901 gear set chart

[Charles Freeborn]

Can anyone direct me to a chart or graph showing the various gear sets that can be configured in a side shift 901?
Current box is from a '73 with AFKSX gears.
Would like to get a little taller 5th and maybe 4th.
Car is track only.
Thx.

Scratch that. Found it.
http://www.914world.com/specs/regearing_901.php
Link in the article goes to a "workbook" Good data there.

[John Rogers]

You mentioned the car is "track only" but nothing about the engine such as maximum RPM, how well the car accelerates, types of brakes/tires and what do you want to have top speed to be? Final item is how much money are you going to want to spend and do you want to add the cost of a cooling system? Is this to be an auto-x car with a very tight curvy course or road race on a track such as Willow Springs CA, PIR in Phoenix or????

My vintage 914-4 later turned into a 914-6 used two different gear sets for top 3 gears M-S-X for large tracks and K-Q-V for tracks like PIR or road courses in Baja Ca (Tijuana, Ensenada and Tecate). I also had to update the shift rods, connectors and the shifter. The bearings, synchros, ETC had to be done over every two years. $$$$$$$$$$
Good luck, John

[GregAmy]

Yup^^^.

Torque at what max RPM (err, uh, "horsepower")
Tracks you run at.
Lowest speed at slowest corner.
Fill in the spaces.

Oh yeah: budget. Most important.

[manbridge 74]

Charles, good to see you still have your 911.

Please let me know when you want to sell 4th or 5th for a type 911 box I have...

[Charles Freeborn]

Guys guys... calm down....I was simply looking for gear ratio data, not everyone's opinion on how I plan to use it.

Since inquiring minds want to know...

2.0L 94/71, Euro pistons, 48 (yes 48!) 38 valves, Webcam 86b, solid lifters, lightened balanced everything, crank fired ignition, 170 +- hp, not much power above 6k rpm so rev limiter set at 6200, downdraft cooling fan, front and back oil coolers, accusump, stage 2 clutch, raked windshield, lowered roof, '85 carrera front suspension, SC brakes, stiffened trailing arms, rear coil overs, 225/45/15 Toyo RR's, box flares, 13 mm front hub spacers, 30 mm rears, race headers, flowmaster muffler, full cage, 6 pt harness, 1700 lbs wet..
Track only means that. AX is not track. I run at PIR, ORP, The Ridge and will pop the cherry at Pacific Raceways in the spring. If I win the lotto I'll trailer down to Thunderhill, Sonoma and Laugna Seca, but I wouldn't bet the farm on that .
Any other questions?


And no, I don't want to sell any gears. There's no such thing as a "911" gearbox. I've got a 915 in my 911 and this 914 has a 901.

[manbridge 74]

Type 911 gearbox was produced for the 70-71 911. Uses 901 gears and such. Truth...

[infraredcalvin]

I used this to figure out my shortbox... double check the gears when selecting “stock” templates.

https://retro-sport.com/calculator/porsche-gears

It’s a little slow to load, but useful and printable.

[Charles Freeborn]

Originally Posted by manbridge 74

Type 911 gearbox was produced for the 70-71 911. Uses 901 gears and such. Truth...

Whatever. I don't have one of those.

[Charles Freeborn]

Originally Posted by infraredcalvin

I used this to figure out my shortbox... double check the gears when selecting “stock” templates.

https://retro-sport.com/calculator/porsche-gears

It’s a little slow to load, but useful and printable.

Thanks. Will have a read through.

[GregAmy]

"Calm down"...?

Here, let me Google that for you: https://lmgtfy.com/?q=901+series+porsche+transmission

I bet you're feelin' lucky, too.

[Emo993]

I did it old school (analog), the yellow is standard 914 gearing and the red is the short gear set. Best, Mark

[Matt Monson]

Originally Posted by Charles Freeborn

Whatever. I don't have one of those.

Yes, but you also said you have a 901 in your 914. You’ve got an aluminum box swapped in that car? Cool. That’s rare and unique. Can you post pictures showing us how the shifting issues are solved?

Sorry Charles. Stock 914 gearbox is a 914, and it shares more with a type 911 gearbox than a 901.

You’ve got really knowledgeable people here. I think the calm down advice would be well heeded.

[kevingross]

https://blueskymotorsports.com/index.php?option=com_content&view=article&id=17&Itemid=6