Ordering New Transmission, but What Gears ?

Aubrey N Bruneau · 03-30-2014, 04:27 PM

SLR ?
HHMMM...
"single lens reflex" camera ? ? ! !
You have to remember who you're dealing with here... the guy who shows up to increase car count, and give the new guys somebody to beat in the first round !
really don't know what SLR stands for

Thanks, guys. That's what I keep hearing from everybody but Jerico.
torque is pretty good on this engine... 490 ft lb, so I'm thinking recovery might not be such a monumental obstacle.

Rory McNeil · 03-30-2014, 05:26 PM

SLR equals Starting Line Ratio. 1rst gear x rear axle ratio.
example, 2.88 x 4.88 is 14.06 SLR.
My Mustang with 3.19x5.13 is 16.36 SLR. I would like even more SLR, but with the steeper 1rst gear, and only a 4 speed, the ratio drops thru the gears get pretty wide. Not as much of a problem for a big engine with good torque, but then you are also pulling a lot more weight.
Also, don`t forget that an engine that doesn`t like a lot of RPM will have less rear end ratio, so to get the SLR more favorable, the only other choice is more low gear. Of course more SLR also increases the chance of wheelspin......

henrys57wagon · 03-30-2014, 05:31 PM

Aubrey, SLR= starting line ratio. Here is a calculator.
When we raced I was one of the cars to increase count, did get into 2nd round the odd time at division meets.

http://www.wallaceracing.com/calc-slr.php

03-30-2014, 05:55 PM

Go with at least a 3.19 or higher. The lower the first gear, the lower you can go starting line rpm and use the tq of that engine to get it moving. The higher you leave, the better the chance of not hooking that car. The slower wheel speed, with give the tires a better chance of hooking. IMHO

james schaechter · 03-30-2014, 07:09 PM

Consider a 3.19. The 3.29 is a 34/15 gear and is not as strong as the 33/15 that the 3.19 has. Could be a concern with yout torque and weight combo. Plus the 3.19 can easily be converted to a 3.08. Stay away from the 3.17 also. It is a 34/16. The 34 tooth mdg is not as strong. Same diameter gear only one more tooth crammed in.

Aubrey N Bruneau · 03-30-2014, 08:55 PM

This is fantastic info, people... no wonder I come in here !
My combination had a 14.52 SLR. Yes, I did use to leave at pretty high RPM... about 6200.
Never did really hook up.

Have to make a decision pretty soon, so I can get the transmission under way.

Sean Marconette · 03-30-2014, 09:13 PM

The statement on what is considered a good SLR being 9,10, or 11 for the Walace Racing calculator might be fine for automatics but is completely wrong for a stick car. We do not have a torque multiplier. So our SLR will be higher. Sorry I did not elaborate on SLR earlier.

So what clutch did you get? The dual 7" is very user friendly and extremely predictable.

Sean

Aubrey N Bruneau · 03-30-2014, 09:35 PM

No, not quite that exotic, Sean. Still just single disk. Rob set it up so it has a "soft hit".

BRIAN SEATE · 03-30-2014, 10:15 PM

You also have to look at the strongest column with regard to gear selection. We have a 3.08 Jerico in our Vette, but the car is light at 3000 pounds . The old Doug Nash was a 3.25. I would try to talk to Richard Feldman if possible. I don't know him but hes been at it for a long time with the big car and stick. Good luck my friend.

03-30-2014, 04:27 PM	#1
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: Ordering New Transmission, but What Gears ? SLR ? HHMMM... "single lens reflex" camera ? ? ! ! You have to remember who you're dealing with here... the guy who shows up to increase car count, and give the new guys somebody to beat in the first round ! really don't know what SLR stands for Thanks, guys. That's what I keep hearing from everybody but Jerico. torque is pretty good on this engine... 490 ft lb, so I'm thinking recovery might not be such a monumental obstacle. __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409

03-30-2014, 05:26 PM	#2
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: Ordering New Transmission, but What Gears ? SLR equals Starting Line Ratio. 1rst gear x rear axle ratio. example, 2.88 x 4.88 is 14.06 SLR. My Mustang with 3.19x5.13 is 16.36 SLR. I would like even more SLR, but with the steeper 1rst gear, and only a 4 speed, the ratio drops thru the gears get pretty wide. Not as much of a problem for a big engine with good torque, but then you are also pulling a lot more weight. Also, don`t forget that an engine that doesn`t like a lot of RPM will have less rear end ratio, so to get the SLR more favorable, the only other choice is more low gear. Of course more SLR also increases the chance of wheelspin...... __________________ NHRA 6390 STK M/S 85 Mustang

03-30-2014, 05:31 PM	#3
henrys57wagon Member Join Date: Jan 2009 Location: Carleton Place, On. Canada Posts: 107 Likes: 5 Liked 0 Times in 0 Posts	Re: Ordering New Transmission, but What Gears ? Aubrey, SLR= starting line ratio. Here is a calculator. When we raced I was one of the cars to increase count, did get into 2nd round the odd time at division meets. http://www.wallaceracing.com/calc-slr.php __________________ old 1608 stock racer

03-30-2014, 05:55 PM	#4
Todd Hoven Guest Posts: n/a	Re: Ordering New Transmission, but What Gears ? Go with at least a 3.19 or higher. The lower the first gear, the lower you can go starting line rpm and use the tq of that engine to get it moving. The higher you leave, the better the chance of not hooking that car. The slower wheel speed, with give the tires a better chance of hooking. IMHO

03-30-2014, 07:09 PM	#5
james schaechter VIP Member Join Date: Dec 2004 Location: Cumming GA Posts: 1,994 Likes: 1,296 Liked 1,439 Times in 301 Posts	Re: Ordering New Transmission, but What Gears ? Consider a 3.19. The 3.29 is a 34/15 gear and is not as strong as the 33/15 that the 3.19 has. Could be a concern with yout torque and weight combo. Plus the 3.19 can easily be converted to a 3.08. Stay away from the 3.17 also. It is a 34/16. The 34 tooth mdg is not as strong. Same diameter gear only one more tooth crammed in. __________________ James Schaechter 3163 STK

03-30-2014, 08:55 PM	#6
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: Ordering New Transmission, but What Gears ? This is fantastic info, people... no wonder I come in here ! My combination had a 14.52 SLR. Yes, I did use to leave at pretty high RPM... about 6200. Never did really hook up. Have to make a decision pretty soon, so I can get the transmission under way. __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409

03-30-2014, 09:13 PM	#7
Sean Marconette Senior Member Join Date: Mar 2006 Posts: 977 Likes: 797 Liked 275 Times in 76 Posts	Re: Ordering New Transmission, but What Gears ? The statement on what is considered a good SLR being 9,10, or 11 for the Walace Racing calculator might be fine for automatics but is completely wrong for a stick car. We do not have a torque multiplier. So our SLR will be higher. Sorry I did not elaborate on SLR earlier. So what clutch did you get? The dual 7" is very user friendly and extremely predictable. Sean __________________ Sean Marconette 84 Mustang 5060 SS/N Last edited by Sean Marconette; 03-30-2014 at 09:17 PM.

03-30-2014, 09:35 PM	#8
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: Ordering New Transmission, but What Gears ? No, not quite that exotic, Sean. Still just single disk. Rob set it up so it has a "soft hit". __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409 Last edited by Aubrey N Bruneau; 03-30-2014 at 11:01 PM.

03-30-2014, 10:15 PM	#9
BRIAN SEATE Member Join Date: Oct 2006 Posts: 177 Likes: 0 Liked 1 Time in 1 Post	Re: Ordering New Transmission, but What Gears ? You also have to look at the strongest column with regard to gear selection. We have a 3.08 Jerico in our Vette, but the car is light at 3000 pounds . The old Doug Nash was a 3.25. I would try to talk to Richard Feldman if possible. I don't know him but hes been at it for a long time with the big car and stick. Good luck my friend.