I don't know that this forum is really appropriate, but it's really the only one I frequent here...so I'll post it. I guess it's not too far off base.

I'm working on an intake manifold and figured I'd post a few pics of the polishing work...so here they are:




You can tell that I don't like to see scratch marks from some 80 grit abrasive. Personally, I don't feel that 80 grit is polished.

 

Oh Snap, jk. Damn thats looks great man!

 

looks super good! what tools did ya use? just wondering thanks

 

I have heard leaving a slightly rough texture on ports will reduce the boundary layer thickness and improve airflow. It would be interesting to see the power differences between parts polished as fine as that and parts left with a rougher finish. I doubt the differences would be even measurable outside of the normal power variations of a motor though.

What abrasives and polishing wheels do you use? Looks like a pretty finish.

 

Beat me to it. ^^^ nice work ^^^^ do some searching in the archives for porting and polishing. There was a great thread awhile back with Bisimoto in it about P&P. You should not be polishing the intake side.

Edit. you gotta think about it like a golf ball. the same principles apply. a smooth golf ball won't fly for ****. the dimples are what make it travel. think about it and you will realize how that applies to airflow on the intake side.

 

Looks like you took a 3m buff to it.As pretty as that is that is it is way too smooth for anything downstream of the injectors , 80 grit works just perfect as it leave a real nice honed finish. Hell you don't even have to use a 80 cartridge roll as if you're good with a porting bit they nice finishes on their own. Most of the time a finish is done like that for the customer as it "looks pretty" and most wouldn't pay big bucks for head work if they saw how it looks before ther polish.

Are you using a air or electric die grinder?


Modified by essex at 5:59 PM 1/7/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silly4lude &raquo;</TD></TR><TR><TD CLASS="quote">You should not be polishing the intake side. </TD></TR></TABLE>
So you think that polishing is only for the exhaust side? ummm don't you think that the exhaust has to flow at least what the intake does?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silly4lude &raquo;</TD></TR><TR><TD CLASS="quote">Edit. you gotta think about it like a golf ball. the same principles apply. a smooth golf ball won't fly for ****. the dimples are what make it travel. think about it and you will realize how that applies to airflow on the intake side. </TD></TR></TABLE>
Why think of it that way, when a ball is an item moving through air, and this is a case of air moving through an opject?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chillinit &raquo;</TD></TR><TR><TD CLASS="quote"> it is my understanding that an extremely smooth surface finish on an intake manifold it not a benefical thing. You want some roughness inorder to achieve a good burn in the combustion chamber. A little roughness allows the intake charge to mix properly with the fuel. </TD></TR></TABLE>
I think that in many cases, people use this theory as an excuse for not taking the time or having the ability to do better work. In most intake manifold applications these days, there is no fuel present. In other words, there is no fuel that contacts this area. The fuel is injected directly at the head. The injector mounts on the intake, but the tip actually sticks into the head's intake port.

The THEORY on having this turbulent layer of air: the slight roughness makes small amounts of turbulence at the outer edges of airflow. This means that velocity is greatest here and it helps to keep fuel from puddling on the surface. Some builders have said that the proper thing to do is to slick polish everything up to the point of fuel injection, then leave it a little rough.

Personally, I doubt you'd see any increase by leaving things rough.

There's a reason they don't make pipe with rough internals...cause it doesn't flow as well!!
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by essex &raquo;</TD></TR><TR><TD CLASS="quote">Looks like you took a 3m buff to it.</TD></TR></TABLE>
and a lot more.... those 3m scotchbrite wheels won't put a shine on it like I wanted. I use a couple of air die grinders.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Engloid &raquo;</TD></TR><TR><TD CLASS="quote">So you think that polishing is only for the exhaust side? ummm don't you think that the exhaust has to flow at least what the intake does?

Why think of it that way, when a ball is an item moving through air, and this is a case of air moving through an opject?

I think that in many cases, people use this theory as an excuse for not taking the time or having the ability to do better work. In most intake manifold applications these days, there is no fuel present. In other words, there is no fuel that contacts this area. The fuel is injected directly at the head. The injector mounts on the intake, but the tip actually sticks into the head's intake port.

The THEORY on having this turbulent layer of air: the slight roughness makes small amounts of turbulence at the outer edges of airflow. This means that velocity is greatest here and it helps to keep fuel from puddling on the surface. Some builders have said that the proper thing to do is to slick polish everything up to the point of fuel injection, then leave it a little rough.

Personally, I doubt you'd see any increase by leaving things rough.

There's a reason they don't make pipe with rough internals...cause it doesn't flow as well!!

and a lot more.... those 3m scotchbrite wheels won't put a shine on it like I wanted. I use a couple of air die grinders.</TD></TR></TABLE>


wow..
glad to see someone on honda-tech who knows what they are talking about. Ever use a eletric die grinder, i do all my headwork in my room =\

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by menkio &raquo;</TD></TR><TR><TD CLASS="quote"> i do all my headwork in my room =\</TD></TR></TABLE>
If you saw the mess in my garage from all the aluminum shavings, you'd know why I don't to these in the house I had to put rugs on the inside and outside of the door going into the garage to help keep from tracking that stuff in the house.

 

that is some beautiful work. I wish my intake would of come out that smooth when I polished it.

 

Looks like you couldve used down to 320 abrasive cartidge rolls to do that nice of a job then possibly buffed it with a small buffing bit

 

looks good.

as far as the golf ball comment and it needs to be rough.. BS. Excuse for lazyness.

Why arent the cars that run at the salt flats all dimpled up to go faster.. smoother.. and have less resistance?

If you knew ANY science behind why a golf ball has dimples you wouldnt have said that, its more then just a smooth golf ball won't fly for ****.... Sniper bullets sure are smooth? They fly a hell of alot better then a golfball.

Just because 'bisi' said you dont need it dosent make it right.. I could be the presedent and at what everyone thinks is a higher level and say that the earth is flat.. would you belive me if you were uneducated on the topic..

 

looks very nice!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HamiltonRex &raquo;</TD></TR><TR><TD CLASS="quote">

Why arent the cars that run at the salt flats all dimpled up to go faster.. smoother.. and have less resistance?


</TD></TR></TABLE>
I remember watching the discovery channel with some tests about cars with dimples all over the body, it was some baller company that did the testing, in the end it was only used under the car because it wasn't pleasing to the eyes.

I'm pretty sure if people could afford it all saltflat cars would be dimpled from what that program said, I can't find what it was but I’m 100% sure cars with dimples&gt; cars w/o.

I go with the old school and say there is such thing as to smooth in port work, What is that thing going on, I can't make it out. Get some power numbers and prove people wrong... or right.

 

i dont see how the golf ball thing applys to this. Golf ***** are dimpled to help them go farther, because the air resistence gives them lift.

 

#1 it's not BS
#2 it has nothing to do with lazyness.
#3 the golf ball theory does apply.
#4 you are right about it being MORE important downstream of the injectors.

I am in no way saying that it is supposed to be as dimpled as a freakin golf ball. a slightly rough texture like an 80 grit roll produces is fine. do a little searching and talk to people who port for a living. I didnt just "hear" it from bisimoto and take it as truth. I've personally sat and talked to a circle track engine builder about head porting. Now dont go off on a tangent and say that it doesnt apply because it's from a domestic car point of view. engines are engines. this theory does apply to import engines as well. now that i've said that dont just take my word for it. do your research and come to your own conclusions.

http://www.theoldone.com

there is a small mention of the rough texture on the intake runner side in this article on the porting of an h22a head.

another linky

http://www.d-series.org/forums...=5553
on another note- the texture is by far secondary to the actual shape of the ports/intake runners. just roughing it up will not do a whole lot. but keep in mind every tiny gain is worth it when trying to extract NA power.

Hamilton- do not ever just call something i post BS. I know you from other sites. You might know me as 4sillypwr. I remember not to long ago you asked if your stripped out bellhousing to block bolt would cause an oil leak from you transmission. I didnt flame you and call you an idiot then. show some respect for someone who answered your questions when you knew oh so little. and i do know the science behind the dimples on a golf ball. i golf and i went to engineering school.

david aka 4sillypwr from the resource, ef-honda.com, cloudpump.net and every other honda board there is.

Modified by silly4lude at 12:46 AM 1/8/2005


Modified by silly4lude at 12:48 AM 1/8/2005

 

essentially the rough finish left on the intake sides is to create a turbulance so to say to help the gas and air mix better together befor it enters the chamber .. pre injector is not as important i belive .. but after injector is when the rough finish should be applied .. both head and intake mani .. not a casting rough but a 80grit flap wheel rought ..

comon guys .. honda_tunning shows this all the time

 

VG30....nissan?

 

there are two types of flow around an object: laminar and turbulent. Laminar flow has less drag, but it is also prone to a phenomenon called "separation." Once separation of a laminar boundary layer occurs, drag rises dramatically because of eddies that form in the gap. Turbulent flow has more drag initially but also better adhesion, and therefore is less prone to separation. Therefore, if the shape of an object is such that separation occurs easily, it is better to turbulate the boundary layer (at the slight cost of increased drag) in order to increase adhesion and reduce eddies (which means a significant reduction in drag). Dimples on golf ***** turbulate the boundary layer.

using that reasoning the only place that should remain turbulent is any area in a manifold or head that has something protruding out of it. Any other area is simply a guide to the air and since there's no objects moving within it (or air moving around an object) there's nothing for air to eddy up against. In the item pictured there is nothing for the air to move around, so there's nothing that would cause seperation and thus there is no reason for the section to be rough.

 

I think this discussion has gone beyond what it fitting for a welding and fabrication forum. While there are point for both sides of the argument i hope that everyone who is involved will decide to go and do the research needed to come to an intelligent decsicion about what to believe. it's a theory born of wet flow manifolds applied to the post injector area of a dry flow manifold. fuel atomization is the main goal here. there are so many variables to think about. if you care enough do some research on the differant types of injector spray patterns, injector placement and the like. While it may not provide huge gains at all remember that every little bit helps. the only beef i had with this thread was the bashing and having my post called BS.

so everyone have a great saturday and maybe you've been motivated to go and seek out some information.

on a side note this is kind of a NA thing anyway. but hey it's a free modification. free power ****** rocks in my book.

 

This is a case where if something looks nice, people are impressed, and therefore many assume it must work really well. Looks has nothing to do with it. Without before/after flowbench charts, it's meaningless.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kb58 &raquo;</TD></TR><TR><TD CLASS="quote">This is a case where if something looks nice, people are impressed, and therefore many assume it must work really well. Looks has nothing to do with it. Without before/after flowbench charts, it's meaningless.</TD></TR></TABLE>
I somewhat agree, as the gians of either method would likely not even be noticed, or would be som small that changes in humidity or ambient temp could be the difference. If you're porting your own head, appearance isn't all that important. However, when you're selling a product, appearance can be the difference in a person buying from you or buying elsewhere...in which case, appearance is everything.

As mentioned, without actual flow charts of each, the only thing that a person can judge the performance by is speculation, based on appearance... Which leads them to choosing between what they see with their own eyes, or something that some head porters claim works best. In the later, there will always be questions, as to whether these people are 100% honest, or if they leave the ports rough to save the time of a smooth polish. It's just part of life...everybody will doubt things they hear at times.

Personally, I can see arguments on both...but would be very interested in seeing a dyno of each, side by side, where a head was left rough, then pulled off and polished smooth and then dynoed again. If anybody has links or dyno comparisons or anything, post them up. I really think we have beat this horse, as far as our own opinions and logical explanations.

 

look guy just becase you go to home depot and buy a flaper wheel and run it in and out for 20min that dose not make you the master head porter you think you are ok

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fabman &raquo;</TD></TR><TR><TD CLASS="quote">look guy just becase you go to home depot and buy a flaper wheel and run it in and out for 20min that dose not make you the master head porter you think you are ok </TD></TR></TABLE>

You know, if person posts pics of their car, does that mean they're claiming to be a master detailer? does it mean they are claiming they have the nicest car?

Home Depot doesn't have flapperwheels that will polish that smoothly... and I never said I was a master of anything...

AND IT'S NOT EVEN A HEAD!! You weren't the brightest kid on the short bus were you?

 

What kind of boring head do you have?