Find Us On: Facebook Twitter
View unanswered posts | View active topics It is currently Mon Aug 21, 2017 8:06 am



Reply to topic  [ 18 posts ]  Go to page Previous  1, 2
 Another new (but vintage) vintage racer 
Author Message

Joined: Thu Dec 26, 2013 2:21 pm
Posts: 18
Reply with quote
Press1 wrote:
Mack - thanks! Already found those articles. Very helpful.

Anyone have suggestions for final drive ratios for Summit Point (or Pitt Race for that matter) in a 510? I have 3.9, 4.4 and 5.13. I believe 5th gear is a 15% overdrive, but I'm stretching the limits of my memory!


A 3.9 will work fine just about everywhere you go. I used to run a Group 3 Datsun 510 (no flares, 1.6L, smaller wheels/tires) and ran a 3.9 everywhere.

_________________
Chris Zappa


Tue Sep 23, 2014 9:39 am
Profile
User avatar

Joined: Wed Jul 23, 2014 10:31 am
Posts: 67
Location: Ligonier, PA
Reply with quote
Hi Mack - thanks for the advice on the final drive ratio! I used the 3.9 at Beaver for a PDE day and it worked well. The rules were passing with a point-by on the two straights and I was pretty busy pointing-by the 600hp Mustangs on those. On the few laps where I was able to wind everything out, I made it into 5th gear on the straights. Not sure I would have run out of revs with the 4.4, but it might have been close.

_________________
Joe Teplitz - Western PA
Datsun 510


Sat Oct 04, 2014 6:02 pm
Profile
Site Moderator
User avatar

Joined: Tue Dec 03, 2013 12:05 pm
Posts: 254
Reply with quote
Actually Joe, that was Chris Zappa who recommended the 3.9. I run a 3.76 FD but then I have 10" wheels. What's the FD in your garden tractor? :D

_________________
Mack


Thu Oct 09, 2014 11:32 am
Profile
User avatar

Joined: Wed Jul 23, 2014 10:31 am
Posts: 67
Location: Ligonier, PA
Reply with quote
Sorry, Chris! Thanks!

I run 5.13s in the lawn tractor because the straights are pretty short!

_________________
Joe Teplitz - Western PA
Datsun 510


Thu Oct 09, 2014 12:08 pm
Profile

Joined: Thu Jan 23, 2014 5:51 pm
Posts: 8
Reply with quote
Welcome to the club! I attended the school at Summit Point last year and also competed in the Jefferson 500. What a great week! The instructors are first rate and the facility is great. I found the school to very informative and the instruction to be spot-on. Just make sure that your car is EXTREMELY well prepared and that you have help available during the school. Not much time between classroom and track sessions for fixing broken car :D , so a crew will be very helpful. Most of all, ENJOY YOURSELF! posting.php?mode=reply&f=34&t=273#

_________________
David Bane


Fri Oct 17, 2014 9:34 pm
Profile
User avatar

Joined: Wed Jul 23, 2014 10:31 am
Posts: 67
Location: Ligonier, PA
Reply with quote
Thanks! Although, not sure I have much of a crew...

_________________
Joe Teplitz - Western PA
Datsun 510


Sat Oct 18, 2014 7:42 pm
Profile
User avatar

Joined: Wed Jan 15, 2014 9:59 am
Posts: 3
Location: Dunbarton, NH
Reply with quote
Joe,
I don't remember what gear I ran at Summit in my Datsun 1200 (SCCA-GTL w/A15 power), but at VIR on 20" tall slicks w/4.88 gears, in 5th (.854) it would hit 8400 on the back straight. Assuming Summit & VIR are close to the same top speed for a small bore car it would be comparable.

In example, if my car were on a vintage tire, say a 205/60-13 Toyo at 22.7" tall (1.135 times taller) the effective top RPM would be 7400.

Based on racing my Datsun 1200 at VIR using the 5.12 & 5th gear on Toyo's it would theoretically have turned 7764 RPM at top end. The 4.44 would have given a theoretical 6733 top RPM in 5th.

Not knowing all the variables of your car (tire diameter, top engine RPM, my 1200/your 510 or even if VIR/Summit are close in comparison) your first choice at Summit could be the 5.12 using 5th and with the 4.44 you would never run out of gear.

One thing on racing with an OD 5th is it will really spin-up the drive shaft speed. In my 1200 at 8400 in 5th the drive shaft is turning over 9800 RPM.

_________________
Dave Patten, Owner

Image
FutoFab, LLC
199 Stark Hwy So
Dunbarton, NH 03046

Dave@FutoFab.com
http://www.futofab.com


Sun Oct 26, 2014 10:10 am
Profile WWW
User avatar

Joined: Wed Jul 23, 2014 10:31 am
Posts: 67
Location: Ligonier, PA
Reply with quote
Thanks! I've been trying to figure out speeds, ratios, etc and ran across this interesting calculator online:
http://www.crawlpedia.com/rpm_gear_calculator.htm

Also - understood about the driveshaft RPM! I have the 2.0 liter engine with the five speed. I believe 5th is a 15% OD, so similar. I'm told there's not much use in going above 7500 RPM.

_________________
Joe Teplitz - Western PA
Datsun 510


Sun Oct 26, 2014 6:30 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 18 posts ]  Go to page Previous  1, 2

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF
Copyright © 2010 - 2016 VRG. All rights reserved.