GN1 alum heads vs Iron ported
- Thread starter rogerv6
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Here, I'll type a little slower for you Sam...
- AND in plain english...It's a good question.
He wants to know:
OTHER than the weight advantage, (aluminum = less weight) Are there any advantages to running Aluminum heads instead of ported irons.
Not much experience in this area but -
I prefer Irons...BUT, aluminum will dessipate heat faster and if it's a different casting than the stock heads, it will (should) have improved runners and geometry.
How fast you want to run will be a better decision factor than anything.
Sam has ALOT more experience in this area than I have (he's owned both!)
- AND in plain english...It's a good question.He wants to know:
OTHER than the weight advantage, (aluminum = less weight) Are there any advantages to running Aluminum heads instead of ported irons.
Not much experience in this area but -
I prefer Irons...BUT, aluminum will dessipate heat faster and if it's a different casting than the stock heads, it will (should) have improved runners and geometry.
How fast you want to run will be a better decision factor than anything.
Sam has ALOT more experience in this area than I have (he's owned both!)
Scott, how the hell did you decipher that?! The aluminum heads flow more, yes. As far as the heat dissipation, well, I've heard two conflicting stories. Some say they reduce detonation because they absorb heat faster, reducing hot spots, which makes sense. Others say that an iron head will be less prone to detonation, something to do with retaining heat? I dunno, I ain't that smart. Nick Micale told me the GN1's actually clamp down harder on the gasket that irons, making them less resistant to lifting and blowing the gasket. So, all things equal, aluminums are better because of the capability to flow more, but there have been some problems with the quality of the heads themselves, and it seems hit or miss. Mine, brand new, have bad guides in them, and I assure you I'm not the first. I guess I have to send them to someone to fix them, out of my pocket of course. If you go with Gn1's, have a GOOD shop that has experience with these heads check them for you. I miss my champion irons at this point. 
The aluminum heads flow more, yes. As far as the heat dissipation, well, I've heard two conflicting stories. Some say they reduce detonation because they absorb heat faster, reducing hot spots, which makes sense. Others say that an iron head will be less prone to detonation, something to do with retaining heat? I dunno, I ain't that smart. Nick Micale told me the GN1's actually clamp down harder on the gasket that irons, making them less resistant to lifting and blowing the gasket. So, all things equal, aluminums are better because of the capability to flow more, but there have been some problems with the quality of the heads themselves, and it seems hit or miss. Mine, brand new, have bad guides in them, and I assure you I'm not the first. I guess I have to send them to someone to fix them, out of my pocket of course. If you go with Gn1's, have a GOOD shop that has experience with these heads check them for you. I miss my champion irons at this point. Hey Scott, that reminded me of that letter from the parents to their son in Arkansas.
"Son, I'm writing this slow cuz I know you cannot read fast. Your father found out that most accidents occur close to home, so we are moving......."
Thats still funny
"Son, I'm writing this slow cuz I know you cannot read fast. Your father found out that most accidents occur close to home, so we are moving......."
Thats still funny
I have heard the aluminums will outflow ported irons right out of the box. Add porting, and they will really kick butt. However, you are also spending twice the money(could be used for turbo, suspension, etc.), plus you have to buy roller rockers (I think?).
I suppose they are good when you want to go very very fast. Under 10.50's. Above that, ported irons should work just fine.
Correct me if I'm wrong guys.
Ross
I suppose they are good when you want to go very very fast. Under 10.50's. Above that, ported irons should work just fine.
Correct me if I'm wrong guys.
Ross
A
AsphaltAnihil8r
Guest
For you Sam Huh??
J/K
J/K
Es mejor se tu usa los de heirro porque seimpre puede encontrar husado parra $600 / $650. Despue puede husar el resto del deniero para otras cosas.
Translation
It is better if you buy irons as you can always find them used for $600 / $650. Then you can use the rest of the money for other things.
I wish I was in Puerto Rico right now.
Translation
It is better if you buy irons as you can always find them used for $600 / $650. Then you can use the rest of the money for other things.
I wish I was in Puerto Rico right now.
strikeeagle
New Member
- Joined
- Jun 6, 2001
- Messages
- 3,326
Whatever heads you buy, don't forget:
Poodle-eee-ooooooowwww-blaaaaaaa. Toooooo-laafffff-fffflabbbbbbbieeeeeeeee.
Can't overstate the importance of this!
Poodle-eee-ooooooowwww-blaaaaaaa. Toooooo-laafffff-fffflabbbbbbbieeeeeeeee.
Can't overstate the importance of this!
IMO, there are several serious advantages to the AL.
There is a proper exhaust port.
You can fill up the EGR stuff, but while the gives shape, it does nothing strenght wise, and all that extra metal just reduces the fluid volume.
One a carbon layer forms in the combustion chamber, it's moot about heat transfer out of the combustion chamber, IMO.
Being able to *wick* heat away from the exhaust guides, and seats, is an advantage the AL enjoys.
If you get the 14 bolt heads, then you'll have all you'll ever need, even when you do that stage motor <G>.
There is a proper exhaust port.
You can fill up the EGR stuff, but while the gives shape, it does nothing strenght wise, and all that extra metal just reduces the fluid volume.
One a carbon layer forms in the combustion chamber, it's moot about heat transfer out of the combustion chamber, IMO.
Being able to *wick* heat away from the exhaust guides, and seats, is an advantage the AL enjoys.
If you get the 14 bolt heads, then you'll have all you'll ever need, even when you do that stage motor <G>.
tminer
Not quite normal
- Joined
- May 25, 2001
- Messages
- 761
Originally posted by BUICKTR
I think the iron's could run some good numbers, but you will probably need more boost to accomplish what an alum head will do with less boost.
I'd still like to know why that matters. Boost is relative. Less boost/more flow or more boost/less flow, at equal air mass and cylinder pressures shouldn't the results be more or less the same?
Tom
Boost is relative. Less boost/more flow or more boost/less flow, at equal air mass and cylinder pressures shouldn't the results be more or less the same?
But you can't get the same mass airflow and cylinder pressure at two different boost pressures without also changing something else like intercooler efficiency. Having to run more boost to make a given amount of hp means you are running higher cylinder pressures (and have more pumping losses because the exhaust manifold pressure is higher) and thus need more octane, relative to a better flowing motor that can make the same hp at lower boost. You can make a ton of power with iron heads, but the aluminum heads flow more and will always let you make the same power at lower boost, or more power at the same boost.
But you can't get the same mass airflow and cylinder pressure at two different boost pressures without also changing something else like intercooler efficiency. Having to run more boost to make a given amount of hp means you are running higher cylinder pressures (and have more pumping losses because the exhaust manifold pressure is higher) and thus need more octane, relative to a better flowing motor that can make the same hp at lower boost. You can make a ton of power with iron heads, but the aluminum heads flow more and will always let you make the same power at lower boost, or more power at the same boost.
tminer
Not quite normal
- Joined
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I don't disagree with what you wrote Carl, but that wasn't my point. The item being changed is the heads (flow). I understand that you can run less boost with the higher flowing heads, I just don't understand why that matters.
A lot of people seem to think that there is some big advantage to running lower boost and making the same power. I don't get that. Boost is just the pressure in the intake. It is cylinder pressure that creates horsepower, aids detonation, and stresses the bottom end.
I also understand that due to the efficiencies, the ultimate potential is higher with higher flow and lower boost. But sans detonation, the same mass of air and appropriate amount of fuel will create the same results, whether they be copious amounts of power or catastrophic failure. With detonation, I could see high boost being an advantage since there will likely be less air mass and fuel in the cylinder because it is less efficient and likely to detonate at a lower power level.
Tom
A lot of people seem to think that there is some big advantage to running lower boost and making the same power. I don't get that. Boost is just the pressure in the intake. It is cylinder pressure that creates horsepower, aids detonation, and stresses the bottom end.
I also understand that due to the efficiencies, the ultimate potential is higher with higher flow and lower boost. But sans detonation, the same mass of air and appropriate amount of fuel will create the same results, whether they be copious amounts of power or catastrophic failure. With detonation, I could see high boost being an advantage since there will likely be less air mass and fuel in the cylinder because it is less efficient and likely to detonate at a lower power level.
Tom
tminer
Not quite normal
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A lot of what I wrote is a simplification. Combustion chamber design, port volumes, exhaust to intake ratios, etc, effect the actual power created from the same mixture with different heads.
I am strictly concerned with the concept that being able to make the same power with less boost is some magic bullit.
Tom
I am strictly concerned with the concept that being able to make the same power with less boost is some magic bullit.
Tom
You also have to upgrade your headers and exhaust to compensate for the increased head flow. I experienced some problems when I switched to GN1 heads because I tried to use the .65 housing. At 20psi it was fine, anything above that and it turned in to reversion, backing up into the intake and making the boost fluctuate rapidly.
