Results 1 to 8 of 8

Thread: Dyno readings

  1. #1
    Junior Member
    Join Date
    Nov 2002
    Posts
    4

    Dyno readings

    Gentlemen:

    I just put a new clutch and a set of rebuilt webers on my 67 S. The 40IDS3C's have the adjustable cam lever bar and were tuned on the dyno. The motor is quite fresh (I'm afraid that I can't be more specific - wish I could) the fuel pump is new and it appears, especially after all this work, to be running really strongly. It is also using an MSD box and coil.

    What should I read as a power rating in either HP or kW at the rear wheels during a dyno test? What kind of losses are expected in the driveline? How can one work back to the flywheel rating? The factory's 160 HP (DIN) rating is flywheel power isn't it? What is a typical rear wheel power rating?

    I was told that I am putting down 62HP to the pavement and that this translates to ~130HP at the flywheel. Further, I was told that the crappy fuel these day full of that MMT crapola could account for the 30HP difference between the factory rating and what was measured - is this true? Anyone else got some results to share?

    Thanks fellas.

    A67911S

  2. #2
    What kind of dyno was this? 62 hp to the wheels is almost unbelievably low. And it's hard to understand the calculation based on more than 50% drivetrain loss.

    More information might explain all this.

  3. #3
    Goldmember ttweed's Avatar
    Join Date
    Oct 2002
    Location
    La Jolla, CA
    Posts
    1,429

    Re: Dyno readings

    Originally posted by A67911S
    I was told that I am putting down 62HP to the pavement and that this translates to ~130HP at the flywheel. Further, I was told that the crappy fuel these day full of that MMT crapola could account for the 30HP difference between the factory rating and what was measured - is this true? Anyone else got some results to share?
    Something is seriously wrong with your figures. I have had my '67S on the dyno and it is set up exactly like yours. It showed 130HP (SAE) at the rear wheels. Driveline losses can be anywhere from 10-20%, depending on what type of car. I figure mine is pretty close to the 160 DIN the factory advertised, considering it has ~70K miles on it since last rebuilt.

    TT
    Tom Tweed
    Early S Registry #257
    R Gruppe #232
    Rennlist Founding Member #990416-1164
    PCA National DE Instructor
    Read my surf novel!

  4. #4
    Junior Member
    Join Date
    Nov 2002
    Posts
    4

    As I suspected...

    I thought those figures were out to lunch. The car is running fantastically now, as it should after spending close to $10,000 CDN on all the work I've done lately.

    My brother drives a BMW 2002Tii and my beauty definitely has more guts than his ride. The FI'd Tii is supposed to be rated at 150HP DIN I'm thinking that maybe I'll go back to the shop and watch him dyno the car. I just want a baseline to work from in the future.

    Anyone been able to squeeze more than 160 out of a 67 S?

    thanks;

    A67911S

  5. #5
    Slow In...fast Out RSupdate's Avatar
    Join Date
    Oct 2002
    Location
    Surf City USA
    Posts
    803
    I would have to go with Jack on this....

    That' unbelieveably low h.p. reading at the rear wheels.

    I've understood the common "rule of thumb" for h.p. loss as this:

    manual trans = 15-17% loss

    auto trans = 20-23%

    Now once again, these are general "rule of thumb" averages, and if that was my car I would be inclined to use the 15% loss and conclude I was probably getting about 110 h.p. to the ground. But that's just me
    Johnny Riz
    73E euro 3.2 w. a few goodies
    Rgrp 152
    S Reg 335

  6. #6
    Junior Member
    Join Date
    Nov 2002
    Posts
    4

    Alrighty then...

    Using those numbers (for a manual of course), and working backwards from the factory 160HP, then at 15% loss the reading should be ~136HP and at 17% should be ~132.8HP, (o.k., o.k., we'll call it 133HP).

    Well I was just out puttering (read leadfootin') about town and WOW is she fun to drive. She gets squirrely in the corners just like she is supposed to, and backs it all up with a mechanical symphony! I guess I'll just have to find someone around here with a regular 2.0 to trade rides with and see how she measures up.

    Thanks again gents;

    A67911S

  7. #7
    Slow In...fast Out RSupdate's Avatar
    Join Date
    Oct 2002
    Location
    Surf City USA
    Posts
    803

    Re: Alrighty then...

    Originally posted by A67911S
    Using those numbers (for a manual of course), and working backwards from the factory 160HP, then at 15% loss the reading should be ~136HP and at 17% should be ~132.8HP, (o.k., o.k., we'll call it 133HP).


    You are correct based on what I understand.

    Also, my appologies for using the 130 h.p. in my example, I intended on using 160 h.p. sorry.
    Johnny Riz
    73E euro 3.2 w. a few goodies
    Rgrp 152
    S Reg 335

  8. #8
    Junior Member
    Join Date
    Nov 2002
    Posts
    4

    No appologies please...

    No appologies necessary amigo. I got the gist. I just wanted to be sure and clarify (if required) for others reading the list.

    Happy motoring.

    A67911S

Similar Threads

  1. AFR Readings (LM-2) - Idle speed vs. Partial load
    By TEC69E in forum Technical Info
    Replies: 9
    Last Post: 02-03-2011, 05:59 PM
  2. what should compression readings be 69 911s?
    By blucille in forum General Info
    Replies: 6
    Last Post: 05-25-2005, 07:07 PM
  3. 2.7 RS hp on a Dyno????
    By RC70SCoupe in forum Technical Info
    Replies: 2
    Last Post: 03-26-2003, 01:06 PM
  4. High compression test readings
    By Baddger74 in forum Technical Info
    Replies: 2
    Last Post: 02-21-2002, 03:30 PM
  5. Compression readings on early S
    By skid in forum Technical Info
    Replies: 6
    Last Post: 03-05-2001, 08:05 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.