Hi, thanks for the video. I'm trying to wrap my head around some of the theoretical flow theory and how it matches up with reality. So my question is, assuming a 2.0L displacement, and appropriate cams to get the valves out of the way from obstructing the flow, would this motor's power peak be in the 8300-8600 rpm range? Or do I need to take another crack at my theory?
@dimman77 All things being equal, this would be about the rpm's you would expect, however from the practical side you are just spinning the engine for no real gain in useable torque. If you can make max power from 6500-7800, why bother revving the engine to 8600? Look at torque figures, not the hp.
@fiatnutz My thoughts were about it needing to spin up to that to take advantage of the flow potential. The engine still can only pump so much air per cycle, right? In this case 2.0L every 2 revolutions. (My assumptions are that it is 280cfm at 28"wc, measured at max valve lift and stock valve diameter.) So I was thinking that the flow would allow the motor to stay efficient all the way up to the 8300-8600 range. (If it will keep pulling to 8600 why shift sooner?)
Hey John, I was just wondering why you sharp-edged the intake passages? I have been in a performance engine building class for the last few months and one of the first things that they taught us was that when you knife-edge anything, you want it to actually be tear-drop shaped at the head and sharp at the end. The same with porting on the intake side of the head. Their theory and proveable information is that the air flows better with a softer curve than with a sharp point. Just wondering.
i was in a machine shop at my voc school we had some sweet HAAS cnc machines i wish i kept with it after high school i would have loved to do stuff like this
It'd be interesting to see the same CNC program on a set of '04-'06 EJ257 heads. The amount of room on those heads are a bit less than the 2.0L heads.
What is the reason they (subaru) did wrong in the factory? , are not supposed to win every HP/Kw to increase efficiency? why you need to open your engine to put all in line ?
Subaru is not cheap as acarburetor FIAT 128 or Tipo (in which commonly these jobs are done )
We actually get very nice power w/stock cams and our different springs & retainers. A lot of people stick in cams because they can and they don't always produce more power, it just moves the power band around.
Why does the head look like they over-ground it and now it has holes around the valve seals? Am I the only one that saw that?
kabooki157 1 year ago
Do you have different cnc programs for particular uses available? i.e. autocross, drag, roadrace uses.
fastnoypi 1 year ago
Hey, I have a nissan 200sx se-r engine and i need to do a valve job on it and i mine as well port the head.. Do you know how much it would cost?
-Please message back!?
Thanks.
gokartmaster123 1 year ago
236cfm 165cfm stock! No wonder they fly! SBC guy's shoot for that with ported stockers.
MrRobGT 1 year ago
@MrRobGT Thats why those (ported or not) stock heads belong in the garbage. 236 cfm is weak, especially for a 4v head.
powerviking 8 months ago
so what does it cost to get some subaru heads ported
actafool2f 1 year ago
@actafool2f - The porting service runs in the neighborhood of $900 for the pair.
fiatnutz 1 year ago
@fiatnutz how about a pair or of 60 degree v6 heads for an 3.9L LZ9 engine? also thinking about taking a couple of th's off to raise compression
MarcsMobileAudio 1 year ago
Hi, thanks for the video. I'm trying to wrap my head around some of the theoretical flow theory and how it matches up with reality. So my question is, assuming a 2.0L displacement, and appropriate cams to get the valves out of the way from obstructing the flow, would this motor's power peak be in the 8300-8600 rpm range? Or do I need to take another crack at my theory?
Thanks.
dimman77 1 year ago
@dimman77 All things being equal, this would be about the rpm's you would expect, however from the practical side you are just spinning the engine for no real gain in useable torque. If you can make max power from 6500-7800, why bother revving the engine to 8600? Look at torque figures, not the hp.
fiatnutz 1 year ago
@fiatnutz My thoughts were about it needing to spin up to that to take advantage of the flow potential. The engine still can only pump so much air per cycle, right? In this case 2.0L every 2 revolutions. (My assumptions are that it is 280cfm at 28"wc, measured at max valve lift and stock valve diameter.) So I was thinking that the flow would allow the motor to stay efficient all the way up to the 8300-8600 range. (If it will keep pulling to 8600 why shift sooner?)
Thanks for responding.
dimman77 1 year ago
@dimman77~ u need to learn about VE (Volumetric Efficiency).
its0a0me 10 months ago
damn nice job! do u do work on ea82t subaru heads?
subiemon 2 years ago
I love this actual flow figures to prove it works.
wackedoutdude 2 years ago 6
Hey John, I was just wondering why you sharp-edged the intake passages? I have been in a performance engine building class for the last few months and one of the first things that they taught us was that when you knife-edge anything, you want it to actually be tear-drop shaped at the head and sharp at the end. The same with porting on the intake side of the head. Their theory and proveable information is that the air flows better with a softer curve than with a sharp point. Just wondering.
thatsupraguy33 2 years ago
@thatsupraguy33 Right, it should be shaped like an airplane wing to promote flow. Rounded on the leading edge, sharp on the trailing edge.
rwolcott23 1 year ago
Thanks for actually posting numbers, although we don't know the lifts... nice work.
Nettikturbo 2 years ago
Comment removed
SuperMegaPie1 2 years ago
i was in a machine shop at my voc school we had some sweet HAAS cnc machines i wish i kept with it after high school i would have loved to do stuff like this
cfundevil 2 years ago
It'd be interesting to see the same CNC program on a set of '04-'06 EJ257 heads. The amount of room on those heads are a bit less than the 2.0L heads.
funitsu 2 years ago
What is the reason they (subaru) did wrong in the factory? , are not supposed to win every HP/Kw to increase efficiency? why you need to open your engine to put all in line ?
Subaru is not cheap as acarburetor FIAT 128 or Tipo (in which commonly these jobs are done )
good videos 5* and sorry for my English
aleu650 2 years ago
John, do you only do porting on Suby heads?
coolrunnings526 3 years ago
nice work buddy 195 to 280 cfm that impresive flow increase.
555Starscream 3 years ago
195 on exhaust, went from 230 to 280 on the intakes. ;-)
fiatnutz 3 years ago
my bad :)
still 230 to 280 still impressive, put in cosworth cams, values & high rate springs you will have a serious package.
555Starscream 3 years ago
We actually get very nice power w/stock cams and our different springs & retainers. A lot of people stick in cams because they can and they don't always produce more power, it just moves the power band around.
fiatnutz 3 years ago
Comment removed
marek0086 2 years ago
Both sides equal out; no engine is equal. I see the jealousy has you on your knees, come on please, you big bush pussy HA HA HAAA!
yamasubaruger 2 years ago
Jealousy of what?!
I hate WRX's!.... they feel retarded!
Nothing beats an S15 for performance per dollar!
marek0086 2 years ago
@marek0086 your obviously an idiot.
73DrtSprt 2 years ago
why?
marek0086 2 years ago
unreal flow numbers. hope your fiat flows like that! nice job porting the intake side looks sharp
enginemasterbuilder 3 years ago
cool
ls6guy 3 years ago