4.30 Rear Axle - Alfa Romeo Bulletin Board & Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 47 (permalink) Old 03-16-2010, 12:03 AM Thread Starter
Registered User
 
Join Date: Dec 2009
Location: Charlotte, NC
Posts: 396
4.30 Rear Axle

Hi,
Looking for a 4.30 ratio rear axle to put under my 1969 GTV any one know what year/model had this ratio rear end?
rusty racer is offline  
Sponsored Links
Advertisement
 
post #2 of 47 (permalink) Old 03-16-2010, 03:06 AM
jpv
Registered User
 
jpv's Avatar
 
Join Date: Feb 2005
Location: Portugal
Posts: 490
I don't know about US-Spec cars but, in Europe, only the Berlina models had that ratio. 1750 had the light, no lsd, axle and the 2000 had the heavy, LSD, axle...

Jo„o Vale
1965 Giulia Super / 1969 GT Junior / 1971 Junior Z
jpv is offline  
post #3 of 47 (permalink) Old 03-16-2010, 06:42 AM
Senior Member
Gold Subscriber
 
Subtle's Avatar
 
Join Date: Oct 2006
Location: Vancouver, B C
Posts: 6,225
Spent about six months looking for a used one to put into my Sprint project. But it was hopeless.

Max Banks at Alfaholics is having new 4.3 ring and pinion sets made for the 1600 diff.

The one from my Sprint is over there and being done up now.

Bob,
Avatar is the 68 Super, bought new.
Subtle is online now  
Sponsored Links
Advertisement
 
post #4 of 47 (permalink) Old 03-16-2010, 07:01 AM
Trained (ex)Professional

1953-2018 RIP

Platinum SubscriberAdministrator
 
papajam's Avatar
 
Join Date: Feb 2003
Location: New Jersey USA
Posts: 16,232
The 4.30 rear was fitted to the European Berlinas (GTVs & Spiders got 4.10s). As such, I'd think one would be hard pressed to find one in the USA.

Jim

Series 2 USA 1750 GTV (in Series 1 European clothing)
papajam is offline  
post #5 of 47 (permalink) Old 03-16-2010, 07:13 AM
Senior Member
Gold Subscriber
 
Subtle's Avatar
 
Join Date: Oct 2006
Location: Vancouver, B C
Posts: 6,225
I tried Europe as well.

Bob,
Avatar is the 68 Super, bought new.
Subtle is online now  
post #6 of 47 (permalink) Old 03-16-2010, 07:40 AM
jpv
Registered User
 
jpv's Avatar
 
Join Date: Feb 2005
Location: Portugal
Posts: 490
What ratio had the US Berlinas?

I've located on in a parts Berlina in a small town 100km away from my city. Going to get it soon for my 1750 Giulia Super...

And there was another berlina in a junkyard for years but last year the cleaned the place before I got the chance to get parts...

Jo„o Vale
1965 Giulia Super / 1969 GT Junior / 1971 Junior Z
jpv is offline  
post #7 of 47 (permalink) Old 03-16-2010, 07:49 AM Thread Starter
Registered User
 
Join Date: Dec 2009
Location: Charlotte, NC
Posts: 396
So the thing seems to be made of un-obtanium guess the new ring gear from alfaholics is the way to go. So those of you who have made the transition to 4.30 do you think it is worth the strugle? Plan to install a twin-spark bout 190-200 hp with lightened but regular ratio gear box.
rusty racer is offline  
post #8 of 47 (permalink) Old 03-16-2010, 07:56 AM
Senior Member
Gold Subscriber
 
Subtle's Avatar
 
Join Date: Oct 2006
Location: Vancouver, B C
Posts: 6,225
The 2 L in my Spider could be developing some 150 lbs/ft of torque over a broad curve.

But in hard driving on tight mountain roads the 4.10 seems a little tall. The 4.56 was away too short.

The 4.3 should be just right.

It could take a couple of months before the Sprint is finished.

Bob,
Avatar is the 68 Super, bought new.

Last edited by Subtle; 03-16-2010 at 08:13 AM.
Subtle is online now  
post #9 of 47 (permalink) Old 03-16-2010, 08:01 AM
jpv
Registered User
 
jpv's Avatar
 
Join Date: Feb 2005
Location: Portugal
Posts: 490
It depends on the track you're racing really.

My car has a 4.3 axle with standard 2 liter engine and is great!

with 195/65 R14 tyres it hits 120km/h at 4000rpm and top speed is 210km/h at 6500/6800rpm...
It's good for a small track with lots of bends and straits that won't let the car pass 200km/h...

If you're racing at a very fast track maybe this is to short and the 4.1 is the one for you.

Jo„o Vale
1965 Giulia Super / 1969 GT Junior / 1971 Junior Z
jpv is offline  
post #10 of 47 (permalink) Old 03-16-2010, 08:55 AM
Senior Member
Gold Subscriber
 
Subtle's Avatar
 
Join Date: Oct 2006
Location: Vancouver, B C
Posts: 6,225
Quote:
Originally Posted by rusty racer View Post
So the thing seems to be made of un-obtanium guess the new ring gear from alfaholics is the way to go. So those of you who have made the transition to 4.30 do you think it is worth the strugle? Plan to install a twin-spark bout 190-200 hp with lightened but regular ratio gear box.
With the standard ratio transmission and 4.56 diff gearing was very short.

Had the Spider gear box re-built (needed new syncros) with taller first, second and third. Much better.

Have the same transmission for the Sprint.

Bob,
Avatar is the 68 Super, bought new.
Subtle is online now  
post #11 of 47 (permalink) Old 03-16-2010, 09:41 AM
Trained (ex)Professional

1953-2018 RIP

Platinum SubscriberAdministrator
 
papajam's Avatar
 
Join Date: Feb 2003
Location: New Jersey USA
Posts: 16,232
Quote:
Originally Posted by jpv View Post
what ratio had the us berlinas?
4.56

.............

Jim

Series 2 USA 1750 GTV (in Series 1 European clothing)
papajam is offline  
post #12 of 47 (permalink) Old 03-16-2010, 01:18 PM
Registered User
 
69alfa's Avatar
 
Join Date: Feb 2003
Location: Toronto Canada
Posts: 811
Here is a nice chart

Here is a nice chart for US cars.

http://centerlinealfa.com/tips/images/diff_ratios.pdf

Will see if there is one like it for over the pond on the net.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

[SIZE="2"]David Munro[/SIZE]
Toronto ON Canada
1969 Spider JR Twin Spark
69alfa is offline  
post #13 of 47 (permalink) Old 03-16-2010, 02:56 PM
1966-2013
Platinum Subscriber
 
Tifosi's Avatar
 
Join Date: Mar 2006
Location: Northern NY, USA
Posts: 13,741
195/60-14 tires on a 4.1:1 differential will give a final drive of approximately 4.26~4.30:1 depending on the exact rollout of whatever given brand tires are used.




Darren
'84 manufacture ~ '85 MY Spider Graduate

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

as hosted by

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
&
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Tifosi is offline  
post #14 of 47 (permalink) Old 03-16-2010, 03:49 PM
Registered User
 
69alfa's Avatar
 
Join Date: Feb 2003
Location: Toronto Canada
Posts: 811
I have Yokohama ES100 tires
195 60 R 14
894 revs per mile

This would give me a final ratio of ?

How do you work this out?

Thanks


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

[SIZE="2"]David Munro[/SIZE]
Toronto ON Canada
1969 Spider JR Twin Spark
69alfa is offline  
post #15 of 47 (permalink) Old 03-16-2010, 07:20 PM
1966-2013
Platinum Subscriber
 
Tifosi's Avatar
 
Join Date: Mar 2006
Location: Northern NY, USA
Posts: 13,741
Compare stock sized tire to what you want to put on here.

Jot down the difference is revs per mile, or as represented as a %.

Take the % and go to this % calculator site.

Using % and the top converter, express the 'what is' as % difference (should be less than 100% if going to bigger diameter tire, more than 100% if going to smaller diameter tire) and bounce that off the '% of' side of the equation which should be your known gear ratio.

Example:
185/70~14 (stock tire) has a 4.06% difference to that of a 195/60~14 (after market tire)

'what is' 104.06 (because the 195 is smaller diameter) '% of' 4.10 (final drive ratio for my 85) = 4.27 corrected final drive ratio

To go with revs per mile instead of %, (slightly more accurate) just use the bottom calculator on the % calculator page first and punch in new tires revs per mile in the 1st box and stock tires revs per mile in the second, then carry that result up to the 'what is' box of the top calculator and finish with known gear ratio.

Example:
894 (your claimed revs per mile) 'is what % of' 859 (claimed revs per mile of stock from the other site) = 104.307

Carry the 104.307 up to the 'what is' box '% of' 4.10 (final drive ratio for an 85) = 4.28 corrected final drive ratio

For either to be truly accurate, you'll need to know the exact revs per mile for both stock and aftermarket tire as measured with a tape and calculated out rather than relying on a tire suppliers pamphlet to account for manufacturing differences and such, then carry that to the % calculator.

The above system is just a 'get you pretty darn close' way of going about it.


Presuming you have a stock 4.56 diff:

894 revs p/mile yoko's 'is what % of' 859 revs p/mile for 185/70~14 = 104.307

'what is' 104.307% 'of' 4.56 = 4.77 corrected final drive ratio




Darren
'84 manufacture ~ '85 MY Spider Graduate

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

as hosted by

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
&
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Tifosi is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome