What this cannot be right!

[arronm]

Did it rev a lot more whilst cruising at 100?

I guess it would be 20% higher based on the difference in ratios?

I worked it out once 100 or 150 rpm. SFA.

I bet you will notice this on a Hwy having 3.45. But if the car is driven locally the lower ration would be ok.
On our SV6 it mainly on Auto 5 gear on 50 or 60 speed limits

An VE SV6 auto will have 2.92 rear. VF has 6 speed auto /man and 3.27.

VE SS has 3.45 man and 2.92 auto. VF SS has 2.92 auto and 3.45 man, VF2 has 3.27 auto and 3.70 man.

you should try the 3.7 (as in HSVs... like mine)

3.7 is Man ratio. Could have , but 3.45 seems about right.

 

[Forg]

I worked it out once 100 or 150 rpm. SFA.

But ... the 'box has to turn the tailshaft 345/292 = 1.19x as many times per km/h.
To be 150rpm at highway speed you'd have to be either doing ~800rpm (or never in top gear)?

 

[arronm]

So lets say before with 2.92 in 6th I was doing 100 kph at 1850 rpm. Now with 3.45 at 100 kph Iam doing 2000rpm. Or something like that, worked it out once but cant find it, and cant be bothered doing it again.

 

[VFSV6FORME]

I bet you will notice this on a Hwy having 3.45. But if the car is driven locally the lower ration would be ok.
On our SV6 it mainly on Auto 5 gear on 50 or 60 speed limits

Just say on a VF V6 if you have 2.92 and then you change it to 3.45 or 3.7, that a big difference

 

[Forg]

So lets say before with 2.92 in 6th I was doing 100 kph at 1850 rpm. Now with 3.45 at 100 kph I am doing

... 345/292 x 1850 = 2185.

It's nearly 350rpm, so IMHO it's significant in terms of revs-percentage ... but I have zero idea of where the engine makes noise, where it makes vibrations, where it's the most efficient (lowest revs <> most efficient) etc etc. So from the point of view of everything that's relevant in highway cruising, I can see how it could be insignificant.

Actually it's probably the 6spd & the torquey V8 that make it so. A mate had the same model 70's 4cyl Volvo that I had, except his was a non-lockup-torque-converter 3spd auto with 1:1 top gear & mine was a 4spd manual with a ~0.82:1 overdrive ... that's about the same difference as the 3.45 vs 2.92 diffs in the Commodores, except his car was STUPIDLY busy at 110-120 whereas mine happily hummed along. Probably a result of the torque-converter not locking up in the ol' BW35.

 

[arronm]

Did some calcs 6th 100kph 2.92 = 1539rpm. 6th 100kph 3.45 = 1818rpm. SO 279 extra RPM in 6th with gear change.

So goes from 6Th 65/1000rpm to 55/1000rpm


To put it is perspective my F6 with 3.73 rear and 6 speed manual is 1923rpm at 100kph.


Hey if you keep standard gearing you can go 307kph in 5th and 389kph in 6th. Watch out Bugatti Veyron.

 

[Nico36]

Best you hop in a capable V8 with a capable driver and see if you change your mind about blistering performance. I am not saying you're incorrect, I am sure the changed diff makes a world of difference. I have seen mildly touched V8s on street tyres get to 100kph in 3.5 or less. Even a stock one is fast with factory diff. Sounds fun, but with a lot of highway miles up here, I like my frugal diff.

Agreed, SV6 with those mods is not going to chop and SS if its got a capable driver

 

[lmoengnr]

Hey if you keep standard gearing you can go 307kph in 5th and 389kph in 6th. Watch out Bugatti Veyron.

You'll need to turn the speed limiter off!

 

[Harli]

If I was in the SS and I was taking off quickly and then noticed that the SV6 also took of quickly, I would get off the throttle immediately and let him pass because if I win the race, or if he doesn't quite make it far ahead enough of me to overtake the end result will be an accident either into me or the parked car.

P.S I wouldn't be racing at the lights in the first place, just proposing an alternative scenario that may have played out

 

[lobbie]

If I was in the SS and I was taking off quickly and then noticed that the SV6 also took of quickly, I would get off the throttle immediately and let him pass because if I win the race, or if he doesn't quite make it far ahead enough of me to overtake the end result will be an accident either into me or the parked car.

P.S I wouldn't be racing at the lights in the first place, just proposing an alternative scenario that may have played out

Spot on harli.