914 901 Gear Ratios, Tech Article, Gear Ratio Workbook, Member Gear Set Library Options

[race914]

To maximize my 914's performance on the track, I've put together several different gear sets for my 901. This has helped me to maximize my top speed on the straights, as well as acceleration out of the corners. This has proved to be a great advantage over stock geared 914s.

I want share the info I’ve collected, as well as what I’ve learned from these projects.

I’ve put together a Gear Ratio Tech Article that includes: why you might consider re-gearing; ways to approach this project; the 914 901 Gear Ratio Workbook (MS Excel required); and references to 914World members that provide related products & services.

Lastly, and perhaps most importantly, I’ll be maintaining the Member Gear Set Library that includes the various gear ratio setups that Members are using for different applications & situations. This centralized repository will greatly facilitate finding information applicable to your re-gearing project. Important Note! The ‘right’ gear set for you is particular to many factors. To list a few, the car’s weight, suspension, engine, and DRIVER! Don’t take the gear-sets listed for a particular application as your ideal setup. Contact the owner, compare corner speeds, suspension setups, engine characteristics, driving skills, etc. All of these factors play into what will work for you.

If you'd like to contribute to the "Member Gear Set library", post your info on this thread and include:

* Applicable Category (Autocross, Street, Track (including track name)
* Engine (cc & cylinders),
* HP,
* Redline RPM,
* Tire Diameter,
* Weight w/driver,
* 1st-5th gear codes, and
* Any short comment that you’d like to pass on, or better yet, a link to the applicable 914World discussion thread on your setup

[neilca]

This is for road racing at Road Atlanta and Roebling Road.
2.0 liter six cylinder
175 hp
max 7500 rpm
tire diameter 23.6
Gears A, I, N, S, X

I have not run the box as yet but these ratios are suppose to work well on track. These are very fast tracks so first igear s considered to be a pit gear only.

[neilca]

This is for road racing at Road Atlanta and Roebling Road.
2.0 liter six cylinder
175 hp
max 7500 rpm
tire diameter 23.6
Gears A, I, N, S, X

I have not run the box as yet but these ratios are suppose to work well on track. These are very fast tracks so first igear s considered to be a pit gear only.

I have now run these gears and they are not correct. The "I" second is too low to use on track. I believe an "M" in second would make a better choice. I still need to optimize the rest of the gears.

[tomburdge]

This is for road racing at Road Atlanta and Roebling Road.
2.0 liter six cylinder
175 hp
max 7500 rpm
tire diameter 23.6
Gears A, I, N, S, X

I have not run the box as yet but these ratios are suppose to work well on track. These are very fast tracks so first igear s considered to be a pit gear only.

I have now run these gears and they are not correct. The "I" second is too low to use on track. I believe an "M" in second would make a better choice. I still need to optimize the rest of the gears.

IMHO I think its just the opposite.'I" is too tall and "M" will be way too tall for 2nd.
You might think about the F,G,H/HA for second depending on revs and torque curve.

"A" should just be a paddock gear and I can't imagine you coming to a 'green flag" with an "m" or anything close to it.The N,S,X package is nice.

(MHO based on racing a production based 914 for the last 15 years at the national level , from Daytona to Mosport)

Tom B. (IMG:style_emoticons/default/biggrin.gif)

[neilca]

This is for road racing at Road Atlanta and Roebling Road.
2.0 liter six cylinder
175 hp
max 7500 rpm
tire diameter 23.6
Gears A, I, N, S, X

I have not run the box as yet but these ratios are suppose to work well on track. These are very fast tracks so first igear s considered to be a pit gear only.

I have now run these gears and they are not correct. The "I" second is too low to use on track. I believe an "M" in second would make a better choice. I still need to optimize the rest of the gears.

IMHO I think its just the opposite.'I" is too tall and "M" will be way too tall for 2nd.
You might think about the F,G,H/HA for second depending on revs and torque curve.

"A" should just be a paddock gear and I can't imagine you coming to a 'green flag" with an "m" or anything close to it.The N,S,X package is nice.

(MHO based on racing a production based 914 for the last 15 years at the national level , from Daytona to Mosport)

Tom B. (IMG:style_emoticons/default/biggrin.gif)

I have been using the third ("N") at turns 5, 7, and 10A at Road Atlanta with good results, that is when I can find it, shifter issues. Road Atlanta is a very fast track.