ECT...aluminum vs iron block
Thread Starter
Joined: Jun 2005
Posts: 2,265
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From: Oskaloosa, Iowa
ECT...aluminum vs iron block For a street car in the 750-850 rwhp range is there any significant difference in keeping the engine cool between an aluminum block and an iron block?
TECH Junkie
Joined: Jul 2015
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I have no experience with an iron LS boosted motor. But I can tell you this, my car has an aluminum LS2 and makes 740whp and it's on E85. During the winter, i actually have trouble keeping heat IN the motor.... runs too cool. During the summer months with the AC on, it runs about 200 on the freeway and creeps up to around 220 around town.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
The reason I ask is in the GTO specifically I’ve read of several iron 408’s with prochargers having over heating issues. They are the only ones I’ve noticed having this issue.
On my LS1 on only 10 psi I have a 160 stat on e85 with first fan on at 179 and 2nd fan on at 185. I couldn’t tell you if the second fan even works because it never gets to 185 even on 90 degree days.
Im planning a forged 6.0 and it made me curious if I should add cooling along with weight as things to consider between aluminum and iron.
eta...I had a 408 in a different car that had no cooling issues, but it was a different ball game...about 500 whp NA and 650 on spray.
On my LS1 on only 10 psi I have a 160 stat on e85 with first fan on at 179 and 2nd fan on at 185. I couldn’t tell you if the second fan even works because it never gets to 185 even on 90 degree days.
Im planning a forged 6.0 and it made me curious if I should add cooling along with weight as things to consider between aluminum and iron.
eta...I had a 408 in a different car that had no cooling issues, but it was a different ball game...about 500 whp NA and 650 on spray.
TECH Junkie
Joined: Jul 2015
Posts: 3,012
Likes: 48
The reason I ask is in the GTO specifically I’ve read of several iron 408’s with prochargers having over heating issues. They are the only ones I’ve noticed having this issue.
On my LS1 on only 10 psi I have a 160 stat on e85 with first fan on at 179 and 2nd fan on at 185. I couldn’t tell you if the second fan even works because it never gets to 185 even on 90 degree days.
Im planning a forged 6.0 and it made me curious if I should add cooling along with weight as things to consider between aluminum and iron.
On my LS1 on only 10 psi I have a 160 stat on e85 with first fan on at 179 and 2nd fan on at 185. I couldn’t tell you if the second fan even works because it never gets to 185 even on 90 degree days.
Im planning a forged 6.0 and it made me curious if I should add cooling along with weight as things to consider between aluminum and iron.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
True...the only difference being the intercooler in front of the radiator and extra load from the blower. I don’t even have that little plastic piece under the radiator that people say will cause it to over heat if you remove it. My trans cooler was in the way so I just left it off.
TECH Resident
Joined: Sep 2013
Posts: 994
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From: Mechanicsburg, PA
FWIW roots style blowers add heat to the intake air just putzing around. My experience is with old school stuff (6-71) so take it for what it's worth. But underdriving it actually lowered the coolant temp driving around normally. I'd love to have some hard data from someone with say, an LSA that ran theirs with different pulleys while monitoring intake air temps.
As far as the OP's question, I can't imagine you'd see any difference.
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I'd like to hear from some users as well as I intend to swap out my turbocharged aluminum LS1 with an iron LM7 and am hoping it doesn't cause me any cooling issues.
Regarding prochargers, a friend of mine ran a procharger on his fbody with the aluminum LS1 and it ran hot constantly, he switched to a S485 and the car now runs cool as a cucumber so I think Prochargers inherently cause engines to run warmer.
Regarding prochargers, a friend of mine ran a procharger on his fbody with the aluminum LS1 and it ran hot constantly, he switched to a S485 and the car now runs cool as a cucumber so I think Prochargers inherently cause engines to run warmer.
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Verdad Gallardo Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
I'd like to hear from some users as well as I intend to swap out my turbocharged aluminum LS1 with an iron LM7 and am hoping it doesn't cause me any cooling issues.
Regarding prochargers, a friend of mine ran a procharger on his fbody with the aluminum LS1 and it ran hot constantly, he switched to a S485 and the car now runs cool as a cucumber so I think Prochargers inherently cause engines to run warmer.
Regarding prochargers, a friend of mine ran a procharger on his fbody with the aluminum LS1 and it ran hot constantly, he switched to a S485 and the car now runs cool as a cucumber so I think Prochargers inherently cause engines to run warmer.
TECH Enthusiast
Joined: Dec 2017
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On my 5th gen camaro i went from the factory aluminium block to a LSX block, no changes to the cooling system and it stayed right at or even a little below the same temp. Maybe its cause of it being LSX but i dont think they cool any better then any other iron block..
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
I live in a hot climate in South Florida. I went from a 436ci LS6 aluminum engine to an iron 390ci LQ9.
Temps are identical in all areas of driving ranges.
Anything will stay cool if the cooling system is operating properly.
.
Temps are identical in all areas of driving ranges.
Anything will stay cool if the cooling system is operating properly.
.
If you have no issues then I'm sure I'll be fine, thank you sir.
they all run the same unless someone decides to do a 1/2 filled block. they work if the rpm is up and water is moving but if you get cought in traffic the back of the engine will go to 250 or so. for your power range you won't find a block that won't hold up if the tune is good.