john.jackson9213
Top Post Dawg
I have a ported 1Z head sitting on my shelf. Fresh valves, but no cam. Would that be something you would like to test?
Porting Porn
- Thread starter Franko6
- Start date
CNGVW
Vendor , w/Business number
- Joined
- Sep 15, 2009
- TDI
- Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
That would be great could you tell what you have for a flow bench and dyno pic would be great too.
If you could do a flow on a stock head then dyno numbers and take A/F ex readings would make a nice baseline.
I would help cover some of the cost for the head gaskets.
I am shore others would help here too.
If you could do a flow on a stock head then dyno numbers and take A/F ex readings would make a nice baseline.
I would help cover some of the cost for the head gaskets.
I am shore others would help here too.
1998TDIMonster
Veteran Member
Here is some more anecdotal evidence. I had failed lifters on my 98 jetta (ahu) and bought a frank head and cam. Right from the box i could tell it was professionally done and was going to be an improvement over how the stock head was set up. That was almost 20,000 miles ago and the car still runs flawlessly and has much improved power over 2,800 rpm whereas the stock head and cam did not seem happy over 2,800 rpm. I believe in concrete facts and data as should everyone else, but I do not see the reason behind the attacks on Frank. I understand shiny doesn't mean better and without a flow bench and dyno you cannot prove Frank's porting job has done anything to increase flow, but I would think it is kind of obvious that porting a stock head with poor internal turns and mismatched ports would be better than stock flow. I achieved a noticeable increase in power,have incurred no early failures and the cam and followers still look great. I think i am speaking for a large portion of Tdi owners here saying who gives a rat's you-know-what about flow on a daily driver Streetable tuned tdi head from Frank. I do not know many people who just want a tdi head built for racing purposes only as that is not necessarily what these cars were made for. I am usually all about numbers and data, but jeez, give the guy a break. He does good head work (harder to find these days) and has excellent customer service.
Franko6
Vendor , w/Business number
I enjoyed the Saturday with my family, watched the grandkids compete in basketball tournaments, and had a great day. That day was better letting this thread rest.
Sunday, I shared time with my brothers and sisters on The Lord’s Day. Helped fix the lunch with another family and it was good. Served about 150 people Barbecued Meatballs, Cheezy Potatos and a salad. Everybody complimented the meal. Then I fixed my son's brakes on his Chevy and polished his headlights. A feeling of accomplishment and bonding.
And I agree, Nevada, I never started this as any chest thumping, but as a desire to get others to compare and hopefully show their pretty pictures, improve a knowledge that is generally felt an elusive, arcane and secretive art.
FUB: When a professional porter comes on my thread and the topic turns to pricing, you think I am in the wrong place? There is a name for taking over another person's thread with talk of sales. It's not right.
The kind of work it takes to turn out a porting job; it’s something I have to steel myself and grit my teeth. It’s hard work. It is not my favorite thing to do. Really, FUB, what is your real problem? You always come around me with a chip on your shoulder. And another points out a little bump in the workmanship. Jeez, what a guy. All I can say is, I keep up the attempt to improve.
I think the point of all this is that I am not trying to get ALL of the flow rate, but what I am doing, and by the way, so have you, FUB, is to attempt improvement to a very 'commercial' cylinder head. My effort was to get some quorum of opinion, but instead, I seem to attract the same 'prove it' mentality, trying to intimidate and undermine. It’s not like it grieves me what some of you think is wrong with my cylinder head work. If you have something to say to improve it, SHOW IT! PROVE IT YOURSELF! This is actually intended to be a self-help study, to dig into the problems, advantages and reality of porting for the TDI cylinder heads. I don’t need another TDI armchair quarterback telling me how I do it wrong.
I have been asked so many times how to port, where to port and what NOT to do. The information from some is helpful, but most do not get that, like you say Nevada, I'm not trying to exceed every top-rated porter's best effort. Even among themselves, the pros would argue. I don't mind allowing club members access to what is definitely working for my customers and if they have the gumption and an air tank to keep up with the grinder, give it a shot themselves.
The question: Is what I do without merit? I have compared porting with another well-known member who builds very aggressive TDI’s. We agreed in principle over most of what we were doing. He got himself in a ringer for 'giving away secrets' with a picture he posted years ago. I repost here showing the verticle bottleneck in the exhaust port of an ALH...
When you see the bottleneck as plainly as this, there is little argument that it is not beneficial to allow exhaust gasses be pinched in this manner. Opinions are stated, "pictures don't help or mean much." I disagree. The lines indicating the change are a very good improvement. As you can also see, there is plenty of room in the port to allow for this relief without getting into the water jacket. Some porting improvements are this obvious. This is not rationalization, but rationale.
Some claim what I am doing is mercenary, with an interest for procuring more porting. I think I'd rather give it away, as porting is very hard work and time-consuming, unless you own a Centroid or it's clone, and then it's just expensive.
My point is to bring some challenge to the Club. Controversial topics like cam design, porting, injector calibration, injection pump work, rod design, intake design, OIL, and soon, sputtered bearings are among the topics I have not been afraid to approach. I’ve spent thousands of dollars and countless hours tempting fate for any return and I get bullied for my efforts. Fine. The effort is good for the Club. Out of controversy and CIVIL discourse, benefit comes to all.
TDIMonster, thank you. I appreciate one of my customers speaking from their experience with me.
Sunday, I shared time with my brothers and sisters on The Lord’s Day. Helped fix the lunch with another family and it was good. Served about 150 people Barbecued Meatballs, Cheezy Potatos and a salad. Everybody complimented the meal. Then I fixed my son's brakes on his Chevy and polished his headlights. A feeling of accomplishment and bonding.
And I agree, Nevada, I never started this as any chest thumping, but as a desire to get others to compare and hopefully show their pretty pictures, improve a knowledge that is generally felt an elusive, arcane and secretive art.
FUB: When a professional porter comes on my thread and the topic turns to pricing, you think I am in the wrong place? There is a name for taking over another person's thread with talk of sales. It's not right.
The kind of work it takes to turn out a porting job; it’s something I have to steel myself and grit my teeth. It’s hard work. It is not my favorite thing to do. Really, FUB, what is your real problem? You always come around me with a chip on your shoulder. And another points out a little bump in the workmanship. Jeez, what a guy. All I can say is, I keep up the attempt to improve.
I think the point of all this is that I am not trying to get ALL of the flow rate, but what I am doing, and by the way, so have you, FUB, is to attempt improvement to a very 'commercial' cylinder head. My effort was to get some quorum of opinion, but instead, I seem to attract the same 'prove it' mentality, trying to intimidate and undermine. It’s not like it grieves me what some of you think is wrong with my cylinder head work. If you have something to say to improve it, SHOW IT! PROVE IT YOURSELF! This is actually intended to be a self-help study, to dig into the problems, advantages and reality of porting for the TDI cylinder heads. I don’t need another TDI armchair quarterback telling me how I do it wrong.
I have been asked so many times how to port, where to port and what NOT to do. The information from some is helpful, but most do not get that, like you say Nevada, I'm not trying to exceed every top-rated porter's best effort. Even among themselves, the pros would argue. I don't mind allowing club members access to what is definitely working for my customers and if they have the gumption and an air tank to keep up with the grinder, give it a shot themselves.
The question: Is what I do without merit? I have compared porting with another well-known member who builds very aggressive TDI’s. We agreed in principle over most of what we were doing. He got himself in a ringer for 'giving away secrets' with a picture he posted years ago. I repost here showing the verticle bottleneck in the exhaust port of an ALH...
When you see the bottleneck as plainly as this, there is little argument that it is not beneficial to allow exhaust gasses be pinched in this manner. Opinions are stated, "pictures don't help or mean much." I disagree. The lines indicating the change are a very good improvement. As you can also see, there is plenty of room in the port to allow for this relief without getting into the water jacket. Some porting improvements are this obvious. This is not rationalization, but rationale.
Some claim what I am doing is mercenary, with an interest for procuring more porting. I think I'd rather give it away, as porting is very hard work and time-consuming, unless you own a Centroid or it's clone, and then it's just expensive.
My point is to bring some challenge to the Club. Controversial topics like cam design, porting, injector calibration, injection pump work, rod design, intake design, OIL, and soon, sputtered bearings are among the topics I have not been afraid to approach. I’ve spent thousands of dollars and countless hours tempting fate for any return and I get bullied for my efforts. Fine. The effort is good for the Club. Out of controversy and CIVIL discourse, benefit comes to all.
TDIMonster, thank you. I appreciate one of my customers speaking from their experience with me.
newlitemotorist
Veteran Member
This thread has become pointless. It's clear no one has the information on improving one of these heads short of saying, "line up those runners" and " we aren't building race heads" 10 different ways.
I was really hoping for some technical info on modifying these swirl ports.
I was really hoping for some technical info on modifying these swirl ports.
Fix_Until_Broke
Top Post Dawg
greengeeker - I've got a set of ALH head bolts and a head gasket (2 hole maybe, need to check) that I'll gladly donate to the cause.
One thing to consider (as CNGVW mentioned) is that the testing is well thought out, instrumented and analyzed otherwise we'll waste a lot of time/effort/$$.
1998TDIMonster - I'm glad to hear that you're happy with the head and cam that you purchased from Frank. If you don't give a hoot about flow, I think you're missing the point of this thread? There's other factors such as swirl and then the cam effects as well which are important on daily drivers.
I'm asking is what is "better" and how do we know? Is that really too much to ask?
One thing to consider (as CNGVW mentioned) is that the testing is well thought out, instrumented and analyzed otherwise we'll waste a lot of time/effort/$$.
1998TDIMonster - I'm glad to hear that you're happy with the head and cam that you purchased from Frank. If you don't give a hoot about flow, I think you're missing the point of this thread? There's other factors such as swirl and then the cam effects as well which are important on daily drivers.
I'm asking is what is "better" and how do we know? Is that really too much to ask?
greengeeker
Vendor
Just so my intentions are clear - I put this offer out there not to call out Frank but instead because I'm curious myself as to the benefits a ported head can have on airflow and the power in a TDI. I'll admit that I'm a pessimist in the value of porting a head. Rightly or wrongly I feel it is toward the bottom of the hp/$ scale.
The dyno that I've used in the past is a Mustang but I have access to others as well.
) and could definitely use some help.
Let's take this topic off of Frank's thread if we want to discuss this further.
I'd prefer to keep it all ALH sorry. Thanks for the offer though!
It's literally been 10 years since I used our flow bench at work. I know it's a large upright Superflow unit. Will have to check on the model.
The dyno that I've used in the past is a Mustang but I have access to others as well.
Thanks for the offer FUB. I've been around long enough to know how this ends if we can't draw rock solid conclusions - pages and pages of bickering about the results. Yes, I fully intend to have this test be as thorough as possible (and reasonable
) and could definitely use some help. Let's take this topic off of Frank's thread if we want to discuss this further.
john.jackson9213
Top Post Dawg
Frank,
I am not knocking anyone - but the "scientific method" would seem to call for specific data and test conditions so that repeatable data can be obtained. How else can we know if we should take X or Y amount of metal away at a given place?
It seems that the flow bench is the "standard" tool to measure head port flow at standard conditions.
If you look at post #4 in this thread I pointed out the work by Alex22 with his published flow numbers and asked for a pointer to other flow numbers. Not to shame anyone - but to see some repeatable, measured data points. Without some kind of measurable data, this whole porting thing is just a time consuming process with no measurable, quantifiable results.
I "suspect" that porting, if "properly done" can produce better, cleaner combustion in the engine. Heck, most/all car makers have made huge strides in producing more power, cleaner power, and more mpg (all at the same time) by paying very close attention to how air and fuel get into the combustion chamber and how they control the burn in the chamber.
Out side of Alex22's work - I just have not seen the raw data to support results from porting work. Alex22 had both flow and swirl data.
That said, I need to say that I paid more than $1000 for a ported 1Z head several years ago (with no flow data to back it up), just sitting on my shelf for future use. I would like to think that I got something for my money besides just the good feeling I get when I say my head is ported but not polished. But without solid data, all I really have is bragging rights - with nothing to back it up.
I am not knocking anyone - but the "scientific method" would seem to call for specific data and test conditions so that repeatable data can be obtained. How else can we know if we should take X or Y amount of metal away at a given place?
It seems that the flow bench is the "standard" tool to measure head port flow at standard conditions.
If you look at post #4 in this thread I pointed out the work by Alex22 with his published flow numbers and asked for a pointer to other flow numbers. Not to shame anyone - but to see some repeatable, measured data points. Without some kind of measurable data, this whole porting thing is just a time consuming process with no measurable, quantifiable results.
I "suspect" that porting, if "properly done" can produce better, cleaner combustion in the engine. Heck, most/all car makers have made huge strides in producing more power, cleaner power, and more mpg (all at the same time) by paying very close attention to how air and fuel get into the combustion chamber and how they control the burn in the chamber.
Out side of Alex22's work - I just have not seen the raw data to support results from porting work. Alex22 had both flow and swirl data.
That said, I need to say that I paid more than $1000 for a ported 1Z head several years ago (with no flow data to back it up), just sitting on my shelf for future use. I would like to think that I got something for my money besides just the good feeling I get when I say my head is ported but not polished. But without solid data, all I really have is bragging rights - with nothing to back it up.
Houpty GT
Veteran Member
https://www.youtube.com/watch?v=yFKm5Nok_WE
https://www.youtube.com/watch?v=DpPI5tPU-rE
https://www.youtube.com/watch?v=xmfsmy5IUU4
https://www.youtube.com/watch?v=qLlz9alr_uw
https://www.youtube.com/watch?v=qnRKRpLOviI
https://www.youtube.com/watch?v=qz_yV6iwE3Y
6 step videos for a good 45 minutes of TDI porting
https://www.youtube.com/watch?v=DpPI5tPU-rE
https://www.youtube.com/watch?v=xmfsmy5IUU4
https://www.youtube.com/watch?v=qLlz9alr_uw
https://www.youtube.com/watch?v=qnRKRpLOviI
https://www.youtube.com/watch?v=qz_yV6iwE3Y
6 step videos for a good 45 minutes of TDI porting
Fix_Until_Broke
Top Post Dawg
Frank - It sounds like you had a very nice weekend with family and friends. All of that is way more important than anything on this thread - Glad that you were able to enjoy that.I enjoyed the Saturday with my family, watched the grandkids compete in basketball tournaments, and had a great day. That day was better letting this thread rest.
Sunday, I shared time with my brothers and sisters on The Lord’s Day. Helped fix the lunch with another family and it was good. Served about 150 people Barbecued Meatballs, Cheezy Potatos and a salad. Everybody complimented the meal. Then I fixed my son's brakes on his Chevy and polished his headlights. A feeling of accomplishment and bonding.
And I agree, Nevada, I never started this as any chest thumping, but as a desire to get others to compare and hopefully show their pretty pictures, improve a knowledge that is generally felt an elusive, arcane and secretive art.
FUB: When a professional porter comes on my thread and the topic turns to pricing, you think I am in the wrong place? There is a name for taking over another person's thread with talk of sales. It's not right.
The kind of work it takes to turn out a porting job; it’s something I have to steel myself and grit my teeth. It’s hard work. It is not my favorite thing to do. Really, FUB, what is your real problem? You always come around me with a chip on your shoulder. And another points out a little bump in the workmanship. Jeez, what a guy. All I can say is, I keep up the attempt to improve.
I think the point of all this is that I am not trying to get ALL of the flow rate, but what I am doing, and by the way, so have you, FUB, is to attempt improvement to a very 'commercial' cylinder head. My effort was to get some quorum of opinion, but instead, I seem to attract the same 'prove it' mentality, trying to intimidate and undermine. It’s not like it grieves me what some of you think is wrong with my cylinder head work. If you have something to say to improve it, SHOW IT! PROVE IT YOURSELF! This is actually intended to be a self-help study, to dig into the problems, advantages and reality of porting for the TDI cylinder heads. I don’t need another TDI armchair quarterback telling me how I do it wrong.
I have been asked so many times how to port, where to port and what NOT to do. The information from some is helpful, but most do not get that, like you say Nevada, I'm not trying to exceed every top-rated porter's best effort. Even among themselves, the pros would argue. I don't mind allowing club members access to what is definitely working for my customers and if they have the gumption and an air tank to keep up with the grinder, give it a shot themselves.
The question: Is what I do without merit? I have compared porting with another well-known member who builds very aggressive TDI’s. We agreed in principle over most of what we were doing. He got himself in a ringer for 'giving away secrets' with a picture he posted years ago. I repost here showing the verticle bottleneck in the exhaust port of an ALH...
When you see the bottleneck as plainly as this, there is little argument that it is not beneficial to allow exhaust gasses be pinched in this manner. Opinions are stated, "pictures don't help or mean much." I disagree. The lines indicating the change are a very good improvement. As you can also see, there is plenty of room in the port to allow for this relief without getting into the water jacket. Some porting improvements are this obvious. This is not rationalization, but rationale.
Some claim what I am doing is mercenary, with an interest for procuring more porting. I think I'd rather give it away, as porting is very hard work and time-consuming, unless you own a Centroid or it's clone, and then it's just expensive.
My point is to bring some challenge to the Club. Controversial topics like cam design, porting, injector calibration, injection pump work, rod design, intake design, OIL, and soon, sputtered bearings are among the topics I have not been afraid to approach. I’ve spent thousands of dollars and countless hours tempting fate for any return and I get bullied for my efforts. Fine. The effort is good for the Club. Out of controversy and CIVIL discourse, benefit comes to all.
TDIMonster, thank you. I appreciate one of my customers speaking from their experience with me.
You're telling us that this isn't a veiled promotion of your business that's not in the vendor section? Come on, let's be realistic here
. If this is really the altruistic goal of improving the knowledge base and bettering the TDIClub community then the questions shouldn't be a problem?My "real problem" is that there's a lot of talk without any data to back it up. You're stating that you're trying to optimize (not maximize) the performance. Ok - what are you trying to optimize and how do you know that it's optimized if you don't have any data to support it? I'm not asking you to give away your trade secrets, but give us something more than "better".
I'm sorry if you feel bullied or intimidated by my challenging the value your efforts. If you read carefully, I've never said that there's anything wrong with your head porting work. I can't opine if it's good or bad until there some data to support either outcome. I truly appreciate you sharing what you do, I just wish there was some way to know what you're trying to do and to know if you've achieved it.
It looks like there's some grass roots efforts to put some numbers/data behind head porting modifications - hopefully you're willing to be a part of that to advance the technical knowledge of the club.
Again, not about the actual topic, but still probably someone finds this interesting around the subject.
As diesel flow numbers are hard to find, I have collected some stock head flow results on my web page:
http://npsheads.com/index.php/flow-database
Cummins lift is with inch scale, others are metric (sorry fellows).
I try to add new heads when I work on a such and remember to add on list. =)
Flow numbers are not really the last word or most important thing when it comes to cylinder heads.
I have seen over 100hp difference in same BBC engine with head swap only when flow numbers were identical.
Also I just fixed seat work to one SBF engine where I ported heads few years back and someone else had refurbished the head..
It lost ~2% of flow after I "fixed" the seats and gained ~50hp being back to 830hp.
Flow is just a one design parameter to help to evaluate and calculate head efficiency, but does not have much to do with HP if other parameters, especially cross section area are not considered and designed as a one working system.
As diesel flow numbers are hard to find, I have collected some stock head flow results on my web page:
http://npsheads.com/index.php/flow-database
Cummins lift is with inch scale, others are metric (sorry fellows).
I try to add new heads when I work on a such and remember to add on list. =)
Flow numbers are not really the last word or most important thing when it comes to cylinder heads.
I have seen over 100hp difference in same BBC engine with head swap only when flow numbers were identical.
Also I just fixed seat work to one SBF engine where I ported heads few years back and someone else had refurbished the head..
It lost ~2% of flow after I "fixed" the seats and gained ~50hp being back to 830hp.
Flow is just a one design parameter to help to evaluate and calculate head efficiency, but does not have much to do with HP if other parameters, especially cross section area are not considered and designed as a one working system.
bmali98
Veteran Member
Hey. Since we're off topic now, I have two questions.
Since we're talking porting I'm guessing intake design is more important. what would be the best design? I was recently googling " dual plenum" manifolds and thought that design would lend best for a smooth strait flow and velocity.
I noticed the heads spin the air in different directions( clockwise and counter) at the intake valve. Each paired cylinders spin left and right handed. I wonder if this is for convenient port location
or
is this to counter the Coriolis effect so you have the same power regardless of which side of the equator you are. Would turning the other two in the other direction benefit?
Good videos above.
Since we're talking porting I'm guessing intake design is more important. what would be the best design? I was recently googling " dual plenum" manifolds and thought that design would lend best for a smooth strait flow and velocity.
I noticed the heads spin the air in different directions( clockwise and counter) at the intake valve. Each paired cylinders spin left and right handed. I wonder if this is for convenient port location
or
is this to counter the Coriolis effect so you have the same power regardless of which side of the equator you are. Would turning the other two in the other direction benefit?
Good videos above.
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note the position of the valve in the cylinder, they're all toward the... 'inboard' side of the cylinders, thus the two in front swirl the opposite of the rear two.
bmali98
Veteran Member
1342 oh no.
LLRR!! That's even worse!.. I think.
And I thought it was only LRLR for a sec there.
Edit: I realize about the port position in the cylinder. Vw could have designed the head and manifolds so all intake ports are on the front or rear of the cylinder but they didn't. It was a stupid question that was only relevant because of there possibly( but not likely, I dunno) being an advantage to having all if the ports swirl in the same direction as to take advantage of the Coriolis effect.
LLRR!! That's even worse!.. I think.
And I thought it was only LRLR for a sec there.
Edit: I realize about the port position in the cylinder. Vw could have designed the head and manifolds so all intake ports are on the front or rear of the cylinder but they didn't. It was a stupid question that was only relevant because of there possibly( but not likely, I dunno) being an advantage to having all if the ports swirl in the same direction as to take advantage of the Coriolis effect.
Last edited:
Digital Corpus
Top Post Dawg
No one else has seemed to say anything so I will: THANK YOU!
interesting how he puts tubes in there. Makes me wonder which head bolt hole is the one the oil runs through.
Houpty GT
Veteran Member
It is an interesting trick that lets them take the porting to the maximum. I had never heard of it before.interesting how he puts tubes in there. Makes me wonder which head bolt hole is the one the oil runs through.
andy2
Veteran Member
- Joined
- Sep 24, 2004
- Location
- Bowmanville,Ontario,Canada
- TDI
- 13 Jetta,94 Golf drag car 585bhp,Samurai buggy BHW 300bhp,97 Ram cummins
I'm pretty sure that there is no need to tube the #2/#3 intake port or possibly any of them as there is no oil drain/supply to worry about.
Yeah, on looking the oil carrying head bolt hole is toward the front of the head
The aluminum's prolly soft enough to get a good seal, but if you had studs with nuts they might leak a little oil down the threads. Hole into the block's blind. Easy enough to install the nuts with pipe dope like you would on any bolt that goes into the water jacket.
CNGVW
Vendor , w/Business number
- Joined
- Sep 15, 2009
- TDI
- Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
Its a old trick for some small block Chevy and Ford heads.
Why you need a tube is engines under vacuum, the engine can pull oil down under the head bolts and under boost can push air up into the top of the valve cover.
That old timer did a good job but we still need good data from that head.
He did a lot of cutting and took out all the swirl .
I still would like to see data on is swirl needed for our high HP engine??
Why you need a tube is engines under vacuum, the engine can pull oil down under the head bolts and under boost can push air up into the top of the valve cover.
That old timer did a good job but we still need good data from that head.
He did a lot of cutting and took out all the swirl .
I still would like to see data on is swirl needed for our high HP engine??
Franko6
Vendor , w/Business number
This will make you think...is it all about CFM? I think it is as much about air speed.
Here is a Rottler Veicomer 5-axis machine doing it's magic 'golf ball' dimpling ports in a cylinder head.
https://www.youtube.com/watch?v=iKbmrQIQOr0
In this next video, watch flow numbers improve from polished port to wavy port to dimpled port on a Honda cylinder head... at lower valve heights and lower port air speeds, wavy or dimpled ports don't improve flow. As a matter of fact, the dimpled port becomes worse at lower valve heights. But at the upper reaches of valve height, way beyond what I believe is reasonable for a TDI, the numbers for dimpling increase dramatically.
https://www.youtube.com/watch?v=U6v2wpk4mjo
The purpose in the dimpling is to reduce the size of the vortices. Every wall has drag and lanier flow happens above the turbulence caused by every surface. To say it another way, every surface has drag. If you make the vortices smaller and closer to the surface, the intent is increased flow. Depending on another factor that is missing from a pure flow number, air speed, the benefit of vortice dimpling will change dramatically at higher air speed in the port.
Here is a Rottler Veicomer 5-axis machine doing it's magic 'golf ball' dimpling ports in a cylinder head.
https://www.youtube.com/watch?v=iKbmrQIQOr0
In this next video, watch flow numbers improve from polished port to wavy port to dimpled port on a Honda cylinder head... at lower valve heights and lower port air speeds, wavy or dimpled ports don't improve flow. As a matter of fact, the dimpled port becomes worse at lower valve heights. But at the upper reaches of valve height, way beyond what I believe is reasonable for a TDI, the numbers for dimpling increase dramatically.
https://www.youtube.com/watch?v=U6v2wpk4mjo
The purpose in the dimpling is to reduce the size of the vortices. Every wall has drag and lanier flow happens above the turbulence caused by every surface. To say it another way, every surface has drag. If you make the vortices smaller and closer to the surface, the intent is increased flow. Depending on another factor that is missing from a pure flow number, air speed, the benefit of vortice dimpling will change dramatically at higher air speed in the port.
1998TDIMonster
Veteran Member
http://s578.photobucket.com/user/adam3797/library/Dimple%20and%20Spiral%20cut%20port
Here are some interesting photos from some Mopar guys running the 5.7L and 6.1Ls claiming 1-2% increases in profile versus spiral cut cnc machines. Claims of 340hp spiral cut to 343-347 whp from the dimples. Not too shabby. Are there any Tdi's running these dimpled heads and/or intakes?
Here are some interesting photos from some Mopar guys running the 5.7L and 6.1Ls claiming 1-2% increases in profile versus spiral cut cnc machines. Claims of 340hp spiral cut to 343-347 whp from the dimples. Not too shabby. Are there any Tdi's running these dimpled heads and/or intakes?
Are you sure about this? usually dimples or rills or any other form of vortex generation features are used to put more 'energy' or turbulence in the boundary layer and cause the flow to stick better to the surface, despite a minor increase in pure 'drag', you see this for example on roof tops of wrc car and on planes upstream of control surfaces, like stabilizer and ailerons. the dimples on a golf all serve same use, you create a better 'sticking' airflow around the ball causing less of a vacuum behind the ball.
these dimples could serve maybe at inner radius of 8v exh port to make the flow stick more to this surface and thereby creating a bigger 'effective' troat
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Franko6
Vendor , w/Business number
Yes, I am quite sure. We might be using different terms to mean the same thing, but the point is to create a boundary layer closer to the wall. The basic rule for any flow is all walls have drag and create turbulence. Reducing drag is controlling the turbulence. The dimpling makes the unavoidable turbulence closer to the surface.
If you look at the numbers, it requires higher velocities before the value of dimpling is apparent; at least when considering the Honda gasoline engine. Also, 13mm lift is rather impressive.
However it happens, the mid-range shown for this particular engine, the dimpling loses CFM over a rilled or polished port.
I have had experience with drain problems with large tanks. It is amazing how a vortex into a 4-8" drain will slow the emptying of a 40,000 gallon tank, sometimes in excess of 20%. We found great advantage to adding vortex breaking plates at the opening of the port. It is hard to understand how the physics could be so different whether spinning air into an air intake or liquid down a drain.
If you look at the numbers, it requires higher velocities before the value of dimpling is apparent; at least when considering the Honda gasoline engine. Also, 13mm lift is rather impressive.
However it happens, the mid-range shown for this particular engine, the dimpling loses CFM over a rilled or polished port.
I have had experience with drain problems with large tanks. It is amazing how a vortex into a 4-8" drain will slow the emptying of a 40,000 gallon tank, sometimes in excess of 20%. We found great advantage to adding vortex breaking plates at the opening of the port. It is hard to understand how the physics could be so different whether spinning air into an air intake or liquid down a drain.
Fix_Until_Broke
Top Post Dawg
That's some cool looking stuff. I agree that it's not all about CFM. I'm guessing that swirl and tumble make a big difference in most everything except maximum effort (and they're important there as well, but I'm guessing that maximum effort does not care about smoke or transient response, etc).
So to pose a question - how do we evaluate what something like dimples or waves (or porting, or cams, etc) does to overall engine performance? What is gained, what is lost, etc?
So to pose a question - how do we evaluate what something like dimples or waves (or porting, or cams, etc) does to overall engine performance? What is gained, what is lost, etc?
andy2
Veteran Member
- Joined
- Sep 24, 2004
- Location
- Bowmanville,Ontario,Canada
- TDI
- 13 Jetta,94 Golf drag car 585bhp,Samurai buggy BHW 300bhp,97 Ram cummins
Seems to me that some of the cam/porting business is being sold as snake oil.You just have to believe and have faith that your very own butt dyno agrees with the investment made.
john.jackson9213
Top Post Dawg
And there is the "placebo effect" of having spent $XXX. That surely changes the butt dyno.
Measuring the Quantifiable changes is the real gold standard for any engineering exercise. So the issue is how to measure and what the margin of error is for your measurement system.
Agree with you. Some of the cam/porting business is somewhat like snake oil sales. The exact, precise change/benefit can be very marginal at best, but "pumped up" to be larger, more important than it is for a daily driver.
newlitemotorist
Veteran Member
Those videos are a joke! Do NOT do what that guy did. Unless I missed it, he makes no mention of increasing valve size or lift. Port volume needs to be appropriately matched to the flow capabilities of the valve as well as the intended rpm range. The valve curtain is the total area under the valve at a given lift and is determined by the valve diameter as a fixed variable. From min to max lift, the valve curtain will only flow so much air. The key is to keep the port volume low enough to take advantage of higher air velocity without choking the potential flow of the valve. What that guy did was hog the crap outta the ports because "bigger is better" but with his total disregard to the valve curtain he effectively killed the efficiency of those ports with how much volume he added.