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Thread: Power potential of AMG P400

  1. #1

    Default Power potential of AMG P400

    I am new the GM diesel world and have done some lurking on here and other sites about the 6.5. I was wondering about the power potential of the new P400. Can more power be made reliably or is it just to fix the flaws of the older models for better reliabilty. I know the 6.5 is not comaparable the the Cummins or Duramax for power. I do not have dreams of 800hp and 1200ft.lbs. Maybe 300 to 350hp and 600 to 650ft.lbs of torque.

    Thanks for any info in advance.

    Stroh

  2. #2
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    Aside from the cast-iron block girdle, there were a number of other substantive upgrades that were designed to increase engine strength and improve durability. For example, the new forged-steel crankshaft is one of the more significant upgrades, but AMG also redesigned the connecting rods to add strength and the piston oil spray cooling nozzles/design were also upgraded both to improve cooling and not affect block strength. This allowed AMG to upgrade the factory power rating to 250....

    Till the hot-rodders among us begin experimenting with power, we may not know the ultimate power potential. However, one limiting factor is the fuel injection system. Whether DB2/DB4/DS4, there are finite limits to the amount of fuel that can be injected - unlike the common-rail systems used on the Duramax. Doesn't matter what sort of performance injectors you might opt to use, the IP can only deliver so much fuel, which is about an absolute max of 90mm3/1000 strokes at 2000-rpm. These IP's are designed (and DS's programmed) to reduce fuel at higher engine rpms where big hp numbers are typically produced (up to 40% less fuel at 3400-rpm when compared to the 2000-rpm max).

    Propane????

    Jim
    Last edited by More Power; 01-29-2009 at 13:10. Reason: add to

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    I remember a link to the 6.2 powered tractor. I believe he had done a twin mechanical setup? How about that for working? Once cooling has been adressed, if you could deliver twice the fuel through a dual setup, would that not help? Or is it the PSI that we are needing here.
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    Quote Originally Posted by 6.5 Detroit Diesel View Post
    I remember a link to the 6.2 powered tractor. I believe he had done a twin mechanical setup? How about that for working? Once cooling has been adressed, if you could deliver twice the fuel through a dual setup, would that not help? Or is it the PSI that we are needing here.
    Pressure is determined by the injectors, not the pump. The pump supplies the fuel volume, and times delivery.
    1985 Blazer 6.2
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  5. #5

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    So the injection pump is the weak link? I suppose since it is a standyne pump a bosch pump won't work. I suppose if it was easy enough to do it would have been evident from what I have read so far.

    Are there any manufacturers looking into a bigger pump?


    Thanks

    Stroh

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    Quote Originally Posted by stroh View Post
    So the injection pump is the weak link? I suppose since it is a standyne pump a bosch pump won't work. I suppose if it was easy enough to do it would have been evident from what I have read so far.

    Are there any manufacturers looking into a bigger pump?


    Thanks

    Stroh
    It's a "distributor type" pump, so it has to be designed/configured for the specific engine. If it were only a pressure pump, anything that would fit could work.

    Simple answer: No. However, pumps are available that will exceed the capabilities of the engine for on-road use (such as the marine DB-4/HO).
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
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  7. #7

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    Which means it is not "legal for on road use" right?

    I did some more searching and a gentleman in U.K. put on a p-pump for pulling.

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    Quote Originally Posted by stroh View Post
    Which means it is not "legal for on road use" right?

    I did some more searching and a gentleman in U.K. put on a p-pump for pulling.
    Not necessarily a "legal" limitation, although local emissions laws may have something to say about it. The problems arise when you have the limited cooling ability of on-road vehicles. In a boat, your radiator is the body of water you are boating on (unlimited cooling abilities). More fuel is more heat, and it has to go somewhere....
    1985 Blazer 6.2
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    Getting a good solid 300 hp is quite doable with torque in the 450 ft lb range

    With a good cooling system (Fan/radiator etc.) I think the 325 hp range is a goal that can be achieved.

    Biggest issue is getting rid of the heat.

    Unlike the direct injected engines (Cummins and Dmax) the 6.5 burns its fuel in the pre cup in the heads which really limits the ability of heat rejection.

    With a high flow water pump and a good radiator and a very responsive fan/clutch assembly the heat issue can be dealt with.


    Setting the bar at 325 hp is a very doable goal.

    A 4911 mechanical pump can get the job done.


    Another issue to contend with is getting a turbo that flows freely and does not hold in a lot of heat.

    The 6.5 also does not do real well over the long haul with boost pressures over 15lb

    This is do to the limited number of head bolts and the head gasket type.

    Keeping the boost pressure at 15 pounds with a charge air cooler in the system the 325 hp level is attainable with fairly good longevity.

    Looking at 18:1 static compression ratio is a very good place to start.

    Running these engines at high boost with the 20:1 or more comp ratio takes things into the "sketchy zone" as far as long life goes.


    325 hp and 500 pounds is likely very doable and still keep the thing alive over the long haul
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