What makes aluminum heads produce so much more power?

cobrayankee · 01-27-2001, 11:37 AM

Why is it that aluminum heads outperform factory, non-aluminum heads? What is the big difference besides obvious material?

------------------
1997 Cobra (Black on black), C+L 80mm MAF, K+N filter, Pro 5.0 shifter, BBK Springs, Taylor Wires, 2 Chamber Flows, ASP Pulleys, BBK off road H pipe.

my name is mud · 01-27-2001, 12:18 PM

Aliminum is lighter than iron, it also transfers heat better. Generally aliminum heads flow much better than factory iron heads also.

Five0 · 01-27-2001, 12:34 PM

Actually aluminum heads will produce a little less power than cast but aluminum is lighter and the weight usually makes up for the loss in power.

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

Rev · 01-27-2001, 02:54 PM

After market head manufactures prefer Aluminum because its easier to cast and machine. That's the main reason. The increased heat transfer does minimize detonation somewhat and that's another plus. Iron heads will produce slightly more power in the same design though, just as Five0 said.

Rev

------------------
'66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.3 mph
1/4 mi.

95mustanggt · 01-27-2001, 03:56 PM

One down side to Al heads is that the rate of contraction and expansion is different between the block and the head (assuming the block is iron, witch in a 5.0 it is). A lot of head gasket failures happen here in the colder climates in the winter due to this fact. For that reason I will not buy an Al head. For you guys down in the south it is not a problem (and if I ever move to the states it won't be a problem for me wither

)

------------------
White 1995 Mustang GT
Dynomax Cat-Back, Offroad H-pipe, K&N Filters w/o Air Silencer
My 1995 Mustang GT

mustangII460 · 01-28-2001, 12:51 AM

Aluminum cylinder heads as stated before transfer heat better from cylinders, producing more power.
With aluminum cylinder heads you can run alot more compression.
Of course aluminum head are of late design and incorperate the latest in, "Swirl" technolgy.
Adding together heat trasfer,3 angle cut large valves and the latest technology of flow, aluminum heads are great.
The down side of aluminum heads is cost. I will probibly get a set in a few years when cost comes down some. In the mean time i will continue to grinding some iron.

smooth · 01-29-2001, 02:27 AM

given a certain static cr, barring octane issues iron will make more power. however you can run a higher cr on aluminum compared to iron given the same fuel.

cobrayankee · 01-29-2001, 09:44 AM

Thanks guys!! I kwow the weight difference is there, but didn't figure that made all that much of a difference.

------------------
1997 Cobra (Black on black), C+L 80mm MAF, K+N filter, Pro 5.0 shifter, BBK Springs, Taylor Wires, 2 Chamber Flows, ASP Pulleys, BBK off road H pipe.

Five0 · 01-29-2001, 12:32 PM

1st. The weight will make a difference in your launch because less weight in the front of the car and the car will have better weight transfer.

2nd. You will be able to run more timing to get a little more power out of it and have less detonation.

3rd. If you damage the aluminum heads they can be fixed.

4th. If you want to, you can run higher compression and run lower octane fuel.(however I would still run no less than 92 octane)

5th. I noticed that the car runs cooler and is cooler under the hood after a hard run.

6th. Less weight will get you down the track faster, and it does make a difference.

7th. Bigger market with the aluminum heads.

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

01-27-2001, 11:37 AM	#1
cobrayankee Registered Member Join Date: Jul 2000 Location: Baltimore, MD Posts: 516	What makes aluminum heads produce so much more power? Why is it that aluminum heads outperform factory, non-aluminum heads? What is the big difference besides obvious material? ------------------ 1997 Cobra (Black on black), C+L 80mm MAF, K+N filter, Pro 5.0 shifter, BBK Springs, Taylor Wires, 2 Chamber Flows, ASP Pulleys, BBK off road H pipe.

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01-27-2001, 12:18 PM	#2
my name is mud Registered Member Join Date: Dec 2000 Location: OK Posts: 21	Aliminum is lighter than iron, it also transfers heat better. Generally aliminum heads flow much better than factory iron heads also.

01-27-2001, 12:34 PM	#3
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	Actually aluminum heads will produce a little less power than cast but aluminum is lighter and the weight usually makes up for the loss in power. ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft

01-27-2001, 02:54 PM	#4
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	After market head manufactures prefer Aluminum because its easier to cast and machine. That's the main reason. The increased heat transfer does minimize detonation somewhat and that's another plus. Iron heads will produce slightly more power in the same design though, just as Five0 said. Rev ------------------ '66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.3 mph 1/4 mi.

01-27-2001, 03:56 PM	#5
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	One down side to Al heads is that the rate of contraction and expansion is different between the block and the head (assuming the block is iron, witch in a 5.0 it is). A lot of head gasket failures happen here in the colder climates in the winter due to this fact. For that reason I will not buy an Al head. For you guys down in the south it is not a problem (and if I ever move to the states it won't be a problem for me wither ) ------------------ White 1995 Mustang GT Dynomax Cat-Back, Offroad H-pipe, K&N Filters w/o Air Silencer My 1995 Mustang GT

01-28-2001, 12:51 AM	#6
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Aluminum cylinder heads as stated before transfer heat better from cylinders, producing more power. With aluminum cylinder heads you can run alot more compression. Of course aluminum head are of late design and incorperate the latest in, "Swirl" technolgy. Adding together heat trasfer,3 angle cut large valves and the latest technology of flow, aluminum heads are great. The down side of aluminum heads is cost. I will probibly get a set in a few years when cost comes down some. In the mean time i will continue to grinding some iron.

01-29-2001, 02:27 AM	#7
smooth Registered Member Join Date: Nov 1999 Location: illinois, USA Posts: 649	given a certain static cr, barring octane issues iron will make more power. however you can run a higher cr on aluminum compared to iron given the same fuel.

01-29-2001, 09:44 AM	#8
cobrayankee Registered Member Join Date: Jul 2000 Location: Baltimore, MD Posts: 516	Thanks guys!! I kwow the weight difference is there, but didn't figure that made all that much of a difference. ------------------ 1997 Cobra (Black on black), C+L 80mm MAF, K+N filter, Pro 5.0 shifter, BBK Springs, Taylor Wires, 2 Chamber Flows, ASP Pulleys, BBK off road H pipe.

01-29-2001, 12:32 PM	#9
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	1st. The weight will make a difference in your launch because less weight in the front of the car and the car will have better weight transfer. 2nd. You will be able to run more timing to get a little more power out of it and have less detonation. 3rd. If you damage the aluminum heads they can be fixed. 4th. If you want to, you can run higher compression and run lower octane fuel.(however I would still run no less than 92 octane) 5th. I noticed that the car runs cooler and is cooler under the hood after a hard run. 6th. Less weight will get you down the track faster, and it does make a difference. 7th. Bigger market with the aluminum heads. ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX 12.565 @109.38mph 1.764 60ft