Maximum boost hot air with 8.2:1

[enkeivette]

SBC 8.2:1 compression, iron heads, not intercooled, anyone have an idea how much boost it will take with 91 octane?

[94cobra69ss396]

It the boat? Forged pistons?

[enkeivette]

Yes and no. Cast.

[big_G]

Yes and no. Cast.

Be careful...lol...maybe 6 psi with a rich tune. Top ring gap is VERY critical here.

[enkeivette]

So blowing into a stock L48, should I expect catastrophy? I will be blowing into the turbos from the water logs, so the exhaust gas should be significantly cooler than usual.

[enkeivette]

Maybe I should run a carb bonnet instead of a carb pad and just suck it up and modify the carb and run a mechanical fuel pump, so I can intercool. Where the hell would I put an intercooler on a boat?

[enkeivette]

Getting complicated. I just want to install a damn turbo.

[SeanPlunk]

If you can afford to blow it up, I say go for it. Otherwise, I'd probably leave it alone.

[enkeivette]

Sigh.

[94cobra69ss396]

Be careful...lol...maybe 6 psi with a rich tune. Top ring gap is VERY critical here.

I agree, I think 6psi with a cast piston would be pushing the limit. Any detonation and you can just kiss them goodbye.

Big G, we are talking about Adam. He won't be pulling the block apart to check the ring gaps so what ever they are now is how they'll stay until he blows them up.

[enkeivette]

I agree, I think 6psi with a cast piston would be pushing the limit. Any detonation and you can just kiss them goodbye.

Big G, we are talking about Adam. He won't be pulling the block apart to check the ring gaps so what ever they are now is how they'll stay until he blows them up.

LOL. You know me pretty damn well.

[enkeivette]

6 psi sounds about right to me. I looked on my handy Procharger boost graph, and the most you can run with a roots blower at that level is 8 psi, with aluminum heads.

[enkeivette]

...blowing stuff up is funny.

[SeanPlunk]

...blowing stuff up is funny.

That needs to be a bumper sticker. I think you're an unintentional genius sometimes Enkei!

[Vettezuki]

What about a cheapy internals kit like this (http://www.summitracing.com/parts/ESP-B13402E030/), port the heads yourself, intercool and run 1 bar?

[jedhead]

I remember my friend installing a whipple on a stock 5.0 and was pushing 8lbs with no cooling.

Bob

[big_G]

What about a cheapy internals kit like this (http://www.summitracing.com/parts/ESP-B13402E030/), port the heads yourself, intercool and run 1 bar?

Not much better than what's in there now. 1 bar would make iron and aluminum salad out of that too. Just get you favorite salad dressing. :lmfao:

[94cobra69ss396]

I remember my friend installing a whipple on a stock 5.0 and was pushing 8lbs with no cooling.

Bob

H.O. 5.0's came with forged pistons from I believe 85-92. In 93 they went to hypereutectic. I broke two pistons in my 302 when I first installed my Vortech using 8-9psi (stock 3.33 pulley). I then boght another stock short block with hypereutectic pistons and broke two more. I then installed a set of Probe SRS forged pistons and have over 70,000 miles on the engine. I've also been running 11-12 psi for about a year and a half now.

[Sonic03SVT]

^ this statement about forged pistons is true. Those 5.0s are a lot stronger than people give them credit for.

[Vettezuki]

Not much better than what's in there now. 1 bar would make iron and aluminum salad out of that too. Just get you favorite salad dressing. :lmfao:

The rods are forged and the pistons hypereutectic. They say, and I imagine they're right based on other similar packages, they'd be good up to 500HP or so, and I seiruosly doubt 1bar on an L48 is going to be that powerful. Now throw some heads and cam and it's a different story.

[94cobra69ss396]

The rods are forged and the pistons hypereutectic. They say, and I imagine they're right based on other similar packages, they'd be good up to 500HP or so, and I seiruosly doubt 1bar on an L48 is going to be that powerful. Now throw some heads and cam and it's a different story.

It's not the horsepower that's the issue. It's the cylinder pressure with 91 octane. With a static compression of 9:1 and 14.7 psi you're looking at the equivilent of 17.5:1 - 18:1 compression.

[Vettezuki]

It's not the horsepower that's the issue. It's the cylinder pressure with 91 octane. With a static compression of 9:1 and 14.7 psi you're looking at the equivilent of 17.5:1 - 18:1 compression.

True,but his is 8.2. What's a Cobra's (like Sean's) static comp? 8.5? Aren't they running about 1 bar with a pulley on 91?

[94cobra69ss396]

Okay, so with 8.2:1 you're closer to around 16 - 16.5:1. That's where I'm at with my Cobra and I had to move to forged pistons because I broke 4 hypereutectic ones.

I'm not sure what the static compression is on a terminator but I believe they came with a forged piston from the factory.

[Vettezuki]

Okay, so with 8.2:1 you're closer to around 16 - 16.5:1. That's where I'm at with my Cobra and I had to move to forged pistons because I broke 4 hypereutectic ones.

But you're running crazy hot IATs. ON the other hand you have aluminum heads. Then again his entire motor will be exposed to the air (off water) and will be carburated, which adds more complexity. I guess all I'm saying is I think a kit like that might plausibly and cheaply put him in the range of pushing considerably more than 6-8lbs. :huh:

[94cobra69ss396]

Looks like we just need Adam to go ahead and add the turbo so we can see how far he can take it. I say 6psi max if he limits the total timing enough.

[enkeivette]

So I was planning to buy Shaolins turbo from his 7.3 diesel.

I asked my friend that worked at Honeywell if he thought I was a moron, and he got back to me today. His answer, maybe. Unlike diesels which have crazy high compression and push a lot more "mass" at lower rpms, my gas engine would need to spin a bit higher to build the boost.

And since my boat tops out at around 3K rpm right now, chances are it might not even build boost till it's already reaching it's top speed. And in that case, or worse if it never does, it is just an exhaust restriction. He said I need a blower.

[enkeivette]

Only problem with a roots blower is the pulley might grab some poor girls pony tail. :/

[enkeivette]

Also, roots blower is going to cost about 10x as much :/

[Vettezuki]

So I was planning to buy Shaolins turbo from his 7.3 diesel.

I asked my friend that worked at Honeywell if he thought I was a moron, and he got back to me today. His answer, maybe. Unlike diesels which have crazy high compression and push a lot more "mass" at lower rpms, my gas engine would need to spin a bit higher to build the boost.

And since my boat tops out at around 3K rpm right now, chances are it might not even build boost till it's already reaching it's top speed. And in that case, or worse if it never does, it is just an exhaust restriction. He said I need a blower.

I vaguely remember some thread about this, maybe even related to the snake. Turbos from diesels are no bueno for most gas engines. Missed that's where you were getting it from. Maybe somehting off an old AUdi or SAAB from a yard would work fine. They're probably too small. :huh:

By the time all is said and done, you may just be better off with an inexepensive stroker kit + red-neck H&C.

[enkeivette]

NA horsepower is expensive. No thanks. I'll probably end up waiting till I get a job, then buying a used mini blower. Actually, if I move somewhere with a bigger garage I'll probably sell this boat and get another one with an open bow to replace it. Then I'll most likely go big block.

Btw, I figured out why you said to me when you were checking out my jeep that diesel is a relatively rare form of fuel and I'd have to map out long trips. It seemed odd to me at first because diesel is so common, especially on long trips where semi-truck drivers are prob the fuel stations largest client base. But now it makes sense, you were trying to get back at me for talking shit on people who use race gas and octane boosters! But you can't buy Torco at Shell, sooo suck it! Haha.

[Vettezuki]

. . . Btw, I figured out why you said to me when you were checking out my jeep that diesel is a relatively rare form of fuel and I'd have to map out long trips. It seemed odd to me at first because diesel is so common, especially on long trips where semi-truck drivers are prob the fuel stations largest client base. But now it makes sense, you were trying to get back at me for talking shit on people who use race gas and octane boosters! But you can't buy Torco at Shell, sooo suck it! Haha.

Technically I just making an observation of fact in CA; relatively few stations carry diesel and that can have an impact on trips if you ain't paying attentino. :judge:

[enkeivette]

Point taken :)

[94cobra69ss396]

Ben's right. There are two gas stations on the way from my house to the freeway. Neither carries diesel. The closest station that carries it is three miles away in the wrong direction.

[enkeivette]

Huh, all of my regular gas stations have diesel. I've noticed a few don't have it when checking out prices just driving around. But it hasn't been an issue.

Even still, gas stations that sell Torco or higher than 91 octane are sliiiiiiiiightly more rare. ;)