Gearbox 3 rib vrs 5 rib vrs 6

Discussion in 'Mech Tech' started by lhu1281, Aug 20, 2015.

  1. I think (I'll check paperwork) it was 3500 ish here's a shot of the magic 80 hp [​IMG]
     
  2. So you would not think ,a 6rib to be an improvement...?
     
  3. You can combine a 4.571 FD and a 0.82 4th gear to give an overall 3.748 ratio. It makes a huge difference in revs, and therefore noise, on the motorway.
     
  4. If it got rid of the flatspot I'd get one but for the money and having had my van for 4 years I'm not running out to get one.
     
  5. Hi Owen, excuse my denseness :) how do you work out that ratio ^^
    Looking at the stats my 5 rib had a 4.318 final drive and I've had the 0.82 4th put in.
     
  6. Stupid question alert: is it a mirror image on both top and bottom of the box? In other words if I look under the van will I see whats being shown on top of the box as per your pics?
     
  7. http://thelatebay.com/index.php?threads/22509/

    I started the thread I've linked to a couple of years ago. It has my experiences before and after changing gearboxes. It has some info on ratios, plus impact on running temperature etc. I got the same ratios as a 6 rib but in a normal gear box rebuilt by bears motorsport, much better than dropping 600+ squid on a gear box that may be knackered
     
    scrooge95, mjones1969 and art b like this.
  8. You can count them from the side
     
  9. Let me go check
     
  10. Does anyone know if there's Someone out there that can fit a longer 4th? Mine is a 2ltr and although it'll do 70 it certainly won't be happy "all day long" more 50 / 60 for a few hours and a nice long cup of tea :)
     
  11. Yep Bears or Cogbox
     
    bluething likes this.
  12. Hard to tell if it is a 6 or not

    Edit : well if the 5 rib looks the same underneath i.e. the ribs dont quite go all the way round then it must be a 6 rib on mine
     
  13. Multiply the 4.857 x the 0.82 to get the overall 4th gear ratio.
     
    chrisgooner likes this.
  14. Cool so that gives me a final drive of 3.540 which is longer than a standard 6 rib's.
     
  15. 3.98 by my maths.
     
  16. Ah right you confused me(not hard) with the above 4.571 isn't the final drive it's the r&p
    So multiply the ring and pinion by the 4th gear gives you the final drive. :thumbsup:
     
  17. Zed

    Zed Gradually getting grumpier

    You can see the ribs have sharp corner on the 5 rib and rounded on the 6. I don't remember what it looks like underneath.
     
  18. Cheers. Definitely 6 rib then. Joy
     
  19. Zed

    Zed Gradually getting grumpier

    5 rib are good too, just not so many about. :thumbsup:
     

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