How much power can an alluminum block handle on Boost

[JD_Z28]

As the title says. What kind of power can a 346 block handle with boost or would it be better to go cast iron and what is the weight diffrence.

[98_Formula]

that depends, are you talkin stock internals... or forged setup...?
generally people have been sayin it should be good up to ~700-800ish... but other people argue that up to about 1300 hp you should be fine... provided you have the correct internals and a good tune. You can buy an engine girdle that is supposed to strengthen the block

stock internals would limit you to ~500hp

[FasstChevys]

stock internals would limit you to ~500hp

500 at the wheels I think is about the limit

[JD_Z28]

How much power can the alluminum block handle with all forged internals. Im just curious because im getting one built.

[sparkyjim]

500 horsepower that would be my limit if not 450 thats alot of cylinder pressure with any forced induction.:slash:

[cailey37]

Well....I'm living proof that the stock blocks are a little fragile when you put a lot of boost to them.....I ran one up to 9lbs and it cracked the cylinder wall in no time flat......and no there was no detonation....

[Beast]

There are engine girdles that should help the bore distortion problem of the aluminum block. From what I understand there are dragsters running LS1 aluminum blocks with 1300+ HP... there was an article in GMHT a few months ago.

I think if you google dm performance ls1 engine girdle... you'll find it.

[cailey37]

There are engine girdles that should help the bore distortion problem of the aluminum block. From what I understand there are dragsters running LS1 aluminum blocks with 1300+ HP... there was an article in GMHT a few months ago.

I think if you google dm performance ls1 engine girdle... you'll find it.

I read that same article and laughed. What they didn't tell you is how many passes they got before it went BOOM!!.....yes an engine girdle is a good thing but you cant get around the cylinder wall thickness.......I've got some nice pics of what happens when you put to much to these motors.......

[denbenZ06]

Id say the internals are going to be the weakest part. I know of a few cars that are pushing well into the 700hp range and havent had issues with the block. Ive seen a couple piston rods and valve train issues though.

[NA$TY-TA]

I read that same article and laughed. What they didn't tell you is how many passes they got before it went BOOM!!.....yes an engine girdle is a good thing but you cant get around the cylinder wall thickness.......I've got some nice pics of what happens when you put to much to these motors.......


You werent doing something right.......

Ive seen the aluminum blocks live with almost 30 psi and 1300 hp. Run all season long running 8.20's @170mph and that same motor is still living strong with another turbo behind it when it was swapped into his daily driver Silverado.

Im running an Iron block now and when it comes time to refresh it im going back to a Aluminum block.

[Fedge]

You werent doing something right.......

Ive seen the aluminum blocks live with almost 30 psi and 1300 hp. Run all season long running 8.20's @170mph and that same motor is still living strong with another turbo behind it when it was swapped into his daily driver Silverado.

Im running an Iron block now and when it comes time to refresh it im going back to a Aluminum block.

just curious, why are you returning to aluminum...I was gonna go with the iron block for boost as well...

[NA$TY-TA]

just curious, why are you returning to aluminum...I was gonna go with the iron block for boost as well...


The reason im going back to Alum. Is the weight. Its almost 90 lbs off the front.
Yes Iron is stronger but with power levels that high, the combo has to be rebuilt pretty often anyways. Most people just throw around the number of 800+ HP combo’s and have no clue what it takes to build and maintain it. Its not just slap it together and hope it stays that way.

[Fedge]

90 lbs...geez...i'm glad i asked! eh, i wasn't gonna go nuts anyway, i wanted it to be durable for daily driver duty, yet kick butt at the track...90 is a lot, so aluminum it is, thanks for the info:)

[cailey37]

You werent doing something right.......

Ive seen the aluminum blocks live with almost 30 psi and 1300 hp. Run all season long running 8.20's @170mph and that same motor is still living strong with another turbo behind it when it was swapped into his daily driver Silverado.

Im running an Iron block now and when it comes time to refresh it im going back to a Aluminum block.

I assure you....a stock block will not last long at 30psi...the cylinder walls are just not going to take it.......we had everything tuned perfectly and when the motor let go we tore it down and there it was plain as day.......a nice crack in the cylinder wall.....so as for your "you weren't doing something right" I'd have to disagree....

[NA$TY-TA]

I assure you....a stock block will not last long at 30psi...the cylinder walls are just not going to take it.......we had everything tuned perfectly and when the motor let go we tore it down and there it was plain as day.......a nice crack in the cylinder wall.....so as for your "you weren't doing something right" I'd have to disagree....


The stock block will last. That motor ran like that for a whole yr with that much boost and is still running fine right now with 15 psi on the street everyday......
Your one instance is not what others should base there choices on. Many have done it.
Iv even destroyed a stock Alum. Block myself. If done right it will last.
Anything can be destroyed if not done correctly.

BTW what YR block???

Kyle

[cailey37]

The stock block will last. That motor ran like that for a whole yr with that much boost and is still running fine right now with 15 psi on the street everyday......
Your one instance is not what others should base there choices on. Many have done it.
Iv even destroyed a stock Alum. Block myself. If done right it will last.
Anything can be destroyed if not done correctly.

BTW what YR block???

Kyle
It was a 98 block and any of the LS1 blocks will suffer from the same problem I'm afraid. The cylinder walls are not that thick! Trust me....it's not just me that has had the problems.....why do you think that everyone is getting their hands on the LS2's....they have thicker walls on them.....I didn't say that it couldn't be done.....I said just dont expect a LS1 to last that long. We built it we built it right and it just didn't last period! Wasn't a programming issue because we had Ken Kelly (the maker of LS1 Edit) helping with that. It was just the simple fact that the block said I've had enough.......Bottom line....anyone that knows anything about these blocks will tell you......you go over 500 hp and it's just a matter of time.....but hey...you may have one that last a while or you have one that blows in no time.....all I'm saying is once you past that threashold you start to go down in reliablility.....but hey.....all you have to remember is this.....it's your motor...do what you want to it.....throw 30# of boost at it all you want.....hell...throw a 100 shot at it also.....it's your motor.....but you dont have to take my word for it.....my best advice is to ask the experts...SLP...LG Motorsports....Cartect...these are the guys that know the limits of the motor.....not the "experts" on here.....

[Salaszar]

If the suspected weak point in the LS1 alloy blocks is the sleeve thickness what about using the Darton Modular LS1 Sleeves.
Has anyone had experience with these as a way of overcoming the suspected weakness of the wall? Definitely a little pricey at $1300 but less than a rebuild if the engine breaks itself. Be nice to find out what the fitting cost is.

[stage274]

guys check out my web site , it will fix all the problems in the stock block, www.dmperformance.org , when you putting a lot of money into an aluminum block why take the chance , one of my customers, is running 1250 horse on stock main caps, and 25 pounds of boost, no problem,he has been running it every weekend for a year so far, you do not have to worry about your block cracking any more, aslo check my project car link from the web site and dyno numbers ,of a stock componet build up before the pt-88, not only does the ls1 girdle strengthen the block it give you more power, because the bottom end is stabalizied.

[cailey37]

If the suspected weak point in the LS1 alloy blocks is the sleeve thickness what about using the Darton Modular LS1 Sleeves.
Has anyone had experience with these as a way of overcoming the suspected weakness of the wall? Definitely a little pricey at $1300 but less than a rebuild if the engine breaks itself. Be nice to find out what the fitting cost is.

Darton Sleeves are good....but if you're looking at cost effective not sure if that is the way to go......it all depends on how much you want to put into the motor......by the time you get someone to grind the old sleeves out and put the Darton's in you just as well got you an Iron 6.0L block and build on it.....they are cheap and that will let you spend the other money on some nice forged parts.......
And I did buy one of the Engine Girdles from DM Performance....just a little added insurance...........well worth it

[Salaszar]

I tend to agree with Cailey37 that the iron block is probably the simplest and cheapest option,,shame about the weight. I believe though that the iron blocks can be bored out a little more than the alloy blocks so the extra cubes should help counteract the weight penalty.
Stage 274: The girdle sounds good to strengthen the bottom end but I cannot see how that overcomes the suspected weakness of the cylinder walls,,or are you disagreeing that they are a problem?

[stage274]

the iron block is 3 times more dense than aluminum ,and your right the thin walled 98 blocks are a problem,but I sold over 200 girdles and not one failure yet, as soon as that girdle is bolted to your engine, it restrains your block from twisting, and that will definetlley help you bores keep square, but I would stay away from 98 and 99 blocks, because you can only hone them .004 over, while later blocks can be bored .010. yhea the iron blocks are slightly more rigid than thier aluminum counterparts, but who wants to stick a iron block in thier already heavy ass camaro or trans am, thats another reason to run a girdle, plus aluminum looks so much cooler.:)