Delrin front differential mount?
08-12-09, 01:13 AM
#1
Delrin front differential mount?
Anyone make a delrin/solid rear differential mount? All I can find is stock + competition. Or would a rigid front mount be bad?
I somehow missed this + bought everything but this in delrin. Now I'm looking for one of these + a pinion snubber.
I somehow missed this + bought everything but this in delrin. Now I'm looking for one of these + a pinion snubber.
08-13-09, 01:44 AM
#7
Hmm so some more searching came up with this.
BAD IDEA WARNING: If I had one axe to grind on this forum it’s the idea of welding the front diff mount solid. Sure you can prevent the nose of the diff from rising but what happened to the other forces? Remember that 1000 ft-lbs coming in from the driveshaft? The front is now locked solid in both pitch and in roll. Suddenly instead of the wings carrying the driveshaft moment the front diff mount is trying to carry the torque. It’s only about 4 inches from the axis of rotation (1000 ft-lb = 1/3 ft X reacting force) so suddenly it’s seeing 3000 lbs instead of the couple hundred the diff wings would see in order to react the same torque. The reality is that the mounting point on the subframe can’t take it and the metal flexes until the diff wings actually start to coming into play. Flex metal back and forth with sufficient force and it cracks. It’s the definition of failure via metal fatigue. DO NOT WELD YOUR FRONT DIFF MOUNT SOLID. GIVEN ENOUGH STRESS CYCLES IT WILL BREAK.
OK I'm done...
I think I'll just go with the mazda comp mount.
Originally Posted by frijolee
BAD IDEA WARNING: If I had one axe to grind on this forum it’s the idea of welding the front diff mount solid. Sure you can prevent the nose of the diff from rising but what happened to the other forces? Remember that 1000 ft-lbs coming in from the driveshaft? The front is now locked solid in both pitch and in roll. Suddenly instead of the wings carrying the driveshaft moment the front diff mount is trying to carry the torque. It’s only about 4 inches from the axis of rotation (1000 ft-lb = 1/3 ft X reacting force) so suddenly it’s seeing 3000 lbs instead of the couple hundred the diff wings would see in order to react the same torque. The reality is that the mounting point on the subframe can’t take it and the metal flexes until the diff wings actually start to coming into play. Flex metal back and forth with sufficient force and it cracks. It’s the definition of failure via metal fatigue. DO NOT WELD YOUR FRONT DIFF MOUNT SOLID. GIVEN ENOUGH STRESS CYCLES IT WILL BREAK.
OK I'm done...
I think I'll just go with the mazda comp mount.
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08-13-09, 01:53 AM
#8
WON'T FORGET DAVE
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I'm going the same way. I'm not making that much power anyway.
If I ever get a reinforced subframe I'll make one of these;
http://rx7.speedrocket.com/diff/index.html
If I ever get a reinforced subframe I'll make one of these;
http://rx7.speedrocket.com/diff/index.html
08-13-09, 12:45 PM
#10
Let me start by saying that I run a welded front diff mount. I have 5000 miles and 12+ track days on it and have had zero issues. The easiest way to make a solid front diff mount is to buy a good used one have have it boxed in with steel. That is what I did, and I installed MMR Subframe and Diff mounts at the same time.
Frijolee and I had a discussion about this topic. You can indeed run a solid diff mount without damage. There are a couple LS1 guys that have been doing it for awhile. Here is what you need to do to make it live.
You CAN run a welded front diff mount IF you also have solid subframe and diff mount bushings. If you don't have solid mounts for both the subframe and rear diff, you will rip the diff mounting tab off the subframe. If you run only one or the other, the subframe or diff can move, and this movement will eventually rip the diff mount off the subframe. If both the subframe and diff are mounted solid, nothing moves, and nothing breaks.
Everyone that I have ever heard of that has had damage from a solid front diff mount did not have both solid subframe bushings and solid rear diff bushings.
Frijolee and I had a discussion about this topic. You can indeed run a solid diff mount without damage. There are a couple LS1 guys that have been doing it for awhile. Here is what you need to do to make it live.
You CAN run a welded front diff mount IF you also have solid subframe and diff mount bushings. If you don't have solid mounts for both the subframe and rear diff, you will rip the diff mounting tab off the subframe. If you run only one or the other, the subframe or diff can move, and this movement will eventually rip the diff mount off the subframe. If both the subframe and diff are mounted solid, nothing moves, and nothing breaks.
Everyone that I have ever heard of that has had damage from a solid front diff mount did not have both solid subframe bushings and solid rear diff bushings.
08-13-09, 09:59 PM
#11
Let me start by saying that I run a welded front diff mount. I have 5000 miles and 12+ track days on it and have had zero issues. The easiest way to make a solid front diff mount is to buy a good used one have have it boxed in with steel. That is what I did, and I installed MMR Subframe and Diff mounts at the same time.
Frijolee and I had a discussion about this topic. You can indeed run a solid diff mount without damage. There are a couple LS1 guys that have been doing it for awhile. Here is what you need to do to make it live.
You CAN run a welded front diff mount IF you also have solid subframe and diff mount bushings. If you don't have solid mounts for both the subframe and rear diff, you will rip the diff mounting tab off the subframe. If you run only one or the other, the subframe or diff can move, and this movement will eventually rip the diff mount off the subframe. If both the subframe and diff are mounted solid, nothing moves, and nothing breaks.
Everyone that I have ever heard of that has had damage from a solid front diff mount did not have both solid subframe bushings and solid rear diff bushings.
Frijolee and I had a discussion about this topic. You can indeed run a solid diff mount without damage. There are a couple LS1 guys that have been doing it for awhile. Here is what you need to do to make it live.
You CAN run a welded front diff mount IF you also have solid subframe and diff mount bushings. If you don't have solid mounts for both the subframe and rear diff, you will rip the diff mounting tab off the subframe. If you run only one or the other, the subframe or diff can move, and this movement will eventually rip the diff mount off the subframe. If both the subframe and diff are mounted solid, nothing moves, and nothing breaks.
Everyone that I have ever heard of that has had damage from a solid front diff mount did not have both solid subframe bushings and solid rear diff bushings.
That makes a lot more sense. I have MMR bushings for the diff, subframe + also subframe spacers. I'm wondering if I can't take a block of delrin + fab up a front diff mount that way.
08-13-09, 10:31 PM
#12
Displacement Replacement
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i thought i broke the mount but i had ripped the bracket off my sub frame so i beefed up the bracket and welded the mount solid , i have solid engine and tranny mounts and all that, but im gonna make one of those brackets in the above link its actuall a really good idea,
i daily drive my car , and its been over a month now since i welded it and have only been pleased with the results
i daily drive my car , and its been over a month now since i welded it and have only been pleased with the results
08-14-09, 12:19 AM
#13
You would need steel backing plates, a way to attach the plates to the delrin. Then you would want to impregnate the studs into the delrin. I would not just drill and tap the delrin for studs.
08-14-09, 11:13 AM
#15
Many guys run a pinion snubber with a mazdacomp front mount. Mazda comp seems fine, I think few people if any have had trouble with it. The drivetrain will be quieter with a soft front mount as well.
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