i just dont get it need help
03-02-2013, 07:24 AM
#1
Launching!
Thread Starter
i just dont get it need help i just cant put my head around the concept of converters / stall speeds and such .
lookin to swap out a stocker in my project if it will make it a bit more fun and still dd use .
85chevy c10 shortbed truck .
03 5.3 from yukon all stock possible small cam later down the road .
04 4l60-e from 2wd truck .
4.11 rear gears / 29.1 tall tire 255/70/15
daily driver use i mind and some play time mabye at local strip from time to time. city driving and country hilly roads also in my area.
what would be a good unit to not kill the reliability of the truck but have some more solid fun . thanks guys .
lookin to swap out a stocker in my project if it will make it a bit more fun and still dd use .
85chevy c10 shortbed truck .
03 5.3 from yukon all stock possible small cam later down the road .
04 4l60-e from 2wd truck .
4.11 rear gears / 29.1 tall tire 255/70/15
daily driver use i mind and some play time mabye at local strip from time to time. city driving and country hilly roads also in my area.
what would be a good unit to not kill the reliability of the truck but have some more solid fun . thanks guys .
03-02-2013, 09:47 AM
#2
Moderator
Your stock converter probably has a stall speed around 1800.
So, from a stop, when you give a lot of gas, the engine speed jumps to 1800 rpm and the car starts moving. At 5mph, your engine is still at 1800; at 10 mph, your engine is still at 1800. With your gearing, somewhere around 10 mph, the engine speed will start to climb linearly with your car speed, perhaps 2500 rpm at 15 mph.
Now lets put in a 3200 stall (probably a good choice for you).
Now from a stop when you give a lot of gas, the engine speed will jump to 3200 rpm and stay there until the car reaches around 20 mph, at which point engine rpm will again climb linearly with car speed.
The difference is that even with a stock cam, your engine is producing a lot more power at 3200 rpm than at 1800. Therefore your acceleration up to 20 mph will be much brisker.
The exact stall speed of a converter will depend somewhat on the weight of the vehicle and amount of engine power, but typically is within 10% of advertised value.
There is obviously much more to it than this, but hopefully this answers your basic question.
To test your current stall speed, have a passenger watch the tach as you (safely!) punch it from a stop. The value where it initially sits for the first 10 mph or so, is your stall speed.
So, from a stop, when you give a lot of gas, the engine speed jumps to 1800 rpm and the car starts moving. At 5mph, your engine is still at 1800; at 10 mph, your engine is still at 1800. With your gearing, somewhere around 10 mph, the engine speed will start to climb linearly with your car speed, perhaps 2500 rpm at 15 mph.
Now lets put in a 3200 stall (probably a good choice for you).
Now from a stop when you give a lot of gas, the engine speed will jump to 3200 rpm and stay there until the car reaches around 20 mph, at which point engine rpm will again climb linearly with car speed.
The difference is that even with a stock cam, your engine is producing a lot more power at 3200 rpm than at 1800. Therefore your acceleration up to 20 mph will be much brisker.
The exact stall speed of a converter will depend somewhat on the weight of the vehicle and amount of engine power, but typically is within 10% of advertised value.
There is obviously much more to it than this, but hopefully this answers your basic question.
To test your current stall speed, have a passenger watch the tach as you (safely!) punch it from a stop. The value where it initially sits for the first 10 mph or so, is your stall speed.
03-02-2013, 04:12 PM
#3
Launching!
Thread Starter
o.k. i like that info for how it works .
did some searchin last night and didnt get half that info in the time i was reading.
looks like curb weight is about 4k lbs for this truck . and bone stock 5.3 will have to find dyno results to see were it realy starts working.
i did put out emails to few places that make / sell convt for there input .
and i read few threads about problems with overdrive not going in after newer convt swap . will i need a reflash for this ?
did some searchin last night and didnt get half that info in the time i was reading.
looks like curb weight is about 4k lbs for this truck . and bone stock 5.3 will have to find dyno results to see were it realy starts working.
i did put out emails to few places that make / sell convt for there input .
and i read few threads about problems with overdrive not going in after newer convt swap . will i need a reflash for this ?
03-02-2013, 08:14 PM
#4
Moderator
The converter sponsors like CircleD, Revmax and Yank are generally very easy to reach. They will ask your weight, engine HP and how you use the truck and give you a recommendation. They all basically custom build a converter exactly to your needs.
Yes, you should get a tune for a high-stall converter. Else you may hit the rev-limit with WOT shifts; the solution is to reduce the "WOT Shift RPM" by e.g. 5%. It won't affect shifting into 4th gear (overdrive), but might prevent TCC Lockup or even trigger the MIL light for a "misfire" code; the solution is to reduce the misfire sensitivity or even disable it.
Yes, you should get a tune for a high-stall converter. Else you may hit the rev-limit with WOT shifts; the solution is to reduce the "WOT Shift RPM" by e.g. 5%. It won't affect shifting into 4th gear (overdrive), but might prevent TCC Lockup or even trigger the MIL light for a "misfire" code; the solution is to reduce the misfire sensitivity or even disable it.
03-03-2013, 12:32 PM
#5
Staging Lane
Join Date: Mar 2013
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Your stock converter probably has a stall speed around 1800.
So, from a stop, when you give a lot of gas, the engine speed jumps to 1800 rpm and the car starts moving. At 5mph, your engine is still at 1800; at 10 mph, your engine is still at 1800. With your gearing, somewhere around 10 mph, the engine speed will start to climb linearly with your car speed, perhaps 2500 rpm at 15 mph.
Now lets put in a 3200 stall (probably a good choice for you).
Now from a stop when you give a lot of gas, the engine speed will jump to 3200 rpm and stay there until the car reaches around 20 mph, at which point engine rpm will again climb linearly with car speed.
The difference is that even with a stock cam, your engine is producing a lot more power at 3200 rpm than at 1800. Therefore your acceleration up to 20 mph will be much brisker.
The exact stall speed of a converter will depend somewhat on the weight of the vehicle and amount of engine power, but typically is within 10% of advertised value.
There is obviously much more to it than this, but hopefully this answers your basic question.
To test your current stall speed, have a passenger watch the tach as you (safely!) punch it from a stop. The value where it initially sits for the first 10 mph or so, is your stall speed.
So, from a stop, when you give a lot of gas, the engine speed jumps to 1800 rpm and the car starts moving. At 5mph, your engine is still at 1800; at 10 mph, your engine is still at 1800. With your gearing, somewhere around 10 mph, the engine speed will start to climb linearly with your car speed, perhaps 2500 rpm at 15 mph.
Now lets put in a 3200 stall (probably a good choice for you).
Now from a stop when you give a lot of gas, the engine speed will jump to 3200 rpm and stay there until the car reaches around 20 mph, at which point engine rpm will again climb linearly with car speed.
The difference is that even with a stock cam, your engine is producing a lot more power at 3200 rpm than at 1800. Therefore your acceleration up to 20 mph will be much brisker.
The exact stall speed of a converter will depend somewhat on the weight of the vehicle and amount of engine power, but typically is within 10% of advertised value.
There is obviously much more to it than this, but hopefully this answers your basic question.
To test your current stall speed, have a passenger watch the tach as you (safely!) punch it from a stop. The value where it initially sits for the first 10 mph or so, is your stall speed.