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One tonner, 308 with M21 close ratio 'box. Vehicle is not mine, so no idea of the carby & cam in it. Currently with a 3.55 diff.
The owner wants a better highway diff, and is thinking of a 2.78.
I wonder if the 2.78 is too tall to get off the mark with the close ratio first gear in the M21?
On the other hand a One Tonner is lighter than the sedans.
Any thoughts- I just don't know. |
Attn camry drivers. The accelerator is the skinny pedal on the right. |
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When the tray is fitted it could be heaver than the sedan.
2.78 diff with a M21 in a good torque 308 would be ok if you did a lot of highway driving but if in town it could be a bit high.
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The combination of manual transmission, a tall first gear ratio & a modified cam is all working against you. With a 2.78 rear end in city driving, it wouldn't be a pleasant drive & clutch life would be short.
If you do 90% open road driving you could get away with it. The cam issue is, that it is ideal to get your peak torque RPM where you do most of your driving. There is no point having a cam which puts the peak torque at 2,800 RPM if you cruise at 1,800 RPM.
Dr Terry |
If at first you don't succeed, just call it Version 1.0 |
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Thanks Dr T & castellan. Confirms my thoughts.
Cheers,
Chris |
Attn camry drivers. The accelerator is the skinny pedal on the right. |
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what about a hk stock 307 with 3 ring saginaw and 2.78 diff how would that go??? Edited by user Monday, 3 September 2012 3:17:21 AM(UTC)
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Yeah no good bullit, i'd blow your doors off with 186, 3 speed man, 3:55 |
The HKTG Garage. The Home of HK HT HG Holden. |
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quote:
Originally posted by HKTG Parts Recovery
Yeah no good bullit, i'd blow your doors off with 186, 3 speed man, 3:55
maybe off the mark but thats about it m8 then goodbye lol....
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I had a 2.78 10 bolt with m21. I nearly burn the clutch out getting up my driveway. If I I warm it up for five minutes I asphyxiate. Way too tall. I have just removed the salisbury in favour of a 9 inch 3.25ratio and toploader which has a slightly lower first. I would suggest 3.08. Diff might be a little better if only cruising.
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