low gear X rear gear, an updated recommendation

Dragsinger · 06-12-2011, 06:25 PM

Many years ago ATI offered a suggested starting line ratio based on engine stroke and car weight. Much has changed since those days. Is there an updated/suggested ratio guide line formula?

Wade_Owens · 06-12-2011, 09:37 PM

Quote:

Originally Posted by Dragsinger

Many years ago ATI offered a suggested starting line ratio based on engine stroke and car weight. Much has changed since those days. Is there an updated/suggested ratio guide line formula?

Larry, I would be very interested in seeing the "old" recommendations if there arent any new ones......

Wade O

Dragsinger · 06-12-2011, 09:44 PM

Wade, I will find them. The chart has been posted on several message boards.

Dragsinger · 06-12-2011, 09:46 PM

Wade, did not take long

http://drr.infopop.cc/eve/forums/a/t...12/m/441102691

Adger Smith · 06-12-2011, 11:05 PM

Larry,
Did you notice something about that chart.... All the different strokes only have a .75 ratio spread between the bottom and top weight. I was way over the suggested start line ratio when I was running a PG in my car. I would say this is just a get started suggested number. I put a 1.76 in place of my 1.98 as an experiment to keep from hitting an index. It worked, my ET dropped .15... Made the 60's way slower. That was a 12.53 over all to a 11.14 in a 3175 lb car. I think the % drop in 1-2 shift made more difference than the start line ratio. It got in high gear too far down track and didn't let the converter work. A long, long time ago a person that was on top of things told me to pick the tire/rear gear for the desired MPH and the tranny low for the launch ratio. With today's converters I think 2 more factors should be considered. The torque converter ratio and the gear drop % go hand in hand.

gtaa · 06-14-2011, 02:57 PM

Hi
Is there a recomendation for 3 speeds also?
M.Lind

Adger Smith · 06-15-2011, 01:16 AM

Low! :~)

06-12-2011, 06:25 PM	#1
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	low gear X rear gear, an updated recommendation Many years ago ATI offered a suggested starting line ratio based on engine stroke and car weight. Much has changed since those days. Is there an updated/suggested ratio guide line formula? __________________ Larry Woodfin 471W

06-12-2011, 09:44 PM	#3
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: low gear X rear gear, an updated recommendation Wade, I will find them. The chart has been posted on several message boards. __________________ Larry Woodfin 471W

06-12-2011, 09:46 PM	#4
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: low gear X rear gear, an updated recommendation Wade, did not take long http://drr.infopop.cc/eve/forums/a/t...12/m/441102691 __________________ Larry Woodfin 471W

06-12-2011, 11:05 PM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: low gear X rear gear, an updated recommendation Larry, Did you notice something about that chart.... All the different strokes only have a .75 ratio spread between the bottom and top weight. I was way over the suggested start line ratio when I was running a PG in my car. I would say this is just a get started suggested number. I put a 1.76 in place of my 1.98 as an experiment to keep from hitting an index. It worked, my ET dropped .15... Made the 60's way slower. That was a 12.53 over all to a 11.14 in a 3175 lb car. I think the % drop in 1-2 shift made more difference than the start line ratio. It got in high gear too far down track and didn't let the converter work. A long, long time ago a person that was on top of things told me to pick the tire/rear gear for the desired MPH and the tranny low for the launch ratio. With today's converters I think 2 more factors should be considered. The torque converter ratio and the gear drop % go hand in hand. __________________ Adger Smith (Former SS)

06-14-2011, 02:57 PM	#6
gtaa Junior Member Join Date: Jan 2005 Location: Sweden Posts: 96 Likes: 36 Liked 4 Times in 2 Posts	Re: low gear X rear gear, an updated recommendation Hi Is there a recomendation for 3 speeds also? M.Lind

06-15-2011, 01:16 AM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: low gear X rear gear, an updated recommendation Low! :~) __________________ Adger Smith (Former SS)