Porting 96+ heads, worth it?

[DreX]

I just wondering if worth to port the 96+ heads?

Any estimate in gains?

I have some pics of mines with the ususal black residue fromt he exaust. If want me to post them let me know.

Thanx
DreX

[SappySE107]

Im sure its worth it, though I don't have any idea on the actual gains. Oh, but you can ask galen exactly how to port it, cause he knows everything about head porting and puts me to shame. Hahahahaha. Sorry, couldn't resist. The exhaust side probably doesnt need anything more than a bowl blend and clean up the casting marks. You could raise the roof/remove the guides some and get more flow, but I dunno how useful that would be on those heads.

[Galen]

I wouldn't know if I my porting would outperform yours or not...but your first sentence seems to be your most accurate post on porting I have seen yet. Get your flowbench running to where you can do some testing using an actual scientific instrument instead of the butt-o-meter!

Galen

[Juglenaut]

Does NOT play well with others!!!!

Galen

Obviously.

[RednBlack]

For Sale: 1 "Butt-O-Meter". Only used on about 30 cars. Apparently doesn't work.

[34T]

For Sale: 1 "Butt-O-Meter". Only used on about 30 cars. Apparently doesn't work.

hey, Ben
I have one that has been used on........oh.....about 46 if memory serves me right.... but I am kinda attached to it.......


I have done a fair bit of porting and polishing in the past (albeit the "unscientific method"....) and the polish I think will be a biggie with these particular heads. The ports go on for days as it is.... they are BIG. So concentrate on getting rid of the little bumps and imperfections and making them shiny everywhere you can possibly reach. The smoother you can make the airflow path the better; and go as far as you can reach or have the patience to do.
Maybe a bit of perspective:
I think that anyone who experiences a really good (oops, wrong word? ) "port and polish" will understand just how effective it is. Granted, mine were not done with a flow bench, either.. but just what is it that we are after here? Do you want to see how good a job you can do or is this for a classed racer that has to have the last 1.75 hp squeezed out of it to get that 3 foot edge at the end of a .75 mile straightaway?

The very first set I ever did was about '85 and those iron SBC heads are STILL doing great. The owner unbolts the headers each fall, wipes inside the exh port with a rag and presto! all the carbon is gone (aGAIN!). That little 350 in my Formula Firebird would blow away my brother's 455 TransAm and it wasn't even CLOSE. Again, there were a few other mods but that was only a 600 cfm vac secondary carb....... the difference was efficiency; the heads (and thus engine) could BREATHE. The car STILL starts just by THINKING about turning the ignition key, it gets great gas mileage and has tons of power. All without a flow bench. All since 1985.

So, for people who NEED the security or whatever of published numbers, go with the flow bench by all means. But it is VERY possible and realistic to get SUPERB results just by applying some skill, craftsmanship and patience. There is no reason to think that can't happen. It works all the time. Have a great day.

[34T]

edit to remove double post

[SappySE107]

Don't polish the intake side, as it will help the fuel fall out of the mix and puddle up. This is bad for emissions, gas milage, and power.

[DreX]

Don't polish the intake side, as it will help the fuel fall out of the mix and puddle up. This is bad for emissions, gas milage, and power.

100% true.


Thanks all of you guys. I have a spare set on the way home and will do it later on.

Thanx
DreX

[Galen]

II mentioned this to Ben in a PM and he kinda challenged me to mention it here. I am too lazy to retype it, so I will just quote the PM.

As for not polishing the intake, that is with a carbureted system. The popular belief with fuel injected engines is to polish all but the short turn radius. The rough surface of the short turn creates a boundary layer of air that actually enhances flow around the bend. Think dimples on a golf ball.

Now, since everyone on here thinks that I am always full of shit with my suggestions, I will post a quick link from www.turboford.org.

http://www.turboford.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=035007

Just to put a little perspective on the players involved in the thread, 67King is Harry King, the Mechanical Engineer in charge of engine development for the Mach I and Boport is a performs head porting professionally at http://replikamaschinen.com. I will probably send my next head to Bo for him to port. This will cost me right at $1,000 for a 4 cyl head done right...guaranteed!

As far as the porting aspect...I agree with 34T. The main thing you can do to help yourself out is to do a thorough polish of your head, smoothing out the runners as you go along. I would probably not even take a bit after the head, only sanding rolls. Any further porting without knowing the airflow characteristics of the head as verified by flowbench testing would be foolish at best. Also, pay for a good valve job...the valve job can make or break all your flow desires.

Galen

[SappySE107]

Ok, so the professional head porter shows no flow difference between polishing to a mirror and leaving an 80 grit surface. Wow, I wonder which I want in my intake bowl area and side walls for the bouandary layer and better atomization. You can tell quite a bit from running the heads for a while and pulling them off to inspect them. Your links really didn't prove that you know anything about head porting, or that you have any experience. In fact, it looks like the texture is desired, not polishing up everything in the intake side minus the short side radius. Furthermore, that is a turbo discussion, which invalidates your reasoning for polishing to begin with. Under boost, there is less chance of fuel drop out, though at idle and when out of the boost it will still show some issues. Im sure indy cars have their intakes polished...cause they use laser injection. How about you discuss something relevant next time.

[Galen]

Actually Ben, I chose that link because it showed two educated angles on the same subject. One side is a ME for Ford who leans in one direction, and then Bo who showed little to no flow difference with polishing. I do know that Bo still polishes his intake ports for reasons other than flow; he was simply stating his observations. Unlike some people, I believe in telling both sides and being honest. I guess it comes from not trying to sell anything.

As far as the puddling theory is concerned, you are not having fuel being pulled through a venturi into a FI engine, it is being sprayed at 35+ pounds out of an injector directly into the flow path immediately prior to the valve opening. The puddling issue is a mute one, unless you have a leaky injector...in which case the car would run like shit...lol.

A flowbench is a flowbench. It does not have different flow levels for a boosted v/s NA application. Just because the topic is on a board dealing with boosted applications does not mean everything on there is only good for a turbo engine. The subject matter is very relevant. There are a couple of porting theories out there that are suggesting volume over flow for a boosted application. In those cases, your assumption about differences between NA and boosted would be correct. That is not the case for this discussion.

For me, I feel that Harry probably has the better handle on things. He is in charge of a budget and R&D capabilities beyond what we can imagine. `Bo was simply stating that he saw no improvement due to polishing...and that was anywhere in the airflow path. Polishing has always been more a personal preference to keep any contaminates from becoming adhered to the walls of your ports. You know what I am talking about when you run your heads for a while then pull them to inspect where crap is sticking to the walls. I guess this is your method for telling what part of the port is a flow restriction.

Oh yea...one other thing. As pressure goes up, it is more difficult to have a liquid suspended in a gas. This is simple condensation. Hence, under boost, according to basic physics, the fuel is more likely to drop out, not less likely as your intellect suggests.

Galen

[SappySE107]

Let me know when you are done assuming things, and attacking me.

[Juglenaut]

Oh yea...one other thing. As pressure goes up, it is more difficult to have a liquid suspended in a gas. This is simple condensation. Hence, under boost, according to basic physics, the fuel is more likely to drop out, not less likely as your intellect suggests.

Galen

As temperature increases a medium such as air which is made up of several different gases that can be liquids, the capacitive of suspended fuel increases from heat to a point of condensation or vaporization where the fuel drops out of the gasous form to vapor it doesn't not skip phases and goes directly to a full liquid state thus condensating. In order of fuel to actually condensate out of a gas (Air) the pressure of the air or gas would have to be in proportion to heat to allow vaporization then condesation on an area that is of a colder substrate or an area in direct low pressure.

Seeing how that the air is pressureized before injecting it with atomized fuel, the air would have a set amount of varibles in play as it absorbes concentrates of fuel at a given temp and then is compressed to allow combustion, this point at where fuel would drop out so to speak is alot more than the average engine would be able to produce.

I have done experiment by taking hot humid air and then compressing it, I found that it required 120+ PSI to pull the water out of it, and as it is compressed heat is lost and decompressing it caused a cooling effect, fuel on the other hand is much more harder to drop out of air, infact I put over 300psi and didn't get a drop. Gasoline is about or alittle lighter than air in gasous state so volitile is it that it almost never drops back in practical ways to liquid once it vaporizes .

Gas freezes at -175ish degreesF, Gas condensates at -100ish DegreesF. At 100 psi fuel freezes at -190, condensates at -85 degreesF. This effect is almost porportional linear as pressure increases as the freezing point increases.

The last time I checked my car ran at 195 degreesF positive. Even on the coldest of days in the north pole gas would still require such a pressure to condensate let alone vaporize first.

One more thing is the point of saturation occurs when the vapor is at the dew point or saturation temperature corresponding to its partial pressure. A gas is never saturated with a vapor. However, the space occupied jointly by the gas and vapor may be saturated.

Saturated vapor pressure is the pressure existing at a given temperature in a closed vessel containing a liquid and the vapor from that liquid after equilibrium conditions have been reached. It is dependent only on temperature and must be determined experimentally.

I am on Ben's side totally on this subject and agree with what he says.

[napatiger]

OK