Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Gear Choice

  1. #1
    Senior Member CamBiscuit's Avatar
    Join Date
    May 2006
    Location
    Adelaide, Australia
    Posts
    1,447

    Gear Choice

    Guys

    Ive searched through the threads on gear ratio's but most of what I found relates to the 2.0's and I'd appreciate some feedback on a 2.4.

    Its an S cammed engine running carbs and 2.2S pistons. I am running a 911 box which I believe to be standard, from my '71 T and according to my owners manual the gears are: A, GA, O, V, ZA. Its getting time to re-do the syncros and what better time to review the current ratios and maybe go the whole hog.

    The car is used a bit on the street, & for lapsprints & tarmac rallies. I run a 6800rpm rotor button and try not to hit cut out too often. I'd like to shorten the box a little without going crazy and would appreciate your thoughts on some well matched and easily available gears. The car runs on 205/60/15s all round.

    Thanks in advance
    Looking for engine # 6208151
    '74 RS 3.0 Replica
    '70 911E Bahia Red (SOLD)
    '71 911 S/T Replica 2.3 Twin plug BEAST (SOLD)
    Australian TYP 901 Register #78
    Early S Registry # 1076

  2. #2
    Cam:

    The readily available A-F-M-S-X stack is a great all-arounder for cars like yours,...
    Steve Weiner
    Rennsport Systems
    Portland Oregon
    503.244.0990
    E-mail: porsche@rennsportsystems.com
    http://www.rennsportsystems.com

  3. #3
    cam

    send alex w a note asking for his gearbox spreadsheets. they're pretty handy for putting in everyone's suggestions and your tyres sizes and revs etc.

    however, that said, i'm sure steve's stack above will ultimately turn out to be spot on.

    if you want to compare for fun, i'm using A-F-K-Q-U - but have a little more than 6300 to play with.

    ps. 6300 is a little conservative isn't it...
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

  4. #4
    First, get back to the stock redline; you aren't doing the motor any favors. If you want to keep the revs that low, get some different cams.

    As far as gears go, I highly recommend AFKQX for anything that is less than a hot 2.7. obrut is right that the U is a good gear, but only for a racer. The X is the lowest gear that will maintain freeway manners. BTW, I am biased as I already run AFKQX in my 2 liter (soon to be 2.3 liter) car and love, I mean LOVE it.
    Kenik
    - 1969 911S
    - 1965/66 911
    - S Reg #760
    - RGruppe #389

  5. #5
    Senior Member CamBiscuit's Avatar
    Join Date
    May 2006
    Location
    Adelaide, Australia
    Posts
    1,447
    Thanks Guys

    Ryan, cheers I have the spreadsheets etc but there's nothing like hearing what works for others.

    And it's a 6800 rotor button!!! OK maybe I'm a bit on the conservative side
    Looking for engine # 6208151
    '74 RS 3.0 Replica
    '70 911E Bahia Red (SOLD)
    '71 911 S/T Replica 2.3 Twin plug BEAST (SOLD)
    Australian TYP 901 Register #78
    Early S Registry # 1076

  6. #6
    Kenik, are you increasing the displacement on your 901/10 motor or replacing it altogether?

  7. #7
    I agree with Kenik. Get that redline back up to 7300 where it belongs - the S cams don't really start to breathe until 38-4000.
    -Marco
    SReg. #778 OGrp: #8 RGrp: #---
    TLG Auto: Website
    Searching for engine #907495 and gearbox 902/1 #229687

  8. #8
    Quote Originally Posted by 69911S
    Kenik, are you increasing the displacement on your 901/10 motor or replacing it altogether?
    Same motor. Going to 85mm P/Cs and hotter cams for an ST experience. .
    Kenik
    - 1969 911S
    - 1965/66 911
    - S Reg #760
    - RGruppe #389

  9. #9
    Cam,

    I have a similar gearset to that as Steve is saying, but I feel the real difference for us lower capacity cars, is the 3rd gear as Ryan and Kenik know from experience. I think the K and Q ratios are key to stop the long gap between 2nd and 3rd. Ryan said that his box was rebuilt with the current 3rd gear after they had tried another one. Get the car on a dyno and work out where it is making its power and then work from there, as the rpm drop between gears gets bigger depending on how hard you can rev the car. That is why Ryan can get away with such a short 5th!!! 6300 max Ryan - bull!!!
    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

  10. #10
    "That is why Ryan can get away with such a short 5th!!! 6300 max Ryan - bull!!"

    now now mr webster - i did say i "have a little more than 6300 to play with."

    and that is also probably why i found an empty earplugs packet when i removed the interior last weekend. 4000rpm plus in 5th with my (lack of) exhaust is a killer!
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

Similar Threads

  1. I really had no choice
    By John Z Goriup in forum Off Topic
    Replies: 13
    Last Post: 09-18-2012, 09:15 AM
  2. Engine Choice
    By Toronto66_911 in forum General Info
    Replies: 20
    Last Post: 02-03-2009, 03:03 AM
  3. choice of brake pads?
    By RPMClassic in forum Technical Info
    Replies: 10
    Last Post: 03-26-2008, 04:46 AM
  4. 73 911 tire of choice?
    By aracerx in forum General Info
    Replies: 3
    Last Post: 10-15-2004, 01:52 PM
  5. Fuel choice
    By speedster in forum Technical Info
    Replies: 5
    Last Post: 09-23-2001, 01:46 PM

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.