High Flow, Low Cost, 8V Cylinder Head Project - Page 3 - Rennlist - Porsche Discussion Forums

High Flow, Low Cost, 8V Cylinder Head Project

Reply

Old 06-10-2012, 12:16 PM
  #31  
msalvatore
Addict
Rennlist Member
 
msalvatore's Avatar
 
Join Date: Mar 2011
Location: tewksbury, NJ
Posts: 86
Default

Pretty cool project good job on the valve source. I agree keep the surface a little rough. The small imperfections will help with the flow. As for the LS motor option, I agree best power to cost around. But I am not going to pollute my engine bay with a non-Porsche motor.
msalvatore is offline  
Reply With Quote
Old 06-10-2012, 12:25 PM
  #32  
Paulyy
Professional Hoon
Rennlist Member
 
Paulyy's Avatar
 
Join Date: Jan 2010
Location: Melbourne, Australia
Posts: 6,966
Default

Originally Posted by odurandina View Post
his work is beautiful. and it sounds terrible to say.... but on the matter of an improved head flow via porting; (short of a full racing program) with this particular engine, you're talking about fractions that can easily be handled purely via the turbine/wastegate. anything you do to the cylinder head would make only the slightest improvement, when all you have to do is increase boost. if he want's to go past what the turbine can theoretically do on it's own, and he isn't limited to 2.5 litres, then going to V8 is the fastest and least-expensive way to more power.
put it this way, id rather make 400 rwhp with 18 psi then 25 psi.
less boost, more power is the way to go.
that's where head work.. getting more air though the head.
this is where the head is a bottle neck by forcing the air to go in, where opening it up is going to allow more air to flow through with the same pressure.
Paulyy is offline  
Reply With Quote
Old 06-10-2012, 12:45 PM
  #33  
odurandina
Slayer of Economic Optimism

Rennlist Member
 
odurandina's Avatar
 
Join Date: Oct 2009
Location: one thousand, five hundred miles north of Ft. Lauderdale for the summer.
Posts: 26,986
Default

if that's true, then that would be sick.

i was thinking more like 350 rwhp with 21 and a half instead of 22. numbers like that.
odurandina is offline  
Reply With Quote
Old 06-10-2012, 12:47 PM
  #34  
67King
Super User
 
67King's Avatar
 
Join Date: Apr 2009
Location: Knoxville, TN
Posts: 3,641
Default

Originally Posted by m73m95 View Post
But to overcome the boundary layer, you need actual disruption of the air. A golf ball isn't just "rough". It has dimples.

The air just simply flows over a rough surface.
You don't "overcome" a boundary layer. It is there any time air flows. The size of it depends on the surface texture, the velocity, and the density of the fluid (note that is relative - air relative to, say, crude petroleum - so there is no notable difference in naturally aspirated or FI applications). And to make air change directions, a thicker boundary layer is better. Disrupt was probably a poor choice, but that's the term that is often used in fluid dynamics when you are talking about making a fluid turn a corner. The typical demonstration is smoke in a chamber with a turn, which shows the vena contracta, comparied with putting a wire on the floor of the champer, which increases the size of the boundary layer in that spot, which allows the air to "stick" to the floor and avoid the vena contracta. There is a WHOLE lot more going on that "air just simply flowing over rough surfaces."

This is the guy who lectures at Ford to the guys who do port work: http://engine.osu.edu/ He is a gret professor, if you want to learn more, go read his stuff.

Interestingly, had some friends working on the new Ford 6.2L several years ago make a bet, one thinking that a dimpled surface would flow well, so they mocked one up and perform CFD. It increased drag drastically, and flowed like crap.
67King is offline  
Reply With Quote
Old 06-10-2012, 12:57 PM
  #35  
67King
Super User
 
67King's Avatar
 
Join Date: Apr 2009
Location: Knoxville, TN
Posts: 3,641
Default

By the way, one needs to be careful with valve sizing. Just throwing bigger valves in something may be an old hot rod trick, but it changes your turning, and slows down the air (at a given RPM). You need to have an intake system designed to allow the engine to breathe at the right RPM for the valve size you stick in there. I'm going off of memory, but when I was messing with a different 2.5L engine (stroked Ford 2.3L), I ended up using 47mm intake valves for peak power at 6500RPM, but had to drastically shorten the intake runners to, going off of memory, 13 or so inches for peak torque near 5250.

Here's some work I did on a 3.0L BMW. Red is before, blue is after. Changed the intake and increased valve size very slightly. Point being it is a system approach. This was with minimal tuning, it now makes 358RWHP. https://www.facebook.com/media/set/?...1250448&type=3
67King is offline  
Reply With Quote
Old 06-10-2012, 12:59 PM
  #36  
V2Rocket
Rainman
Rennlist Member
 
V2Rocket's Avatar
 
Join Date: Jan 2007
Location: Alta Loma, CA
Posts: 40,698
Default

Originally Posted by msalvatore View Post
But I am not going to pollute my engine bay with a non-Porsche motor.
Porsche already did that with the 924

Originally Posted by Paulyy View Post
put it this way, id rather make 400 rwhp with 18 psi then 25 psi.
less boost, more power is the way to go.
that's where head work.. getting more air though the head.
this is where the head is a bottle neck by forcing the air to go in, where opening it up is going to allow more air to flow through with the same pressure.
+400
Originally Posted by odurandina View Post
if that's true, then that would be sick.

i was thinking more like 350 rwhp with 21 and a half instead of 22. numbers like that.
boost numbers get higher with the more work that has to be done to get the air in/out of the motor. it is not uncommon on prettymuch any forced-induction car to see boost drop with the same or better power output by opening exhaust up or cleaning intake side.
V2Rocket is offline  
Reply With Quote
Old 06-10-2012, 01:22 PM
  #37  
m73m95
Super User
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,099
Default

Originally Posted by 67King View Post
You don't "overcome" a boundary layer. It is there any time air flows. The size of it depends on the surface texture, the velocity, and the density of the fluid (note that is relative - air relative to, say, crude petroleum - so there is no notable difference in naturally aspirated or FI applications). And to make air change directions, a thicker boundary layer is better. Disrupt was probably a poor choice, but that's the term that is often used in fluid dynamics when you are talking about making a fluid turn a corner. The typical demonstration is smoke in a chamber with a turn, which shows the vena contracta, comparied with putting a wire on the floor of the champer, which increases the size of the boundary layer in that spot, which allows the air to "stick" to the floor and avoid the vena contracta. There is a WHOLE lot more going on that "air just simply flowing over rough surfaces."

This is the guy who lectures at Ford to the guys who do port work: http://engine.osu.edu/ He is a gret professor, if you want to learn more, go read his stuff.

Interestingly, had some friends working on the new Ford 6.2L several years ago make a bet, one thinking that a dimpled surface would flow well, so they mocked one up and perform CFD. It increased drag drastically, and flowed like crap.
The boundary layer is always there. However, you can manipulate its size, and effects.

Yes. I realize that you can use the boundary layer to help the flow of air, rather than hinder it. You can slow the air in the inside of the curve in the port, to help the air turn. However, working in broad generalizations (since cylinder head work is one of the best kept secrets in racing, and no one here is Robert Yates) keeping a smooth port is best.

And, for the green portion of what I quotes..... OMG YES!! LOL. Fluid dynamics is unbelievably complicated, that won't be solved in an internet forum. I got interested in it from watching F1, and now its kind of a hobby. Its one of those things that, the more you learn, the more you figure out you don't know. Knowing what little I do, I know that I know very little about it.

The initial conversation was "rough" vs "smooth"....as a whole. I still say, without being Ross Braun or Robert Yates, that smooth will give greater benefit than rough...as a whole. I know, there are areas that SHOULD be rough, but by making the entire port rough, you're eliminating the advantage you would have made by only making the needed sections rough...and hurting air flow/speed as a result. Am I right in that thought?

Every racing engine I have seen had smooth ports.
m73m95 is offline  
Reply With Quote
Old 06-10-2012, 02:00 PM
  #38  
67King
Super User
 
67King's Avatar
 
Join Date: Apr 2009
Location: Knoxville, TN
Posts: 3,641
Default

Originally Posted by m73m95 View Post
I know, there are areas that SHOULD be rough, but by making the entire port rough, you're eliminating the advantage you would have made by only making the needed sections rough...and hurting air flow/speed as a result. Am I right in that thought?

Every racing engine I have seen had smooth ports.
I think we are way beyond crap that should be posted on a message board, and I think we are on the same page rather than different ones, semantics notwithstanding. Yes, you are right, you want the lowest loss total you can have, and that means as few rough sections as possible. For similar reasons, you actually want to shape the port differently in different sections, too.

Anyway, the conversations I'd have in a professoinal environment versus a forum are differrent. Like you said, it is extremely complicated, and people generally take a snippet and run wiht it.

As far as the race engine and its ports, that goes back to what I said in my first post - it depends. A purpose built race engine like an F1 one (have you ever gotten your hands on an F1 head!? Great googly-moogly. Was lucky to get my hands on one of the Jag ones when I was at Ford) will have very different ports than a production based race head. The more the port lays down, the rougher you need the ports.

Good for you for picking up this stuff as a hobby! I had no need for most of the stuff I learned when I was at Ford, but I was a bit like you, and wanted to, so it was initially largely self taught, albeit with some great mentors at my disposal (then I started using it when folks realized I knew what I was doing). There are far too many people, at every level, that just want a cook book, and don't want to learn the details behind why.
67King is offline  
Reply With Quote
Old 06-10-2012, 02:40 PM
  #39  
m73m95
Super User
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,099
Default

Originally Posted by 67King View Post
I think we are way beyond crap that should be posted on a message board, and I think we are on the same page rather than different ones, semantics notwithstanding. Yes, you are right, you want the lowest loss total you can have, and that means as few rough sections as possible. For similar reasons, you actually want to shape the port differently in different sections, too.

Anyway, the conversations I'd have in a professoinal environment versus a forum are differrent. Like you said, it is extremely complicated, and people generally take a snippet and run wiht it.

As far as the race engine and its ports, that goes back to what I said in my first post - it depends. A purpose built race engine like an F1 one (have you ever gotten your hands on an F1 head!? Great googly-moogly. Was lucky to get my hands on one of the Jag ones when I was at Ford) will have very different ports than a production based race head. The more the port lays down, the rougher you need the ports.

Good for you for picking up this stuff as a hobby! I had no need for most of the stuff I learned when I was at Ford, but I was a bit like you, and wanted to, so it was initially largely self taught, albeit with some great mentors at my disposal (then I started using it when folks realized I knew what I was doing). There are far too many people, at every level, that just want a cook book, and don't want to learn the details behind why.
HA! The Wynn has a Ferrari dealer in it. They sell old, used F1 parts. They have a v10 Ferrari F1 engine for sale ($20k IIRC). I looked at it for an hour, with my small maglight, and strange looks from the people working there . Even that "old" technology is unbelievable.
m73m95 is offline  
Reply With Quote
Old 06-10-2012, 02:44 PM
  #40  
V2Rocket
Rainman
Rennlist Member
 
V2Rocket's Avatar
 
Join Date: Jan 2007
Location: Alta Loma, CA
Posts: 40,698
Default

Originally Posted by m73m95 View Post
HA! The Wynn has a Ferrari dealer in it. They sell old, used F1 parts. They have a v10 Ferrari F1 engine for sale ($20k IIRC).
will it fit in an NA?
V2Rocket is offline  
Reply With Quote
Old 06-10-2012, 02:52 PM
  #41  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,311
Default

Originally Posted by robstah View Post
Well, rough is relative. I would actually try and match the finish of the inside of the intake. Based off of the castings, that might be pretty hard, so a machined surface should be alright.

The boundary layer is still in effect and can make a difference with spooling characteristics and low end torque, which you will be losing a bit due to the bigger port sizes.

While I do enjoy this project, I do worry about the possible loss of low end torque and driving manners just for the kick in higher horsepower.
I appreciate your feedback Rob. Been following closely your axle and suspension threads and always carefully consider your input. But don't worry too much for me, I do all this for FUN. For me FUN is grinding away in my shop or reading article after article about head porting. I find it to be a BLAST. Also, this head is not going on my current motor. I have a solution for the loss of torque. I in no way plan on giving up my low end performance.
refresh951 is offline  
Reply With Quote
Old 06-10-2012, 04:20 PM
  #42  
67King
Super User
 
67King's Avatar
 
Join Date: Apr 2009
Location: Knoxville, TN
Posts: 3,641
Default

Originally Posted by m73m95 View Post
HA! The Wynn has a Ferrari dealer in it. They sell old, used F1 parts. They have a v10 Ferrari F1 engine for sale ($20k IIRC). I looked at it for an hour, with my small maglight, and strange looks from the people working there . Even that "old" technology is unbelievable.
They used to cast the F1 heads in one of Ford's labs in Windsor, CA. Can't recall the name of it, Casting Research Center, maybe? Anyway, I was doing cylinder head work back then, and had to go there for some reason, and got to, I think "grope" is probably a good word!, the head.
67King is offline  
Reply With Quote
Old 06-10-2012, 04:21 PM
  #43  
m73m95
Super User
 
m73m95's Avatar
 
Join Date: Dec 2007
Location: Las Vegas, NV
Posts: 7,099
Default

Originally Posted by V2Rocket_aka944 View Post
will it fit in an NA?
You could fit 2 of them in an NA. They are so small, for the power they put out.
m73m95 is offline  
Reply With Quote
Old 06-10-2012, 11:01 PM
  #44  
refresh951
Moderator
Rennlist Member
Thread Starter
 
refresh951's Avatar
 
Join Date: Jun 2010
Location: Marietta, Georgia
Posts: 3,311
Default

This head in this picture was done for Alain by Parker in Canada. Anyone know anything about it. Looks like something is going on around the intake valves in the chamber but hard to tell.

refresh951 is offline  
Reply With Quote
Old 06-11-2012, 12:28 AM
  #45  
67King
Super User
 
67King's Avatar
 
Join Date: Apr 2009
Location: Knoxville, TN
Posts: 3,641
Default

By the way, I should also advise you that you need to make sure those are 1 piece valves. The majority of cheap valves are 2 piece, where the head is friction welded to the stem. Not as big of a deal in an NA application, but there's a lot more heat in a boosted application.
67King is offline  
Reply With Quote

Thread Tools
Search this Thread

Contact Us Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: