3.9 Diff
Author
Discussion

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
Was just wondering what difference i should notice from the change in Diff. I mean i know it will be quicker but does anyone know the stats on rpm in each gear from the 3.4 - 3.9???????????
Also when crossing the quarter beam i'm in high revs third gear/ low revs fourth, I'm guessing i'll be in fourth every time now.

I will speak to Roger about it on Tuesday but bless them they've had a busy week (plus our cars posed a few problems)

TIA

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
Hello, where are the smart arses when i need them?

SimonV8ster

13,030 posts

259 months

Sunday 27th September 2009
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I'm sure somebody has posted all the different rev ratios depending on what diff you have on before - remember seeing it.

I'll have a quick search......nerd

SimonV8ster

13,030 posts

259 months

Sunday 27th September 2009
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Can't find it but its in here somewhere !! Sure Granadaman posted it as its his sort of thing smile

after_shock

8,751 posts

251 months

Sunday 27th September 2009
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What problems did yours create Mel?

Magic919

14,585 posts

232 months

Sunday 27th September 2009
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You might as well say you'll be a touch over 10% slower for any given revs/gear combo. 89 mph is the new ton. You'll use 4th to cross the line on your quarters I expect.

k15tox

1,680 posts

212 months

Sunday 27th September 2009
quotequote all
www.monkfishperformance.co.uk/diffspeedsummary.html

im thinking of going 3.7. the gearing of my cv8 is a joke it really blunts the cars performance. 3rd and 4th are good. but when i hit 120, i put it in 5th and it drops to like 4k! feels like i hit a brick wall!

why couldnt vauxhall for once just do it right the first time!!!

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
k15tox said:
www.monkfishperformance.co.uk/diffspeedsummary.html

im thinking of going 3.7. the gearing of my cv8 is a joke it really blunts the cars performance. 3rd and 4th are good. but when i hit 120, i put it in 5th and it drops to like 4k! feels like i hit a brick wall!

why couldnt vauxhall for once just do it right the first time!!!
Thanks do you have the standard 3.4 diff???? Or are you saying yours is the 3.9 now????

k15tox

1,680 posts

212 months

Sunday 27th September 2009
quotequote all
Bonnie and Clyde said:
k15tox said:
www.monkfishperformance.co.uk/diffspeedsummary.html

im thinking of going 3.7. the gearing of my cv8 is a joke it really blunts the cars performance. 3rd and 4th are good. but when i hit 120, i put it in 5th and it drops to like 4k! feels like i hit a brick wall!

why couldnt vauxhall for once just do it right the first time!!!
Thanks do you have the standard 3.4 diff???? Or are you saying yours is the 3.9 now????


no probs, i have the crappy uber long geared standard diff

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
after_shock said:
What problems did yours create Mel?
Monkfish had no problems, it all went smoothly when fitting the diff and RRP, it was when Roger took it for a test drive he noticed a noise coming from the front drivers side wheel. Cant remember exactly what he said it was shout Roger. They stripped it down and found that the lower of the two arms/ball joint(or something like that) was badly worn. There was movement in the wheel when he pulled on it(if you know what i mean) He's never had to change one before and has never come across that problem with one of these cars.
On talking through what might have caused it we traced it back to when that dick head window cleaner ran a red light in his Fiat Scudo van. I tried to steer left to get out of his way but failed to avoid the collision. He hit the front drivers side. Luckily my traffic light had only just changed to green so i was only going slowly. If they'd been on green when i got to them I'd have been going a lot faster and it may have been a side impact
We'd only had the car two weeksmad when we got a Vectra hire car for five weeksvomit
Anyway the body shop said it was only aesthetic damage. It's only now we realise there was more damage done than that. I'm bloody pleased Roger found the problem. I'm not sure how safe it would have been at TR.

higgster5.7

308 posts

238 months

Sunday 27th September 2009
quotequote all
Mine does 110 in 3rd and just shy of 140 in fourth the only brickwall gear is sixth but I have an ancient 04 cv8

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
k15tox said:
Bonnie and Clyde said:
k15tox said:
www.monkfishperformance.co.uk/diffspeedsummary.html

im thinking of going 3.7. the gearing of my cv8 is a joke it really blunts the cars performance. 3rd and 4th are good. but when i hit 120, i put it in 5th and it drops to like 4k! feels like i hit a brick wall!

why couldnt vauxhall for once just do it right the first time!!!
Thanks do you have the standard 3.4 diff???? Or are you saying yours is the 3.9 now????


no probs, i have the crappy uber long geared standard diff
Thank god for that. I thought you were saying you'd had the 3.9 and was unhappy with ityikes

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
Magic919 said:
You might as well say you'll be a touch over 10% slower for any given revs/gear combo. 89 mph is the new ton. You'll use 4th to cross the line on your quarters I expect.
I'm sure i read on this topic somewhere that the car would be 24% quicker than before????????

Magic919

14,585 posts

232 months

Sunday 27th September 2009
quotequote all
Bonnie and Clyde said:
Magic919 said:
You might as well say you'll be a touch over 10% slower for any given revs/gear combo. 89 mph is the new ton. You'll use 4th to cross the line on your quarters I expect.
I'm sure I read on this topic somewhere that the car would be 24% quicker than before????????
Don't start getting confused, Mel. The gearing is lower, so the speed has to be lower too. However, the lower gearing improves acceleration.

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
Magic919 said:
Bonnie and Clyde said:
Magic919 said:
You might as well say you'll be a touch over 10% slower for any given revs/gear combo. 89 mph is the new ton. You'll use 4th to cross the line on your quarters I expect.
I'm sure I read on this topic somewhere that the car would be 24% quicker than before????????


Don't start getting confused, Mel. The gearing is lower, so the speed has to be lower too. However, the lower gearing improves acceleration.
But the 0-60 and 1/4 miles will be quicker, yes?

Magic919

14,585 posts

232 months

Sunday 27th September 2009
quotequote all
Bonnie and Clyde said:
But the 0-60 and 1/4 miles will be quicker, yes?
I expect 0-60 to be slower if you can't hit 60 in second any more. I don't know the gearing on CV8 VZ to work it out.

1/4 mile will improve once you've got used to launching it again. TR will give you a chance to check.

Bonnie and Clyde

Original Poster:

11,701 posts

223 months

Sunday 27th September 2009
quotequote all
higgster5.7 said:
Mine does 110 in 3rd and just shy of 140 in fourth the only brickwall gear is sixth but I have an ancient 04 cv8
Yeah Higgster what is going on with your car. That's one seriously quick 04CV8?????????????????? What diff do you have??? Reveal all please

stigmundfreud

22,454 posts

241 months

Sunday 27th September 2009
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have to say I would actually like slightly longer gearing on the r8 well only in 1st 2nd 3rd and 4th, 5th and 6th are brilliant

davegreg

1,099 posts

220 months

Sunday 27th September 2009
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Had nigh on 80mph in 2nd gear in my standard diff CV8 today as i chased after a gaggle of motorcyclists! laugh

hsv_rulz

957 posts

253 months

Sunday 27th September 2009
quotequote all
k15tox said:
www.monkfishperformance.co.uk/diffspeedsummary.html

im thinking of going 3.7. the gearing of my cv8 is a joke it really blunts the cars performance. 3rd and 4th are good. but when i hit 120, i put it in 5th and it drops to like 4k! feels like i hit a brick wall!

why couldnt vauxhall for once just do it right the first time!!!


Not a rant - just a few facts.
First of all, Vauxhall had nothing to do with it - they don't build the cars, just import them. Secondly the cars are Australian and built for Australian conditions - Long distance cruising, like 250 - 300 miles between petrol pumps for instance. Thirdly, 5th and 6th gears are 'overdrive' gears - 0.75 and 0.50 to 1 ratios, again, for cruising not accelerating - for acceleration stick to 1,2,3 and 4th. Holden is a mainstream consumer car manufacturer not Ferrari or Porsche, I think Holden building a car that will accelerate to and cruise at 140MPH is way above they're normal products. If you want breakneck acceleration in all gears then 'You' need to modify it to 'Your' needs as lots of others here have done.