Extruded Honed?
12-20-2005, 06:53 PM
#21
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Re: Extruded Honed?
apples and oranges guys.... apples and oranges.
NOW i understand what you are talking about and i can tell you reasonably authoratatively that those protrusions into the plenum were originally developed on winston cup motors and work very very well in a normally aspirated motor... they make the curve fat and flat like hell across the board as opposed to being peaky and narrow which is what happens when you are trying to make big numbers with a restricted intake area... i would predict that if you took them out on a back to back on a stock motor w/ absolutely no other changes you would see an increase of maybe 15 hp at 5500 rpm and a loss of about 30 at 3500 to 4200 and i wouldn't be surprised is the total area under the curve was less and that the throttle response suffered substantially. at daytona in the draft at 7700 you might like it... at watkins glen , youde get your butt handed to you.
but you guys have superchargers... what YOU need for an intake manifold is essentially a sewer pipe ( exageration of course) that will flow , without any significant restriction at least 110 % of your rated blower output... and of COURSE you need a lower static mechanical compression ratio w/ blowers and turbos and the like.... GEEZE you probably make a dynamic 13 to 1 at speed which is why you need all that extra fuel curve..CERTAINLY to service the airflow but mostly to keep the piston tops cool enough to not melt into the pan in the first 30 nano seconds you run it....
two galactically different scenarios... you can litterally make as much horsepower as you want out of any size engine with supercharging and/or turbocharging.... i mean in the heady days of imsa and gtp , toyota was making roughly 1000 hp out of 1600 cc... thats a litre point six or just under 100 cubic inches.... they did it by running turbo boost numbers that were astronomical.... and the same was true in the early days of F1 and turbos.... making hp with blowers or turbos is not a matter of sophisticated air managment... it is a function of making everything strong enough and cool enough to withstand the monumental dynamic pressures you can now create internally and the stresses that result. i would suggest to you that the difference between a nice nc finish on the intake manifold and one that was done with a chain saw when run at 3 atmospheres of boost is absolute zero.
WHOLE dif ball game with normally aspirated...
NOW i understand what you are talking about and i can tell you reasonably authoratatively that those protrusions into the plenum were originally developed on winston cup motors and work very very well in a normally aspirated motor... they make the curve fat and flat like hell across the board as opposed to being peaky and narrow which is what happens when you are trying to make big numbers with a restricted intake area... i would predict that if you took them out on a back to back on a stock motor w/ absolutely no other changes you would see an increase of maybe 15 hp at 5500 rpm and a loss of about 30 at 3500 to 4200 and i wouldn't be surprised is the total area under the curve was less and that the throttle response suffered substantially. at daytona in the draft at 7700 you might like it... at watkins glen , youde get your butt handed to you.
but you guys have superchargers... what YOU need for an intake manifold is essentially a sewer pipe ( exageration of course) that will flow , without any significant restriction at least 110 % of your rated blower output... and of COURSE you need a lower static mechanical compression ratio w/ blowers and turbos and the like.... GEEZE you probably make a dynamic 13 to 1 at speed which is why you need all that extra fuel curve..CERTAINLY to service the airflow but mostly to keep the piston tops cool enough to not melt into the pan in the first 30 nano seconds you run it....
two galactically different scenarios... you can litterally make as much horsepower as you want out of any size engine with supercharging and/or turbocharging.... i mean in the heady days of imsa and gtp , toyota was making roughly 1000 hp out of 1600 cc... thats a litre point six or just under 100 cubic inches.... they did it by running turbo boost numbers that were astronomical.... and the same was true in the early days of F1 and turbos.... making hp with blowers or turbos is not a matter of sophisticated air managment... it is a function of making everything strong enough and cool enough to withstand the monumental dynamic pressures you can now create internally and the stresses that result. i would suggest to you that the difference between a nice nc finish on the intake manifold and one that was done with a chain saw when run at 3 atmospheres of boost is absolute zero.
WHOLE dif ball game with normally aspirated...
12-20-2005, 09:12 PM
#22
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Re: Extruded Honed?
A word about these cross ram intakes and supercharging. Those long runners were designed to boost torque down low for getting on plane. In fact you may remember that the 502 MPI engine came out at the same time as the Blackhawk and the Merc engineer interview that I read said that the intake created an extra little torque peak at 1500 RPM just so that the two big surfacing props wouldn't stall the engine when you tried to get on plane.
So if you want the same "look" to the torque curve just higher values, you keep the manifold more or less as is and increase air density with the blower. But if you want a higher revving, peakier torque curve switch to a single plane Holley EFI intake. Jim Shofner told me once that such a switch was worth 80 HP. But it isn't hard to figure out what you would give up.
Shortening the runners in the MPI intake sounds like a good solution that splits the difference between the stock intake and the single plane. As far as the intake only being good to a certain HP level, I don't buy it if you can increase boost. Dying after a certain RPM level I believe.
Something else to think about. At WOT the air is just whistling through the throttle body into that intake. I have to think the momentum of that air favors some runners more than others. This makes the plenum's job of spreading the air around equally more difficult.
On the HP500EFI intake, which is similar, we block off the throttle body flange, and bring air into the plenum from the top through an intercooler. This is nice laminar, slow moving air brought into the center of the plenum. I think this has to help volumetric efficiency, but I have no back to back testing to prove it since we are adding a blower at the same time.
This is the resulting HP curve with stock heads and cam, and I don't see any choking effect of the intake. I would like to plot articfriends curve along side this one just to look at the shapes.
So if you want the same "look" to the torque curve just higher values, you keep the manifold more or less as is and increase air density with the blower. But if you want a higher revving, peakier torque curve switch to a single plane Holley EFI intake. Jim Shofner told me once that such a switch was worth 80 HP. But it isn't hard to figure out what you would give up.
Shortening the runners in the MPI intake sounds like a good solution that splits the difference between the stock intake and the single plane. As far as the intake only being good to a certain HP level, I don't buy it if you can increase boost. Dying after a certain RPM level I believe.
Something else to think about. At WOT the air is just whistling through the throttle body into that intake. I have to think the momentum of that air favors some runners more than others. This makes the plenum's job of spreading the air around equally more difficult.
On the HP500EFI intake, which is similar, we block off the throttle body flange, and bring air into the plenum from the top through an intercooler. This is nice laminar, slow moving air brought into the center of the plenum. I think this has to help volumetric efficiency, but I have no back to back testing to prove it since we are adding a blower at the same time.
This is the resulting HP curve with stock heads and cam, and I don't see any choking effect of the intake. I would like to plot articfriends curve along side this one just to look at the shapes.
12-21-2005, 12:22 AM
#23
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Re: Extruded Honed?
Originally Posted by stevesxm
apples and oranges guys.... apples and oranges.
NOW i understand what you are talking about and i can tell you reasonably authoratatively that those protrusions into the plenum were originally developed on winston cup motors and work very very well in a normally aspirated motor... they make the curve fat and flat like hell across the board as opposed to being peaky and narrow which is what happens when you are trying to make big numbers with a restricted intake area... i would predict that if you took them out on a back to back on a stock motor w/ absolutely no other changes you would see an increase of maybe 15 hp at 5500 rpm and a loss of about 30 at 3500 to 4200 and i wouldn't be surprised is the total area under the curve was less and that the throttle response suffered substantially. at daytona in the draft at 7700 you might like it... at watkins glen , youde get your butt handed to you.
but you guys have superchargers... what YOU need for an intake manifold is essentially a sewer pipe ( exageration of course) that will flow , without any significant restriction at least 110 % of your rated blower output... and of COURSE you need a lower static mechanical compression ratio w/ blowers and turbos and the like.... GEEZE you probably make a dynamic 13 to 1 at speed which is why you need all that extra fuel curve..CERTAINLY to service the airflow but mostly to keep the piston tops cool enough to not melt into the pan in the first 30 nano seconds you run it....
two galactically different scenarios... you can litterally make as much horsepower as you want out of any size engine with supercharging and/or turbocharging.... i mean in the heady days of imsa and gtp , toyota was making roughly 1000 hp out of 1600 cc... thats a litre point six or just under 100 cubic inches.... they did it by running turbo boost numbers that were astronomical.... and the same was true in the early days of F1 and turbos.... making hp with blowers or turbos is not a matter of sophisticated air managment... it is a function of making everything strong enough and cool enough to withstand the monumental dynamic pressures you can now create internally and the stresses that result. i would suggest to you that the difference between a nice nc finish on the intake manifold and one that was done with a chain saw when run at 3 atmospheres of boost is absolute zero.
WHOLE dif ball game with normally aspirated...
NOW i understand what you are talking about and i can tell you reasonably authoratatively that those protrusions into the plenum were originally developed on winston cup motors and work very very well in a normally aspirated motor... they make the curve fat and flat like hell across the board as opposed to being peaky and narrow which is what happens when you are trying to make big numbers with a restricted intake area... i would predict that if you took them out on a back to back on a stock motor w/ absolutely no other changes you would see an increase of maybe 15 hp at 5500 rpm and a loss of about 30 at 3500 to 4200 and i wouldn't be surprised is the total area under the curve was less and that the throttle response suffered substantially. at daytona in the draft at 7700 you might like it... at watkins glen , youde get your butt handed to you.
but you guys have superchargers... what YOU need for an intake manifold is essentially a sewer pipe ( exageration of course) that will flow , without any significant restriction at least 110 % of your rated blower output... and of COURSE you need a lower static mechanical compression ratio w/ blowers and turbos and the like.... GEEZE you probably make a dynamic 13 to 1 at speed which is why you need all that extra fuel curve..CERTAINLY to service the airflow but mostly to keep the piston tops cool enough to not melt into the pan in the first 30 nano seconds you run it....
two galactically different scenarios... you can litterally make as much horsepower as you want out of any size engine with supercharging and/or turbocharging.... i mean in the heady days of imsa and gtp , toyota was making roughly 1000 hp out of 1600 cc... thats a litre point six or just under 100 cubic inches.... they did it by running turbo boost numbers that were astronomical.... and the same was true in the early days of F1 and turbos.... making hp with blowers or turbos is not a matter of sophisticated air managment... it is a function of making everything strong enough and cool enough to withstand the monumental dynamic pressures you can now create internally and the stresses that result. i would suggest to you that the difference between a nice nc finish on the intake manifold and one that was done with a chain saw when run at 3 atmospheres of boost is absolute zero.
WHOLE dif ball game with normally aspirated...
Last edited by articfriends; 12-21-2005 at 12:25 AM.
12-21-2005, 01:42 AM
#24
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Re: Extruded Honed?
Originally Posted by tomcat
A word about these cross ram intakes and supercharging. Those long runners were designed to boost torque down low for getting on plane. In fact you may remember that the 502 MPI engine came out at the same time as the Blackhawk and the Merc engineer interview that I read said that the intake created an extra little torque peak at 1500 RPM just so that the two big surfacing props wouldn't stall the engine when you tried to get on plane.
So if you want the same "look" to the torque curve just higher values, you keep the manifold more or less as is and increase air density with the blower. But if you want a higher revving, peakier torque curve switch to a single plane Holley EFI intake. Jim Shofner told me once that such a switch was worth 80 HP. But it isn't hard to figure out what you would give up.
Shortening the runners in the MPI intake sounds like a good solution that splits the difference between the stock intake and the single plane. As far as the intake only being good to a certain HP level, I don't buy it if you can increase boost. Dying after a certain RPM level I believe.
Something else to think about. At WOT the air is just whistling through the throttle body into that intake. I have to think the momentum of that air favors some runners more than others. This makes the plenum's job of spreading the air around equally more difficult.
On the HP500EFI intake, which is similar, we block off the throttle body flange, and bring air into the plenum from the top through an intercooler. This is nice laminar, slow moving air brought into the center of the plenum. I think this has to help volumetric efficiency, but I have no back to back testing to prove it since we are adding a blower at the same time.
This is the resulting HP curve with stock heads and cam, and I don't see any choking effect of the intake. I would like to plot articfriends curve along side this one just to look at the shapes.
So if you want the same "look" to the torque curve just higher values, you keep the manifold more or less as is and increase air density with the blower. But if you want a higher revving, peakier torque curve switch to a single plane Holley EFI intake. Jim Shofner told me once that such a switch was worth 80 HP. But it isn't hard to figure out what you would give up.
Shortening the runners in the MPI intake sounds like a good solution that splits the difference between the stock intake and the single plane. As far as the intake only being good to a certain HP level, I don't buy it if you can increase boost. Dying after a certain RPM level I believe.
Something else to think about. At WOT the air is just whistling through the throttle body into that intake. I have to think the momentum of that air favors some runners more than others. This makes the plenum's job of spreading the air around equally more difficult.
On the HP500EFI intake, which is similar, we block off the throttle body flange, and bring air into the plenum from the top through an intercooler. This is nice laminar, slow moving air brought into the center of the plenum. I think this has to help volumetric efficiency, but I have no back to back testing to prove it since we are adding a blower at the same time.
This is the resulting HP curve with stock heads and cam, and I don't see any choking effect of the intake. I would like to plot articfriends curve along side this one just to look at the shapes.
I could email you the graph and dyno sheet if you want to do a better graph,i was using the edit/paint feature and it took me several trys to get it even close to right.
12-21-2005, 03:34 AM
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Re: Extruded Honed?
well... the steps they took sound completely well reasoned to me. a bit more compression , a bit more cam and some manfifold work that they knew from somewhere would work with that combination. sounds exactly correct... my point is/was that i don't think it was an accident that the left those 200 thou sitting above the floor...my " argument " to support my guess would be " look they are sitting there with their millng machine and just milled off the first 70 % , why would they stop there if making it ALL go away was better ? " i think they are illustrating exactly what i am trying to say. whats right is right and everything else is wrong to some degree. someone in that group, through a lot of time and effort figured out that with that combo, THOSE bumps were better than NO bumps. illustrates that just because something LOOKS wrong or doesn't SEEM to make sense doesn't mean that thats the case.
thats why god gives you dyno's tig welders and di grinders.
i would like to see the article.... can you e mail it to me ? [email protected] ?
thats why god gives you dyno's tig welders and di grinders.
i would like to see the article.... can you e mail it to me ? [email protected] ?
12-21-2005, 08:38 AM
#26
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Re: Extruded Honed?
Originally Posted by tomcat
So if you want the same "look" to the torque curve just higher values, you keep the manifold more or less as is and increase air density with the blower. But if you want a higher revving, peakier torque curve switch to a single plane Holley EFI intake. Jim Shofner told me once that such a switch was worth 80 HP. But it isn't hard to figure out what you would give up.
Of course as you know all that pretty (ugly to you) tubing is going away and being replaced with your big toy next month
Dave
12-21-2005, 09:44 AM
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Re: Extruded Honed?
Originally Posted by articfriends
Steve,lets forget about supercharging for now,I was refering to modifying the intake runners in a N/A application. I dug up the Hot boat magazine article I was refering to (january thru april of 1997) and I was wrong in my memory of 20-25 hp gain from modifying the runners . The article goes in steps of modifications and at the point of modifying the intake the ignition timing had been optimized,headers had been added and the ecu re-programmed. The motor was making 554 ft lbs tq at 3800 vs 508 in stock form at 3800 and had gained 50 ft lbs tq at 3400 over stock and 31 ft lbs over stock at 4900 and corresponding amounts in between. These intake runners are quite long before any modifications(12 1/2 inches) and they shortened them .600 (leaving them sticking into intake plenum above floor .200) and also cut .500 out of the center dividers which leaves them effectively still 11.4 inches long.At the same time they had also done slight port clean up and bumped compression from 8.75 to 8.9 and added stiffer valve springs (for the cam change further in the article).They saw 5-10 ft lbs of increase tq acrossed the tested power band but how much came from the slight compression increase,how much they lost from the intake runner mod (if any) and how much power the stouter valve springs cost is only a guess.But no clear 30 hp loss from 3500-4200 and no 20-25 hp gain either,If I was fountainlast and was looking for most bang for buck I'd skip the intake mods and go with the headers and ecu mod ,Smitty
12-21-2005, 09:49 AM
#28
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Re: Extruded Honed?
articfriends: Centrifugal blower engines have a characteristic curve don't they. I'm not sure why yours flattens out above 5500, maybe cam and intake, but it may have more to do with the compressor HP required at higher pulley ratios. That is an exponential curve and when you hit that wall it becomes the controlling factor. Too much power being used to spin the blower. Compressor HP is rarely measured but you can see this effect very clearly if you model the engine on Engine Analyzer Pro.
Hi Dave: No, I was talking about the intake runners; the intercooler plumbing is a whole other story. don't get me started.
Your engine and articfriend's engine are very similar except he uses the MPI intake and you use the Holley single plane EFI. A comparison of those two curves would be interesting to see if the single plane carries the torque peak at a higher RPM.
Hi Dave: No, I was talking about the intake runners; the intercooler plumbing is a whole other story. don't get me started.
Your engine and articfriend's engine are very similar except he uses the MPI intake and you use the Holley single plane EFI. A comparison of those two curves would be interesting to see if the single plane carries the torque peak at a higher RPM.
12-21-2005, 11:16 AM
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Re: Extruded Honed?
stevesxm
You ever work with Keith Wilson? I agree with your "holistic" approach about building an engine, and I'm someone who has written more than 1 check to Extrude Hone.
You ever work with Keith Wilson? I agree with your "holistic" approach about building an engine, and I'm someone who has written more than 1 check to Extrude Hone.
12-21-2005, 11:26 AM
#30
Re: Extruded Honed?
TC and Artic, Nice plots. What does your boost curve look like? Above 5000 rpm it gets more difficult to control belt slippage. What size blowers are these and would going up a size in blower help that above 5000 rpm?
