what gearbox (race 901?)

[BlutorangeS]

I have a 1969/70 2,2S type 911534

chassisnumber: 9110300328

The gearbox has a long first and then the gears are like on a motorcycle, very close stacked. Fifth is short about 60 mph @ 4000 rpm. It has first down to the left as a normal 901. The number on the box is 7798766. Can anyone here identify the gearbox? It seems likely that it is some sort of a race gearbox, maybe from a S/T?

And the engine is the original but lacks numbers on the fan, goes like stink...after 4000 rpm it just takes off and goes with anger to 8000 rpm but I close down before 7300 rpm I think maybe the car have some sort of race history. Does anyone recognize the vin?

Best regards,

Christer

[EARLY911ZOO]

your numbers throw me off a bit:

9110300328= a 1970 911 S
911534? might be on the block as 911/53 or 911/54 for a 72-73 S engine
7798766?? turbo trans but not a 901 shift pattern??
you sure its not 7198766?? this is a 901 for 69-70 S and E cars.

[BlutorangeS]

Thanks for the answer.

I send my chassis number to Porsche Norway and got this info:

Chassis number 9110300328 belongs to:

type 911534=911S Coupe 2,2l 180hp / Motor 6300505 / delivered 01.Dec.`69 to Grand Rapids / Color 2323=bloodorange / Interior 11=leatherette black,middle of seats basketweave / Options 453=Radio Blaupunkt Frankfurt , 470=comfort-equipment

So far so good. That is my car all right. Color and interior is right. But the info says nothing about the gearbox and my friends 69 T has much higher ratio than me. Maybe the box is the original, but then those old 911s boxes were really low geared. How can i know this is a matching # box? And if not, how do one tell it is a race/special box?

You are probably right with the number 7198766. Lots of dust down there and dark too. Then it is a proper S box anyway.

Cheers,

Christer

[sithot]

Simple; somebody changed the ratios. Not a big deal. If you got a 904 mainshaft in the deal, even better.

Tom

[BlutorangeS]

Thanks Tom,

Then I really do not know what I have until it is dismantled. I have gotten some mails though so I think I will keep the box. Strange how people want to help out with swapping my lousy racebox with original gearboxes to take me out of my misery

So conclusion is original 901 S 1970 box with race internals maybe a 904 mainshaft.

Thanks all for help!

[NeunElf]

You should be able to estimate gear ratios by turning a rear wheel and watching the fan pulley go around. With the spark plugs out there shouldn't be too much resistance.

If you do not have a limited slip two turns of one rear wheel is the same as one turn of the rear axle. If you do have a limited slip turning both rear wheels at once might be a challenge.

This document has the gear ratios from the spec booklet. Under the attachment rules I can't upload the original Excel spreadsheet--this is tab-delimited text. Open it with Excel (or some other spreadsheet). I hope you can figure it out without the Excel formatting.

[BlutorangeS]

Thanks for helping. I have gotten lots of good advice here and on the swedish early911 forum. One guy suggested that I had the 901/52 Flugplatzrennen -67
100kph @3800rpm
Gearing: 7:31
1 12:34
2 18:34
3 21:31
4 23:28
5 25:26

Do anyone know what that equals out to in mph or km/h @ 4000 rpm on all gears? It is so nice to have this forum with all the knowledge.

Cheers,

Christer

[NeunElf]

I added rows for mph per 1000 rpm to the attachment.

For 4000 rpm, and a 165R15 tire (25.6 inch diameter):


________teeth____ratio_________mph@1000rpm_mph@400 0rpm
1st_____12:34_____2.83____AA_______6.1________24.3
2nd_____18:34_____1.89_____F_______9.1________36.4
3rd_____21:31_____1.48_____J______11.6________46.5
4th_____23:28_____1.22_____Q______14.1________56.4
5th_____25:26_____1.04_____S______16.5________66.1
final
drive____7:31_____4.43

Sorry about the funky underscores but it was the only way to defeat the forum software's auto formatting.

[BlutorangeS]

Thanks Jim,

I´ll be out driving tomorrow and check if the ratios match. If so I have found my box

[ajwans]

Scrub off the grime and confirm the type and serial number from the
box itself, that will go a long way to confirming which gearbox you have.

FWIW, the information I have for 911 boxes (i.e. 1970-71 cars) is that
the special ratio boxes are numbered 911/80 special order, 911/81 hill
climbs, 911/82 airfield, 911/83 high speed circuits, & 911/84 Nuerburgring.

andy