LSWHO

iTrader: (1)

Ok so, I came from the supercharged grand prix world. The stock GTP bottom end has run 8s. Yes, stock bottom end.

THOSE MOTORS AREN'T EVEN FORGED. I was wondering what would happen if you freshened up a bottom end utilizing as many stock parts as you could and put on a thickER head gasket and low compression heads to lower the compression and tuned it VERY well.... how much boost do you think it could handle?

I know tuning is a huge part of the puzzle.

Only BIG issue is the PTV issues, but couldn't these be somewhat addressed by a custom cam? I haven't looked into the heads yet. Just bored at work thinking.

10#? more?

So tell me how stupid I am.

RamAir95TA

iTrader: (2)

Hypereutectic pistons have a high silicone content. This is great for wear resistance, but it also makes the alloy brittle under extreme temperatures. Boost increases cylinder temperatures dramatically. Put two and two together and you have a recipe for disaster.

Hopefully "as many stock parts as you could" only means rods, crank, and pistons. I would assume you wouldn't use stock rod bolts, rings, hardware, etc.

pyro719

iTrader: (5)

I bet you could get away with 10#'s on e85 real easy. LS1 guys boost stock motors all the time with hyper pistons.

BlackBird87

iTrader: (6)

Sounds like a huge waste of time/money.

ttranssam

iTrader: (10)

oh....lol u mean 1/8th mile right? for a sec i thought u were talking qt mile.

Yea i dont know what lt1 motors do as for the heads but us ls1 guys put 317 heads on and that lowers our compression to around 9.5-1 and some ppl will boost to like 14psi

LSWHO

iTrader: (1)

And spending $7-10k on a forged motor isn't? that's not what this thread is about.

ttranssam

iTrader: (10)

7-10k for a forged motor? ltx's can be had complete for 4000

BlackBird87

iTrader: (6)

Youre right its about you being retarded for wanting to cut every corner and build something thats a ticking time bomb, take it to the track and make everyone wait for your "great idea" to get cleaned up off the track.

LSWHO

iTrader: (1)

See other than tuning (which for us stock is amajor hinderance), this is the only issue I see. If we can drop compression to the same why can't we run more boost on stock components?

There's nothing special about L67 bottom ends, and they have run high teens easily in boost.

LSWHO

iTrader: (1)

Thanks for your input *******. GTFO.

I'm asking the reasons why, not for your blind perpetual bullshit.

LSWHO

iTrader: (1)

Where?

The only ones I've seen complete are made with parts I wouldn't bother with.

Badazz 97 TA

iTrader: (18)

eh.....

BlackBird87

iTrader: (6)

Its just a bad idea why build it if it wont last, Try a budget ebay build i met a local guy that has a twin turbo ls1 in the 8's that was under 9k for the motor and entire turbo setup

wysemunky

iTrader: (2)

http://www.theturboforums.com/smf/in...&topic=61219.0

Not an lt1 but its stock sbc 350 with a bunch of boost.

brucer

i think its more the top ring land being not thick enough on the stock pistons..

Speedy

Forged pistons won't save you from an engine that detonates and detonation is what will blow holes in the pistons, bend/break rods, and generally destroy a block. If you can tune your engine well it can live with stock hypereutectic pistons. Plenty of people have done it. The reason forged are recommended is that in the event of an anomaly, like a damaged injector, bad fuel or anything causing a lean condition there is a greater margin of error before they crack, but not much. That is not to say you won't have other damage like busted rings, valves etc. Detonation is detonation, something has to give.

Your GP had smaller (narrower) pistons. Smaller pistons are generally less likely to crack in extreme conditions because they have less exposed area. Small piston area is the reason Ford's mod motors tend to withstand boost levels so well. The LT1 is a broad 4" bore engine. It will withstand boost if tuned rich enough, but do the math on compression and don't confuse it with a small bore engine. There are pistons specifically designed to take boost, with added anti-detonation features. Pricey, but it would be a good idea to consider them.

LSWHO

iTrader: (1)

I'm not educated on pistons (clearly)... Are 3.8x" that much smaller in the scheme of things?

Speedy

Not an expert on the 3800, but yes it makes a big difference, even though it doesn't seem like much. You would know better than me about how much boost, compression etc. there was in the Pontiac and anything else they did to avoid detonation. Obviously you would want to take everything into account, but bear in mind the LT1s hypereutectic pistons were designed for different combustion conditions than the Pontiacs. There are a lot of factors. Just visit Wiseco's site and look at all the different weights of pistons, volume, etc. How heavy were the pistons in your GP? How thick were the tops of the pistons? If you check the boost designed pistons for the LT1 you'll probably find some similarities. Hypereutectic provide much tighter piston to wall clearance than forged, allowing less blow-by, startup knock, and better efficiency. The Buick 3.8 was a fantastic engine by any measure.