Joey Mitchell

Ok, I am almost done with a light porting on this z6 head I've been working on and it hit me... Should I gasket match??? There is a decent amount of material on both exhaust and intake side that could come out. I plan on keeping it na, it's going on a y7 block, and I'm shooting for high compression. Understand, this is a labor of love, and if it helps any, I'm going to do it. Please don't give me, "don't waste your time, just engine swap" or some junk like that. If it makes any posative difference at all, I will do it. I just want to know if anyone here has had experience with gasket matching a d series head, and if it will have any negative effect on performance. Should I may one side and not the other? Both? Neither? I want this thing to flow as preficient as possible, but I don't want to screw up this head. Thanks in advance.

TomCat39

I'm curious to know what research you have done regarding runner size, length and intake manifolds etc.

The reason I ask is bigger isn't always better.

From what I understand, changing runner sizing shifts the power band but doesn't necessarily add anything and sometimes you lose a bit.

JRCivic1

You are absolutely right TomCat... chances are really good that anything you do to a Z6 cylinder head will likely reduce performance somewhere in the power band when being used in a naturally aspirated application. Usually this occurs in the low to mid range... and peak power remains unchanged. Gasket matching reduces velocity... and reduced velocity reduces volumetric efficiency.

Joey Mitchell

Well, i have done a ton of research on porting and polishing, and gasket matching as well, mostly pretaining to d series engines. However, Ive not done any on runner/port size. Honestly didn't know or think that the information was out there. I will try to research it tonight, if I can find anything this would be exactly the info I'm looking for. That was my biggest fear, that by opening up the ports I may lose something. Ive been talking to alot of Honda guys on this subject, and most say they have felt noticeable gains from Port matching and porting runners. I know without a flow bench you are going at this blind, but I don't plan on taking much of anything from the combustion chamber or runners, and if I gasket match I will feather that into the exsisting port size in the first inch or so of the runner. Almost like a funnel, to funnel the air into and out of the runners.

TomCat39

There is only bits and pieces of information out there. I was trying to research formulas for engine building purposes and ran into a snag when it came to intake theory.

Here is some of the bits and pieces... Long small runners build velocity in the air, fat runners have more air volume but at slower velocity (speeds).

Also on the subject of flow benches, guys have opened their IM's so the flow bench shows higher flow rates through them (fatter openings, runners etc. But when dyno'd the car lost power as the velocity was also impacted. I learned the flow bench is only a part of the equation and does not represent a full picture. I also learned the theory behind it all is fluid dynamics or fluid physics which is one of the most complicated maths around. The same maths used to calculate weather systems etc.

I think it's great you want to practice and learn about port and polishing, I just wanted you to not be disappointed if the results of your efforts actually go reverse of what you were/are hoping for.

Joey Mitchell

Wow... Really great information here... I really appreciate you sharing this with me. I know that this is kind of a shot in the dark, and unfortunately I haven't ran the z6 head on my y7 block so I won't really know if I did any good, bad, or if what work I do makes little difference. However, I find it very interesting that using a flow bench (which i won't even be using) is only part of the equation. That's why it's nice to hear from someone who has had actual physical experience doing this type of stuff. I will have to read your comments over and over to make sure I have the concept, because you really gave me a lot of very useful info. I will do some research on fluid Dynamics, which until tonight if never even heard of. I'm still going to toy around with this head, I'd hate to mess the head up, but it was a freebie so I wouldn't really be at a loss.. but maybe this will something I do in stages, removing only a small amount of material and running the head for a while, and then removing the head and doing a little more... Just so I can compare and see what's working best.. but again, thank you very much for sharing all of that knowledge with me. I'm sure it will serve me very well in my porting endeavors. Also, to try and get the most out of what i do to the head, I plan on upgrading the TB (prob from a b18b1), upgrading to larger cc injectors, a larger fuel pump, and I'm going to learn to and try my hand at tuning.. so this will be a HUGE learning experience for me. Lol. Is there anything else on top of what I listed that I should include to get the best results from my ported z6/y7 mini-frank? I will be using an adjustable timing gear as well to make sure no matter what my mechanical timing doesn't wind up being a half a tooth off or anything. Should I upgrade the fuel pressure regulator to allow for more fuel flow?

DaX

iTrader: (1)

I'm honestly not trying to be negative, but unless you're great with math and/or are studying engineering, doing internet research on fluid dynamics isn't going to get you very far. I'm a mechanical engineer and fluids was part of my BS engineering program, but at the undergrad level you barely scratch the surface. Deeper understandings are usually gained at the graduate levels. There are CFD software packages (like SolidWorks) that allow you to either create or import a model and run fluid simulations, but you'd still have to be able to accurately interpret the (simulated/theoretical) results and apply them to real world applications. To me, porting is one of those things I would just leave to the pros.

TomCat39

If you are doing your own tuning, that will tell you what you need for each change.

If you are porting before learning how to tune, you are doubly blind and will have no clue what the car needs until you learn how to tune.

I'd suggest learning to tune before you change anything, then start your changes/porting so you can retune each step of the way.