Thoughts on 901 gear selection

[buddeman]

Hoping for some opinions on the gearing selection the previous owner made for the 901 box I have. This is going into a '67 911 that has the original 2.0L normal rebuilt to a 2.2L S spec engine, with the power band from 5100 to 7100 rpm. Primarily spirited street driving, with the requisite auto-x and DE days at PIR here in sunny (for the day) Portland.

The tranny was rebuilt 30 years ago, filled with oil but never driven. I just opened it up today and found everything in fantastic, like-new condition. It has a 904 mainshaft and has the gearing of A, E, J, Q, X.

Included in the breadth of parts was also the original shafts that still held the gears A, F, M, S, X, as well as a few additional gears including V and W.

Opinions greatly appreciated if you think AEJQX would be a fun box, or if I should revert back to the original given it's received such rave reviews, or a combination thereof? Thanks in advance.

Pat

[Flieger]

What kind of driving do you do? The box you have is made for twisty canyon roads with X for the highway, not that it is a cruiser gear.

I have AFMSX with a 2.7 RS spec and it feels good in the tight curves and is only tolerable for freeways used to get to those nice mountain twisties.

If you like hillclimbs, yours is a pretty good gear combo.

[davep]

There was a 914/6 GT gearbox built with those ratios. I'm not sure if that was a common factory combination (it is not in any 911 list I know of, but I don't know about 914/6 GT combos). I have been considering building that combo, but need to find the E & J gears to do so.

9140431571 was the car I'm thinking of. Perhaps this box was track specific.

[kenikh]

Weird splits on that box. 2 > 3 is soooo short, then OK until you hit the 4 > 5. That gear set is just "off". So close to the "perfect" AFKQX, but so far away.

[t6dpilot]

So close to the "perfect" AFKQX, but so far away.

I was curious to hear your comments on that ratio make up. I am still looking forward to installing Kenik's "perfect" small displacement gear box ratio.

[kenikh]

The standard config for an E 2nd is AEINS, but that is a very short, focused gearbox. Pretty much Auto-X only. Not fun on the freeway. A friend with this gearbox dislikes it enough given limited freeway driving that he is replacing his gearbox with an AFKQX.

I'd of course suggest the AA-F-K-Q-X first, but otherwise, given the 904 shaft, I'd sell the rare J gear, possibly the Q and X, then build something else on the 904 mainshaft like a C-HA-M-Q-V or even sell the 904 and get a GA mainshaft for a AA-GA-M-S-X or B-GA-M-S-X based gearbox.

The C-HA-M-Q-V actually has mee drooling a bit at the prospects. A little buzzy at freeway speeds, V is probably the last 5th that could be considered a usable "road" gear.

[buddeman]

Thanks for the thoughts and opinions thus far. Sounds like I may want to pursue an alternate gearing setup. I really have no attachment to the current setup, and now is certainly the time to make changes!

Sounds like I'm close enough to the elusive AFKQX between my gearsets to seriously consider that option. Where does one find these gears - K in particular, but AA if it's easily available?

Or, I'm open to being a guinnea pig if there is enough conviction that C-HA-M-Q-V makes for an intriguing box... in which case I'd need help finding the C and HA gears, provided they are not uber-rare / pricey.

How would the driving characteristics of the above two boxes differ?

davep - looks like regardless of the path I take, I may have J and E gears available if you are interested.

[kenikh]

AA - relatively easy to find factory gear from early 901/0 gearbox
B - rare and expensive
C - rare and expensive

HA - 904 mainshaft gear: rare and expensive

M - most common 3rd gear; cheap and easy to find
K - rare and expensive
KA - flipped ZD; common 914 gear, but some don't like flipping gears

Q - common 914 gear; cheap and easy
V - common 914 gear; cheap and easy

Items marked rare and expensive are likely only available used from Carquip ($$$) or new from Guard ($$$, but better quality than NOS or used).

If you go the "rare" path, I'd go for the C-HA-M-Q-V route. You could likely sell your E for what it would cost the acquire the HA and the J would definitly make some headway in sale for acquiring the C first. This would make for a gearbox with a very long first gear (OK, IMHO, as 1st is a "getting moving" gear, which shouldn't be used as a driving gear ), and would get you on top of your powerband and into the ridiculously fast splits between the top 4 gears.

Bang for buck, AA-F-KA-Q-X is hard to beat. C-HA-M-Q-V (or even X in 5th) would be very cool.

[aporschaguy]

The standard config for an E 2nd is AEINS, but that is a very short, focused gearbox. Pretty much Auto-X only. Not fun on the freeway. A friend with this gearbox dislikes it enough given limited freeway driving that he is replacing his gearbox with an AFKQX.

I'd of course suggest the AA-F-K-Q-X first, but otherwise, given the 904 shaft, I'd sell the rare J gear, possibly the Q and X, then build something else on the 904 mainshaft like a C-HA-M-Q-V or even sell the 904 and get a GA mainshaft for a AA-GA-M-S-X or B-GA-M-S-X based gearbox.

The C-HA-M-Q-V actually has mee drooling a bit at the prospects. A little buzzy at freeway speeds, V is probably the last 5th that could be considered a usable "road" gear.

Is this in XLS by chance? If yes can I get a copy please? Thanks Either way

[C.Plavan]

I think I have a few V gears- Maybe some others- Let me know if you go that route.