80e billet direct drum > at what power level?
Thread Starter
Joined: Nov 2013
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From: Portlandia
80e billet direct drum > at what power level? so I'm currently using a stock internal 80e with a brake and i'm getting ready add more power.
The trans I'm building for it has a 300m input and IM shaft and I'm considering a drum upgrade.
the turbo, cubes, cam and fuel system will support ~950 wheel in a 3600 lb car, fastest 60' has been a 1.65 ( hope to get that into the 1.5 range)
I am looking of course at the CK drum as it's by far the most affordable one I've seen.
The trans I'm building for it has a 300m input and IM shaft and I'm considering a drum upgrade.
the turbo, cubes, cam and fuel system will support ~950 wheel in a 3600 lb car, fastest 60' has been a 1.65 ( hope to get that into the 1.5 range)
I am looking of course at the CK drum as it's by far the most affordable one I've seen.
TECH Junkie
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From: Iowa
The direct drum sprag strength is as much a factor of power as it is rpm
The sprag, once applied, can hold an absurd amount of power.
The breakage always happens either on the shift, or if the tires shake/you pedal the car and shock it
1000whp is OK as long as you shift 1-2 UNDER 6600 rpm
I say that because the sprag's job is to stop that drum from spinning INSTANTLY. the mass of that steel drum over 6600 is often just too much for the sprag to take.
You'll have guys spin them to 7000...it can be done...but it is a risk they take every time.
If you're going to upgrade to a steel drum, the 36 element can support a good bit more than the 34. The elements are taller and help spread the load.
An aluminum 34 element will take similar power to a steel 36 because there's so much less rotating mass to stop on a dime.
The sprag, once applied, can hold an absurd amount of power.
The breakage always happens either on the shift, or if the tires shake/you pedal the car and shock it
1000whp is OK as long as you shift 1-2 UNDER 6600 rpm
I say that because the sprag's job is to stop that drum from spinning INSTANTLY. the mass of that steel drum over 6600 is often just too much for the sprag to take.
You'll have guys spin them to 7000...it can be done...but it is a risk they take every time.
If you're going to upgrade to a steel drum, the 36 element can support a good bit more than the 34. The elements are taller and help spread the load.
An aluminum 34 element will take similar power to a steel 36 because there's so much less rotating mass to stop on a dime.
TECH Junkie
Joined: Jun 2008
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From: Nitro Alley
The Intermediate Clutch pack is also a factor.
The use of a Waved-Steel plate can reduce some of the shock to the Intermediate-Sprag.
When nearing the limits of the 34-Element (Stock) Intermediate-Sprag...
The use of OEM THM400 Intermediate Waved-Friction plates can help reduce the shock to the Sprag as well.
The 4T80E 36-Element Forward-Sprag is a substantial upgrade over the 4L80E 34-Element Intermediate-Sprag.
The use of a Waved-Steel plate can reduce some of the shock to the Intermediate-Sprag.
When nearing the limits of the 34-Element (Stock) Intermediate-Sprag...
The use of OEM THM400 Intermediate Waved-Friction plates can help reduce the shock to the Sprag as well.
The 4T80E 36-Element Forward-Sprag is a substantial upgrade over the 4L80E 34-Element Intermediate-Sprag.
TECH Junkie
Joined: Jun 2008
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From: Nitro Alley
For your Transmission; I would use an early THM400 direct drum with:
-Both sets of feed passages
-That is deep enough for SIX 0.090" steels and SIX 0.080" frictions
-Uses an early THM400 aluminum Direct piston with the WIDE apply rings; and cut-down to a height of approx. 0.620".
-Machined for the 4T80E 36-Element Forward-Sprag
-Uses the CK-Performance 36-Element outer Sprag race for use with OEM dimension Intermediate clutch pack (instead of a Ford based clutch pack).
-Both sets of feed passages
-That is deep enough for SIX 0.090" steels and SIX 0.080" frictions
-Uses an early THM400 aluminum Direct piston with the WIDE apply rings; and cut-down to a height of approx. 0.620".
-Machined for the 4T80E 36-Element Forward-Sprag
-Uses the CK-Performance 36-Element outer Sprag race for use with OEM dimension Intermediate clutch pack (instead of a Ford based clutch pack).
Thread Starter
Joined: Nov 2013
Posts: 6,389
Likes: 558
From: Portlandia
yep i'm on the wavy plate train, especially since the brake I use doesnt have EPC
i'll have to research more about fitting the 36 element sprag. I have this nice lathe here and its terribly wasted just honing bushings and whatnot
Does the altered surface need heat treatment post machining?
i'll have to research more about fitting the 36 element sprag. I have this nice lathe here and its terribly wasted just honing bushings and whatnot
Does the altered surface need heat treatment post machining?
The direct drum sprag strength is as much a factor of power as it is rpm
The sprag, once applied, can hold an absurd amount of power.
The breakage always happens either on the shift, or if the tires shake/you pedal the car and shock it
1000whp is OK as long as you shift 1-2 UNDER 6600 rpm
I say that because the sprag's job is to stop that drum from spinning INSTANTLY. the mass of that steel drum over 6600 is often just too much for the sprag to take.
You'll have guys spin them to 7000...it can be done...but it is a risk they take every time.
If you're going to upgrade to a steel drum, the 36 element can support a good bit more than the 34. The elements are taller and help spread the load.
An aluminum 34 element will take similar power to a steel 36 because there's so much less rotating mass to stop on a dime.
The sprag, once applied, can hold an absurd amount of power.
The breakage always happens either on the shift, or if the tires shake/you pedal the car and shock it
1000whp is OK as long as you shift 1-2 UNDER 6600 rpm
I say that because the sprag's job is to stop that drum from spinning INSTANTLY. the mass of that steel drum over 6600 is often just too much for the sprag to take.
You'll have guys spin them to 7000...it can be done...but it is a risk they take every time.
If you're going to upgrade to a steel drum, the 36 element can support a good bit more than the 34. The elements are taller and help spread the load.
An aluminum 34 element will take similar power to a steel 36 because there's so much less rotating mass to stop on a dime.
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TECH Junkie
Joined: Jun 2008
Posts: 3,202
Likes: 1,390
From: Nitro Alley
7,400 RPM is getting high...
You might be able to get away with that.
I do not like to spin the OEM drums that high regardless of power level.
Both the Forward Drum and Direct Drum are very heavy compared to many other transmissions (aprox. 15 Lbs per drum).
Lightened OEM parts and lighter material aftermarket parts for the 4L80E/ THM400 are a HUGE part of my business.
My favorite Drum-System for the THM400 is from John Kilgore... called the "SuperLite"
Stamped Steel is used instead of cast Iron... 30 Lbs of iron gets replaced by 8 Lbs of steel.
If a 4L80E is being used without an Intermediate Band... I would go to an Aluminum Direct-Drum.
Otherwise, use an OEM Direct -Drum with the 36-Element Sprag.
In first gear the Direct drum is spinning the reverse direction at about 2.5 times the engine RPM.
The transmission must instantly STOP the Direct drum (aprox. 15 Lbs) from spinning to shift up into second gear.
In third gear the Direct drum must instantly accelerate to engine speed in the forward direction.
You might be able to get away with that.
I do not like to spin the OEM drums that high regardless of power level.
Both the Forward Drum and Direct Drum are very heavy compared to many other transmissions (aprox. 15 Lbs per drum).
Lightened OEM parts and lighter material aftermarket parts for the 4L80E/ THM400 are a HUGE part of my business.
My favorite Drum-System for the THM400 is from John Kilgore... called the "SuperLite"
Stamped Steel is used instead of cast Iron... 30 Lbs of iron gets replaced by 8 Lbs of steel.
If a 4L80E is being used without an Intermediate Band... I would go to an Aluminum Direct-Drum.
Otherwise, use an OEM Direct -Drum with the 36-Element Sprag.
In first gear the Direct drum is spinning the reverse direction at about 2.5 times the engine RPM.
The transmission must instantly STOP the Direct drum (aprox. 15 Lbs) from spinning to shift up into second gear.
In third gear the Direct drum must instantly accelerate to engine speed in the forward direction.
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4l80 7,400 RPM is getting high...
You might be able to get away with that.
I do not like to spin the OEM drums that high regardless of power level.
Both the Forward Drum and Direct Drum are very heavy compared to many other transmissions (aprox. 15 Lbs per drum).
Lightened OEM parts and lighter material aftermarket parts for the 4L80E/ THM400 are a HUGE part of my business.
My favorite Drum-System for the THM400 is from John Kilgore... called the "SuperLite"
Stamped Steel is used instead of cast Iron... 30 Lbs of iron gets replaced by 8 Lbs of steel.
If a 4L80E is being used without an Intermediate Band... I would go to an Aluminum Direct-Drum.
Otherwise, use an OEM Direct -Drum with the 36-Element Sprag.
In first gear the Direct drum is spinning the reverse direction at about 2.5 times the engine RPM.
The transmission must instantly STOP the Direct drum (aprox. 15 Lbs) from spinning to shift up into second gear.
In third gear the Direct drum must instantly accelerate to engine speed in the forward direction.
You might be able to get away with that.
I do not like to spin the OEM drums that high regardless of power level.
Both the Forward Drum and Direct Drum are very heavy compared to many other transmissions (aprox. 15 Lbs per drum).
Lightened OEM parts and lighter material aftermarket parts for the 4L80E/ THM400 are a HUGE part of my business.
My favorite Drum-System for the THM400 is from John Kilgore... called the "SuperLite"
Stamped Steel is used instead of cast Iron... 30 Lbs of iron gets replaced by 8 Lbs of steel.
If a 4L80E is being used without an Intermediate Band... I would go to an Aluminum Direct-Drum.
Otherwise, use an OEM Direct -Drum with the 36-Element Sprag.
In first gear the Direct drum is spinning the reverse direction at about 2.5 times the engine RPM.
The transmission must instantly STOP the Direct drum (aprox. 15 Lbs) from spinning to shift up into second gear.
In third gear the Direct drum must instantly accelerate to engine speed in the forward direction.
TECH Junkie
Joined: Jun 2008
Posts: 3,202
Likes: 1,390
From: Nitro Alley
Using an outer sprag race like the one that CK Performance uses (36-Element Sprag); will allow you to keep using 4L80E or THM400 frictions (most vendors are changing to this style outer race now).
Generally though people use an outer sprag race, that would use frictions from a Ford C6/ GM 4T80E.
TECH Junkie
Joined: Dec 2012
Posts: 3,615
Likes: 1,327
From: Iowa
It has been my experience that the smooth intermediate frictions with relatively tight clearance (.0065 per friction versus the standard .010 per friction) when combined with the bottom plate being a wave can substantially help the life of the sprag.
For anyone that wants to make their own 36 element, I don't have the exact dimensions for ya, but I can tell you that you need to indicate the drum using the sealing ring bore. Not the OD of the drum.
If you cut the race using the OD of the drum it may be off center by quite a good margin when compared to the sealing rings.
For anyone that wants to make their own 36 element, I don't have the exact dimensions for ya, but I can tell you that you need to indicate the drum using the sealing ring bore. Not the OD of the drum.
If you cut the race using the OD of the drum it may be off center by quite a good margin when compared to the sealing rings.
Thread Starter
Joined: Nov 2013
Posts: 6,389
Likes: 558
From: Portlandia
thanks for all the data gents. it looks like the CK piece is a heckuva deal for the money.
I dont rev to the moon, so I'll keep going with the BW 34 element sprags and OEM drum.
I hope this thread is useful for those folks on the fence.
I dont rev to the moon, so I'll keep going with the BW 34 element sprags and OEM drum.
I hope this thread is useful for those folks on the fence.