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-   -   Dyno - results with 540s (https://www.offshoreonly.com/forums/general-q/133785-dyno-results-540s.html)

articfriends 06-27-2006 07:20 PM
Re: Dyno - results with 540s
 
Originally Posted by Rebel_Heart
What results would an engine builder strive for when converting 502s to 540s? I think these are pretty good numbers, just do not want to lose too much in the engine compartment. What would have been better numbers and how would I have experienced a difference in the boat?

I do appreciate you input. Most of you have had years of experience with this type of thing.
That cam is pretty big,the 244/256 at .050 duration and 110 lobe seperation are the reason your tq peak is around 5000/5100 rpms,ideally you'd like that peak to be a little earlier so the boat will be easier to prop and drive. Your limited on the peak power by the hydraulic roller lifters,other wise it probably would have continued to climb then peak around 6300. You already own the cams and they are in your motors so I'm not going to say anything else,don't be surprized if you can't pull as much prop as you'd like to. Sometimes its a vicious cylce,you get good high rpm numbers but lose some lower midrange,then you try to prop boat and it can't get to those higher rpm's unless you prop it with fairly small props but then your cruise rpm's are higher than you'd like but they have to be to be able to get the rpm's up. Were the fuel A and B your fuel in pounds per hour? Have fun on the water,it still made 600 plus ft lbs in the midrange so its not like it will be a dog or anything. Are you going to start with about a 26 pitch or 28 pitch prop? Let us know how it turns out,Smitty

Elite Marine 06-27-2006 08:19 PM
Re: Dyno - results with 540s
 
What exhaust will you be running? Let me know if we can help. We will give you a great deal on headers.

Kirk

GPM 06-27-2006 08:51 PM
Re: Dyno - results with 540s
 
Not knowing where the cam is set in the motor, you might be able to advance it about 4 degrees to bring the peak torque down a few hundred RPMs. The peak HP should stay close to the same if valve float is causing the drop off at top end. I wouldn't go past a 102 CL. Just a thought.

Rebel_Heart 06-27-2006 09:52 PM
Re: Dyno - results with 540s
 
Thanks for the information. I do know that the cam is set at 106. When I spoke with Crane, they said this cam likes to be run at about 105. The engine builder had his own idea.

Props - I spoke with Hydromotive and am trying 29 Quads, and BBlades recommended 30 Bravos or if I wanted to go to a lab finished product a 32. Drive is at a standard height, any suggestions as to which prop will be the best? Yes, the fuel was in lbs/hr. You know, I should know what intake I am using, and Jim V. told me and said it was a good one, but I can't remember. The carb is a 1050 Dominator blue printed by Nickerson. I know they had Nickerson on the phone while dynoing leaning it out. I already have the CMI e-tops with 4 1/2" tails. We are introducing the water as far back as possible.

I don't know if it will run, but it sure is pretty! I'll have to post some pictures. Appreciate anyother ideas.

GPM 06-27-2006 10:11 PM
Re: Dyno - results with 540s
 
Run them the way they are, new motors always seem to need some tweaking.

jryan26 06-27-2006 10:36 PM
Re: Dyno - results with 540s
 
Looks good!

PatriYacht 06-28-2006 10:29 AM
Re: Dyno - results with 540s
 
I'd say over 700 hp is a good number for any 540. Keep in mind all dyno's and operators are different. I'm with Smitty that the numbers probably would have kept climbing if not for the valve float that seems to start around 5800-6000. Alittle more spring pressure or different springs might give you a little more hp. A better cam might've been a 741. It probably would've peaked at 5800 at the same numbers while adding low end and better idle quality.

Rebel_Heart 06-28-2006 08:22 PM
Re: Dyno - results with 540s
 
Thanks for the input. I wonder how much hp will be lost at the prop? 50 per engine?

ROTAX454 06-28-2006 08:36 PM
Re: Dyno - results with 540s
 
Originally Posted by Rebel_Heart
Since I don't have the technology skills to scan this in - here goes. This is my run with my 540s. What do you think?

rpm torque hp BSFC
3800 640 463 .456
3900 620 460 .474
4000 609 464 .458
4100 604 472 .478
4200 600 480 .460
4300 604 495 .449
4400 625 524 .424
4500 636 545 .406
4600 657 575 .396
4700 678 607 .403
4800 684 626 .405
4900 681 636 .421
5000 692 659 .431
5100 692 672 .431
5200 690 683 .435
5300 676 682 .443
5400 663 682 .447
5500 662 693 .457
5600 654 698 .470
5700 646 702 .487
5800 642 709 .480
5900 618 695 .491
6000 607 693 .490
6100 589 684 .494
6200 546 645 .539
I am will Artic on his comment regarding the Torque to HP spread. You are looking at only an 800 rpm difference between those peaks. That boat is going to be one tough cookie to prop right. Ideally you would like to see a minimum of 1000 to a better 1200 rpm spread. I would also recommend doing something in the cam department to lower your torque peak.

RaggedEdge 06-28-2006 10:45 PM
Re: Dyno - results with 540s
 
Originally Posted by PatriYacht
Sb, I missed that post you made in the other thread. Good points. With Morel lifters, Comp behive springs, titanium retainers etc you can raise the rpm limit to maybe 6300. After that you're going to have to go solid with high spring pressures and lifter longevity issues. Maintanence skyrockets above 6000 rpm.
Where would one find info on the Morel lifters ? Have seenthem mentioned but can't find info.

Sorry there Rebel, your project looks like it's comming along nicely.Congrats.


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