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-   -   New roller 502-peak HP, prop question (https://www.offshoreonly.com/forums/general-q/159072-new-roller-502-peak-hp-prop-question.html)

hydrophilic 05-23-2007 09:56 PM

New roller 502-peak HP, prop question
 
I had a new 502 dropped in my 270 powerquest. I had the motor converted to a full roller setup(hydraulic). I went with a dominator intake, 850 Holley, rect. port heads, stock compr., ported manifolds, and a crane cam.(#139011). It's 226/234 with 610/587 lift on a 112. The motor was not dynoed. Any guesses where peak HP would be?
Tom

Bajapred 05-24-2007 12:57 AM

292/298 Duration @ .004
230/236 Duration @ .050
.598"/.610" Lift
114 Lobe Center.
These are cam specs on a 500efi

I guess your hp @ 500-525 ..5000-5200rpm
I guess a 26p 4 blade bravo1

Pat McPherson 05-24-2007 07:22 AM


Originally Posted by Bajapred (Post 2138684)
292/298 Duration @ .004
230/236 Duration @ .050
.598"/.610" Lift
114 Lobe Center.
These are cam specs on a 500efi

I guess your hp @ 500-525 ..5000-5200rpm
I guess a 26p 4 blade bravo1

Great info.
I'd say prop for 5200-5300 running light.

hydrophilic 05-24-2007 07:26 AM

Thanks for the input. It looks like the cam has specs almost identical to the 731. I told them I wanted reliability, no reversion issues, and specs similar to a HP500. I'd really like to know where peak HP is. Should I prop it to 5200,5300?
From crane:
Lift: Intake @Cam 345 @Valve 587 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 359 @Valve 610
Rocker Arm Ratio 1.70
Cam Timing: TAPPET @.004
Lift: Opens Closes ADV Duration
Intake 33.0 BTDC 75.0 ABDC 288 °
Exhaust 81.0 BBDC 35.0 ATDC 296 °
Spring Requirements: Triple Dual Outer Inner
Part Number 99896
Loads Closed 150 LBS @ 1.900 or 1 29/32
Open 454 LBS @ 1.310

Recommended RPM range with matching components
Minimum RPM 1600
Maximum RPM 5600
Valve Float 6200
Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 6.0 BTDC 40.0 ABDC 107 226 °
Exhaust 54.0 BBDC 0.0 ATDC 117 234 °

Bajapred 05-24-2007 02:32 PM

Well, you need some gurru engine guys to help on this..but from my experience your engine torque will max out around 4000rpm while your hp will keep climbing and drop off around 5600-5800 rpm..valves will float in the low 6000 rpms...so your optimum & safe operating range should be 5000-5400 ish..depending on how hard you want to run her...test a prop and go from there to get your desired rpm...


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