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#1
10-31-2017, 06:56 PM
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When to consider billet drum for a turbo 400
At what level is it a good idea to upgrade the drum in a 400? Is it overkill for a heavy 10 second car? Does anyone here run one in their street/strip car?
More concerned with the safety and reliability factor rather than the very slight performance gain from saving 5 lbs or so of rotating weight.
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68 GTO,3860# Stock Original 400/M-20 Muncie,3.55’s 13.86 @ 100 Old combo: 462 10.75 CR,,SD 330CFM Round Port E's,Old Faithful cam,Jim Hand Continental,3.42's. 1968 Pontiac GTO : 11.114 @ 120.130 MPH New combo: 517 MR-1,10.8 CR,SD 350CFM E's,QFT 950/Northwind,246/252 HR,9.5” 4000 stall,3.42's 636HP/654TQ 1.452 10.603 @ 125.09 http://www.dragtimes.com/Pontiac-GTO...lip-31594.html |
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#2
10-31-2017, 07:36 PM
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We had our trans guy (Proformance Trans) install a billet drum along with every thing else needed to push over 1k h.p. in my sons car this last spring. I feel better for my son and his safety. My sons car also runs on the street a lot. I know it's not cheap but nothing is when you run fast.
Brian
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 Boobs & bacon 
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#3
10-31-2017, 07:43 PM
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My transmission guy told me that high rpm is when the good drums are needed.
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#4
10-31-2017, 09:42 PM
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I did the same Brian.
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 A new best of 9.135 @ 145.4171 Lemans Sport. 72 Lemans Sport. |
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#5
10-31-2017, 10:58 PM
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Quote:
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Matt 70 GTO 400 4-speed "Turbos make no noise and leave the line like Baby Diarrhea!" - GTOGeorge |
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#6
11-01-2017, 05:22 PM
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I thought Pontiacs kick the rods out at anything over 5200 RPMs?
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First Pontiac powered street car in the 7's 7.940@170.84. 3460#s |
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#7
11-01-2017, 07:12 PM
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Quote:
As good as a governor. |
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#8
11-01-2017, 09:49 PM
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Quote:
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#9
11-01-2017, 09:54 PM
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What's more important the drum or the input shaft being billet??
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#10
11-01-2017, 10:02 PM
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Quote:
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John Marcella Marcella Manifolds Inc. john@marcellamanifolds.net ph. 248-259-6696 |
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#11
11-02-2017, 07:37 AM
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Direct Drum
The Direct Drum is traveling at 84% of the Turbine Shaft (Input Shaft) Speed in First Gear. When the 1-2 Shift Occurs the Intermediate Clutch Stops the Direct Drum from Rotating by way of the Intermediate Sprag. When the 2-3 Shift Occurs the Direct Drum has to Accelerate to Turbine Shaft Speed.
So, this is why the Intermediate Sprag Fails and why the Billet Aluminum Drum not only Reduces Sprag Failure but also makes the Car Accelerate Harder, ALL due to the Weight of the Drum. FYI, Turbine Shaft Speed = Engine RPM - Torque Converter Slippage. The Billet Aluminum Direct Drum has the 36 Element "Super Sprag" as an Option. My $0.02.... Although Pricey, the Billet Direct Drum is a very worthwhile upgrade in any Turbo 400 Transmission. Larry S.
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---------- http://www.pas4performance.com Proud to Say, "Made in the USA"  ---------- |
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#12
11-02-2017, 05:20 PM
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I am on a learning curve with automatics. Was always a stick shift guy, but I am tired of breaking stuff. Going auto as we speak.
The billet drums are 5 lbs lighter than oem, guess that helps. I already have a billet hub and a 34 element sprag, some say I should go to a 36 element sprag. I am going to test my luck with the billet hub,drum, input shaft, and 34 element sprag since it is what I have now. |
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#13
11-02-2017, 06:31 PM
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JSPont, the aluminum drum wont live too long when you street drive the car. Im not sure if it changed nowadays.
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#14
11-02-2017, 08:58 PM
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Quote:
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#15
11-02-2017, 09:27 PM
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I was told the same thing that with a lot of street driving the band will wear on the drum.
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#16
11-03-2017, 07:23 AM
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Intermediate Brake Band
In a Turbo 400, the Intermediate Brake Band Applies on the Outer Surface of the Direct Drum. It Holds the Direct Drum and Provides Engine Braking in Manual Second Gear.
In a Racing Application with a Manual Valve Body or a Transbrake, the Intermediate Brake Band and Its Apply Servo are Eliminated. Larry S.
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---------- http://www.pas4performance.com Proud to Say, "Made in the USA" ---------- |
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#17
11-03-2017, 08:24 AM
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It was the spline in the drum. It will wear out the teeth and eventually strip.
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#18
11-03-2017, 11:39 AM
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Quote:
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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#19
11-03-2017, 11:48 AM
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409 NSS buddy popped his into neutral at the big end and grenaded his TH400.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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#20
11-03-2017, 05:16 PM
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I was at Rosslers’ shop and was told their proprietary drum they machine in house uses a steel sleeve and will live no problem on the street. They make a lot of the parts they use in their builds. I’ll ask about the input shaft wearing the splines.
I twisted the input shaft out of a turbo 350 drum with a lot less power than I’m making now.
__________________
68 GTO,3860# Stock Original 400/M-20 Muncie,3.55’s 13.86 @ 100 Old combo: 462 10.75 CR,,SD 330CFM Round Port E's,Old Faithful cam,Jim Hand Continental,3.42's. 1968 Pontiac GTO : 11.114 @ 120.130 MPH New combo: 517 MR-1,10.8 CR,SD 350CFM E's,QFT 950/Northwind,246/252 HR,9.5” 4000 stall,3.42's 636HP/654TQ 1.452 10.603 @ 125.09 http://www.dragtimes.com/Pontiac-GTO...lip-31594.html |
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