High Flow, Low Cost, 8V Cylinder Head Project
06-10-2012, 12:16 PM
#31
Rennlist Member
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.
06-10-2012, 12:25 PM
#32
Professional Hoon
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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.
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.
06-10-2012, 12:45 PM
#33
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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.
i was thinking more like 350 rwhp with 21 and a half instead of 22. numbers like that.
06-10-2012, 12:47 PM
#34
Race Car
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.
06-10-2012, 12:57 PM
#35
Race Car
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
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
06-10-2012, 12:59 PM
#36
Rainman
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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.
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.
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.
06-10-2012, 01:22 PM
#37
Nordschleife Master
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.
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.
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.
06-10-2012, 02:00 PM
#38
Race Car
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.
Every racing engine I have seen had smooth ports.
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.
06-10-2012, 02:40 PM
#39
Nordschleife Master
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.
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.
. Even that "old" technology is unbelievable.
06-10-2012, 02:52 PM
#41
Rennlist Member
Thread Starter
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.
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.
06-10-2012, 04:20 PM
#42
Race Car
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.
. Even that "old" technology is unbelievable.
06-10-2012, 11:01 PM
#44
Rennlist Member
Thread Starter
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.
06-11-2012, 12:28 AM
#45
Race Car
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.