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Solid engine mounts and ET improvement?

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  • Solid engine mounts and ET improvement?

    I currently run stock motor mounts with a Prothane mount on the auto trans. I have a home made "torque strap" set up that has a rod end at the engine on the top of the cylinder head and it attaches to the sway bar mount with a bracket I made that has two cut down shock absorber isolator bushings to prevent rattles and/or tearing up the frame mounts. Under load, chassis dyno or drag strip the engine torques over a very small amount, maybe an 1/8th of an inch.

    Is this amount of movement, compression of the mounts and bushings, costing me measurable ET?
    Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?

  • #2
    1/8"? I doubt you are leaving much on the table. Although if you are running with the big dogs for serious stakes, every little bit counts, but at that level you would have left stock mount territory long ago.

    I say you are fine. Just never run a solid trans mount, especially with non-solid motor mounts. You can go solid on the motor, and flexible on the trans, just never the other way around. Even better, just never run a solid trans mount.
    Of all the paths you take in life - make sure a few of them are dirt.

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    • #3
      on my old 2001 Grand prix. it picked up 1 tenth by switching to solid engine and trans mounts. but this car was also FWDand stock there is alot of movement
      Originally posted by Remy-Z;n1167534
      Congratulations, man. You've just inherited the "Patron Saint of Automotive Lost Causes" from me. No question.

      75Grand AM 455:Pissed off GrandMA, 68 Volkswagen Type1 "beetle":it will run some year

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      • #4
        Bill its not the TQ of the enine that slows it down, its the front to back. Remember "objects at rest tend to stay at rest" The Car will tale off around the engine and trans. It can and has caused some unloading when it catches up shocking the car. Its quick and made a huge difference in Docs 52 plus we quit breaking dist caps that where 3/8 inch from a cage bar at the firewall with motor and mid plates we put a front to back limiter on it one each side with left and right heims to preload it
        2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
        First to run in the .90s .80s and .70's in SBN/A
        2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
        2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

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        • #5
          I'd not worry about it in a unit body convert.. frame connectors and rollbar, it'll still flex more than the engine mount is

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          • #6
            I've heard that a cage can be worth as much as a second off your ET... Adding weight to go faster.......

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            • #7
              Originally posted by Stich496 View Post
              I'd not worry about it in a unit body convert.. frame connectors and rollbar, it'll still flex more than the engine mount is
              true.
              I learned quite a bit about this welding a ten geared subaru.


              I did not stop welding until there was no creaking in plastic trim on pillars. above is the end result.
              like a cat chasing its own tail.. to find the tires needed an exact depth in the wheel well...and now the other side is still broken same spot. Awaiting welding again.

              reminds me of the f1 race cars that blow both front tires at the same time.

              frame rails or unibody.. too tight is just that. Some go crazy on the subes, same stuff.. solid mounts and AWD. it is crazy.
              Previously boxer3main
              the death rate and fairy tales cannot kill the nature left behind.

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              • #8
                Originally posted by boxer3main View Post

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                • #9
                  Originally posted by boxer3main View Post
                  true.
                  I learned quite a bit about this welding a ten geared subaru.

                  .
                  I don't think I have ever been more confused than right now.
                  Yes, I'm a CarJunkie... How many times would YOU rebuild the same engine before getting a crate motor?




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                  • #10
                    The unibody has been stitch welded, sub-framed, caged and all the suspension pick-up points reinforced as best I can, and yes it added weight. The front to rear that Jeff raises is interesting. The way the stock Ford mount encapsulates the rubber portion makes me think that fore and aft movement is low, but it is something I will check out and address. I will mount an under hood Flip camera to see if I can catch what happens in slo-mo as well as a simple wire with a plastic sleeve as witness marker to measure relative motion. We found really interesting stuff in suspension movement at launch with the Flip cameras.
                    Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?

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                    • #11
                      Originally posted by CDMBill View Post
                      The unibody has been stitch welded, sub-framed, caged and all the suspension pick-up points reinforced as best I can, and yes it added weight. The front to rear that Jeff raises is interesting. The way the stock Ford mount encapsulates the rubber portion makes me think that fore and aft movement is low, but it is something I will check out and address. I will mount an under hood Flip camera to see if I can catch what happens in slo-mo as well as a simple wire with a plastic sleeve as witness marker to measure relative motion. We found really interesting stuff in suspension movement at launch with the Flip cameras.
                      the cowl forward if those cars weak point..

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                      • #12
                        I've been using solid mounts for about 30 years on the same block. I put them in because I had a torque strap and thought it looked ugly. I don't know if it made may car any quicker.

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                        • #13
                          Does your Camaro have factory body mount bushings or have they been replaced with solid ones as well?
                          Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?

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                          • #14
                            I think Dad's has solid bushings in it now Bill, but I can't be sure. If they aren't solid then they are Poly.

                            Note: I've never run a set of poly or rubber motor mounts in any car I've swapped the engine in. People always talk about vibration and noise, but my thought on that is that if you have enough camshaft you are going to have vibration and noise anyway.

                            Like was already said, always use a poly mount for the trans. Solid is a bad call on all but a tube chassis car. Solid mounts on the engine and poly trans are what I always do.

                            When you install solid mounts on a Chevy, sorry can't remember how the Fords look, you want to make sure that they slight snuggly over the frame towers to limit the fore and aft movement that Jeff mentioned. A limiter up front isn't a bad idea though. Your testing and video should show you what you are really having move around or not.
                            "A cross thread is better than a lock washer." Earl Lanning...My Grandpa

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