Airflow bench specifically for boosted engines

[Sweet P]

Do you think its better to test cylinder heads that will be run with boost on a flowbench that is much different than a "normal" flowbench (IE Superflow 600)?

Check this out, https://www.facebook.com/video.php?v=88 ... =2&theater
In the video he mentions flowbench, do you think its something they specifically built?

Do you know of anyone porting heads specifically for boosted engines?

[Farrell]

I built a pressurized flow bench and in my opinion, unless you have mad visualization skills, you need this type of equipment to do a proper
job. A good naturally aspirated head, of course, will work, but a properly ported boosted head will work MUCH better. I''ve tested as high as 300". Recently, on a RB26, my head and some cams picked power up 140whp. This is a 2.6 litre motor. Same turbo with less boost because of the head.

[Dave Koehler]

A former Funny Car fellow, named Frank Oglesby (Quarter Horse) built just such an animal for buddy Austin Coil when he was at JFR.
JF still has it. I forget the specs but it is capable of some stratospheric numbers. I think he built a couple of others but is retired now.
Kind of like the clutch dyno I suspect it is scary being in the same vicinity when it is running.

[Sweet P]

Thanks Dave and Farrell!

There arent a lot a people as serious about boosted cylinder head performance.

People like Brad Anderson, Ken Veney and Alan Johnson seem to give hints that they have a "boosted airflow benches" and I'd love to know more about them.

I assume they pressurize them to a "normal" psi that their heads see instead of using 28"?

[Dave Koehler]

The premise and from what was relayed to me long ago is that pressurized flow shows up a different animal and characteristics than vacuum flow on a normal bench. But then all the have not players buy their stuff from the usual suspects and the haves create their own copy via in house cnc. In the end it's a level field via NHRA rules on heads. The real smart tuning is in the can and the time box anyway.
I do recall that it took a huge motor to pull this off. Check your power bill at the door in other words.
I remember when the blower contingent believed that porting and flow bench work was useless as they had nitro and blowers....and it really wasn't all that long ago. Silly boys.

[vwchuck]

I think this would be useful in a supercharged engine but not real useful if turbocharged. The delta P across the intake valve is just not that high on a turbocharged engine. The delta P across a supercharged intake could be massive if you get all the exhaust out.

[Erland Cox]

It doesn't matter if you pull or push, it is the same to the air.
If you want to test flow at very high pressure differences it is easier to blow the port but you will not have access to probe the port or test things with flow balls.
Creating a lot of pressure is easier than a lot of vacuum.

Erland

[Lockwire]

A former Funny Car fellow, named Frank Oglesby (Quarter Horse) built just such an animal for buddy Austin Coil when he was at JFR.
JF still has it. I forget the specs but it is capable of some stratospheric numbers. I think he built a couple of others but is retired now.
Kind of like the clutch dyno I suspect it is scary being in the same vicinity when it is running.

Actually the 1 st one went to Brad Anderson, the 2nd one ( Forces ) went to Mississippi and John Medlen ran the bench in his shop there. The 1st pass on Brads bench at Franks during calibration it was evident that adjustments were required to the motors. This would not have been seen under depression, simple as that. sds.

[Erland Cox]

Does the density do any difference? You can not blow with several bars because in the real world pressure will build up in the cylinder.
0,5 bars of depression is the same as 1 bar of boost except for air density.

Erland

[Sweet P]

[/quote]

The 1st pass on Brads bench at Franks during calibration it was evident that adjustments were required to the motors. [/quote]

"motors", you mean the electric motors that pumped the air or the BAE motors?

[Lockwire]

The 1st pass on Brads bench at Franks during calibration it was evident that adjustments were required to the motors. [/quote]

"motors", you mean the electric motors that pumped the air or the BAE motors?[/quote]

We did not have any thing to do with Andersons stuff. I did not mention BAE ? . At that time we done some work on another team that ran Top Fuel motors. Frank built the bench top test Top Fuel Cylinder heads not electric motors. If you read what I said you would understand the message. Erland did. sds.

[vwchuck]

Motors are electric.

[Sweet P]

I've heard it takes about 500 HP to spin a modern 14-71 at its maximum.

500 HP divided by 8 cylinders = 62.5 HP to pump enough air for 1 port

Seems a 75 HP electric motor would be enough although if you are trying to test at max lift it would probably take more CFM and therefore more electric motor HP.

I assume this is pretty close, thoughts?

[David Redszus]

A normally aspirated engine can only pull one atmosphere of pressure. In actual practice, it will pull only about 1/2 atmosphere until it hits the sonic velocity wall at a pressure ratio of .528, at which point it is choked.

A forced induction engine can push much more, since the pressure can be raised well beyond one atmosphere. But at a pressure ratio of 1.894 we again bump into the wall of choked flow and velocity cannot be increased no matter how high the pressure. Even though the velocity cannot be increased, the inlet air density certainly can be increased. That is why it so important to always measure air mass flow not velocity or volume.

Many years ago, Chrysler Engineering built a flow bench using, not a blower but a compressed air tank. It was very large with a pressure of about 150psi. On their flow bench, a valve was openend and mass flow through the entire inlet system was measured. It only took seconds for each test. But much longer to rebuild tank pressure.

That is how I would build a real Super flow bench.

[Erland Cox]

Are you sure it was at Chrysler David? AMC had such a bench though.
But they regulated the pressure and did not use more than we usually flow at today.
There is a very good SAE paper about their work.

Erland.