EMC 2017 353ci SBC

[GARY C]

Great engine and great job!

That said, can anybody tell me how the results would change if a 4.155" b x 3.25" s = 352.5" engine was made using a 400 SBC block and a 327 crank.

I think that "T" might be down due to the shorter stroke, but that Hp should hold up well. Jmho is all though, no data..

pdq67

My opinion is that the results and torque curve would be very, very similar.

I agree, from the test I have seen is that tq is primarily a function of ci and not stroke.

[GARY C]

I find this interesting, however I would like to take this further than what dyno difference their might be. I wonder with a bigger bore and shorter stroke could you take advantage off any more head/cam than used considering the constraints and goals of the competition?

We tried heads that flowed considerably more and were bigger csa and volume with bigger valve, but it made less average power and wasn't better at any rpm tested.

The bigger bore would present some options for posible advantages but most likely off set by the negetives of the bigger bore and set deck height.

Not saying there isn't anything at all to bore/stroke combos at the emc, but it's well down the list.

Induction tract size/shape runs the show.

Randy

It would be interesting to reconstruct that test with valve size only to eliminate the loss due to runner size.

[CGT]

I find this interesting, however I would like to take this further than what dyno difference their might be. I wonder with a bigger bore and shorter stroke could you take advantage off any more head/cam than used considering the constraints and goals of the competition?

We tried heads that flowed considerably more and were bigger csa and volume with bigger valve, but it made less average power and wasn't better at any rpm tested.

The bigger bore would present some options for posible advantages but most likely off set by the negetives of the bigger bore and set deck height.

Not saying there isn't anything at all to bore/stroke combos at the emc, but it's well down the list.

Induction tract size/shape runs the show.

Randy

It would be interesting to reconstruct that test with valve size only to eliminate the loss due to runner size.

The larger heads ran virtually identical to the smaller set prior to the larger valve and different valve job.

[GARY C]

We tried heads that flowed considerably more and were bigger csa and volume with bigger valve, but it made less average power and wasn't better at any rpm tested.

The bigger bore would present some options for posible advantages but most likely off set by the negetives of the bigger bore and set deck height.

Not saying there isn't anything at all to bore/stroke combos at the emc, but it's well down the list.

Induction tract size/shape runs the show.

Randy

It would be interesting to reconstruct that test with valve size only to eliminate the loss due to runner size.

The larger heads ran virtually identical to the smaller set prior to the larger valve and different valve job.

Thats why It would be interesting to see it the other way around to get an idea of which one has more of an effect. Based on SN with the 50* 2.08... just thoughts I ponder.

[randy331]

Thats why It would be interesting to see it the other way around to get an idea of which one has more of an effect. Based on SN with the 50* 2.08... just thoughts I ponder.

Your saying we shoulda tried a bigger valve and shallower seats in the smaller size heads ?

The thought on going bigger valve/shallower seats on the larger heads was maybe the engine wasn't using the csa because of lack of window area. The heads clearly liked the change on the flow bench, but not on the dyno. The test shows how the flow bench and running engine need to be separated more than it is in motorsports.

One of the important and overlooked factors in making power at emc type rpm is lack of depression, not lack of cfm.

Randy

[user-9274568]

Thats why It would be interesting to see it the other way around to get an idea of which one has more of an effect. Based on SN with the 50* 2.08... just thoughts I ponder.

Your saying we shoulda tried a bigger valve and shallower seats in the smaller size heads ?

The thought on going bigger valve/shallower seats on the larger heads was maybe the engine wasn't using the csa because of lack of window area. The heads clearly liked the change on the flow bench, but not on the dyno. The test shows how the flow bench and running engine need to be separated more than it is in motorsports.

One of the important and overlooked factors in making power at emc type rpm is lack of depression, not lack of cfm.

Randy

How can you paint the broad brush and claim this should be the standard that the bench vs dyno isn't valid?

Just curious. I wonder how things would have changed with a 7500 rpm max? A lot...

[swampbuggy]

Engines running above 6500 rpm do not behave the same as engines below that. Wave probogation<may not be spelled correctly was mentioned, by D.M.

[GARY C]

Thats why It would be interesting to see it the other way around to get an idea of which one has more of an effect. Based on SN with the 50* 2.08... just thoughts I ponder.

Your saying we shoulda tried a bigger valve and shallower seats in the smaller size heads ?

The thought on going bigger valve/shallower seats on the larger heads was maybe the engine wasn't using the csa because of lack of window area. The heads clearly liked the change on the flow bench, but not on the dyno. The test shows how the flow bench and running engine need to be separated more than it is in motorsports.

One of the important and overlooked factors in making power at emc type rpm is lack of depression, not lack of cfm.

Randy

Not necessarily with a shallow seat but more to see the effect of the bigger valve alone with all else being the same.

When you look at the progression of heads and valve train from the days of factory heads and lazy cam lobes when a 30* seat might have been useful vs the heads and valve train and popular 45* seat vs what we have today, I can see where a 50* could be beneficial especially on a very aggressive street engine due to the rpm range and cam lobes available today.

Looking at flow on the bench doesn't put it in relation to piston placement/position, it would be interesting to map the old vs the new in relation to piston, or flow at TDC but thats above my brain capacity.

[randy331]

Engines running above 6500 rpm do not behave the same as engines below that. Wave probogation<may not be spelled correctly was mentioned, by D.M.

All that may be true, but from what I've seen, if a set of heads is behind at peak tq rpm, and behind at peak hp rpm, and behind 500 rpm past peak hp rpm, they won't be ahead 1000 rpm after peak hp rpm.

Randy

[levisnteeshirt]

6500 is old news with EMC, 7000 or 7500 would be nice for a change ,,

[levisnteeshirt]

My drill I'd guess typically gets ~ 3-400 RPM (6-800 engine) once the pressure comes up and depending on clearances, temperature and viscosity, ~ 20-30 psi. I don't know the range of the resulting flow rates but my S.W.A.G. is it draws <0.10 hp. (I suppose I could use a corded drill and compare amps running free vs. under pressure, assume a number for efficiency and calculate the power demand, but that sounds too much like work!

first time i installed a new hyd pump in a small system, the electric motor controller overloads were tripping, come to find out the new pumps relief valve was too low , so it was moving more volume of oil in relief than not , and the motor drawing too much current ,, raised the relief valve setting to keep it out of relief during normal system operation , overloads would stay in , so volume not pressure placed more load on the motor