*** INA : CNC'ed Ported 2.0 FSI | TSI HEADS - Intro ***

[INA]

Stock BPY FSI Head with Stock Sized Ferrea Valves flow #'s.

AT PEAK:
intake port flows : 218 cfm's
exhaust port flows : 170 cfm's

Test #'s are at 28" of water. Ported #'s will be up late next week.Followed by Ported #'s + 1mm oversized valves. We are currently working with H2sport to offer a complet cylinder head solution so stay tuned.



For reference, here was a similar chart done 6 years comparing the 1.8T 20V's to the older 9A/PL 16V heads.

[Backdraft]

Just thought I'd share our UK figures with you from the heads we do. As you can see the curves and figures are a tad different. (see attached jpg)

Possibly down to a couple of reasons

Our intake was flowed with the port divider in rather than removed, although that and a change of valve wouldn't amount to almost a 10% flow increase so I can only assume calibration is accountable here like comparing dyno to dyno (although your 1.8t intake figures are spot on in the chart below).
Saying that the curve is slightly different too, which may be down to the bore adapter, ours was flowed on an 83mm bore adapter to simulate actual shrouding whereas we have noticed a lot of companies in the US using a 100mm bore adapter which can give inflated low lift results. We will assume you didn't do the same as some other well published 1.8t results which is flow the head without the spark plug fitted

Exhaust wise quite a common fault is that people flow the exhaust like an intake sucking the air through it as opposed to blowing it through from the combustion chamber. Which looks to be the case as it would yield the same peak figures in theory, either limited by valve seat throat or port exit; But give a completely different curve leading up to it. You can usually tell whether a port has been correctly flowed on the exhaust as it will show flatspots/spikes in the flow curve on a stock casting due to the turbulence introduced by the short side.

[INA]

Originally Posted by Backdraft

Just thought I'd share our UK figures with you from the heads we do. As you can see the curves and figures are a tad different. (see attached jpg)

These figures you are showing me are on your modified head or your stock head?

[Backdraft]

The graph shows intake stock, exhaust stock, intake ported and exhaust ported.

[INA]

hmmm....why isnt the exhaust linear?

[Backdraft]

Hi Sam,

Simple flow dynamics.

When you suck through a port the majority of the airmass hugs the roof of the port which in casting terms is generally pretty good which results in a predictable flow curve relative to valve and seat throat size and port entry size.

When blowing through the port you now have a turbulent airmass as it is attempting to use the roof and floor of the port equally resulting in a tumbling airmass that is attempting to make a turn. The worse the casting is on the short side the more turbulent the airmass and the more erratic the flow figures jump.

A lot of companies stopped flowing heads by pushing through the exhaust as it is difficult to regulate on a conventional liquid manometer flow bench. Originally trying to work round the issue by taking lift figures at 100, 200, 300, 400 and 500 then filing in the blanks inbetween making a smooth curve because it looks better. Our guy uses a digital manometer flow bench so that although figures are non linear they are stable when measured. It also allows him to measure airspeed at different locations to pick up on points of turbulence so the port work up can be adjusted to suit.

The end result being a parabolic flow curve that picks up quickly and plateaus when sonic choke of the port is reached which is determined by the port exit size as opposed to the valve and seat size like on the intake.

Recognizing the fact that there is a turbulence flat spot in the exhaust flow and addressing it results in excellent throttle response, smooth power delivery and significant midrange torque gains on FI motors which is why we don't hide the fact that there is a flow issue by smoothing over figures so they look pretty on a line chart.

[ibizacupra]

as if JP posted it himself

[Backdraft]

Originally Posted by ibizacupra

as if JP posted it himself

Ive just spent too much time with JP that its 2nd nature all this porting lark

[Mook]

LOL - glad I got him to P&P my head!

[INA]

Originally Posted by Backdraft

Recognizing the fact that there is a turbulence flat spot in the exhaust flow and addressing it results in excellent throttle response, smooth power delivery and significant midrange torque gains on FI motors which is why we don't hide the fact that there is a flow issue by smoothing over figures so they look pretty on a line chart.

Coupled by the fact that there are more reference points on your charts than there are on ours has something to do with the "smoothing over".

Whatever the case I am sure our heads will be up to par in the performance sector considering one of the most powerful FSI engines in the world run a hand ported version of the head of which the CNC'ed model was based off of.
Will update this when I can.
Thanks for now.

[INA]

Sorry been busy....enjoy the show. All done in house here at INA .Love my new machine

20V Heads coming in June