6-speed box?

6-speed box?

Author
Discussion

SILICONEKID345HP

14,997 posts

231 months

Thursday 15th January 2015
quotequote all
domV8 said:
IIRC about 6% difference from yours as a quick indicator Daz...

Thought about changing from my 3.23 to a 3.45 - but when I calculated it all up, I cam to the conclusion it was going to cost lots $$$ for very little real world difference...
Why would you want to go to a 3.45 ? What rpm is your 3.23 doing at 70mph ?

3.45 is about 2700

Derek reckons his 3.08 is doing about 2330 but the calculator shows more like 2400 .

The GKN diff i removed was a 3.31 ,at 70mph the rpm was just under 2600rpm .




Edited by SILICONEKID345HP on Thursday 15th January 20:21

domV8

1,375 posts

181 months

Friday 16th January 2015
quotequote all
Faster acceleration.

Although its my daily - I only do about 50 miles a week with virtually no motorway usage, so cruising at 70 is very low on my priority list...

Acceleration on the other hand - well... yes

Also, I came to the realisation that I actually liked the length of gears 1,2 & 5 with the 3.23 diff ratio - I just wanted shorter 3 & 4 gears, more like a close ratio 4-speed with overdrive (after all, how often are you using 5th for max acceleration purposes?)...

So I may at some point change the ratios in the 'box (at rebuild time maybe), rather than change the diff ratio as a band-aid solution...

Edited by domV8 on Friday 16th January 12:09

domV8

1,375 posts

181 months

Friday 16th January 2015
quotequote all
SILICONEKID345HP said:
3.45 is about 2700

Derek reckons his 3.08 is doing about 2330 but the calculator shows more like 2400...
Well as 3.23 is roughly halfway between those 2 - a quick calculation would indicate you are looking at around 2500-2550rpm at 70mph...

Car is having MOT done at the mo' so cannot visually confirm.

I believe you can also use smaller wheel (tyre!) rolling radius to achieve an end result similar to lowering the gearing - but that's another discussion... wink

HTH,


Dom

Edited by domV8 on Friday 16th January 12:11

SILICONEKID345HP

14,997 posts

231 months

Friday 16th January 2015
quotequote all
domV8 said:
Well as 3.23 is roughly halfway between those 2 - a quick calculation would indicate you are looking at around 2500-2550rpm at 70mph...

Car is having MOT done at the mo' so cannot visually confirm.

I believe you can also use smaller wheel (tyre!) rolling radius to achieve an end result similar to lowering the gearing - but that's another discussion... wink

HTH,


Dom

Edited by domV8 on Friday 16th January 12:11
Do you think i may be disappointed with the 3.08 ? It might take the thrill away .