Page 1 of 3 123 LastLast
Results 1 to 10 of 24

Thread: Gear Ratios For a SWB

  1. #1
    Lighting Specialist jaudette3's Avatar
    Join Date
    Jun 2003
    Location
    Bend, Oregon
    Posts
    4,255

    Gear Ratios For a SWB

    I'm setting up my '67 SWB primarily for light track and road rally use. It has the original engine built to 2.7 and the original transmission built with four speeds. I'm not sure what the current ratios are, but I wasn't impressed with them at Portland International Raceway a couple of months ago -- and that's the main track I will be running the car on.

    I'm going to change things and I have a couple of options:

    (1) I have a 915 stock 5-speed out of a '72 (don't know if it was a T, E or S) that has only 4,000 miles on it. If I use this one I will probably also install a WEVO gated shifter, which I really like.

    (2) I've found a 901 5-speed newly built by a great shop with a 904 main shaft, very short gears (A-F-J-O-S) and limited slip.

    I'm leaning to #2 -- what do you think?

    Regards,
    John Audette
    Lighting Resources for Hardcore Air-Cooled Porsche Enthusiasts”
    ——-
    John Audette - Porsche Lighting Anorak
    AC Shop: BEST-IN-CLASS Air Cooled 911 Lighting Parts => 911BestInClass.com
    AC Site: The Air Cooled 911 Light Resource => AudetteCollection.com
    Instagram: Please Follow => AC Shop Instagram

  2. #2
    (2) might be too short for a 2.7, especially when you take it out in the winter. Besides that can a 915 handle the torque of a 2.7 better (we rally in a 65 w/ a similar set up and switched from the 901 to the 915 for that reason).

    I would opt for (1) and have the gears setup to your preferences.

    Richard

  3. #3
    Too short for a 2.7; almost too short for a 2 liter. Great box though!
    Kenik
    - 1969 911S
    - 1965/66 911
    - S Reg #760
    - RGruppe #389

  4. #4
    The second option would be awfully short for a 2.7, but it's really cool for a small motor (thats what I have in my S). If your 915 has standard gears you'll be selling the 2.7 short, and you'll have to take a hammer to you tunnel. AFMSX are cheap gears for the 901 and would work well with the 2.7. Earl Green had those gears in front of his 2.7 and it rocked. He spent lots of time on the track with that car.

    By the way, I doubt you have a 904 main shaft if F is indeed your second gear. F is fixed on the shaft and was standard in all of the early 911s and 912s.
    Tom F.

    '67 911S Slate Gray
    '70 911T 2.8 hotrod (in progress)
    '92 964

    #736

  5. #5
    Hello: The 901 will work fine with your 2.7. I raced one for many years and they work great. A nice gear setup using stock factory gears is a,ga,n,s,z if you still drive it on the street. I would also install a Quaife or GT diff if you drive it on the street as well. Hope this helps. Thanks Eric

  6. #6
    Buy both. Put a ZF LSD in the one you like, but do not put in a Wevo (it is overkill for your purposes).
    Randy Wells
    Automotive Writer/Photographer/Filmmaker
    www.randywells.com/blog
    www.hotrodfilms.com

    Early S Registry #187

  7. #7
    Can anyone please give me the airport gear letters please?
    Alex Webster

    1967 911S Sunroof - RHD
    1969 911E - LHD - Historic Racecar
    1975 911 Carrera 2.7 MFI - RHD - Historic Racecar

    My historic racing videos - www.youtube.com/aewebster

  8. #8
    Senior Member
    Join Date
    Aug 2006
    Location
    Sonoma, CA
    Posts
    376

    Not a simple swap

    Putting a 915 (or even a LWB 901) box in a SWBisn't a simple swap. The Lobro driveshafts are different between short and long wheelbase cars. One cannot make driveshafts with LWB outers and SWB inners and LWB outer end stuff doesn't like to fit in SWB bananas. I believe you will end up changing drive flanges and perhaps even the differential carrier to make things fit.

    johnt

  9. #9
    Alex..

    Airport gears AA,F,J,O,S

  10. #10
    Lighting Specialist jaudette3's Avatar
    Join Date
    Jun 2003
    Location
    Bend, Oregon
    Posts
    4,255
    I really appreciate the input here - very helpful.

    The transmission in my SWB is the original one and was rebuilt into a 4-speed. He told me that he wanted to build a hill-climb car and to get first gear off of the reverse spindle for more strength. As I say, I'm not sure what the four gear ratios are right now, but they're pretty short. If the speedo is accurate, would it be possible to determine the gearing from RPMs vs. MPH?

    I'm aware that installing a 915 requires some modifications -- and I'm not sure I would like the ratios anyway. My car is an odd combination of original and hot rod and after the input here, my thought is that the best way to go is to use my case and install five short gears and a LSD.

    If that's a good idea, what gearing should I use? (primarily for PIR)

    Thanks again - what a great group!

    John
    Lighting Resources for Hardcore Air-Cooled Porsche Enthusiasts”
    ——-
    John Audette - Porsche Lighting Anorak
    AC Shop: BEST-IN-CLASS Air Cooled 911 Lighting Parts => 911BestInClass.com
    AC Site: The Air Cooled 911 Light Resource => AudetteCollection.com
    Instagram: Please Follow => AC Shop Instagram

Similar Threads

  1. 71 901 transmission ratios from a T to an S?
    By Rino71 in forum Technical Info
    Replies: 1
    Last Post: 11-29-2012, 07:56 PM
  2. How to figure out gear ratios without opening the box?
    By Cornpanzer in forum Technical Info
    Replies: 19
    Last Post: 08-25-2010, 04:41 PM
  3. Anyone on here used these 901 gear ratios ?
    By andyjboy in forum Technical Info
    Replies: 33
    Last Post: 12-17-2009, 03:45 PM
  4. is there a list of trans codes + ratios ?
    By Maybe-68S-Targa in forum Technical Info
    Replies: 3
    Last Post: 06-04-2008, 07:33 PM
  5. Steering Ratios
    By RTincher in forum Technical Info
    Replies: 9
    Last Post: 08-28-2006, 07:03 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Message Board Disclaimer and Terms of Use
This is a public forum. Messages posted here can be viewed by the public. The Early 911S Registry is not responsible for messages posted in its online forums, and any message will express the views of the author and not the Early 911S Registry. Use of online forums shall constitute the agreement of the user not to post anything of religious or political content, false and defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, threatening, invasive of a person's privacy, or otherwise to violate the law and the further agreement of the user to be solely responsible for and hold the Early 911S Registry harmless in the event of any claim based on their message. Any viewer who finds a message objectionable should contact us immediately by email. The Early 911S Registry has the ability to remove objectionable messages and we will make every effort to do so, within a reasonable time frame, if we determine that removal is necessary.