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  1. #1

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    How crazy is a Rude with 42#s

    Very crazy, I know. The recipe for Rude is 50lb injectors with either a Riva ECU or fuel controller.

    -BUT-

    Has anyone ever considered the possiblilty of getting a Rude w/42s & stock ECU and propping really high, so max RPMs are somewhere in the 7900-7950 range. If the Rude is producing boost in that range close to what an S3 SC produces at 8150, I would think it would be easier on gas and easier on the engine to run at those lower RPMs, and most importantly, faster on the top end than the S3 SC would give.

    I'm thinking this could be remotely feasible because I'm in a boat, so the pump's not out of the water much, and also I'm using an XS IC, which lets about 1 pound less of boost through, compared to some other intercoolers. I'm at 8.8 - 9.0lbs with the green wheel at 8120. I'm afraid the S3 SC on my setup will only be 9.6. Just seems I could tune the Rude right at 10.0 at a lower RPM and I'd be doing just fine?!?

    It has been said that the volume of air is so much greater with the larger superchargers, but I'm having a hard time seeing how that is so. If I haven't changed the size of my throttle body and intake manifold, it seems to me that the volume of air going into the engine would be solely dictated by the boost number taken at the manifold.


  2. #2
    Site Admin Green Hulk's Avatar
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    I have already measured the AFR with just a rude, stock ECU and 42# injectors. The AFR was in the high 14's by the time i hit 7200 RPM's

    Now, i have successfully run a rude, stock ECU and 50# injectors. Afr was in the low 11's at WOT, but at idle and midrange its pig rich.... in the 10's

    The only way to do it is with a fuel controller or a much easier method the rising rate fuel pressure regulator. You might even get by with the stock injectors with the rising rate regulator, but someone would have to try it to confirm.

  3. #3
    can we order the fuel pressure reg. through your store or does it have to come right from piranha?? thanks

    I think im gonna try the rude/ stock ecu/ 42s/ and the fpr!! I will report back on the afr's.

  4. #4
    DaveC's Avatar
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    I am fairly sure that you will be lean in the AFR with that combination. I ran a similar setup for a short time. Rude charger, Rude fuel controller and 50# injectors with the stock ECU at 8100 RPM. For me at 8100 I had 12.3-12.5 PSI boost.

    You may be able to get away with it at least short term, but you would really need a LM1 AFR gauge to be safe. So why chance all of that ? Just go ahead with the 50# injectors and fuel controller and be safe and run the max boost you can at 8100 RPM. I do not know if anyone has tested it yet but, maybe one of the rising rate fuel pressure regulators and the 42# injectors would be safe with the Rude.

    The boost numbers maybe similar between the Riva SC3 and the Rude charger, but they are no way similar in the volume of air. Huge difference in the two performance wise even at 8100 RPM.

  5. #5
    DaveC's Avatar
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  6. #6
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by DaveC View Post
    Thanks for posting the link Dave. The rising rate fuel pressure regulator comes from Australia, but in 30 days or so there will be an alternative here in the US.

  7. #7
    DaveC's Avatar
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    I have been thinking about trying one out, but I think that I will opt for the new one.

  8. #8
    MIARider's Avatar
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    Jerry does this mean, a new type of regulator, or that we are going to be able to get it straight from you ?
    Quote Originally Posted by Green Hulk View Post
    Thanks for posting the link Dave. The rising rate fuel pressure regulator comes from Australia, but in 30 days or so there will be an alternative here in the US.

  9. #9
    Dave Sharp dav_dman's Avatar
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    JD runs Rude with stock everything (38 injectors? not sure what stock is).

    Stock intake and stock IC critical to this because they are so restrictive. Not saying I would do this because this limits top end to 75 and it's very tempting to put all the goodies on with the rude and get 80; but he is one of the top tuners on here.

    no idea what afr is at wot with that setup.

  10. #10
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by MIARider View Post
    Jerry does this mean, a new type of regulator, or that we are going to be able to get it straight from you ?
    Its a different brand of regulator, does the same thing and it will come direct from me.

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