Tranny gears,..for more pull.???

[flmont]

Now that Iam going with the 2.5 Ltr big four set-up from 914-lite spec's,.....a 190 HP with 185 Lbs of torque per Dr.Nugent,.. Iam now curious,..could I get more benifit from changing to shorter gears,...to get more pull / power thru the twisties,..??? but still want decent MPG,....Thanks

[flmont]

but only2nd 3rd and fouth..keep 1st and 5th,..tall ????

[John Rogers]

When I had my 2.4L and 2.8L fours and also the 2L sixes in my car we had two transmissions for various tracks. Both keep stock 1st and second. First had M-S-X for large tracks such as CA Speedway or Willow Springs and another had K-Q-V for short twisty tracks such as Las Vegas or Phoenix or the Mexican road races. The cost for this is just slightly over the top......

You can replace the input shaft and go with higher 1st and 2nd and use either of the above and you get 5 real usable gears, BUT now the cost is way high!

You can and probably should install a limited slip so that is more $$$$$$$ and to increase life, especially if you do any racing, a lube and cooler setup to increase gear and bearing life.

Last of all is an update to a 915 or other transmission type but.....

[flmont]

you can install a 915 tranny..??? didnt think they would fit,..I intend to drive hiway,..then run twisty mnt roads..???around the southwest,....plus who could I get to do the gear changes..Thanks Frank PS...how did u like the 2.4 for pwr and MPG...the last 914 I owned (1996) i dont think big 4's exsisted,..

[Dave at Pelican Parts]

The 915 trans will fit, but it's a good bit of work. You'll either need to find a 912E transmission (they only made 2099 of those, so good luck!) which has a 901-style main shaft to connect to the 914 engine's flywheel. Or you get a conversion flywheel of some type, likely from Kennedy Engineering. And you'll have to flip the ring gear around inside the transmission, and work out a shift linkage, and so on.

Freeway fuel economy will be greatly influenced by the 5th gear. The 914 already has the tallest 5th gear that they made for the 901 gearbox. You can go higher by getting a 3rd gear and flipping it--switching which shaft the larger and smaller gears go on, inverting the ratio.

On a 901 box, 2nd is fixed. It is literally part of the main shaft. The only way to change it is to either change out the main shaft, or to get a 904-style main shaft which doesn't have a fixed 2nd gear. Either way will be $$$.

Since 2nd is fixed, barring the above, there isn't much point in changing 1st.

You can change the other gears out, and even do some swapping as mentioned above. Going with stock 1-2 and then low 3-4 and a tall 5th will leave you with odd RPM drops between gears, but that can be lived with. Some gear sets are hard to get ahold of, so they're pretty $$ if you do. You can talk to Guard Transmission about that--Matt Monson knows more than anyone else I can think of about these gearboxes.

So the short version is: You can change things around, but it will get expensive very quickly!

--DD

[John Rogers]

Here are some of the things I learned in the years I had my hot rodded 914 race car.

- Since you are in the AZ area I would suggest a visit to Jim Patrick's race shop as he knows 914s pretty well and I raced with him for many years. You will be shocked at prices, but that is the way it is now days.

- While the transmission is getting worked up I would suggest rebuilding the shift linkage starting with the shifter (a JWest type is best), replace the firewall bushing with a racing type, replace the center flex joint with an aircraft type joint and redo the bushings in the rear. Do bushing maintenance at least yearly!

- Use SWEPCO oil and I strongly suggest a lube/cooler system and clean the strainer every 6 months.

- In the span of years, a 901 setup as noted here and a 915 will about even out.

- Do NOT downshift and then brake, brake hard and then downshift. Makes the transmission last longer and that is the way the factory racers with 901 transmissions did it.

- Adjust the clutch so it disengages/engages at about 50% pedal travel. Do not shift fast as a 901 is NOT a BW T10 or similar.

- A transmission with stock 1st and 2nd and M-S-X gears will let the car top at 135 MPH at about 7000 RPM. This was verified by myself and several other 914 vintage racers with GPS. No matter what others say, drag and losses limit the top speed.

Good luck and don't be too shocked at the amount of $$$$$ you'll spend.

[PCA7GGR]

A-F-M-S-ZD

1-4 for the track and the long legged ZD for freeway cruising.