(revised)

i am thinking that since i don't use 1st gear and 2nd gear is not removable - that my changes are limited to 3rd, 4th, 5th.

with 2nd being an F gear - 18:34 (1.889)

and the highest 5th being an H gear - 32:19 ( 0.59 )

what are the best gears for 3rd and 4th so that all gears are evenly spaced?

maybe a flipped V as 3rd gear? (1.08 -vs- N 1.261 )

maybe ZD as 4th? (0.71)

with H as overdrive? (0.59)

1.889
1.080
0.710
0.590

admins - pls put this attched chart under 914 tab

how will you use the car? AX? big track? street rod? daily driver?
what power band charachteristics will your v8 have? rpm range? power band?

not daily driver with gas guzzling V8 : )

street rod i suppose.

i just feel that 2nd winds out immediately when i get on it.

but 3rd as well and 4th too.

so H in 5th

and stock 5th gear used in 4th gear location seems to make sense to me.

and a slightly lower 3rd should be comfortable?

thanks

jim

I think that I remember Mike having a source for the 904 shafts that let you use independent 2nd gears - which means you could change it.

Zach

Dr Evil may want to chime in on this one. I have also been looking at what gears to use for my V8 conversion. Seems a flipped H for 5th is best. I dont know if you can put the stock 5th in the 4th gear place. Are you running a stock transmission right now?

yes - and i am running 195x60x15 tires which i like how they look on the car but are less tall than stock.

for the record - i won't be happy until i have a 930 gear box with massive axles and cvs on my car )

jim

Here's some existing resources on 914world for gear ratios:

Re-gearing info & gear ratio charts:

http://www.914world.com/specs/regearing_901.php

Feedback from 914world members on their setups (includes higher ratios for V-8 setups):

http://www.914world.com/bbs2/index.php?showtopic=79893

Hope this helps!

those skinny tires should help prevent braking trans and cv joints. shorter 3rd will make it pull harder down low but y9ou lack the grip for that

Jim, Have you thought about going with a taller tire?

Personally Im going to go with a 285 35 18 vs what I should be running which is 285 30 18. I have even contemplated 285 40 18's or similar. But I have a feeling it will look ridiculous.

Currently the 285 35 18 is ~ 26" tire height where as a 285 30 18 is just under 25". Which is ~ a 4% reduction in overall speed the engine runs.

Unfortunately im on the stock gearbox, but that is a whole other issue.

no - i like the way my size tire doesn't fill the wheel well and keeps my non flared 914 car low.

the stock trans is totally driveable - 3000 rpm at 65 mph - per my gps.

if i had a decent/quiet exhaust - i'd be fine.

the flipped H gear though should help get my rpms down for highway driving and get my mpg's up.

in a typical situation - being lazy : ) - off a red light - i go 2nd, the 3rd, then drop it into 5th. thus my thought of replacing 3rd and 4th with a ratio more centered between a F 2nd and a ZD 5th. when i put an H in it.

Race914,

Your excel sheet, how do you get the lines to transfer all the way down? I get tired of putting a ruler on my screen to determine my crusing RPM's

Thanks!

Here is a example run from the 914 re-gearing tech article workbook.
A-F-Q-X-Flipped H

Click to view attachment


Run more models and what-if setups with the workbook included in the tech article:

http://www.914world.com/specs/regearing_901.php

After you've entered your 'what if' gear ratios in the workbook, the RPM/MPH is shown in 5mph increments (see the verticle lines on the example graph above).

An option is to go to the next tab in the workbook (901 Gear Ratios & RPM-MPH Table) and you get a table with RPMs/MPH that may be easier to read. Here is an example of what that looks like

Click to view attachment

Hope that helps.

It shows the 5mph increments only in the shift range, I get #NA for all the other ranges below it. However I didnt know the next tab changed with the gear ratio's/tire diameter. Thanks!!

I believe the "H" gear change translated to a drop of 7-800 RPM's. I did it in my v8 conversion. I sold the dang tranny after as my motor is still out. I plan to build another with an "H" gear in another month or so. I'm no help on the other as mine was just a nice driver with the occasional autoX. I was happy with the 2,3,4 for my uses.

According to what Im seeing in the charts it looks like 500rpm drop between H and ZD at ~ 75mph

Similar to what you guys are looking at, I found this helpful when rebuilding my transmission.

Click to view attachment

You are all on the right track. Another consideration is to change the R/P. This lets you have all kinds of different options. There are some special R/Ps for sale on ebay right now (not cheap). I am interested in developing a special V8 box, but need someone to pay for and test it. The parts are all that I will charge for, the labor is free for development.

I'm not sure what my 5th gear is but... At 2800rpm with 245/45/16 tires, My car does 80mph according to my GPS.

Now that my new engine turns 8000rpm, I think that equals to 245,864,903mph

Who wants to trade trannies???

Dr Evil send me a PM on how much $$ you think it will be.

Might want to take that adventure with you.

PM sent.

If anyone local-ish to me with a V8 wants to be my test bed, I will build, install, repair as necessary my test box. I need someone who will abuse it and see if it will break.

Evil one, thanks for the PM. I am in Kansas City. Too far to be a test bed. At least I tried. No points for trying though.
Lots o time here in the Stan to contemplate gear ratios, and keeping an eye on engine prices.
Cheers from the other side.
Jim

Not being local does not rule anyone out. It does increase the cost due to shipping back and forth for repairs should they be needed.

Regarding shipping...
I did some research recently and FedEx ground for a 901 was only $79 from Florida to California. Was going to go with Greyhound but they won't insure. FedEx did. Insurance was important to me since the 901 included a limited slip setup.

Regarding V-8 gear ratios...
If anyone has recommended gear setups for their V8 that they want to share, post them here, and I'll add your setup to the Member Gear Set Library.