pcmhacking.net

try here

http://pcmhacking.net/forums/viewtopic. ... =flowbench

we have no bell mouth in either case of pipe or TB, the TB actually is machined radius on the inside. Pipe length played 99% of the effects. It didn't care of bellows, turns, filter no filter, bits of pipe held by hand end to end, fingers over the end of the pipe. No of that effected. Added 400mm of pipe and power and torque went up everywhere.

We tested this for most of the day, dyno run after run and backed up the results. No doubt what was going on. And how many engine builders/tuner have worked this out? probably 2/5th of bugger all.

Only car makers take this into consideration and know what they are doing.

That flow bench doesn't consider resonance...

You'd want an engine with a pressure sensor in place of a sparkplug. You could map real time intake flow variations by measuring peak cyl pressures. No vac pumps, blowers, just a hacked up engine.

vlad01 wrote:we have no bell mouth in either case of pipe or TB, the TB actually is machined radius on the inside. Pipe length played 99% of the effects. It didn't care of bellows, turns, filter no filter, bits of pipe held by hand end to end, fingers over the end of the pipe. No of that effected. Added 400mm of pipe and power and torque went up everywhere.

We tested this for most of the day, dyno run after run and backed up the results. No doubt what was going on. And how many engine builders/tuner have worked this out? probably 2/5th of bugger all.

Only car makers take this into consideration and know what they are doing.

What was the effect of more than 400mm?

BennVenn wrote:That flow bench doesn't consider resonance...

You'd want an engine with a pressure sensor in place of a sparkplug. You could map real time intake flow variations by measuring peak cyl pressures. No vac pumps, blowers, just a hacked up engine.

That seems like a fantastic idea but why isnt that method widely used?

Not sure. How much Hp does it take to spin an engine up to 7000rpm?

Not sure, a commercial machine exists to do such a job, called a spintron...

http://trendperform.com/p-30013-spintron.html

Actually, using 6/8 sensors would show the variations between cylinders due to runner locations in the plenum. Far better than flow only testing

Biggvl wrote:

BennVenn wrote:That flow bench doesn't consider resonance...

You'd want an engine with a pressure sensor in place of a sparkplug. You could map real time intake flow variations by measuring peak cyl pressures. No vac pumps, blowers, just a hacked up engine.

That seems like a fantastic idea but why isnt that method widely used?

This is done, used for tuning purposes. I believe it is a spark plug with a pressure sensor incorporated.

vlad01 wrote:we have no bell mouth in either case of pipe or TB, the TB actually is machined radius on the inside. Pipe length played 99% of the effects. It didn't care of bellows, turns, filter no filter, bits of pipe held by hand end to end, fingers over the end of the pipe. No of that effected. Added 400mm of pipe and power and torque went up everywhere.

We tested this for most of the day, dyno run after run and backed up the results. No doubt what was going on. And how many engine builders/tuner have worked this out? probably 2/5th of bugger all.

Only car makers take this into consideration and know what they are doing.

I have heard others talking of this, most don't go any further other than hinting at the intake pipe length been an issue. It's certainly not something that is not shared openly but then unless you have the facilities to test it's a mute point anyway.