Cylinder head swirl and flow data.

What changes when you have a positive pressure gradient in a forced-induction engine as opposed to vacuum?

TDIMeister said:

What changes when you have a positive pressure gradient in a forced-induction engine as opposed to vacuum?

Click to expand...

i'd of thought you would have known.doesn't the ph.d degree your getting give you privy access to air flow software or something like that.
i just port to known port designs and shapes(w/i reason,every head i see from vw is different in construction,close)) that flow well.and use seat cutters w/ excellant flow characteristics under boost.works pretty well so far for me and btw,i took my port design from pd's about 4yrs ago and moved on and up from there.

TDIMeister said:

What changes when you have a positive pressure gradient in a forced-induction engine as opposed to vacuum?

Click to expand...

All the principles of airflow will be the same, but more air will be flowing through the port with the turbo attached. In order to get the air velocity up for flow bench tests the valve needs to be opened up further to get more air flowing through the port. The velocities in the active areas of the port will continue to rise and if there are any areas where the airflow is moving too fast to make the turn the flow will become turbulent. The goal is to make a stable port

I have also been concentrating on improving the low lift flow and swirl in favor of the high lift numbers.

~Alex

Great thread. Going to make sure I keep up on reading this one.

Great work so far!

Brendan

This is what porting a swirl port diesel can make you want to do.....





I am making progress though, even when I make a change to the port and it is not beneficial I know what not to do next time.

The test engine is just about finished up and should be installed in my brother's car in a week and ready for a baseline test.

87turboquattro said:

i just port to known port designs and shapes(w/i reason,every head i see from vw is different in construction,close)) that flow well.and use seat cutters w/ excellant flow characteristics under boost.works pretty well so far for me and btw,i took my port design from pd's about 4yrs ago and moved on and up from there.

Click to expand...

Flow at low valve lift heights has to do with the valve head shape, the valve job and chamber (in gas engines) and not actually the port shape. Since the TDI cam barley lifts into what would be considered "mid lift" the valve job and valve shape are critical to a performance cylinder head, almost more important than porting on the intake side. These are all of the valves I've tested so far, all of them have a flat face.


Those are all intake valves, and I have a few more shapes that I want to test.

~Alex

I always wanted to try pumping an abrasive putty like diamond or silica based compound in direction of flow through the head to port it.That way one could ensure even portwork on swirlports where your dremel port tool doesnt even reach.Tdi meister what would you say?i know nascars get there heads done there too.Im in the process of building one with industrial hydraulic rams.extrude honing

A Canadian alternative to Extrudehone, sure, why not. Just watch out for any patents on the process they may have.

Alex22 said:

Flow at low valve lift heights has to do with the valve head shape, the valve job and chamber (in gas engines) and not actually the port shape. Since the TDI cam barley lifts into what would be considered "mid lift" the valve job and valve shape are critical to a performance cylinder head, almost more important than porting on the intake side. These are all of the valves I've tested so far, all of them have a flat face.


Those are all intake valves, and I have a few more shapes that I want to test.

~Alex

Click to expand...

well i wish you the best of luck and just maybe you can dethrone me on hp/tq in the alh head.i hope you complete a ported head sometime soon.love to see some results.

VDUB TECH said:

I always wanted to try pumping an abrasive putty like diamond or silica based compound in direction of flow through the head to port it.That way one could ensure even portwork on swirlports where your dremel port tool doesnt even reach.Tdi meister what would you say?i know nascars get there heads done there too.Im in the process of building one with industrial hydraulic rams.extrude honing

Click to expand...

w/ the right air grinders,theres no place in an alh or pd head that can be ported.the extrude hone process is great for getting each port to flow w/i small percentages of each other.remember you have to start w/ hardened adapters so the entrance is protected.
love to see if you can build a machine.last time i looked for a used one it was 75 g's.i'll never port enough to get that money back.

VDUB TECH said:

I always wanted to try pumping an abrasive putty like diamond or silica based compound in direction of flow through the head to port it.That way one could ensure even portwork on swirlports where your dremel port tool doesnt even reach.Tdi meister what would you say?i know nascars get there heads done there too.Im in the process of building one with industrial hydraulic rams.extrude honing

Click to expand...

As Bill mentioned, there aren't any tight spots in the port that cannot be reached with the traditional die grinder with porting burrs and sandpaper. Even though this head can be ported with a grinder I have been considering sending a head off to have one intake and one exhaust extruded after taking a baseline flow & swirl test to compare the results to. If I do send a head off to have it extruded it won't be for a while, just too many projects at the moment.

I've seen a set of Ford FE cast iron shorty headers that were extrude honed and they sure were nice looking inside and didn't suck as much power away from the engine (compared to long tube headers) and let the customer have the original look but get some power out of them.

~Alex

Its not going to be 75 gs lol.More like 1000 bucks canadian.Not that complicated at all...why spend hours porting a head if you can go hook it up and walk away?and it will be more even than any handjob.Plus it saves flowbench testing.Im going to start by pumping diamond grit (that can be used , over and over again).Then for the finish go with something a little finer.Plus using gritty diamond it will take much less time aswell.I just get pissed off when i get home and my hair is full of metal.I know you can get at all spots but its a pain and takes so much time.When its done i will post some results

Good potential business opportunity for you if you get it to work. IMO porting still requires a human brain and hands to do (at least the first go, then can be reproduced on a CNC en masse, for example), just like in my field of engineering computers are starting to do more of the work but it's the human intelligence that makes the difference. I'm not knocking the idea; Extrudehone has made a great business for itself. But Extrudehone has not yet rendered every single manual porter obsolete (maybe just the bad ones) as humans have been able to use creativity and ingenuity to make even better-flowing heads than an automated process is able to yield. In fact, I could be one of your first customers when you get up and running

Im working on the plans with my pops hes an engineer and owns a millwright company in ontario.A while ago we built a Rhino squeeze so the zoo keepers could cut the rhinos toenails.I dont think he will have a problem designing a pump that presses putty through a hole....I was always under the assumption that the swirlports somewhat make a tdi a tdi, with other things aswell.Im not really into making money doing it, i just want to do it for fellow tdi buddies that want some nice flowing heads at minimal labour and cost.Porting a head takes 40 hours plus if you want it perfect.Why waste 40 hours?Id rather be doing other things while the machine does its own thing.The only challenge will be designing as system that wont wear itself out , but we got some ideas already.This long weekend we will have a drawing ready.Oh yeah Meister , the drawings will be made in woodstock

how much is this diamond putty gonna cost?

Keep an eye out for a used cement pump. They pump abrasive all day long, and aren't very complicated. The slurry may be tricky...a heavy oil, or a drilling mud as a carrier to keep the grit from settling out.

No price on the diamond grit , but id say it sounds more expensive than it is.And it can be reused over and over again.Thanks for the input shootist might be worth considering

You might want to also look at corundum crystals as an alternative.

this is a diesel swirl port head, it has to be a certain shape there for making the entire thing bigger won't be the best improvement. it will help but not as much as a properly ported and shaped port will when done by hand then digitized and CNC machined after that for easy mass production. if this was a 8-9,000 RPM big block drag car motor then bigger is better because all it sees is high RPMs or idle and it's also a gas motor so there is no need for the swirl to burn the fuel better.

have you tried it?Do you know of anyone that tried it?Ill use the cnc to open the valves up and then pump it with abrasive.The swirl port will be uniformly enlarged.The shape remains the same just bigger.If someone that actually had there tdi head extrude honed chimed in that would be great.

VDUB TECH said:

have you tried it?Do you know of anyone that tried it?Ill use the cnc to open the valves up and then pump it with abrasive.The swirl port will be uniformly enlarged.The shape remains the same just bigger.If someone that actually had there tdi head extrude honed chimed in that would be great.

Click to expand...

all i'll say is,,don't deter and keep on your path.

The problem is that it would uniformaly make the port larger. Thats not the way to go. Its already too large in some parts.

hatemi said:

The problem is that it would uniformaly make the port larger. Thats not the way to go. Its already too large in some parts.

Click to expand...

No, rate of material removal is proportional to the local flow velocity and so therefore will be selective on parts of the ports that are relatively restrictive first. The only time the ports are enlarged uniformly larger is when the flow velocity is also uniform throughout. That's why you do the abrasive extrusion in stages, alternating with the measurements in a flow bench. At some point you reach diminishing returns.

Exactly just picture a straw with a restricted end , when pumping abrasive through, the end of the straw thats restricted will open up first before the rest gets bigger.Im sure it will take some practice to get things right and there will be a certain point until it actually wont help anymore.The unit im thinking of will have a pressure regulation on it so we can dial in the pressures.Again needs to be played with

We had an extra engine laying around....







This will be the engine that gets a head swap to get some dyno numbers on the ported head.

The engine had about 140K so nothing was too warn out, Here's what I did:

• Decked the block the minimum amount to clean it up.

• Rigid honed the cylinder bores for new ring break in.

• New piston rings on the factory pistons.

• Intake valve reliefs cut .030 deeper and .080 larger in diameter.

• Exhaust valve reliefs cut .045 deeper and .060 larger in diameter.

• Measured clearances.

• All new bearings and bolts.

• Basic 3 angle valve job, intakes and exhausts. When I checked the factory valve job one of the exhaust seats did not lap in so I used the intake seat cutter who's flow and swirl numbers were closest to the factory (marginally better.) I used a basic 3 angle exhaust seat cutter on the exhausts. The factory valves were reground.

• Minimum resurface on the cylinder head.

• ARP head studs.

• 3 hole head gasket was required.

• Balanced rotating assembly to race spec.

• South Bend DD clutch kit with a 22lb flywheel.

• Stealth race pipe.

• New timing set and replaced all of the one time use bolts.

The car is a 2003 Jetta with balanced PP520's and a full 2.5" exhaust. Before the head swap I want to install an air to water intercooler, D24 intake manifold and have it tuned. I do not want to turn this thread into a debate about which tuning company to go with or which intercooler to use, lets try to keep this on topic.

This engine has about 1000 miles on it already and is running great with almost no smoke, just a little on cold starts. The car that this engine came out of would let out quite a bit of smoke while accelerating.


It looks like I will be getting back to porting and flowing this week, I will need to either modify my valve opening tool or make a new one to test the PD head.

~Alex

Update? Pics?
D

VDUB TECH said:

Exactly just picture a straw with a restricted end , when pumping abrasive through, the end of the straw thats restricted will open up first before the rest gets bigger.Im sure it will take some practice to get things right and there will be a certain point until it actually wont help anymore.The unit im thinking of will have a pressure regulation on it so we can dial in the pressures.Again needs to be played with

Click to expand...

Correct me if I'm wrong, I have zero knowledge of porting heads just tossing this out. With a "media blasting" your talking about on the swirt ports, I'm thinking the flow of media through the swirl ports would be similar to that of a water through a menandering lazy river. It'd be thorwn against the walls whenever there is a change of direction, wouldn't this eat away at the "outer bank" exagerating the swirl, the "meandering" is that the desired goal? Or are you guys talking about using this technique on non swirl ported heads?

Lofty86 said:

Update? Pics?
D

Click to expand...

Updates: The fresh engine now has about 5K on it and an RC3+ tune (Thanks Jeff!) and the clutch is starting to slip a bit in 4th and 5th gear but my brother has made a phone call about that and we are waiting to hear back. Looks like we should have gone with a SB endurance or stronger. The car is also going to be getting a set of Porsche calipers as well. I should be getting back to this project in a few weeks.

As for the head porting R&D I got a bit burnt out around the 100 hour mark and moved over to a few other projects and put some time into the schoolwork I had been putting off. When I left off I had a good idea of what the shape of the custom valves will be, the valve seat profile and was still working on the port's shape. I also have a valve spring kit that should be able to clear 12mm of lift, the math works out that way, but I have not assembled one yet so we will see.

740GLE said:

Correct me if I'm wrong, I have zero knowledge of porting heads just tossing this out. With a "media blasting" your talking about on the swirt ports, I'm thinking the flow of media through the swirl ports would be similar to that of a water through a menandering lazy river. It'd be thorwn against the walls whenever there is a change of direction, wouldn't this eat away at the "outer bank" exagerating the swirl, the "meandering" is that the desired goal? Or are you guys talking about using this technique on non swirl ported heads?

Click to expand...

The idea behind extrude honeing is that the abrasive paste will follow the port's flow paths and the higher flow areas will have higher velocities and therefore a higher rate of material removal. The slow and dead areas of the port will have less material removed from them. Extrude honeing is quite a bit different than media blasting where a high velocity air propelled media is used. I'm not sure how well extrude honeing will work on the swirl port of a TDI head and I have not been able to get a head extrude honed to test. The one company that replied to my email said that they have not honed any swirl port heads and didn't want to do a test head for me.

~Alex

Time for me to get back to the porting work...

PD head vs. an AHU head, both are as cast and have only had the valves lapped in to make sure the valves are seating correctly. I used the same runner from a D24 intake manifold and an exhaust pipe bent into an oval shape to better fit the exhaust port for this test.




And now the exhaust ports.


I have a couple of valves on order to test more valve shapes and seating angles.

~Alex

Any updates?

I'm curious to how much the exhaust port can be improved. Does anyone have modified exhaust flow numbers?