What Kind Of Gain For Ported Heads

[Boost231]

i have done a search and cant find it. i was wondering what the average et gain you see from going from stock heads to ported cast irons like the champions. i know it really depends on setup but for a car running 12.5 what kind of gain will it be seeing? thanks

Boost231

 

[Boost231]

ok found a few post saying .5 and 4mph. im thinking with my hotair car that i will gain alittle more but i could be wrong.

 

[Nick Micale]

Going from a stock iron head to a max ported iron head with high flow valves, you should see the gain you stated, assuming all else stays the same [applies to hot air cars too!].

 

[tom h]

All else being "equal" , does a high flow head (eg, Champion iron) move the power band to a higher RPM, necessitating a higher stall torque converter to take full advantage of the new heads?

 

[Mike Licht]

All else being "equal" , does a high flow head (eg, Champion iron) move the power band to a higher RPM, necessitating a higher stall torque converter to take full advantage of the new heads?

Not really. IMO power band has way more to do with Cam/Turbo than heads
Mike

 

[VadersV6]

Cam and turbo will more or less shape the band. The heads and turbo will determine how fat that curve is. Ormand is going to come in here any minute and start telling us that ported heads dont gain power at less boost cause of volume flow vs. mass flow.
You have a given mass of air, or oxygen molecules, in a given volume of air. If you open the heads up and increase the flow, you have increased the mass of air (number of oxygen molecules) by increasing the volume of the air, by increasing the volume of the runner. Opening up the volume of the runner up say 10%, can increase the mass of air into the cylinder by say, 20%, on a boosted motor. Just about every dyno test out of thousands upon thousands, with heads and turbo combinations, have shown that increasing the flow of the heads, will deliver more oxygen molecules into the cylinders with less "boost", or backpressure, which is all a boost reading is...a measurment of how inefficient the intake and heads are. Its all about airflow, not boost. Boost doesnt mean anything in terms of how much air is in the cylinders. You look at a map of a turbo, and if you do the calculating, you can surmise that you can make 650hp at 35psi, or you can make....650hp at 18psi. You can run the stock heads and crank the boost WAY up to 35psi and get your 650, while heating the air up to a huge number, reducing the number of oxygen molecules, requiring a huge IC, you're also heating the turbo WAY up and WAY out of the efficiency range, you have to pull timing and run high octane...a big mess. Or, you can maximize the flow potential of the heads, and get your 650hp at 18psi, require less octane, run more timing, heat the turbo and air up less, require less IC.....
But to answer your question, it all depends on your combo. The wrong heads/turbo combo can cost you 200, while the wrong cam will cost you say, 40. If you have a huge turbo and the rest of the combo is good for 10's, but you're running stock unported heads, then switching to a killer set of heads could be worth 200hp. It could also be worth 40 on a mild street combo. All depends on what you have.

 

[Super6]

ported heads

Not smart enough to get deep into this subject but i went low 12's at 112 mph with stock turbo,heads,big neck stock intercooler,and alky, boost at 23psi. Now with ported heads, atr roller cam,te44,RJC FM,another nozzle for the alky with the same 009's but with the ME-R i cut 1 second off my 1/4 and added 10 mph with 23psi..ported heads really wake these cars up ..........Bob

 

[Underboost]

Not smart enough to get deep into this subject but i went low 12's at 112 mph with stock turbo,heads,big neck stock intercooler,and alky, boost at 23psi. Now with ported heads, atr roller cam,te44,RJC FM,another nozzle for the alky with the same 009's but with the ME-R i cut 1 second off my 1/4 and added 10 mph with 23psi..ported heads really wake these cars up ..........Bob

Maybe Im slow but whats ME-R? Fuel?

 

[Pronto]

I don't know Super6, you changed too many things to say ported heads made a difference...
The only way to find out how much porting is worth is to keep everything the same and just replace the heads which I don't think anyone would really do. I believe most would want to change stuff while the engine is half apart.

 

[Super6]

Max effort

Maybe Im slow but whats ME-R? Fuel?

MaxEffort Digital Programmable Fuel Management

 

[Underboost]

MaxEffort Digital Programmable Fuel Management

Thanks I already have the turbo tweek chip.

 

[DonnieShort]

You will see a gain with properly ported heads over stock non-ported, it would be non-sense to think that you wouldn't. How much of a gain will depend on the set up, but the fact of the matter is there will be a gain. It's well worth doing, if it wasn't nobody would be doing it.

 

[Nemesis]

Will the size of the turbo also effect the gains of the ported heads? For example an engine with a 44 turbo will not gain as much as an engine with a 70 turbo from a set of ported heads due to the volume.

 

[justabuickv6]

I'll be installing my Champion irons soon. I won't be changing anything other than that. I will post my results. I run 116MPH now with PT52, DIY alky, THDP, chip, stock block/heads.

 

[bison]

Any one of the 3 things mentioned wont make a substantial differece (heads, cam, turbo). But when all 3 are made to work together you could gain 150-200 hp if you have the fuel for it. You didnt mention if you had a stock turbo or upgrade. With an old TE44 and a set of iron champions i would guess you could gain 70-80hp with some tuning over the stock heads and turbo at 25 psi. Even more at 28psi.

 

[bison]

Will the size of the turbo also effect the gains of the ported heads? For example an engine with a 44 turbo will not gain as much as an engine with a 70 turbo from a set of ported heads due to the volume.

Air flow is determined by engine speed and size. If your heads flow more air than you need to increase the cubes or increase the speed to further take advantage of the heads. You will gain some power but not as much as if you revved it more. The most common and easy thing to do is change the cam (speed). You would see more performance with a 44 over a 70 on a stock headed engine that doesnt ever past 5000 rpm. Even if you only threw heads at that combo you still wouldnt see much without a bigger cam. The 70 turbos make the power on a 231 ci over 5000 rpm and 23+psi. Another reason why torque converter selection becomes so important. A good selection will keep the engine in the meat of the power curve as long as possible before coupling on the top end.

 

[Ormand]

which is all a boost reading is...a measurment of how inefficient the intake and heads are

Not, not, not! Boost is the ratio of air pressure on the discharge side of the compressor to the pressure on the intake side of the compressor. You can increase boost by speeding up the compressor. How does that affect the efficiency of the heads and intake? The post by Bison is accurate and factual. Air flow VOLUME is determined by engine size and speed. Period. You can increase pressure and density and get more MASS, as Vader says, but to get more volume, you got to use more rpm, or get a bigger engine. When you are flowing higher VOLUME, then porting heads and intakes will help more than if you increase pressure/density without going to more cubic inches or rpm.

 

[tom h]

note concerning "volume" measurements of gases -

Obviously, any gas can be compressed or expanded, to fill its containment vessel. So "volume" directly is not a good measure of how much "stuff", or amount of air molecules are present. That is better represented by the "mass" of the air.

But "volume of gas" is a convenient concept, so the notion of a "standard cubic foot" (or "standard liter" for metric folks) evolved.

http://en.wikipedia.org/wiki/Standard_cubic_foot
A standard cubic foot (abbreviated as scf) is a measure of quantity of gas, equal to a cubic foot of volume at 60 degrees Fahrenheit and either 14.696 pounds per square inch (1 atm) or 14.73 PSI (30 inHg) of pressure. ... A standard cubic foot is thus not a unit of volume but of quantity.

caution- the "pressure" referred to in the Wikipedia definition is the 'absolute' (psia), not 'guage' (psig), pressure. At sea-level, 14.7 psia would measure about 0 psig. Generally "psig" is more common, in most contexts.

A gas at any temperature, pressure, & container volume (if all 3 are known) is easily converted into "standard cubic feet", a measure of quantity ... and it's the quantity (ie, mass) of air (oxygen) & fuel that makes power, not "volume" or "boost", strictly speaking.

Now that a "standard cubic foot" of a gas is defined, it's a short step to defining "quantities per minute" (ie, "flow" or "volumetric flow") by introducing "standard cubic feet per minute" or "SCFM". SCFM is a well-accepted measure of how much "gas quantity" is truly moving into or out of any pipe, vessel, air compressor, cylinder head, etc. People often say "CFM" when they mean "SCFM" ... just make sure it's really SCFM being specified!

 

[Ormand]

But "volume of gas" is a convenient concept

It is also the factor that determines flow velocity, which is used in sizing ports. Volume flow=velocityxarea. And not in SCFM, but in ACFM, "ACTUAL" cubic feet per minute. The flow velocity at any point is determined by volume flow at that point. Not mass flow, but volume flow. Not flow through some other part of the system, but flow at the point in question. ACFM through the air cleaner will be different from ACFM into the turbo and a LOT different from ACFM out of the turbo, and that, in turn, is different from ACFM out of the intercooler. Mass flow will be the same at every point, due to the law of conservation of mass. But there is no law of "conservation of volume".

 

[tom h]

Ormand,

I dont know what you mean by "actual" cubic feet by minute ... and neither would any other engineer (mechanical or otherwise).

"actual" CFM is not a defined term.

While narrowly true that "Volume flow = velocity x [cross-sectional] area" , the absolute pressure of the flowing gas has a direct bearing on how much "quantity" or "mass" of air is moving.

Of course, "mass" is conserved. And the way "standard cubic foot per minute" (SCFM) is defined, it is representing the quantity of air and is effectively equivalent to mass -- it is a measure of how many "air" molecules are present. 1 SCF = 1 SCF, no matter what sized vessel it is contained in, or what its pressure is.

Eg,
consider a cross-sectional area of 1 sq ft (1 SF).
air moving at velocity 1 foot per minute (FPM) through this area.
assume temperature is 60ºF.

Then:
-- if the air pressure is 1 atmosphere absolute (=14.7 psia = 0 psig), then 1 SCFM is flowing.
-- if air pressure is 2 atm absolute (=29.4 psia = 14.7 psig), 2 SCFM is flowing.
-- if air pressure is 3 atm absolute (=44.1 psia = 29.4 psig), 3 SCFM is flowing.
-- corrections for non-standard temperature are also similarly made.

This is why "SCFM" (or "SLM" standard liters per minute) are the unambiguous, preferred conventions in the mechanical engineering community...

I think in the end, we're both agreeing that "mass" of air (or O2), combined with fuel, is the critical parameter that affects power .... we're just using different units.