Drag Racing Discussions > Front Engine Dragsters

1.69 low gear

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Van:

--- Quote from: retroboy on April 28, 2015, 07:07:59 PM ---I chose a Torqueflite because it has 2.45/1.45/1.00 thinking the lower first gear combined with 4.56 rear gears will make my converter work better at multipling torque. I'm a hand brake guy have I made the wrong choice? I want a car I can drive.

--- End quote ---

 I think of it this way, I run a 3 speed (T400) and run a 3.90 or even a 3.50 gear. With the low gear launch the converter is done doing its job right at the hit. The motor will stay in it's peek torque if you shift it right and the tall gear will give great MPH without buzzing the motor. You do not need a 4.56 gear or a killer converter with a 3 speed.   

LZ:
Hi buds:
Say Can someone have anything to say about the starting line ratio for a FED?? Some generalities? Have talked and read some with people and they always relate to a heavier or suspended car. just thought this should go along with the talk here.
Here is a sample of info for conversations sake. Page 155 and 156.
https://books.google.com/books?id=SOIYFkfXdocC&pg=PA155&lpg=PA155&dq=starting+line+ratio+for+dragster&source=bl&ots=8IVq331lYu&sig=dwdICBWUpeXfLR0cIT2JzY2M2wA&hl=en&sa=X&ei=QV9AVcpLhMWiBOiugPgM&ved=0CC0Q6AEwAg#v=onepage&q=starting%20line%20ratio%20for%20dragster&f=false

I will be facing this whole issue when we dyno the engine. So thanks to everyone for sharing. 8)
Luke

afuelcoupe:
yes for you guys running decent power a 1.69 is the way to go but one important thing none of you have mentioned is that with the higher ratio your spit is much more favorable as well, this helps with your fuel curve as well as preventing the RPM  fall back on the converter........In fact some of you guys would benefit from an even higher first gear......one of the posts above mentioned it generates higher wheel speed.......That is not true with a shallower gear.....
just food for thought

wideopen231:
Look at this way. Suspended RED's weight in 2000 lb area for most part. FED's in the 1400 to 1600(heavy) are. You need the tq multiplacation of lower gear(bigger number) to get the heavier car going ,but not so much with lite weight car.   

wideopen231:
Not saying 3 spd is wrong. It is lot heavier and lot more rotating mass.Some have been built under 100#. While there are lots of parts for3  spd's ,theres nowhere near the parts as for PG and well built pg can handle 2500 hp. As for rpm range. Glide will drop  plus or minus around 900 to 1000 rpm pretty narrow power band will be larger.

Need someone with racepak to post there stage,hit,shift rpm,fallback and time between leave and shift,Wouldbe great if someone had same info for 1.69 and 1.80.

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