3.73 or 4.10 on a LS1 automatic

[Hypsi87]

Ok I made out this huge long post to help a guy with a gear selection problem and it turns out he has a stick. Well I did all my reasearch for an automatic. Well im not going to waste it. That and I wanted to anwser Formulas question on as to why I suggested a high stall torque converter over a set of gears.

Originally Posted by FormulaLT1

Very good suggestion. but Do you really think that high of a stall with just 3.42's and most likely stock everything else?

yup well, and a trans cooler, high stall torque converters generate alot of heat.

Here is my reasoning, Like I said once you put a gear in, your done. With a torque converter, it is variable. With a high stall converter, when you are cruising down the road at normal curising RPM's you have close to a 1:1 drive raito between the impeller and the turbine in the converter.(If you have a lock up clutch for your turbine you have a direct 1:1.) anyway, at cruise speeds with a stock gear ( Im using a 3.42 gear as my stock gear in this situation.) you will have the gas mileage, Lower RPM's and quieter cruise that a higher gear has to offer.

Now lets say your ready to race. Ok your lined up at line pre-staged and ready to go. you got your 4.10 gear just waiting to be unleashed. The first yellow light drops and you flash the converter (For thoes of you that don't know that is the techincal term for power brake) but you have the stock stall converter which is something like 2100 RPM. Your converter is mulitplying engine torque like mad and you have that light gear in the ass end with stock size tires, weather they be drag raidals or slicks or street tires. Any way the light turns green and you let off the brake and SCREEEEEEEEEECH!!!!!!!! tires are up in smoke so bad that you can't see shit out of your rearview. Lost time on the launch, the most important part of drag racing. On top of that , your having to grab your overdrive gear at the end of the track and that so soooo counter productive it is not even funny.

Now your racing and you have a stock gear and a 3300 3200 stall. you have a 3.42 rear end gear and your sitting at the line same senario. you flash the converter and now you have even more torque multiplacation* sp and a gear that can put more of that power to work. It's like having a low gear by sending more torque to a higher gear. Then locking it up as your speed increases (Which is why an automatic is faster in the qtr mile) Now you have a kick ass launch, you don't have to bottom out 3rd gear and you can stay out of overdrive,you have the mileage and quitetness of not having to run 3000+ RPM on the street, you don't have to tear apart and put back together your rear end which can be a pain in the ass to set up correctly. All you do is drain your tranny, pull it, pull the stock converter, put the new one on, bolt all the crap back up and fill the tranny. I would also suggest a Trans cooler for a higher stall converter.

[Chevyracincamaro]

haha, you are the freakin man hypsi...

[Chevyracincamaro]

although you couldnt have been a little earlier with this, suppose before i bought a higher gear and ripped apart my rear-end which will be a pain in the ass to setup correctly...

[FormulaLT1]

All very good points.
I was always told to not go too crazy on higher stall with a car that had a stock cam and listened my first time out when I got a converter with a 2000 rated stall (which we know is just a estimate) but I recently purchased one with a 2600 stall but have yet to drop it in but I have 3.73 gears

[Hypsi87]

you would be fine. Alot of people think that if you have a high stall ( Like 3300 RPM) your car will just sit their untill you rev up past the set RPM and the car will just Jump foward, Not true

[FormulaLT1]

I know that but what I was concerned about was WOT launches with too high of a stall

[Hypsi87]

I run a 3200 NON lockup on a v-6 and my cam is like a 48something lift and a 198 duration. You should be fine.

Anyway, My point was to tell people that just going and throwing a gear in the back is something to sit back and think about.