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  1. #1
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    Moton Shock Pressurization for comp coupe

    Folks, my .pdf copy of the comp coupe manual doesn't mention anything about pressurizing the Moton shocks with nitrogen. I've had Moton shocks on other cars that required you pressurize them with Nitrogen gas (typically 100-150psi more or less).

    I assume the comp coupe shocks are the same, is that correct? is there a recommended pressure to run them at?

    Thanks,

    Mark
    Mark O'Dell
    2002 Viper Competition Coupe Prototype P4

  2. #2
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    Probably won't help, but my MCS shock canisters came pressurized at 175 psi. I've run them between 150 and 200 psi just to see what difference it made, and have settled around 185 psi for my use (99% street driven, with the other portion being at the drag strip).

    Do they have the canisters with the compression adjusters? If they do, they also probably have Schrader valves on them that will allow you to check/change the pressures. I use a PowerTank setup (using nitrogen) to adjust mine.
    2008 SRT-10 Coupe - Venom Red Metallic w/ White Stripes - 1/4 Mile Passes (YouTube)
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  3. #3
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    MOTON specifies 175psi as a starting point for shocks with 22mm shafts which is what you should have. Keep in mind that the pressures will change depending on temperature, etc. So it's good to set/check your baseline pressures under the same conditions.
    Last edited by Back In Black; 05-04-2021 at 03:43 PM.
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  4. #4
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    I always check/adjust the pressures when the car is completely cooled off, with the car up in the air so no weight is on the suspension.

    Also, you need to keep in mind that what you use to check the canister pressures will reduce the volume of nitrogen in the canisters every time you connect the hose/pressure gauge to it. In other words, I wouldn't recommend checking the pressures unless you have the equipment to recharge them...it is not an insignificant amount that gets bled off.

    Guess I could always do a write-up on how to check/recharge the canisters if there was any interest. Most don't check or care, and the equipment to do it yourself is not cheap.
    Last edited by Steve M; 05-05-2021 at 07:37 AM.
    2008 SRT-10 Coupe - Venom Red Metallic w/ White Stripes - 1/4 Mile Passes (YouTube)
    High Flow Cats | Gen 5 Intake Manifold | UDP | HPTuners | 3.55s | MCS | DSS Axles | McLeod RST | 11.027 @ 130.06 (Vid), 1.78 60' (+1,622 ft DA, w/ 3.55s & Hoosier Drag Radials)

  5. #5
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    Thanks all for the informative posts - much appreciated!

    Mark
    Mark O'Dell
    2002 Viper Competition Coupe Prototype P4

  6. #6
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    I like this gauge for checking canister pressures. You only lose a few PSI per check. I'll use my fill setup to go past my target pressure and then connect this gauge to bring it down. It has a button that bleeds off pressure. If I do the check with my fill hose/gauge setup, I'll lose at least 25psi. Not on the initial fill, just if I use it to check the pressure.20210505_093852a.jpg
    2008 Viper ACR
    2009 Viper SRT-10X | 190mph Standing Mile | 10.76@133.7mph 1/4 Mile

  7. #7
    Another thing to think about when changing canister pressures is that the lower pressures make the rebound valving more sensitive (better controlled) and higher pressures affect the compression settings the same way. this is a useful tuning aspect once you zero in on what the car is doing and what will help further.
    Mark Jorgensen

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  8. #8
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    Quote Originally Posted by mjorgensen View Post
    Another thing to think about when changing canister pressures is that the lower pressures make the rebound valving more sensitive (better controlled) and higher pressures affect the compression settings the same way. this is a useful tuning aspect once you zero in on what the car is doing and what will help further.
    Thanks for posting that Mark! I remember you sharing this information on some other Viper sight years ago. I tried to find it again but no joy. I thought I had saved the link. Great info.
    2008 Viper ACR
    2009 Viper SRT-10X | 190mph Standing Mile | 10.76@133.7mph 1/4 Mile

  9. #9
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    I run from 175-225 psi in my Penske triples, but tend to settle right at 200. If you just hook the tool to the shock and open the Shrader valve depressor, pressure will drop quite a bit.

    I attach this tool to the canister, then to my nitrogen hose. I leave the nut a little bit loose on the canister connector and begin the N2 flow at low pressure to purge air from the hose and tool, then tighten the nut. I always use the N2 bottle regulator to either raise or lower the canister pressure. The regulator will bleed any overpressure. Remove by closing the canister valve first.
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  10. #10
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    Good advice all - thank you for sharing!

    Mark
    Mark O'Dell
    2002 Viper Competition Coupe Prototype P4


 

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