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Diff Ratio's ,help?

jmedps

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VZ Berlina Sedan 06/V6 175kw
Vz Berlina 2006 , 175kw auto.
Reason i am asking is that i would like more torque bottom end.

1.What is the factory ratio? is it 3.08:1?
2.What are common ratios that fix the stock sluggish take off.

cheers :)
 

gohrdrgomad

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VxCaly57
Vz Berlina 2006 , 175kw auto.
Reason i am asking is that i would like more torque bottom end.

1.What is the factory ratio? is it 3.08:1?
2.What are common ratios that fix the stock sluggish take off.

cheers :)
To be honest a diff ratio change isn't the best way. Most factory efi vehicles have a progressive timing advance that alter regularly and to the drivers habits. Also the air fuel table etc are calibrated and alter to assist favoring the ecconomy path to my understanding. Exhaust, intake, tune etc will be a better overall application in my opinion for you. It might cost you 2k+ for 20+ or more kwts depending who does the tune. Possibly best to allow the tuner to select the appropriate application to acheive the best tuning outcome.
 

Tonner Matt

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Vz Berlina 2006 , 175kw auto.
Reason i am asking is that i would like more torque bottom end.

1.What is the factory ratio? is it 3.08:1?
2.What are common ratios that fix the stock sluggish take off.

cheers :)
A ratio change won't improve your bottom end torque, you will need a tune to help with that
What a ratio change will do is give you noticeably quicker acceleration, especially from a standing start

I'm not 100% sure on the factory ratio of V6 auto....There's a white sticker on the diff with the ratio printed on it, if it's still there
Common ratio swaps (in general) are to fit a V8 LSD with 3.46, 3.7, 3.9, or 4.11 gears

You also have to consider how much highway driving you do, as you don't want the engine revving it's guts out at 100km/h on the highway
There is a simple way to work out the engine RPM at 100km/h with the different ratios:
Here is an example on how to work it out:
So lets say that at 100km/h in top gear your engine is doing 2000 RPM and the diff is a 3.08
You divide the Engine RPM by the diff ratio
2000 divided by 3.08 = 649
To work out engine RPM in top gear at 100km/h you multiply the new ratio x 649
3.46 x 649 = 2245 rpm
3.7 x 649 = 2401 RPM
3.9 x 649 = 2531 RPM
4.11 x 649 = 2667 RPM
 
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vr304

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It won’t physically make any more torque with the lower diff Ratio but it will pick up a lot quicker than what it would normally, have done diff Ratio changes in 2 of my Commodores now (although v8) and the difference is night and day it’s a well worthwhile mod in my opinion, as the others have said be aware you will be doing higher revs at cruise speed but as long as your sensible with the choice of gears u should be fine I’d go for a 3.45 ratio if I were u
 
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