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

[race914]

How can I get my top speed up. I dont race but would like to get my freeay rpm's down and a faster top speed

Here's a recent thread on ways to achieve a taller 5th

[Randal]

Went to the "914 901 Gear Ratio Workbook" but couldn't find the tabs in that .xls spreadsheet.

Help, where are they hidden? (IMG:style_emoticons/default/wacko.gif)

Nice work pulling all that information together!

[race914]

Went to the "914 901 Gear Ratio Workbook" but couldn't find the tabs in that .xls spreadsheet.

Help, where are they hidden? (IMG:style_emoticons/default/wacko.gif)

Nice work pulling all that information together!

Hi Randal,

When you open the 914 901 Gear Ration Workbook, open the excel sheet in full screen. Sometimes you won't see the excel tabs (worksheets) on the bottom of the page if not in full screen.

Here's what you should see at the bottom of the excel sheet



Let me know if that works.

Greg

[naro914]

I basically did what's in the link above 'to achieve a taller 5th'.

Stock was A F N V ZD
Flipped 5th to 3rd, and 3rd to 5th, and swapped V 4th to R, I now have:

A F KA R Z

It's a real cheap way to bring all the ratio's down for MUCH better acceleration, only have to buy 4th.

When someone asks, I say it feels like I have a 2 1/2, 3 1/2 and 4 1/2 gear, not 3, 4 and 5.

So:
* Applicable Category - Track
* Engine - 2.2 liter 6 cyl
* HP - approx 200
* Redline RPM - 7400
* Tire Diameter - don't know?
* Weight w/driver - 2000
* 1st-5th gear codes, - A F KA R Z

Works great at CMP, VIR, Barber, Watkins Glen. Not so great for Road Atlanta - could use a taller 5th.

[J P Stein]

Specs of the shitbox.....er...Britbox:
Wt approx 1700 wet.
204 hp @ 6300 at the wheels.....bout the same torque 3500 to 5100.
rev limit 7100.
Gearing F, ZD (flipped 3rd).
Tire dia 22.5 in back.

Need more "umph" to run with the real big dogs.

[tomburdge]

I basically did what's in the link above 'to achieve a taller 5th'.

Stock was A F N V ZD
Flipped 5th to 3rd, and 3rd to 5th, and swapped V 4th to R, I now have:

A F KA R Z

It's a real cheap way to bring all the ratio's down for MUCH better acceleration, only have to buy 4th.

When someone asks, I say it feels like I have a 2 1/2, 3 1/2 and 4 1/2 gear, not 3, 4 and 5.

So:
* Applicable Category - Track
* Engine - 2.2 liter 6 cyl
* HP - approx 200
* Redline RPM - 7400
* Tire Diameter - don't know?
* Weight w/driver - 2000
* 1st-5th gear codes, - A F KA R Z

Works great at CMP, VIR, Barber, Watkins Glen. Not so great for Road Atlanta - could use a taller 5th.

Doesn't get much taller then a ZD, does it? I've got one if you need it.

Tom B.

[BKLA]

* Applicable Category Track: Portland (w/festival corners), Oregon Raceway Park
* Engine 2.7L 6
* Max RPM 7100
* HP: 228
* Tire Diameter: 25.4" (245/40-17)
* 1st-5th gear codes are: A GA M Q V

[naro914]

Doesn't get much taller then a ZD, does it? I've got one if you need it.

Tom B.

I have two tranny's, one stock with the ZD, and the other listed above. I change over to the stock one for Road Atlanta...

[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)

[brant]

I am blown away with how versatile my ratio's are
my 5th is too high for the little tracks around here but will be great for big tracks
I never find a hairpin that I can't use either my 1st or 2nd gear in.

F - 1st
J - 2nd
O - 3rd
S - 4th
V - 5th

seriously its a lot of work to put into a box
but then you have a box that will do nearly any track
it sure makes tow's to other states and first time visits to new tracks a lot more reassuring!

brant

[bam914]

I am blown away with how versatile my ratio's are
my 5th is too high for the little tracks around here but will be great for big tracks
I never find a hairpin that I can't use either my 1st or 2nd gear in.

F - 1st
J - 2nd
O - 3rd
S - 4th
V - 5th

seriously its a lot of work to put into a box
but then you have a box that will do nearly any track
it sure makes tow's to other states and first time visits to new tracks a lot more reassuring!

brant

Do you have reverse with the F 1st? I just bought a JNSX for my 914.

[brant]

no reverse... The F gear is too physically wide. The F gear doesn't actually fit inside of the case either because of it's size. The case has to be machined larger on the inside and then layers of magnesium weld are built up on the exterior to re-seal the case where the F gear now resides.

mechanic jokingly told me; "its part of the commitment"
I've run this way for about 4 years and its ok to give up reverse. There are a lot of 915's out there without reverse and its more common in the PCA club race ranks than I realized.

but on the upside, its 5 useable gears (theoretically kinda like having a 6speed box). And with F and J, there is always the right gear for a rolling start or hairpin corner.

[bam914]

Must have reverse in SCCA.

[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.

[stownsen914]

I know one ex-914/6 racer who ran a J 1st gear at Road Atlanta, if you can believe that. He was also fond of M for second. Personally I have a "KA" second (ZD flipped backwards and welded in place of second gear on the mainshaft), and for most tracks it's great. For some tracks with slow corners, KA is too tall and I have a GA first gear. No reverse when using that ratio, but that has been inconvenient only a few times. The bigger pain is getting the car rolling in 1st when an unsprung clutch disk!

Scott

[vintage914racer]

Any proven setups for Road America?

[Dr Evil]

(IMG:style_emoticons/default/popcorn[1].gif)

[shoguneagle]

Just had Doc rebuild my transmission for the following:

Use: Street
Engine 3.2 (1987) Sixer
Hold max RPM to 6000
Wheel size: 17 inch Cup II rims, diameter - approx 25.3 inches
Weight: Estimated 2,200 to 2,300 lbs.
Gearing: 1st - A; 2nd - F; 3rd - O; 4th - X; 5th - Flipped H

Goal: To have good gear ratios in each gear for peppy response and shift points; fifth gear to run somewhere below 2800rpm for extended highway cruising - have large front cooler to compensate for any increase in the oil temperature from running at lower rpm levels. Oil capacity is approximately 20 plus quarts and has been running 180 degrees at 7000ft without thermostat bypass opening; at temperature and lower altitude targeted to run in the range of 200 to 215 (temperature in target plan is at 100degrees and more; desert type environment).

[gil914]

Use: Rally
Engine 2.2S
Max RPM: 7300
Wheel size: 17/65-15, diameter - 25.6
Weight: 2600lbs.
Gearing: A, F, HB, M, Q

Limited top speed but excellent acceleration out of slower corners. Needed an E 2nd but never got around to it. Transits were strictly speed limited so Q 5th was OK.