Iron or aluminium?
Thread Starter
Staging Lane
Joined: Mar 2002
Posts: 71
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From: Florida
Iron or aluminium? I just bought a second hand incon TT kit, my original intensions were to build an ls6 motor with the turbos. figured 405 hp is alot to start with with <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> now I notice most factory FI cars are iron block, and I even remember reading that the Cobra no longer has an aluminium option because it cant handle boost.
Anyway, recently I was telling a friend about my plans and he thinks its a bad idea to use an aluminium block( he has an 87 GN and a 97 single turbo 383 z28) he said that it may nt last along time over 600rwhp. so I told him about :worship: Steve harlan and how he was putting down close to 600rwhp on the stock motor and plans to make more after his rebuild. My friend thinks it wont last forever. he advised me to get a 6.0L truck block, the thing is, I saw Godspeeds car, and it didnt seem all that fast I dont know if it was his heads and cam combo, or his heavy motor.
So anyway, I would like to know if the ls6 block could handle 700-800rwhp,( built of course) or would I be better off getting the iron block, if so, do I use teh ls6 heads, or the 6.0L heads?
Anyway, recently I was telling a friend about my plans and he thinks its a bad idea to use an aluminium block( he has an 87 GN and a 97 single turbo 383 z28) he said that it may nt last along time over 600rwhp. so I told him about :worship: Steve harlan and how he was putting down close to 600rwhp on the stock motor and plans to make more after his rebuild. My friend thinks it wont last forever. he advised me to get a 6.0L truck block, the thing is, I saw Godspeeds car, and it didnt seem all that fast I dont know if it was his heads and cam combo, or his heavy motor.
So anyway, I would like to know if the ls6 block could handle 700-800rwhp,( built of course) or would I be better off getting the iron block, if so, do I use teh ls6 heads, or the 6.0L heads?
Moderator
Joined: Nov 2001
Posts: 3,048
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From: Raleigh, NC
Re: Iron or aluminium? I'm going to a 7.0 Liter Iron block bored and stroked to make 422 CID.
I'm told when you make in excess of 600 or 700 RWHP, it gets harder to keep the Aluminum block stable. Keeping the heads down with a lot of boost gets problematic, too.
<small>[ June 03, 2002, 11:34 AM: Message edited by: Black LS1 T/A ]</small>
I'm told when you make in excess of 600 or 700 RWHP, it gets harder to keep the Aluminum block stable. Keeping the heads down with a lot of boost gets problematic, too.
<small>[ June 03, 2002, 11:34 AM: Message edited by: Black LS1 T/A ]</small>
Thread Starter
Staging Lane
Joined: Mar 2002
Posts: 71
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From: Florida
Re: Iron or aluminium? 7.0l with boost? you sick basterd <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> anyway thanks, I will definately use the truck block but I got a few stupid questions... one of the firsthings I noticed with my ls1 was that it got much better gas mileage than my lt1, and mod for mod it made more power yet STILL got better gas, I was thinking that maybe it was because the lt1 was heavier :shrugs: thats teh reason I wa sso against iron bocks, yay,ya I know, I cant worry about gas if I plan to boost really high, but I would be on low boost 80% of the time. wanted to know if the weight had anything to do with it, also how many cubes does teh 6.0L have?
Re: Iron or aluminium? I'm also building a motor with boost. I'm planning on going with a 6.0L truck block and 6.0L truck heads. The aluminum block is good, but I'd rather not risk it with as much boost as I'm planning on running. Your LS1 got better gas mileage partly because of weight, but probably had more to do with the fact that the LS1 is much more efficient.
Adkoonerstrator
iTrader: (4)
Joined: Nov 2001
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From: Deep in the seedy underworld of Koonerville
Re: Iron or aluminium? Has anyone ever tried using the iron block and iron heads from a 99-00 6.0L truck. It seems to me that this would be the strongest setup available. There would definately be a weight penalty but, if the motor stayed together with big boost who cares. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I think the aluminum heads are the biggest issue with high boost apps. The current clamping techniques seem to be able to hold them down but, the heads themselves distort. The aluminum blocks also seem to be decent(for how long is the ?) in high power apps. but, the iron block should add some insurance.
Once Harlan gets his car running we may see the first split LS1 aluminum block. Sorry Harlan <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
John
I think the aluminum heads are the biggest issue with high boost apps. The current clamping techniques seem to be able to hold them down but, the heads themselves distort. The aluminum blocks also seem to be decent(for how long is the ?) in high power apps. but, the iron block should add some insurance.
Once Harlan gets his car running we may see the first split LS1 aluminum block. Sorry Harlan <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
John
TECH Enthusiast
Joined: Nov 2001
Posts: 650
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From: Toronto, Canada
Re: Iron or aluminium? The Ligenfelter 427 TT is a C5R block, much stronger than stock. Stock bore on this block is 4.120" and with a 4" crank you get 427 CID.
The C5R block is a nice piece and comes with billet main caps. Pretty pricey, but if price is no object well worth the investment.
Paul
The C5R block is a nice piece and comes with billet main caps. Pretty pricey, but if price is no object well worth the investment.
Paul
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TECH Addict
Joined: Nov 2001
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From: Nawf Carolina
Re: Iron or aluminium? C5R is a GMPP block, big money but can go over 460 ci.
As mentioned above, its not that the heads wont stay on, its more that they bow up in the middle. Iron heads might stop this, good idea but it will probably be awhile before anyone trys it (we're all too weight consious.)
Iron block will be more resistant to detonation, but I believe the bottom end will be more stable as well. Sure, alum is lighter, but it takes twice as much to do the job. Aluminium's expansion rate is nearly twice what cast iron's is. Alum has better heat disspertion, but that isn't really the name of the game with performance motors. Heat = horsepower. If you notice most LS1s run better w/o a 160 degree 'stat, but some need it to control detonation.
Alum heads let you run more timing and compression, but thats because there's less mass and its dissipating the heat more. I'd rather have a ridgid block that is going to hold the boost and not deform.
+++ to alum is it's lighter, and the often overlooked ease of repair. Aluminium is a lot easier to weld and patch than cast iron. This means you can get a lot more radical in the head porting, cause if you hit water you can just weld over it and keep on porting vs having to get new castings.
I'm also weary about the differences in rates of expansion between the cast iron cylinder sleeves and the alum block in the LS1/LS6 blocks under extreme heat and/or detonation. Of course I'm the type that worries a lot.
Aluminium is over-rated, ceramics are where its at. But I'm rambling now so I'll shut up....
J.
<small>[ June 04, 2002, 11:18 AM: Message edited by: Crazyquik ]</small>
As mentioned above, its not that the heads wont stay on, its more that they bow up in the middle. Iron heads might stop this, good idea but it will probably be awhile before anyone trys it (we're all too weight consious.)
Iron block will be more resistant to detonation, but I believe the bottom end will be more stable as well. Sure, alum is lighter, but it takes twice as much to do the job. Aluminium's expansion rate is nearly twice what cast iron's is. Alum has better heat disspertion, but that isn't really the name of the game with performance motors. Heat = horsepower. If you notice most LS1s run better w/o a 160 degree 'stat, but some need it to control detonation.
Alum heads let you run more timing and compression, but thats because there's less mass and its dissipating the heat more. I'd rather have a ridgid block that is going to hold the boost and not deform.
+++ to alum is it's lighter, and the often overlooked ease of repair. Aluminium is a lot easier to weld and patch than cast iron. This means you can get a lot more radical in the head porting, cause if you hit water you can just weld over it and keep on porting vs having to get new castings.
I'm also weary about the differences in rates of expansion between the cast iron cylinder sleeves and the alum block in the LS1/LS6 blocks under extreme heat and/or detonation. Of course I'm the type that worries a lot.
Aluminium is over-rated, ceramics are where its at. But I'm rambling now so I'll shut up....
J.
<small>[ June 04, 2002, 11:18 AM: Message edited by: Crazyquik ]</small>
TECH Apprentice
Joined: May 2002
Posts: 320
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From: Phoenix, AZ
Re: Iron or aluminium? The 650hp TT Lingenfelter vette is still the stock Aluminum block. Twins put allot less stress on the motor than a single does. If you're running just the stage I Incon setup (what is that, 4-6psi right?), the LS6 should hold just fine. If you plan on 10+ psi, I might look into the iron setup. ARE was working with some high boost setups--they were lifting the heads at boost. I don't know if they ever solved that. You might want to contact someone there for some better insight into their experiences.