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| WagonDad |
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I have just finished porting my 95 DA head for the second time, got a flow test done this time to see if I was on the right track. From what I can understand and from what I have been told it is flowing very well at lower lifts up to .350"/.400" and drops off up to .500", so should be good at filling the cylinders at the lower revs our 4.0l run at. Any one got flow charts of standard heads or modified to make a comparison. Got some pictures in my gallery of the port work if your interested.
Blue boxes Intake. Red boxes Exhaust.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
Last edited by WagonDad on Wed Aug 05, 2009 11:05 pm, edited 2 times in total. |
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| gogetta |
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so those 2 sets of numbers are for the inlet and exhaust?
do u have the figs for a non ported head?
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
I have some test data here. but it's at a different pressure drop, so it wont help you much.
good falcon heads will get up to about 240/250@.550" at your pressure drop. hence the reason for lack of power past 5500rpm and why no one gets the 'magical' 200rwkw |
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| WagonDad |
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Yes, figures in blue boxes are Intake and Red are Exhaust. No, I havent got flow figures for a standard head, would be good to make the comparison.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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| gogetta |
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it would seem to me that a high lift cam would def help....
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
gogetta wrote: it would seem to me that a high lift cam would def help.... how do you figure that from a flow chart with poor high lift flow? there would be no real point in more then .500" aside from the valve opening faster with higher lift on the same duration. |
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| gogetta |
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it doesnt drop off at high lift...it grows slightly....greater total area under the curve if u say go to .500 instead of limiting it at .350-.400....the valve will be open more for longer and the flow will still be as good as at the lower lift....
this is my theory....id check it with some dyno software
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| WagonDad |
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I have been running a Wade 1636 which has a Intake valve lift of .496", I havent really thought about fitting a different cam to suit the new flow caracteristics but if gains can be made it should be considered.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
gogetta wrote: it doesnt drop off at high lift...it grows slightly....greater total area under the curve if u say go to .500 instead of limiting it at .350-.400....the valve will be open more for longer and the flow will still be as good as at the lower lift.... this is my theory....id check it with some dyno software exactly the reason i said not much point in more then .500" Quote: aside from the valve opening faster with higher lift on the same duration. ^^^ that equates to exactly what you just said. generaly the more lift with the same duration will give more torque. as you are opening and closing the valve faster = more area under the curve. You do need to be carfull with overlap though. Note this ^^ is very simplified......... When you said 'high lift' i took it as meaning in the .550 to .650 range. in which case the extra stress on the valve train would out weigh the gain in power for a street engine. |
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| WagonDad |
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Spoke to the Guy who flowed my head today (someone else droped off and picked up the head) and asked if he had any flow figures for a standard head, unfortunately he has been running a new flow bench for the last couple of weeks so figures wont be comparable, he did say that the flow testing he has done with the new bench it is generally reading 5cfm lower than the old one and that standard heads have flowed between 180 -190cfm at .500" on the old bench, add 5cfm to my .500" figure and you get 220cfm so a gain of around 30 - 40cfm compared to standard. He also explained to me about the swirl figures he supplied on another chart and how the swirl jumped extremely high at the same time the cfm dropped off, he said some swirl is good and to much robs cfm flow. I will be speaking to him more about how to reduce the swirl at higher lifts, it shouldnt require to muck work as the swirl only jumped high in the .400" to .500" range of lift.
The hand written figures are his cfm flow results from one of his own ported 4.0l heads.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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| WagonDad |
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Did some more work to the intake ports and got the head flowed again. Happy with the results I think I will stop at this point and get the head back on the car. There is 12% increase in flow at .400" and .500" over the first flow test, 239.4 cfm @ .500" is theoretically 370 HP using a online calculator, so i dont think the head will be a restriction any time soon.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
Last edited by WagonDad on Sun Sep 13, 2009 3:53 pm, edited 1 time in total. |
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| fiend |
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So, if I am reading this correctly - You are getting the same flow at less than .5 lift that you expect from a normal head with .65 or more lift?!
That's good and handy huh? Any photos and descriptions of what you re-shaped on the head? Is that standard valve sizes? Sheez - You are tempting me to stop selling my other Tickford EF head and start attacking it (as per original plan before deciding I'm too broke...) |
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
be interesting to see the same head with a larger intake valve.
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| WagonDad |
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The flow increase from the top chart to the bottom chart was gained by laying the short side radius back about 2mm and also widening the short turn to flatten out the floor a bit, this increased the cross sectional area allowing the air to flow more uniformally to the back of the valve, reducing turbulance. Intake valve is standard 47mm, exhaust is XR size 41mm.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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| WagonDad |
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quote "how do you figure that from a flow chart with poor high lift flow?"
Not having a dig, but are the high lift flows good enough for you now tickford_6 
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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