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 Post subject: Re: Kinda funny
PostPosted: Tue Nov 13, 2018 2:14 pm 
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Posts: 500
Falcon67 wrote:
That's how I used my home brew in the way back. It only used manometers to measure flow and pressure drop and there was a thin copper pipe with a manometer for checking "velocity". You could run some base numbers at a certain pressure drop, then grind a little, put the head back on and compare manometer readings. Not a Super Flow lol but the concept was sound IMHO.

Seems to me, as a tech guy, that we have the technology to put a head on a device that would cycle the air in the port as it might on an engine and use sensors to collect data at a high enough rate to study activity in the port in real time.


I think that the problem with a bench that would introduce cycling dynamics might be that you'd end up measuring the effects of the bench itself more than the cylinder head. With that said there are people who feel that testing a cylinder head at a fixed amount of depression at all valve lifts is not the best way to do flow testing. If you think about this it does make sense in that the depression produced by the piston movement changes per degree peaking at about 75 degrees ATDC. With a typical camshaft producing max lift at around 100-110 ATDC having a depression that does not change tends to overemphasize the importance of flow at high lift as well as low lift. Could be.. And this could be how sometimes a head that really stalls out above .25D doesn't seem to run any different than one that doesn't..


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 Post subject: Re: Kinda funny
PostPosted: Tue Nov 13, 2018 2:59 pm 
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BAck when I got to flow the 2V heads I ported, we did the standard open valve .1 at a time, raise the depression and read the flow meter. AT just past .450, the air went BANG when it apparently lost control at the short turn. Flow was about 260 IIRC, dropped to about 245 then climbed back around 250ish @ .500 and pretty much didn't do anything else at .6 or .7. That was interesting but I always wondered if the motor was ever actually affected by anything like what happened on the bench. I don't think "real world" ever cared. I would think that the improvement in low lift flow would have been the primary benefit from the work, since that motor was never really spun past 6500. It had a couple of different cams and several different size carbs - always made around 400 depending on the weather, car ran about the same MPH at the track.

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 Post subject: Re: Kinda funny
PostPosted: Tue Nov 20, 2018 10:08 am 
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Joined: Mon Oct 29, 2012 1:52 pm
Posts: 500
Falcon67 wrote:
BAck when I got to flow the 2V heads I ported, we did the standard open valve .1 at a time, raise the depression and read the flow meter. AT just past .450, the air went BANG when it apparently lost control at the short turn. Flow was about 260 IIRC, dropped to about 245 then climbed back around 250ish @ .500 and pretty much didn't do anything else at .6 or .7. That was interesting but I always wondered if the motor was ever actually affected by anything like what happened on the bench. I don't think "real world" ever cared. I would think that the improvement in low lift flow would have been the primary benefit from the work, since that motor was never really spun past 6500. It had a couple of different cams and several different size carbs - always made around 400 depending on the weather, car ran about the same MPH at the track.


The 2V head is a weird design. The short side is so tall and so abrupt but there isn't enough metal in the head to fix it and keep it hanging on past .25d. The sizing is about right for a lot of engines and it might be interesting to experiment with it by moving the intake valve away from the short side say .050-.075, put in a seat and see what it does.


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