Stall speed for converter question

[Carsten]

I think it is a common problem... Which converter should i use or better said which stall speed or what factors are involved on the stall speed ?
Car is a 1979 Oldsmobile with a 350 chevy out of a corvette with a weiand open plenum intake and Holley 750cfm (3310) vakuum secondaries , camel hump heads and maybe other cam , but do not know exactly, hooker headers , 2,25 inch dual exhausts , about 280 hp at the wheels , weight should be as stock , but no a/c and Weld Draglites , so maybe a little lighter.
Trans is a th350 with shiftkit and a 2000stall converter(on break , on acceleration 2100 to 2200 , depending of trans temperature, rear is standard Olds , i think it has 2,29 gears , but will change to 3.3? or 3.73 soon.
Car goes really good over 3000 rpms up to 6000rpms , i think because of the carb - intake - rear combination...
So , i could get 2 differnt converters :
2500 to 3000
3000 to 3500
This is what they say ist the rpm stall range. As i know , on a smallblock in a light car they may end up at 2500to2600 and the second 3000to3100...maybe !?
I think a 3000 stall would be good for the car... or ???
What do you think ? What have you in your cars ?
Thank you for any ideas , help , informations !!!!!!!

I have some videos on youtube under : The79OldsCutlass

Greets , Carsten

 

[SLICK79WGN]

I would start with the gear then re-evaluate the stall

 

[Carsten]

I would start with the gear then re-evaluate the stall

Why ?
Greets , Carsten

 

[SLICK79WGN]

because it will change everything and with a higher gear set you are going to be pulling more rpms to begin with and the stall is not going to help that any if anything make it worse, so if you are planning a gear change then you should do that before you up the stall speed IMO

 

[Carsten]

because it will change everything and with a higher gear set you are going to be pulling more rpms to begin with and the stall is not going to help that any if anything make it worse, so if you are planning a gear change then you should do that before you up the stall speed IMO

So will the stall rpm go up with the converter i have when i put in a higher gear set ?
Greets , Carsten

 

[SLICK79WGN]

it should work like it is suspose to so before I bought a higher stall I would throw a gear in it

 

[custom442]

He's saying to up the gearing cuz it won't work properly with really high gearing.

This is how I think of a stall converter - think of a driving a manual. If you want to take off at a stoplight, you're stepping on the clutch (i.e. stall slippage) and let the rpms go up to around say 3000. Then you let off the clutch (stall converter slips a lesser amount) until it reaches the point where the torque curve of your engine allows the wheels to get moving forward, past the friction being pushed against it (road/tires/wheel spin). So if the converter is suppossed to stall at 3000, then an engine with less torque (or real high gears) will drop rpms a little more before the power is sent to the pavement.

Now relate the driveability aspect to driving a manual on the highway (lets say your 'stall' is 3,000 rpms). So if you cruise at 2400 rpms on the hwy, any time when you're driving under 3 grand, it's like having your foot in the clutch slightly. That's not a good thing - wears down your trans, too much heat, wastes gas. It's why people say dont get higher than around 2000 (maybe 2500) on the street. But then that depends on how you drive and how much you drive. But you can have your cake and eat it - get a lock up stall and it fully engages the driveline (no clutch slippage), so when your on the highway you dont need to worry about that 3500 stall slipping the whole way.

The way i see it- factoring in 100-200 rpm differences for a street car is like trying to decide what color jacket you wear that day. Either get the lower stall for better driveability, or the higher one for more stoplight fun

 

[shotgun]

X2 on what he said, wrong gear/convertor vs single plane manifold also.

Also adding more gear will lower the stall that it sees now.

There is less "load" on the convertor with steeper (higher number) gears.

Street or race car?

 

[Carsten]

X2 on what he said, wrong gear/convertor vs single plane manifold also.

Also adding more gear will lower the stall that it sees now.

There is less "load" on the convertor with steeper (higher number) gears.

Street or race car?

Street car , but no daily , just having fun in the city and some strip use.
When i understand you the right way , when i go from my 2.29 gears to 3,43 for example , the stall will go down ? Problem is that the car goes from standing at lights from 2000 to 3000 like a 50 hp Honda and then beginns to get fast and from 3500 on it gets really fast. So that was my idea to get a 3000 stall converter in it.
Cruising on the highway sees about 2500 to 3000 rpms , due to we have no speed limit over here. So a stall of 3000 would be no problem as i will put in higher gears later on .
Carsten

 

[shotgun]

When i understand you the right way , when i go from my 2.29 gears to 3,43 for example , the stall will go down ? YES, ever drive a stick/manual. Using custom442s idea, leave from a traffic light in first, now do the same thing but put the car in third then pull away. You are going to rev it higher and slip the clutch more to get it going. Higher gears do the same thing. Right now you are leaving in "third" better gears will be more like leaving in "first". Hope that explains it better.
Problem is that the car goes from standing at lights from 2000 to 3000 like a 50 hp Honda and then beginns to get fast and from 3500 on it gets really fast. So that was my idea to get a 3000 stall converter in it.Right idea but you need to do the rear gears FIRST or you will kill your transmission from excessive heat
Cruising on the highway sees about 2500 to 3000 rpms , due to we have no speed limit over here.I loved driving the Autobahn, kinda sucked have a small Renault. Nothing like driving with the car matted for 30 minutes at a time :lol:
So a stall of 3000 would be no problem as i will put in higher gears later on .
Need to know the tire size to help on rear ratio.
Carsten