(Very) Close ratio final drive

[alanoo]

Hi all,


As you know, I'm building a somewhat high RPM z22se.
Engine would be fine, but one of the worst things when going high RPM is that your gearbox ratios become inappropriate.

Vx220 ratios are :
1st 3.58:1
2nd 2.02:1
3rd 1.35:1
4th 0.97:1
5th 0.81:1

Final drive ratio is 3.95:1 for the NA and 3.63:1 for the tubby

With the 3.95 ratio and a (conservative) 7600 rpm rev limit I should get :
Top Speed in 1 gear = 64.235 KPH (40 mph)
Top Speed in 2 gear = 113.843 KPH (71 mph)
Top Speed in 3 gear = 170.343 KPH (106 mph)
Top Speed in 4 gear = 237.075 KPH (147 mph)
Top Speed in 5 gear = 283.904 KPH (176 mph)

Let's say the 5th gear is almost totally useless...

Now with the 4.17 from the z22se zafira or the US engines (available from Courtenay sport for example), I'll get :
Top Speed in 1 gear = 60.846 KPH (38 mph)
Top Speed in 2 gear = 107.837 KPH (67 mph)
Top Speed in 3 gear = 161.356 KPH (100 mph)
Top Speed in 4 gear = 224.567 KPH (139 mph)
Top Speed in 5 gear = 268.926 KPH (167 mph)

which is still not much better :?

Now, I learnt the US Saturn Vue (a small SUV which is sold in Europe as the Chevrolet Captiva and Opel Antara), uses in the US another type of the F23 gearbox which is the MG3.

Final Drive Ratio: (M86) 3.84( Cobalt, ION ), 4.17( HHR )
Final Drive Ratio: (MG3) 4.41( VUE )

Top Speed in 1 gear = 57.535 KPH (36 mph)
Top Speed in 2 gear = 101.968 KPH (63 mph)
Top Speed in 3 gear = 152.574 KPH (95 mph)
Top Speed in 4 gear = 212.346 KPH (132 mph)
Top Speed in 5 gear = 254.291 KPH (158 mph)

That is much better !

Anyway, I know nothing about gearboxes !
If I want to fit this final gear, what do I have to order (especially I do not know the name of the parts in English)
I think it should be something like : Diff Ring gear and Main shaft ?

for the moment I was unable to find these parts numbers, but I'll update the post as soon as I'll have them.

 

[slindborg]

the large gear on the diff is the Crown Wheel and the shaft with the smaller gear is the Pinon (plus shaft)


you are aware that this will be insanely expensive.... £500+

 

[alanoo]

I know, but I hope they could be (a lot) cheaper in the US...

 

[vocky]

now that would be quick acceleration 8)

 

[alanoo]

Finally got the parts numbers !

PN 12571819 Main/output shaft

PN 12571821 Differential ring gear.

And... get prepared to be shocked !

Part Number: 12571819 Core Price Your Price

SHAFT-RR MAIN
$136.40


Part Number: 12571821 Core Price Your Price

GEAR-FRT DIFF RING
$164.80

 

[vocky]

blimey thats cheap !

 

[alanoo]

Well, just need to find another F23 to do the conversion now

 

[ATOM X]

Alanoo
Did you have any luck with those part numbers?

 

[ATOM X]

Just ordered final drive parts
It will be going into super/very close ratio gearbox

1st 3.577
2nd 1.877
3rd 1.192
4th 0.907
5th 0.809

diff ratio 4.41

2nd & 3rd ratios from WR gearbox
1st, 4th & 5th from CR gearbox
Deep bell-housing used for dual mass flywheel
this will allow me to fit to saab bottom end

 

[vocky]

those ratios are basically the same as a 3.94 M32 V1 :silent:

the corsa vxr 4.17 M32 would be similar to a 4.55 F23 and the Alfa CR 4.17 M32 is similar to a 4.85 F23

 

[ATOM X]

those ratios are basically the same as a 3.94 M32 V1 :silent:

the corsa vxr 4.17 M32 would be similar to a 4.55 F23 and the Alfa CR 4.17 M32 is similar to a 4.85 F23

You have made the statement, where are the FACTS
I have shown you mine you show me yours (ratios that is)

 

[vocky]

maximum speeds in each gear with a 225/45/17 tyred car and a 7800rpm limiter;

4.41 F23
1 - 37
2 - 70
3 - 110
4 - 145
5 - 162

3.94 V1 M32 - I had this gearing for a while and ended up only using gears 1, 2, 3
1 - 39
2 - 72
3 - 113
4 - 153
5 - 198
6 - 240 (in your dreams people)

4.17 corsa vxr M32
1 - 36
2 - 64
3 - 94
4 - 130
5 - 159
6 - 187 (you are still dreaming)

4.17 Alfa CR M32 simply the best gearbox currently available for our engines :clap:
1 - 36
2 - 59
3 - 88
4 - 121
5 - 147
6 - 161 (yes you could hit the limiter in 6th)

The Alfa gearbox is geared perfectly to my engine, I now use all the gears instead of just a few 8)

 

[ATOM X]

Thanks Neil
Can I have the base ratios
speed is irrelevent if different tyre sizes are used

 

[vocky]

3.94 V1 astra turbo
3.818
2.053
1.302
0.959
0.744
0.614

3.94 V2 astra vxr
3.818
2.158
1.475
1.067
0.875
0.744

4.176 V1 corsa vxr
3.818
2.158
1.475
1.067
0.875
0.744

4.176 Alfa
3.818
2.353
1.571
1.146
0.943
0.861

 

[ATOM X]

Just checked your figures


maximum speeds in each gear with a 225/45/17 tyred car and a 7800rpm limiter;

4.41 F23
1 - 37
2 - 70
3 - 110
4 - 145 (should read 135)
5 - 162

not bad for a £200 mod

 

[ATOM X]

maximum speeds in each gear with a 22.5 inch slick tyred car and a 7800rpm limiter;

4.41 F23
1 - 33
2 - 62
3 - 100
4 - 120
5 - 145

Excellent for the atom 0-60 & 0-100 times

 

[alanoo]

Alanoo
Did you have any luck with those part numbers?

Haven't ordered these as I don't have a cheap way for the full gearbox rebuild those means and not equipped to do these myself, but had confirmation these are indeed the good part numbers ( and these are now even cheaper than before )
Maybe I'll try these this winter with the ITB's project

 

[ATOM X]

I have bought a F23 tooling kit
this allows a complete breakdown of the gearset clusters using a 40 tonne hydraulic press
I can now mix & match gearsets

 

[alanoo]

That's a smart buy, if only F23s were easy to find in France too, I would have bought one too

Why the dual mass bellhousing too ? A flywheel availibility question I guess ?

 

[ATOM X]

That's a smart buy, if only F23s were easy to find in France too, I would have bought one too

Why the dual mass bellhousing too ? A flywheel availibility question I guess ?

I am using a saab bottom end so I have a saab single mass flywheel with same Dims as dual mass so I need deeper bellhousing