Starting line ratio for manual transmission application

tavbfl · 01-04-2021, 05:20 PM

This may be common knowledge for those in the stock/super stock community, but searching the internet only comes up with automatic info.
My slr is 14.19 with a 5.14 and I cross the finish line 500 rpm below peak hp. Changing to a 5.57 would change it to 15.6 and I'm concerned as to whether it would be a gain or a loss for et as well as consistency. Thanks in advance for any insight, Tony Aiello.

Dave Noll · 01-04-2021, 08:13 PM

The SLR in my automatic Cougar is 18.1 & my EF/S Stick Escort is 12.1. I may be changing the Cougar to 19.6 & the Escort to 13.5. The Cougar I'm trying to get to the "Airing Out" point. The Escort I'm just trying to get more.

Rory McNeil · 01-04-2021, 08:24 PM

My starting line ratio is 16.39, and I drop the clutch at 6000-6600 RPM, and run similar 1/8th mile numbers to you, although I run on 1/4 tracks.It looks like you have plenty of tire,so I see no reason why your consistency should suffer at all, provided you are somewhere close on your clutch setup. I always like to be crossing the finish line a little higher than my shift RPM. Are you 60 foot and 330 numbers pretty consistent now?

Nmbr1GMfan · 01-05-2021, 10:51 AM

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Jim Caughlin · 01-05-2021, 12:00 PM

Quote:

Originally Posted by Nmbr1GMfan

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Oh man, I'm completely off the chart 21.4 with a 28" tall tire...

Mike Pearson · 01-05-2021, 01:18 PM

When I ran a stick in my super stock car the SLR was about 19 to 1 3.11 low gear and 6.17 in the rear. Had to yank the handle real quick low to second.

Rory McNeil · 01-05-2021, 10:48 PM

I am assuming the original poster must have a low gear ratio of 2.76, which is quite tall for a drag car, especially as it looks like he has a fairly big tire on there. Going to 5.57s should increase his trap RPM around 600 RPM, but I would also be looking for a lower first gear in the transmission. What the current 60 foot and 330 numbers, and what size tires on the car would be helpful.

bykr · 01-06-2021, 12:31 PM

Quote:

Originally Posted by Mike Pearson

When I ran a stick in my super stock car the SLR was about 19 to 1 3.11 low gear and 6.17 in the rear. Had to yank the handle real quick low to second.

Real close to my #'s 3.28 and 6.20's. 2nd gear has to be in about 1 second.

01-04-2021, 05:20 PM	#1
tavbfl Junior Member Join Date: Feb 2016 Location: Florida Posts: 5 Likes: 0 Liked 1 Time in 1 Post	Starting line ratio for manual transmission application This may be common knowledge for those in the stock/super stock community, but searching the internet only comes up with automatic info. My slr is 14.19 with a 5.14 and I cross the finish line 500 rpm below peak hp. Changing to a 5.57 would change it to 15.6 and I'm concerned as to whether it would be a gain or a loss for et as well as consistency. Thanks in advance for any insight, Tony Aiello. Attached Thumbnails __________________ '69 Camaro 468ci Doug Nash 4+1 6.36@107 1/8

01-04-2021, 08:13 PM	#2
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,681 Liked 240 Times in 112 Posts	Re: Starting line ratio for manual transmission application The SLR in my automatic Cougar is 18.1 & my EF/S Stick Escort is 12.1. I may be changing the Cougar to 19.6 & the Escort to 13.5. The Cougar I'm trying to get to the "Airing Out" point. The Escort I'm just trying to get more. __________________ Dave Noll, EF/S ,?/SA 6526

01-04-2021, 08:24 PM	#3
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,311 Likes: 317 Liked 1,106 Times in 303 Posts	Re: Starting line ratio for manual transmission application My starting line ratio is 16.39, and I drop the clutch at 6000-6600 RPM, and run similar 1/8th mile numbers to you, although I run on 1/4 tracks.It looks like you have plenty of tire,so I see no reason why your consistency should suffer at all, provided you are somewhere close on your clutch setup. I always like to be crossing the finish line a little higher than my shift RPM. Are you 60 foot and 330 numbers pretty consistent now? __________________ NHRA 6390 STK M/S 85 Mustang

01-05-2021, 10:51 AM	#4
Nmbr1GMfan VIP Member Join Date: Aug 2013 Posts: 1,763 Likes: 1,197 Liked 1,955 Times in 492 Posts	Re: Starting line ratio for manual transmission application [IMG][/IMG] __________________ Todd Greene

01-05-2021, 01:18 PM	#6
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,456 Likes: 618 Liked 1,945 Times in 586 Posts	Re: Starting line ratio for manual transmission application When I ran a stick in my super stock car the SLR was about 19 to 1 3.11 low gear and 6.17 in the rear. Had to yank the handle real quick low to second. __________________ Mike Pearson 2485 SS

01-05-2021, 10:48 PM	#7
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,311 Likes: 317 Liked 1,106 Times in 303 Posts	Re: Starting line ratio for manual transmission application I am assuming the original poster must have a low gear ratio of 2.76, which is quite tall for a drag car, especially as it looks like he has a fairly big tire on there. Going to 5.57s should increase his trap RPM around 600 RPM, but I would also be looking for a lower first gear in the transmission. What the current 60 foot and 330 numbers, and what size tires on the car would be helpful. __________________ NHRA 6390 STK M/S 85 Mustang

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