Javascript Disabled Detected

You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

At 100 Km/hr, what revs ?

Started by Pop's-SS , Apr 24 2007 10:21 PM

Please log in to reply

8 replies to this topic

#1 Pop's-SS

Pops

Members
4,971 posts

Name:Barry
Location:Riverina South West Slopes
Car:1976 Mandarin Red SS Hatchback
Joined: 08-November 05

Posted 24 April 2007 - 10:21 PM

G'day All

I haven't been able to confirm that the diff in my SS Hatch is a 3.08 and I have looked in the usual spots but there are no numbers.

At how many revs at 100 Km/hr should the motor be doing with 253 V8 and M20 box and the diff being a 3.08?

Regards ............. Barry

Back to top

#2 rodomo

To advertise here, call 13TORANA

Members
18,018 posts

Name:R - O - B Dammit!
Location:Way out west of Melbourne Awstraylya
Joined: 10-December 05

Posted 24 April 2007 - 10:39 PM

You might want to add your tyre size Baz.

Back to top

#3 Pop's-SS

Pops

Members
4,971 posts

Name:Barry
Location:Riverina South West Slopes
Car:1976 Mandarin Red SS Hatchback
Joined: 08-November 05

Posted 24 April 2007 - 11:02 PM

At how many revs at 100 Km/hr should the motor be doing with 253 V8 and M20 box and the diff being a 3.08?

Add into that equation 205 x 60 x 13 inch Yokohamas

Thanks rodomo

Regards ............ Barry

Back to top

#4 rodomo

To advertise here, call 13TORANA

Members
18,018 posts

Name:R - O - B Dammit!
Location:Way out west of Melbourne Awstraylya
Joined: 10-December 05

Posted 24 April 2007 - 11:27 PM

My calculation is 2836 Rpm using the "Miata" tyre size calculator "pinned" in wheels and tyres. It says your tyres have a rolling circumference of 1.81 meters per rev. My son's UC has the same size tyres and diff ratio and that is what it sat on on the way to Winton last year.

Back to top

#5 TerrA LX

Fulcrum Fixture

Members
14,241 posts

Location:Sid 'n' knee
Joined: 31-May 06

Posted 24 April 2007 - 11:30 PM

seems a bit high to me for 3.08.

Back to top

#6 _CHOPPER_

Guests

Posted 24 April 2007 - 11:37 PM

The 205/60R13 is a very small diameter tyre for a Torana, which is why the revs would be higher than expected. Using my $5 calculator, I came up with the same RPM that Rob got.

Back to top

#7 _devilsadvocate_

Guests

Posted 24 April 2007 - 11:37 PM

Rodomo has calculated correctly.

Back to top

#8 _devilsadvocate_

Guests

Posted 25 April 2007 - 12:11 AM

Of course figuring your diff ratio using road speed, rpm and tyre size assumes you have the correct speedo drive fitted and no errors in your speedo(common) or tacho(rarer) . Remove uncertainty by measuring the ratio

Back to top

#9 REDA9X

Removed

Inactive
0 posts

Joined: 08-November 05

Posted 25 April 2007 - 09:27 PM

Mine with the 285 40 15 does around 2300 rpm at 100, my SS 253 3.08 rear with 225 50 15 did the same. If you work out the tyre diameters, it's almost identical to the originals. The VK Group A I drove today was about the same.