^^ convenient text document i keep around

also, pm me with some carb/tbi experiences/info

[TurboJerry]

Carb Automatic cars seem to have the .91 transfer gears BTW.