RLW

Does anyone have the peak torque and horsepower numbers from a dynoed HP525EFI? Those numbers and their related rpm's would be of interest to me and others on this board.
I know John B asked for the cam specs, some time ago, for this motor but according to his post, never received that information.
Is that information available?
Thanks in advance for any replies.
Russ

nitro/max

I read on here that the 525EFI were dyno at 540-545HP. This came from Dustain (whipple). I also read in a mag that the torque was in the mid 500.

throttleup

I was told by Innovation Marine that peak hp is at 5380, just before the rev limiter. I would estimate peak torque to be in the low to mid 4000 range.

Matt

RLW

Matt,
The numbers you posted definitely make sense and do not attribute to the "torque loading" of the drive.
Now, I would like to see the cam specs on this engine.
Russ

rmbuilder

Russ,
The cam for the 525 EFI is
Crane 16HR00004 BBC Hydraulic Roller
Duration (advertised) - 298/306
Duration (@ 0.050) - 236/244
Lift - .610 Intake, .632 Exhaust
Lobe Center - 114°
There are multiple factors at work in this application that determine the relation to duration and TQ/HP peak.
Bob

MESABALANCING

Rmbuilder Has Always Got The Cam Info Down.i Have Dynoed 525efis And Have Had As Much As 560hp Right At The Rev Limit And As Much As 540 Ft Lbs Of Torque And Have Checked These Numbers With A Friend At Inovation That Runs A Dyno Room There And The Numbers Match . Generally They Are Anywhere From 535 Hp To 560 Even 565 On The Real Good Ones. Sincerely Laz Mesa

tomcat

Hey Bob and Lazaro:

I have a couple questions about this engine too. Is this cam the same as the 741 or are there important differences? And what do you think would be the result if the runners were lengthened 1-1.5"?

Tom

rmbuilder

Tom,
Not the same cam. The 525efi has:
2* more duration I/E @ .004 and .050
114*LSA vs 112* LSA
109*/119* ICL/ECL vs 107*/117* ICL/ECL
74* vs 76* overlap
Great points of discussion, runner length and torque/HP curve placement,fuel injection vs carb (single plane vs dual plane),intake cross section, duration and cylinder head flow. There is a significant difference in how this cam will perform (and the cam requirements) with the Edelbrock heads and FI as compared to say a single plane carb motor with ported AFRs. It can alter the peaks 500+ rpm.
139741
Cam Timing: TAPPET @.050 Lift:
Opens Closes Max Lift Duration
Intake 10 BTDC 44 ABDC 107 234 °
Exhaust 58 BBDC 4 ATDC 117 242 °
16HR00004
Cam Timing: Tappet @ .050 Lift
Opens Closes Max Lift Duration
Intake 9.0 BTDC 47.0 ABDC 109 °ATDC 236 °
Exhaust 61.0 BBDC 3.0 ATDC 119 °BTDC 244 °
Bob

MESABALANCING

Tom There Are Many Variables Generlly Speaking Lengthen The Runner And The Max Hp Number Will Most Likely Come Down Slightly And Also Lower In The Rpm Range And The Torque Will Most Likely Increase Throught The Rpm Range.sincerely Laz Mesa

cobra marty

1.1HP/CID not too bad from the big Merc. Blue. Does anyone have a HP and TQ printout?