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Thread: Megasquirt MS3X spark cut and retard

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    Sick 660r's Avatar
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    Default Megasquirt MS3X spark cut and retard

    I posted this on RM but maybe it will get some attention here.

    This may be a trivial topic but I was wondering if there would be a "best" setting for small block mopars. Given our firing order (1,8,4,3,6,5,7,2) are there certain values for x and y that would be less stressful? Maybe one setting will reduce the amount of unburnt fuel in the exhaust. Obviously this would be whatever setting is less violent. Also, if you cut every 3 of 5, does mean it's cutting the first 3 and firing that last two? Is there an order that MS follows? If there is an order, is it important to make sure that there is no cylinder that is always cut?

    Maybe it would be helpful is people posted a screen shot of their settings and how/why they came to them.


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    in for info . I was just thinking about this the other day. I do not have experience with ms yet. plan on getting pro if i get my money back from paypal, so im not sure the settings for the limiters. are you doing spark and fuel?

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    Quote Originally Posted by niebs View Post
    in for info . I was just thinking about this the other day. I do not have experience with ms yet. plan on getting pro if i get my money back from paypal, so im not sure the settings for the limiters. are you doing spark and fuel?
    Not going to lie, I was overwhelmed at first. With my recent build and the help of a circuit theory class, I've begun to understand everything involved with MS much much better. I will only be using spark cut and retard. I really want to setup traction control, launch control and flat shift. Heck, I may even go to the track if it all works lol Need to figure out the rear speed sensor and abs sensor for traction control. I only need to add a clutch sensor for launch control and flat shift.

    traction control...
    http://www.hotrod.com/news/1601-watc...-the-pavement/

    launch control and flat shift...
    https://www.youtube.com/watch?v=y54yQ14KOMw


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    niebs's Avatar
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    flat shifting is just fun haha. im sure ill be asking hundreds of questions when i go to install the ms. hopefully someone here will have more info on your main concern.

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    I'm hoping for at least a useful thread

    RM had a lot of people running MS but the topic has died down recently. I'm sure a lot more people would join in if one of use figures out traction control


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    niebs's Avatar
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    are you piggy backing or stand alone?

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    MS controls all aspects of the engine and a few other things but I'm still using the PCM for gauges, abs etc. I'm waiting another 4 years, when its considered historic, to rewire the whole truck.


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    On my aem I'm cutting fuel as a soft limiter and spark for the hard limiter. If I cut spark first or both it will backfire reallllly loud.
    10.25 @131 SBE 5.9 360 turbo!!!

    Check me out on YouTube - ThatTurboDakota

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    Backfire is a given but I would rather have that than a possible lean condition.

    That's for an exhaust system without a cat...


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    Shouldn't have lean problem because it cuts fuel all together. Can't go lean if it has nothing to burn
    10.25 @131 SBE 5.9 360 turbo!!!

    Check me out on YouTube - ThatTurboDakota

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    if that's true then I would have never toasted my stock piston...


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    you would have to be 100% sure no fuel is left. I too would be worried about running lean when cutting fuel.

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    I've been running mine all year with fuel cut. No problems here. Stock short block
    10.25 @131 SBE 5.9 360 turbo!!!

    Check me out on YouTube - ThatTurboDakota

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    Hopefully it lasts. Fuel cut, especially with boost, is frowned upon. Its just easier on the exhaust system.


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    i get what your saying but factory turbo cars with cats cant backfire every time it hits the limiter or it will blow the cat out. so what do you think they do?
    10.25 @131 SBE 5.9 360 turbo!!!

    Check me out on YouTube - ThatTurboDakota

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    I am also talking about rev limiters for launch etc where there may be a load. You can only do so much when you have to have a cat. I'm sure there is plenty of testing with cutting fuel and spark. They also don't use cable throttle bodies...


    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    Tested the rev limiter on the new motor for the first time. Set cut to 3k and retard to 2500 and a max of 15. I tried every x/y combo up to 20 and nothing but 1/1 would hold. After a little research I found that 1/1 was a common setting especially with no load. I will but max retard up to 30 and hope that it makes the rpm more stable while on the limiter. This will be useful during launching and flat shift.

    Cregger, you may want to google "Megasquirt rev limiter settings" and take a look at what people have to say about fuel cut and boost. Those stock Pistons don't like fuel cut.....





    Quote Originally Posted by BluRT00 View Post
    Part your red sport out and buy a gen 2. Problem solved.

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    ouch. no bueno.

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    the turbo fox i tuned on ms2 pnp is set up with rev retard only. soft limiter at 5800 and hard limit at 6000.

    im gonna leave my aem on the truck alone and see what happens haha it hits the limiter all the time from 1st to 2nd on the street. the trans cant keep up. so far so good
    10.25 @131 SBE 5.9 360 turbo!!!

    Check me out on YouTube - ThatTurboDakota

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