Page 1 of 2 12 LastLast
Results 1 to 20 of 21

hp limit on alum bocks

This is a discussion on hp limit on alum bocks within the Internal Engine forums, part of the LSx Technical Help Section category; I'm working on a winter project and debating getting the parts and rebuilding the alum one, or building an iron ...

  1. #1
    Junior Member
    Join Date
    May 2007
    Location
    Seattle
    Posts
    88

    Purple
    1998 T/A convertable

    hp limit on alum bocks

    I'm working on a winter project and debating getting the parts and rebuilding the alum one, or building an iron one. I'd like to aim for 500hp, maybe add a 100 shot, too. Supercharging is a little more than I want spend as I have a '70 Formula that needs finishing, and that thing is dang thirsty.....

    It would be alot easier to build a motor, then just swap it, but no sense buying another alum block for it. Anyone know the weight difference in the 2? based on the density it should be about 1/3 the wieght of the steel one, I wanted a relative amount. I'd like to stay with teh add a pound here, remove one there idea.

    I did a search and saw many hp numbers and it looks like over 550-600 needs iron

  2. #2
    Member silverz28camaro's Avatar
    Join Date
    Apr 2006
    Location
    Washington MO
    Age
    31
    Posts
    796

    sebring silver
    2000 z28

    some people out there are running 450 hp on 383 ls1 aluminum block strokers, i would say 500-525 is the limit and as far as weight goes do a search on the millennium motor and it will tel you the entire history of the ls1 motor and how it became how it is today, i do believe the block alone is 60lbs lighter the a regular 350 small block and is also shorter in length and hight dimension wise by 1-2 inches making it alot easier to work on compared to lt1 camaros.
    2000 auto camaro
    13.54 @ 104 2.049 60' stock 2.73

    12.94 @ 109 2.002 60' full exhaust, lid, tune, nitto 555r 2.73

    11.899 @ 114.44 1.686 60' full exhaust, lid, tune, nitto 245/50-16 555r 3.73 moser 12-bolt 2800 fuddle, ls6 intake manifold, slp under drive pully,fiberglass hood, bmr k-member

  3. #3
    Member danziger's Avatar
    Join Date
    Aug 2006
    Location
    Chesapeake, VA
    Age
    49
    Posts
    570

    Le Mans Blue
    2004 Z16

    This topic has come up before if you want to do a "search." I've never heard/read of someone splitting the aluminium block due to excess HP. The iron block may add stability of cylinder shape at ridiculous levels of power and may offer better head clamping strength in high cylinder-pressure applications, but under 800rwhp, I wouldn't sweat it. My factory LS1 short-block survived for a few years of H/C/100shot to the tune of 576rwhp/590rwtq before pushing a head-gasket (my fault). When torn down, it looked beautiful... My current aluminum 383 is well into the 600s on the squeeze...no problems.

  4. #4
    Slow'er'Ass Mr. Luos's Avatar
    Join Date
    Aug 2005
    Location
    Thornton, CO
    Posts
    23,785

    Red Tint Jewelcoat
    2008 Trailblazer SS

    As mentioned, the aluminum block will take plenty of abuse.

    Unless you are building an all out drag car that makes 850-900+, stick with a forged aluminum motor.

  5. #5
    Member Bouvers's Avatar
    Join Date
    May 2006
    Location
    Canada
    Age
    31
    Posts
    857

    Blue 1997 Trans Am(Sold)
    Pewter 2001 Trans Am Vert

    I'd like to see more input into this thread, I too am aiming for 500 rwhp someday and I expect that I will redo the bottom end. I have had one friend tell me that I might aswell change out the block too but I have never heard anything to justify that. I've never seen a video of an ls1 engine blowing the block out its always pistons.
    I think this thread needs the input of people that have blown their stock ls1 internals or even block, and tell us at what hp and build this occured with.

  6. #6
    Member danziger's Avatar
    Join Date
    Aug 2006
    Location
    Chesapeake, VA
    Age
    49
    Posts
    570

    Le Mans Blue
    2004 Z16

    Quote Originally Posted by Bouvs View Post
    I'd like to see more input into this thread, I too am aiming for 500 rwhp someday and I expect that I will redo the bottom end. I have had one friend tell me that I might aswell change out the block too but I have never heard anything to justify that. I've never seen a video of an ls1 engine blowing the block out its always pistons.
    I think this thread needs the input of people that have blown their stock ls1 internals or even block, and tell us at what hp and build this occured with.
    The problem with asking for folks that have blown their stock internals, is that it is usually due to user error, not factory limitations. A faulty tune or getting greedy with boost/nitrous will result in failure and most people won't "man up" to their mistakes.

    The weak links in the factory LS1 are:
    a) pushrods
    b) piston ring-lands
    c) rod-bolts

    500rwhp is a joke for factory aluminum block. If you avoid detonation/pre-ignition, it is no problem for the factory bottom-end as well. The stock crank is seriously tough and folks have gone over 600rwhp with them easy.
    2000 Z28 382/nitrous...sold and missed.
    2004 Z06 CE Z16...still looks stock.

  7. #7
    used and abused at wot ibanez7's Avatar
    Join Date
    Aug 2005
    Location
    Crystal Lake IL
    Age
    40
    Posts
    2,517

    Pewter
    2001 Camaro Z28 M6

    Quote Originally Posted by danziger View Post
    The problem with asking for folks that have blown their stock internals, is that it is usually due to user error, not factory limitations. A faulty tune or getting greedy with boost/nitrous will result in failure and most people won't "man up" to their mistakes.

    The weak links in the factory LS1 are:
    a) pushrods
    b) piston ring-lands
    c) rod-bolts

    500rwhp is a joke for factory aluminum block. If you avoid detonation/pre-ignition, it is no problem for the factory bottom-end as well. The stock crank is seriously tough and folks have gone over 600rwhp with them easy.



    exactly!!!!!

    to add to this, top fuel and funny car engines are aluminum blocks! yes they do get rebuild after each race however it is still an aluminum block holding the 7,xxx + HP together for those 4-8 seconds.


    Two reasons why many people switch to iron over aluminum is because of the misconception that aluminum is not strong and will not hold up. That is just the old way of thinking and being unsure of a new(er) technology. The other reason it because many people believe the only way to increase HP is to increase displacement and they bore the hell out of their blocks. The factory 346 aluminum block can be bored however when it starts pushing over 404 (bore+stroke) the block does lose rigidness.

  8. #8
    Junior Member
    Join Date
    May 2007
    Location
    Seattle
    Posts
    88

    Purple
    1998 T/A convertable

    The LS7 I assume is an aluminum block, is it that different from a LS1 block? I know they're getting 505hp on a 427cid.

    Thanks for the info, everyone I talked to said 500 is the limit for alum blocks, none of them have ever owned one. Ironic that they thing 400hp is acceptable from an alum 2.5L 4 banger

  9. #9
    Junior Member Bigjohn366's Avatar
    Join Date
    Mar 2007
    Location
    topeka kansas
    Posts
    23

    red
    ls? that is the answer

    well iv hurd the alum blocks dont like to be bored over so thin , imagine the ls7 a tempered sleeved block

    thats why im building a 5.3 project

    rod bolts and pushrods an rockers id say that sums it up to have a motor

  10. #10
    Senior Member Sleeper101's Avatar
    Join Date
    Oct 2007
    Location
    Springcity
    Posts
    1,152

    Red
    Vette,240sx,ls1 camaro

    Alright guys I personally work on a professional race team, We run Drag Boats instead of cars, But we run the 500 C.I Keith Black Hemi aluminum block we put down over 7000HP. The block is not what holds the power, Its the cylinder sleeve, out of the 6 years on the team we have never busted a block due to too much power, We have bust lots of blocks due to rods coming out of the side, But since its aluminum we just weld in another plate in the side of the block and put in a new set of sleeves.
    The Creaters of this disaster!!!! The crew..... Im the youngest in the middle.


    Here is a busted Block.

    You can see the plates we welded in were previous rods have showed there face.

    If you run aluminum you def want a good set of sleeves, but I would go alumium over cast/steel block, The Hp is only limited by what quality of internals you run. But aluminum is very strong, proven over 8000HP worth.

  11. #11
    Junior Member
    Join Date
    May 2007
    Location
    Seattle
    Posts
    88

    Purple
    1998 T/A convertable

    I thought ALL alum blocks were sleeved? I'm reading the HP book for LS1's and they state Chevy has a C5R Vette block that the have to a 383 size and get 1200 hp out of. It is a different block, probably the LS7 one, but it was slightly changed for 427 cubes.

  12. #12
    Member ApexVIII's Avatar
    Join Date
    Jun 2007
    Location
    Modesto, CA
    Posts
    307

    Red
    1998 Camaro Z28

    Quote Originally Posted by Sleeper101 View Post
    Alright guys I personally work on a professional race team, We run Drag Boats instead of cars, But we run the 500 C.I Keith Black Hemi aluminum block we put down over 7000HP. The block is not what holds the power, Its the cylinder sleeve, out of the 6 years on the team we have never busted a block due to too much power, We have bust lots of blocks due to rods coming out of the side, But since its aluminum we just weld in another plate in the side of the block and put in a new set of sleeves.
    The Creaters of this disaster!!!! The crew..... Im the youngest in the middle.
    Click for full size
    Click for full size
    Here is a busted Block.
    Click for full size
    You can see the plates we welded in were previous rods have showed there face.

    If you run aluminum you def want a good set of sleeves, but I would go alumium over cast/steel block, The Hp is only limited by what quality of internals you run. But aluminum is very strong, proven over 8000HP worth.
    wow thats sick!!
    M6, Lid, Ported and Polished Throttle Body (By Me!), LT, Custom Catted Y, Electric Cutout, PHB, LCA13.21@108 with a 2.3 60'

  13. #13
    Member danziger's Avatar
    Join Date
    Aug 2006
    Location
    Chesapeake, VA
    Age
    49
    Posts
    570

    Le Mans Blue
    2004 Z16

    Quote Originally Posted by xirxious View Post
    I thought ALL alum blocks were sleeved? I'm reading the HP book for LS1's and they state Chevy has a C5R Vette block that the have to a 383 size and get 1200 hp out of. It is a different block, probably the LS7 one, but it was slightly changed for 427 cubes.
    Yes, all aluminum LSx blocks are sleeved. The C5R block is different from stock LS1 castings and was made stronger with endurance racing in mind.

  14. #14
    Impounded
    Join Date
    Mar 2007
    Location
    Milwaukee
    Age
    30
    Posts
    2,159

    Red
    2000 Trans Am

    Well if this helps any, custom alum blocks can handle alot, my girlfriends uncle has a 468 alum block twin turbo setup in his 78 T/A and is moving it to his 98 formula, it holds 1400rwhp at the track most weekends in summer.

  15. #15
    Member danziger's Avatar
    Join Date
    Aug 2006
    Location
    Chesapeake, VA
    Age
    49
    Posts
    570

    Le Mans Blue
    2004 Z16

    Quote Originally Posted by Sleeper101 View Post
    The block is not what holds the power, Its the cylinder sleeve, We have bust lots of blocks due to rods coming out of the side,

    If you run aluminum you def want a good set of sleeves, but I would go alumium over cast/steel block, The Hp is only limited by what quality of internals you run. But aluminum is very strong, proven over 8000HP worth.
    Well, yes and no. The block holds the sleeves, so ultimately holds the power. The design of the block, webbing, water-passages and such will come into narrow focus at higher power levels. I'm sure you guys have filled engine blocks with cement at some point in your racing career to increase rigidity...
    Having a rod ventilate a block is a whole different scenario...
    Iron blocks have their place in the LSx world due to cost and clamping pressure. Unless you want to spend big dollars for a LSX block with extra head studs, there is something to be said for the security of the threads in iron vs. aluminum. FI and big nitrous hit guys will often opt for iron.
    Having said all that (pshew!), I would still go with aluminum.

  16. #16
    Senior Member Sleeper101's Avatar
    Join Date
    Oct 2007
    Location
    Springcity
    Posts
    1,152

    Red
    Vette,240sx,ls1 camaro

    Well We also run a pro mod which is a 550 C.I motor all aluminum, 2500HP,alcohal, The only maintanence we ever do is check the valves per round and change plugs every 10 rounds, also change the oil every 10 rounds, We never have a problem with head studs backing out on that engine.

    So I have not seen a problem with the head studs backing out, on our smaller engine, Might not be the case in the Lsx world, I have never been able to experiment with one.

    Although on our Top fuel motor the head studs will back out about 5 turns per pass, But were cranking so much boost its hard not too, I have never seen a stud stripped, nor the block. Its really weird that it don't but in 6 years it hasnt. plus each head bolt is locked down with 160 ftlbs of torque.

    The difference in the LSx aluminum and ours is we dont run water jackets or any type of coolant, Both engines are cooled by the fuel, and is only ran for a short time period, So I have no experince when it comes to that, But I do know the aluminum structure will be fine for any amount of HP you can throw at it.

    TFX, Keith Black, Billet, B/A are the most top name brand blocks used in the racing we do. One of these might make a Lsx block.

  17. #17
    I Like It Stroked 99Ls1fever's Avatar
    Join Date
    Aug 2007
    Location
    Greeley,Co
    Posts
    1,006

    Artic White
    1999 Z28 408 Stroker M6

    Quote Originally Posted by Sleeper101 View Post
    Alright guys I personally work on a professional race team, We run Drag Boats instead of cars, But we run the 500 C.I Keith Black Hemi aluminum block we put down over 7000HP. The block is not what holds the power, Its the cylinder sleeve, out of the 6 years on the team we have never busted a block due to too much power, We have bust lots of blocks due to rods coming out of the side, But since its aluminum we just weld in another plate in the side of the block and put in a new set of sleeves.
    The Creaters of this disaster!!!! The crew..... Im the youngest in the middle.
    Click for full size
    Click for full size
    Here is a busted Block.
    Click for full size
    You can see the plates we welded in were previous rods have showed there face.

    If you run aluminum you def want a good set of sleeves, but I would go alumium over cast/steel block, The Hp is only limited by what quality of internals you run. But aluminum is very strong, proven over 8000HP worth.
    Good call case dismissed amen people have seen the light. for some reason people always have this idea the block will blow, personal I dont think there is but a few people that even have the money to try to accomplish this task lol...

  18. #18
    Member
    Join Date
    Mar 2006
    Location
    Fort Benning, GA
    Age
    35
    Posts
    435

    Black
    '91 turbo fox, '97 vette

    Blocks certainly do hold the power and must be strong enough to handle it. Iron or aluminum material can both be used in high hp blocks. The design of the specific block matters more than the material used. Case in point: the 302 windsors will typically split down the middle at somewhere between 500rwhp and 650 rwhp. Put the strongest billet internals, and the most conservative "safe" tune and when you get to that power levelt, the block still splits right down the lifter valley.

    This isn't the case with the LS1s, though. With good strong internals, I wouldn't be afraid to run 700 rwhp. North of that, I'd have to start doing some research.

    Chris

  19. #19
    No Compromise davered00ss's Avatar
    Join Date
    Jul 2005
    Location
    Plainfield CT
    Posts
    382

    RED
    2000 Camaro SS

    Stock shortblock is good for 500rwhp. Forged are good well into the 800-900rwhp area. As stated above the rods & pistons are the weak point. The stock crank is even good for 900rwhp.

  20. #20
    Junior Member
    Join Date
    May 2007
    Location
    Seattle
    Posts
    88

    Purple
    1998 T/A convertable

    I'm kind of torn between buying a 427 set up or just building the stock to ~500hp. I'm debating buying a new Z28 next year and this would be more of a toy car. I'm just not sure if I want to put the kind of $$ into a 427. If I get a new Z, it will need upgrades

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Wanted: stock alum. 3-4 fork
    By hec33 in forum Parts Wanted / Trade
    Replies: 3
    Last Post: 08-09-2010, 02:09 PM
  2. Alum Polishing HELP
    By BDowning in forum Showcar and Detailing
    Replies: 14
    Last Post: 07-03-2009, 05:53 PM
  3. ALum Covers
    By BDowning in forum Showcar and Detailing
    Replies: 79
    Last Post: 05-06-2009, 12:00 PM
  4. Question: New Alum Air box
    By BDowning in forum External Engine
    Replies: 2
    Last Post: 01-22-2009, 02:57 PM
  5. Alum or steel flywheel?
    By BIG D's SS in forum Camaro / SS
    Replies: 8
    Last Post: 10-16-2005, 08:01 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •