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Holden 202 12 Port - Who is good at porting?


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#26 Ned Loh

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Posted 02 May 2013 - 07:50 AM

I can use a booth, a bench i would have to learn stuff haha.

 

The learning is the fun part, but having a booth and knowing how to use it means cash only jobs and/or lots of beer!



#27 Ned Loh

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Posted 02 May 2013 - 07:58 AM

If you don't mind spending a little extra I think either of these would be great, the Audie unit in particular seems to have a very good reputation. I'd still tend to go with a variable speed motor; it's just so quick and easy to set the pressure that way. Bear in mind that most of the time you don't really need a direct readout in cfm, you just need to know whether it is getting better or worse as well as the manometer reading that's equivalent to your cfm target.

 

Cheers. I've pretty much decided to build one.  don't mind spending a little more to make it what I want, and easy to use.  will go with variable speed motor (or some form of electricity regulator/controller).

 

This also looks pretty interesting. http://flowperforman...om/basic25.html



#28 Bomber Watson

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Posted 02 May 2013 - 07:58 AM

Sactly.

#29 orangeLJ

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Posted 02 May 2013 - 09:17 AM

and with the cash you earn from cash jobs.... you can buy a flow bench...... and beer



#30 Ned Loh

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Posted 20 May 2013 - 09:16 AM

If you don't mind spending a little extra I think either of these would be great, the Audie unit in particular seems to have a very good reputation. I'd still tend to go with a variable speed motor; it's just so quick and easy to set the pressure that way. Bear in mind that most of the time you don't really need a direct readout in cfm, you just need to know whether it is getting better or worse as well as the manometer reading that's equivalent to your cfm target.

 

Oldjohnno, do you know if the 202 12 port responds closley at 10" to what it does at 28"?



#31 oldjohnno

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Posted 20 May 2013 - 10:32 AM

No it doesn't. The 10'' numbers converted to 28 will be better than the actual 28'' numbers. And I suspect you'd find a similar effect as you go beyond 28'', so it'd probably pay to test at as high a pressure as you can.

#32 Ned Loh

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Posted 20 May 2013 - 01:38 PM

No it doesn't. The 10'' numbers converted to 28 will be better than the actual 28'' numbers. And I suspect you'd find a similar effect as you go beyond 28'', so it'd probably pay to test at as high a pressure as you can.

 

That's good to know.  Thank you.

 

I'm guessing flow doesn't stay attached to the port floor and skips over the short turn...???  Less of an issue in the EFI heads?



#33 oldjohnno

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Posted 20 May 2013 - 08:58 PM

Yes to both, though keeping the roof relatively low seems to help. Concentrate on the floor; that's where all the action is. I can't go much beyond 28" but I'd love to see what the short turn does with 40 - 50", it wouldn't surprise me if it started flowing backwards. These things are ridiculously sensitive to the shape of the back of the valve, small, almost invisible changes can have a big effect, so plan to spend a day or so testing valve shapes. I found a very nice improvement using a modified Ford valve, but lost it all and more when I ground it further looking for more flow. Tried other valves, grinding and reshaping with bog but never got back to where I was. Eventually cracked the shits and gave up. But I will revisit it one day, and learned that there is flow there if you have the time and patience.



#34 Ned Loh

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Posted 21 May 2013 - 07:53 AM

cheers for the info oldjohnno



#35 greens nice

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Posted 21 May 2013 - 07:06 PM

Oldjohnno, have you found 9 ports to be as sensitive to the 28' compared to 10'.

of course 28 is going to be closer to a running engine but are they as bad as in this area to holden 12 port?



#36 oldjohnno

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Posted 21 May 2013 - 08:49 PM

Oldjohnno, have you found 9 ports to be as sensitive to the 28' compared to 10'.

of course 28 is going to be closer to a running engine but are they as bad as in this area to holden 12 port?

 

I don't know, I haven't done much with 9 ports. The pressure drop thing isn't so bad with the 12 ports that the 10" numbers are irrelevant, but it's enough that I think anyone building a "serious" engine should really work with the biggest pressure drop practicable - these are very high velocity ports and I'm not even sure if 28" is enough. I'm toying with the idea doing a 9 port motor though so if I do I'll check it out and let you know. I suspect that they may be marginally less sensitive to pressure than the 12 ports.



#37 greens nice

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Posted 21 May 2013 - 09:19 PM

ah okay awesome  :spoton:

it's just that i had my head flowed at 28" and the only numbers i have to compare to are at 10"

my head is up 20 'theoretical' hp from .150" -.400 lift  and then head flowed at 10 inches walk's away from it.

i think i will just run it and see.



#38 sonic_injection

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Posted 03 August 2013 - 10:49 PM

Oljohnno as usual your comments are worth Bottling. I been doing my testing at 28 as. You know. For the record I'm using a flow performance set up on my bench. I had the calibration plate that came with it tested on a sf600, result was on the money.

I'd love to know what conversion different people use to get flow to hp. There seems to be plenty of variation in the calcs being used

Greens nice. Test pressures are only of value if you want to compare your results with others. If your testing a head before and after porting then the test pressure used for your before and after is what's important. This way you get a % increase which is the desired result right.

For anyone building a flow bench. They are addictive and they dont care for your ego, pride or work ethic. They tell you how it is. Great tool and affordable these days for anyone who like tech stuff

Regards Brett

#39 oldjohnno

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Posted 04 August 2013 - 09:05 AM



I'd love to know what conversion different people use to get flow to hp. There seems to be plenty of variation in the calcs being used



For anyone building a flow bench. They are addictive and they dont care for your ego, pride or work ethic. They tell you how it is. Great tool and affordable these days for anyone who like tech stuff

Regards Brett

 

Great to see you back Brett!

 

The trouble with cfm to hp conversions is that there are so many other factors involved that they can only give the very vaguest of an indication of its performance potential. It's a bit like those quick meal things from the supermarket where it says "Serves 4". Four what? Toddlers? Sumo wrestlers?

Anorexic models?

The commonly used formula for six cylinders is cfm x 1.5 = HP. You only have to give it a little thought though for it to be obvious that the process is severely limited. What if the cam used doesn't lift the valve to the peak flow lift? And there's no accounting at all for the overall breathing or combustion efficiency. Which is why in the real world an engine can make substantially more or less than the formula indicates.

 

Having said that, I think the flow numbers are a good indication of how hard you're gonna have to work to get to your HP goal. For example if your flow is low according to the formula (and you simply can't improve it) then you know that you're going to have to put more effort into the cam and pipe tuning etc. just to get the power you want, and the width of the powerband may suffer accordingly. Conversely, if you exceed the flow requirement comfortably it might mean that you can run a little less duration (or CR, or carb) and maybe have a nicer torque curve. A good example is the Super Stock guys, or the circle track guys limited to a 500 two barrel. They make good power, but they really have to work hard for it. Ultimitely though, I think the flow number/HP formula isn't much more than an indication that you're in or out of the ballpark.

 

frOcking flowbenches. They take everything you thought you knew and show you how wrong you are, then rub your nose in it. I'm in the process of building a new dyno and I've got a horrible feeling it's gonna humiliate me in the same way.



#40 Ned Loh

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Posted 05 August 2013 - 03:41 PM

...I'm in the process of building a new dyno and I've got a horrible feeling it's gonna humiliate me in the same way.

 

even if it does 10 points to you for building one.  Nothing like hands on results to prove or debunk the theory or a hunch.

 

Are you considering measuring vibration? 



#41 warrenm

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Posted 06 August 2013 - 07:19 AM

Oldjohnno

What type of dyno are you building?

What are you using as a brake?



#42 oldjohnno

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Posted 06 August 2013 - 07:24 AM

Nothing like hands on results to prove or debunk the theory or a hunch.

 

Are you considering measuring vibration? 

 

Agreed. Even something as simple as 1/4 mile speed gives a good indication of HP and will quickly confirm or debunk your pet theories.

 

It hadn't occured to me to monitor vibration  - and I guess you mean torsional vibration specifically? I'm not sure what's involved (an encoder at each end of the crank?) but it could be interesting.



#43 oldjohnno

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Posted 06 August 2013 - 07:35 AM

Oldjohnno

What type of dyno are you building?

What are you using as a brake?

 

It'll be specifically made for Holden sixes, and have a pretty limited capacity - not much more than 400hp. I want it to be compact and portable (mounted in a trailer) and not require a big external supply of either water or power. This would make it practical to lend/hire out.

 

The absorbing element will be a screw type blower, mainly so it can be self contained and not need a water supply. It'll need a bloody big muffler though..



#44 Ned Loh

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Posted 06 August 2013 - 09:06 AM

Agreed. Even something as simple as 1/4 mile speed gives a good indication of HP and will quickly confirm or debunk your pet theories.

 

It hadn't occured to me to monitor vibration  - and I guess you mean torsional vibration specifically? I'm not sure what's involved (an encoder at each end of the crank?) but it could be interesting.

 

The (2nd hand) story I heard a few years ago was that a certain group nc engine owner was asked to remove his I6 engine from a well known dyno as the vibration sensors were going off the charts.  Ever since I heard that I've always thought, if I win lotto, I'd like to try different balancer and flywheel combos and see the effect, as it feel like a bit of an eductated guess at the best of times. Now I don't exactly know the ins and out what sensors the dyno was equiped with, but I know the dyno shop if your inetersted in calling them.

 

Your idea sounds quite interesting.  I read something along those lines on the BHJ website a little while ago.

 

EDIT linky: http://www.bhjdynami...mponentdev_dyno


Edited by Ned Loh, 06 August 2013 - 09:06 AM.


#45 Ned Loh

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Posted 06 August 2013 - 09:22 AM

I see that mainline offer a vibtration meter as an option.

 

from here: http://www.mainlined...sories-software

"OPTIONAL - Advanced Diagnostics - Vibration Meter

Vibration analysis can detect a multitude of defects in many rotating devices and components. The unit can be used stand alone, or connected to the dyno via RS232 cable to log data along with other dyno channels."

 

 



#46 oldjohnno

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Posted 06 August 2013 - 11:07 AM

I can access that sort of thing, they're pretty basic. What I'd be more interested in is the torsional movement of the crank. Realistically though, it's very unlikely that I'll go to that much trouble.



#47 Ned Loh

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Posted 06 August 2013 - 02:18 PM

I can access that sort of thing, they're pretty basic. What I'd be more interested in is the torsional movement of the crank. Realistically though, it's very unlikely that I'll go to that much trouble.

 

I'll let you know once my lotto numbers have come up.  Must remember to buy a ticket one of these days.  So many dreams, so little cash...



#48 oldjohnno

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Posted 06 August 2013 - 02:22 PM

What?

 

You have to buy a ticket?



#49 Bomber Watson

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Posted 06 August 2013 - 03:25 PM

Portable engine dyno, you are so invited to all of my pissups from now on.




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