Here is a comparison of the difference in powercurve between the MD and dynojet dynos: The blue lines are the MD.
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I've seen 500rwhp engines with FR500 intakes gain no power with the addition of a 1" and 2" spacer. The C intake would absolutely kill power production at 6400.
In most cases you can take the superflow engine dyno graph, reduce its numbers by 15% and get the rwhp on a dynojet. The MD dyno is a bit different though and produces a curve with a different shape and peaks.
Great power regardless of dyno type.
i saw you say one time that you seen a car equipped with an fr500 intake manifold gain ~25rwhp with the intake lid removed. wouldn't adding spacers unshroud the runner inlets? also with the bottom half cut off the fr, i'd imagine it's starving for plenum volume at 8000rpm.
Mihovetz did a test where he removed the lid and the power did increase, but for some reason a large spacer does nothing. Brandon Alsept put a thick spacer on his NMRA Pure Street car and gained nothing, this engine was over 500rwhp at the wheels and spinning over 8k.
I'm not saying it needs less air. I'm saying a cam limited motor does weird stuff to the harmonics. You try an turn a bunch of rpm with it but the lift rules it makes it difficult. As far as road race engines yes, you do need a somewhat decent power band. It has to come off of corners and also needs to make power past peak.
"Turn it tight" means more rpm.
The difference in power/cfm requirements is very little on a 4v when the lift difference is only .050-.075". In fact, I've seen little to no gain when going from .425" to .475". The curtain area is so great that lift matters little.
I'd advance the intake cams a little to broaden the powerband, rather than spinning it higher, but that's me.
There are 4v cams that run in American Iron SCCA that run .585-.625+ lift. I'd put as much lift in the car as I could if rules permitted for a class engine. If a pure road race car, no street driving, I would put the highest lift cam that would fit, but the maintenance required between races isn't practical for someone who plans to drive it around not on a road course.
You cannot compare the engine masters engines to race engines or road race for that matter. You are talking about an engine that needs to peak around 6k and have wide power band. The emc engines have an rpm limit which is below the peak of any road race modulars. Two completely different world's
The difference in power/cfm requirements is very little on a 4v when the lift difference is only .050-.075". In fact, I've seen little to no gain when going from .425" to .475". The curtain area is so great that lift matters little.
I'd advance the intake cams a little to broaden the powerband, rather than spinning it higher, but that's me.
Valves slamming shut is not stability. As you increase in rpm lift becomes more paramount. As velocity increases with piston speed it's important to get the valve out of the way to prevent turbulence. 4v heads already have very high velocities for the csa of the valve and size of the port. Turbulence kills power past peak almost as bad as valvetrain issues do. Yes you may have not noticed anything at emc but what was the piston speed at peak torque and at peak hp? Also what was the average csa of the head?
I don't need to know where it is to recommend advancing it, one loom at the graph is all that's needed.
Knowing where they are at currently isn't needed? They are in @ 113, as tight as I could get them with adequate clearance. If I could have got them to 112, that's where they'd be.