Try to lower rotating mass weight....
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Try to lower rotating mass weight....
I think the main reason for the 2piece shaft is to prevent it from deflecting enough to fall out of the transmission. The longer the driveshaft, the more the pipe can wobble out of round under severe loads. The whole trick with the 2piece shaft is to keep the transmission end perfectly straight so that you don't have friction in the front ujoints. That way the driveshaft is nothing more than an extension of the transmission output shaft and you don't loose much power turning it.
I think you could get away with a small diameter front half or one made from aluminum or carbon fiber if you wanted to go exotic.
<div class='quotetop'>QUOTE(RedHeartbeat @ Oct 29 2006, 05:58 PM) [snapback]71557[/snapback]</div>I'm not seeing anyone who will make a one-piece aluminum. Only the C/F. ACPT seems pretty confident they could put a 1piece C/F together for me which would handle the "wobble" - which sounds accurate. I know some fab work would have to be done to cut out the carrier bearing and all and then the pinion angle would have to be set a bit differently. I would figure a two-piece assembly would be pretty heavy (60 or so pounds) compared to a C/F - maybe 20....don't know what that would translate to rwhp/rwlbtq-wise.Quote:
I think the main reason for the 2piece shaft is to prevent it from deflecting enough to fall out of the transmission. The longer the driveshaft, the more the pipe can wobble out of round under severe loads. The whole trick with the 2piece shaft is to keep the transmission end perfectly straight so that you don't have friction in the front ujoints. That way the driveshaft is nothing more than an extension of the transmission output shaft and you don't loose much power turning it.
I think you could get away with a small diameter front half or one made from aluminum or carbon fiber if you wanted to go exotic.
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They say 1500.00 tops for the driveshaft.....
Figure this and a Nelson tune might be able to help me get closer to where I feel I should be in the quarter...13.7/13.8.....don't know if a full second is in there or not...but it just doesn't make sense to be putting down 355rwhp@4700lbs and be pulling a 14.6 in 60 degree temps. :(
<div class='quotetop'>QUOTE(93Ext5.7ltr @ Oct 30 2006, 12:05 AM) [snapback]71608[/snapback]</div>Do you have a stall converter. I think your TQ/Hp is up in the power band. This is the prob. I had. Nothing down low, now I have a cam and stall. I just need to go to the track and test it out.Quote:
I'm not seeing anyone who will make a one-piece aluminum. Only the C/F. ACPT seems pretty confident they could put a 1piece C/F together for me which would handle the "wobble" - which sounds accurate. I know some fab work would have to be done to cut out the carrier bearing and all and then the pinion angle would have to be set a bit differently. I would figure a two-piece assembly would be pretty heavy (60 or so pounds) compared to a C/F - maybe 20....don't know what that would translate to rwhp/rwlbtq-wise.
They say 1500.00 tops for the driveshaft.....
Figure this and a Nelson tune might be able to help me get closer to where I feel I should be in the quarter...13.7/13.8.....don't know if a full second is in there or not...but it just doesn't make sense to be putting down 355rwhp@4700lbs and be pulling a 14.6 in 60 degree temps. :(
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Jamest
the main reason for the 2 piece driveshafts is to eliminate the imbalance issue. Driveshafts have a critical speed where they vibrate themselves to death. Stock 1 pieces ae most likely only balanced up to 100 +/-. I know this first hand as my driveshaft went out on my truck at 122 on the dyno. The only trucks with one piece driveshafts that GM produces these days are std cab, short bed. Food for thought. Safety wise, I think you are better off with the 2 piece.
Andrew
<div class='quotetop'>QUOTE(agreif @ Oct 31 2006, 06:28 AM) [snapback]71717[/snapback]</div>Nope! Ext cab, short bed 4x4 are one piece shafts.Quote:
The only trucks with one piece driveshafts that GM produces these days are std cab, short bed. Food for thought. Safety wise, I think you are better off with the 2 piece.
Andrew
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<div class='quotetop'>QUOTE(foggy @ Oct 31 2006, 07:40 AM) [snapback]71723[/snapback]</div>Those have a transfer case to use up some of the length to the rear axle.Quote:
Nope! Ext cab, short bed 4x4 are one piece shafts.
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1 piece steel propshafts can only be so long before they wobble. the longer they are the bigger around they need to be. a standard steel shaft should be no longer than 53" with 3" dia. the aluminum shafts can be like 8" dia and super long while being ultra light. hear is a bullitan for some super long alumnium shafts, you could start with one of these propshafts and cut to length or get a conversion u-joint
Document ID# 862282
2002 Chevrolet Chevy K Silverado - 4WD
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Subject: Launch Shudder on Acceleration (Install New One-Piece Propeller Shaft) #01-04-17-001B - (02/21/2002)
Models: 1999-2002 Chevrolet and GMC K2500/3500 Extended Cab Long Box and Crew Cab Short Box Pickup Models
With Automatic Transmission
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This bulletin is being revised to add model information, remove procedure steps and change parts information. Please discard Corporate Bulletin Number 01-04-17-001A (Section 04 -- Driveline Axle).
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Condition
Some customers may comment on a vibration during acceleration from 0-40 km/h (0-25 mph). This may also be referred to as launch shudder. This condition may be more noticeable when the vehicle is carrying cargo or is used for towing.
Correction
A new propeller shaft is available for service to correct this condition. This new propeller shaft is a one-piece design and will replace the current two-piece design.
Install a new one-piece propeller shaft on affected vehicles. Refer to the service procedure and the parts information listed below. Match the affected vehicle with the appropriate propeller shaft. Refer to the usage information below. This fix does not apply to the Chassis/Crew Cab Models (K35943).
Remove the propeller shaft assembly and the center bearing. Refer to the Propeller Shaft - Two Piece procedure in the Propeller Shaft sub-section of SI2000. For this bulletin, it is not necessary to mark the components for re-assembly.
Center Bearing Support Bracket
Important: The center bearing support bracket (1) must be removed in order to provide enough clearance for installation of the one-piece propeller shaft. Avoid damaging the crossmember during removal of the center bracket. For proper clearance, no more than 13 mm (½ in) of the bracket may remain on the crossmember after removal.
Remove the center bearing support bracket from the kick-up crossmember using a cut-off wheel.
After removal of the center bearing support bracket, grind the rough metal edges smooth that remain on the crossmember.
Coat the exposed metal surfaces with frame coating using the information found in the applicable Service Manual and GM Refinish Material Booklet #4901M-D-2002 (English) or #4901M-D-F2002 (French).
Install the new propeller shaft. Refer to the Propeller Shaft Replacement - One Piece in the Propeller Shaft sub-section of SI2000 for installation guidelines and yoke retainer tightening specifications.
Parts Information
P/N
Description
Usage
15077431
Shaft Asm.- Prop
K25953 w/ LQ4, MT1, C6P
(99-00 8600# GVW)
15077434
Shaft Asm.- Prop
K25953/35953 w/ M74 (Allison Trans)
15077435
Shaft Asm.- Prop
K25953 w/ LQ4, MT1
(HD Model 9200# GVW)
15077436
Shaft Asm.- Prop
K35953 w/ LQ4, MT1
(11,400# GVW)
15093466
Shaft Asm.- Prop
K25743 w/LQ4, MT1
(HD Model 9200# GVW)
15093467
Shaft Asm.- Prop
K25743 w/M74 (Allison Trans)
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
F1280
To remove Two-Piece Propshaft and Center Bearing Mount Bracket and Install One-Piece Propshaft
0.9 hr
I sometimes get this shudder under acceleration, but i have a 1 piece driveshaft so i dont know if that included me or not