Gear question:, what are stock gears, and what gear would be a better 2nd? Options

[naro914]

Am i correct in thinking that the stock gears are:

1 = A
2 = F
3 = N
4 = V
5 = ZD

Does that sound right?

So here's what I want to do...I want to put in a higher 2nd gear. Would be much better for Autocrosses because I hit the rev limiter on 2nd all the time, but not fast enough for 3rd or if it is, its too quick so I have to downshift back to 2nd really quick....like I'm sure most of us do.

1st is basically useless - just a means to get to second anyway. I can ALMOST start in 2nd from a stop more quickly than 1st to 2nd....

So, what would be a good taller second gear?

[Dr Evil]

There are a lot of variables to consider. What engine do you have? What size tires/wheels? You can easily shift your shift points with wheel/tire change.

[naro914]

3.2 6 cyl engine
16 x 8 wheels. running Hoosier A6 245/45 16. Not going to change wheels (or engine for that matter).

[jimkelly]

I though 2nd gear was integral to the input or output shaft - you are stuck with it.

3rd 4th 5th are swap out able

see it here - (IMG:http://www.914world.com/bbs2/uploads/post-2-1097020488.jpg)

see post 36 - http://www.914world.com/bbs2/index.php?showtopic=18128 target=

[naro914]

OK so now I understand what this chart means....

If you want anything other than stock 2nd (F), you need a 904 mainshaft.



So I'm out of luck, huh??

[VaccaRabite]

You can get the 904 main shafts.
Evil was trying to get together a group buy a while back, I think.

Zach

[sixnotfour]

GA 2nd

[stownsen914]

GA 2nd

^ What he said. The GA second was standard on the 70-71 911 models. Not as many of them around as the F 2nd/mainshafts, but they're around.

Scott

[J P Stein]

So here's what I want to do...I want to put in a higher 2nd gear. Would be much better for Autocrosses because I hit the rev limiter on 2nd all the time, but not fast enough for 3rd or if it is, its too quick so I have to downshift back to 2nd really quick....like I'm sure most of us do.

I used the stock F mainshaft 2nd for starts & a flipped ZD for 3rd. You have the motor to pull it, IMO.....my little ole 2.7L did. The flipped ZD drops the revs right into the gut of the torque curve and is good to about 75mph @6500 with your tire set up.

You prolly don't want the go the the pictured lengths that I did, but bypassing first gear eliminates the weakest part of the 901......and gives a straight shift to 3rd gear.
The limits were found for the 901.....hay, all the bits stayed inside the box (IMG:style_emoticons/default/biggrin.gif) ...........but you aren't close to the limits.

I tried the GA mainshaft. The gain wasn't enough.....bout 5 mph........bong,bong, bong. Grew to hate that sound.

[brant]

I have a GA mainshaft in my stash if your interested.

[Matt Romanowski]

Tremper has someone that will weld a new gear on for you and it will hold together. It's what he has in the black car.

[r_towle]

Chris Foley offers this service also.
He lathes of the old one and welds on a new one.

The 904 main shafts are available.
Ottos Venice made a run a while back and still has them on the shelf, but I am not sure of the status of that shop with Johns passing.

Carquip also has them.

If you get the 904 shaft, you can be fickle and change gears more often, and easier, than welding.

rich

[Krieger]

I am not sure if it is harder to get. I thought the 914/6 had a different 2nd gear than four cylinder cars.

[brant]

I am not sure if it is harder to get. I thought the 914/6 had a different 2nd gear than four cylinder cars.

it did
the "GA" 2nd gear main shaft.

[naro914]

OK, just getting online since my last post.

JP, 3rd is not my issue, 2nd is. Most of our autocrosses around hear are a bit tighter and rarely need 3rd, BUT, I end up bumping the rev limiter in second a few times a lap for like 100 ft or so...so I end up having to back off and lose time. Shifting to 3rd, then immediately back to second loses time too... I've tried just starting in 2nd, and while it will pull it, I lose over a second per lap doing that. Car has much more power and tq above 4000 rpm, so the time it takes to get there in second loses a lot of lap time...

My box is...I think...from a '74 so I assume a F gear?

I have a spreadsheet that used to be posted on the Carquip website that maps out your gears and max HP based on your inputs. Using the chart above, you plug in everything and get a simple X, Y graph and it shows max MPH (not as complex/complete as what you sent me Matt). I guess more what I was asking is what others do or find works best. I can chart it out and pick something, but if there was a tried and true option, I'd go that route...

FYI, I have a trans that has the flipped 5th & 3rd gears, plus an "R" 4th gear, effectively making: A, F, KA, R, Z set which will probably be for sale in the near future.

[BKLA]

I am not sure if it is harder to get. I thought the 914/6 had a different 2nd gear than four cylinder cars.

it did
the "GA" 2nd gear main shaft.

Try the GA, I think you'll like it.

I do.

[J P Stein]

Tossing first gear does require a commitment.
One needs to trust torque. Granted, my old car was 1780lbs (with ballast)is XP trim and probably lighter than most 914s. Here is a vid of a fairly open course with a spot of bother getting going but then, one shift into the Flipped ZD gear. Even that kept the home built 2.7L in the gut of the torque band.....Unfortunately only good for 2nd place in XP at this SCCA NT event.

http://www.youtube.com/watch?v=11xqdJlhiow

[wndsrfr]

You say that you have a box with flipped 5th & 3rd....that KA 3rd should give you a pretty good match...swap the stack in and give it a try.....practice a 1st to 3rd shift.....won't cost you anything & it might work out!

[naro914]

the problem with that flipped box is that its not good on the highways. 75 mph runs about 4000 rpm - not a great cruising RPM for the engine and it's REALLY loud as in the pass compartment. We use Huey for a lot of weekend drives.

The flipped trans was for the track. Plus, the stock trans that's in the car has a LSD in it...

and honestly, I don't feel like swapping trans all the time. PITA and I usually don't have time.

Replacing 2nd would do everything I need...

[naro914]

Granted, my old car was 1780lbs (with ballast)is XP trim and probably lighter than most 914s.

And mine is 2200 lbs. Nothing light about it at all - heavy really since not much has been taken out that weighs anything AND it has a full roll cage, heavier engine, 12 qt oil, oil cooler, braided SS lines running throughout, etc. And as noted, good, usable torque in a 3.2 is at higher rpms. It will get going in 2nd, but not quickly.

It was not built to be a purpose made AX car, but if I had a taller 2nd, it would do much better. I usually am in the top 3 or 4 for FTD at our local PCA autocrosses, and gotten one FTD overall. Honestly, FTD usually goes to a fully race prepped 997 GT3RS that has a 8300 RPM rev limit and can do 85+ mph in second gear....and I'm usually only a few tenths off his time. But I hit the rev limiter all the time in 2nd for short spurts so I have to back off...losing those precious tenths...