velix

I think that it is important to point out that nearly every high power platform uses a Closed Deck block design. It is generally what separates the purpose built for FI power from the not. Open Deck designs are for everything else. There have been attempts to weld close and re mill vq blocks, to iron sleeve them, to brace the cylinders with girdles: all with varying success. Billet blocks are also an option, as well as quick and stupid cement if streetability is of no concern to you. But we're talking about making a thing do something it's not supposed to now aren't we?









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turboed350z

thank you so much for that. thats something really neat and interesting that ive learn today.

so if the engine is a closed blocked and FI, is the stress level the same as an open block NA? by that i mean, lets say the bursting point is 10, will both block be experiencing a 4/10 stress level? being that the close block is stronger so it can handle more stress.

or would it be more that open block bursts at 10, close block bursts at 15 and stress level is 5 for NA open and 7 for FI closed.

Conway_160

iTrader: (1)

Closed deck typically has stronger sleeves so yes it can handle more power.

iideadeyeii

iTrader: (6)

Why do people have to quote the entire post INCLUDING all pictures to reference the post right before their post

turboed350z

Why do people have to have crap internet that cant handle the loading of extra pics.

Zivman

iTrader: (19)

this thread is beyond stupid... your first argument makes no damn sense and cannot believe people were as nice to you as they were. your question was answered very early on with this post:
yet you continue on....

now you want to again try to massage the question again asking an impossible to answer question in relation to the block type. You are looking at it completely @ss backword.

The block style simply implies how the block handles a given stress. there are so many factors involved that one could only answer in generalized terms... and you even go so far as expecting someone to objectively quantify them?

I know that what I don't know could easily fill a warehouse, it's clear that what you don't know could fill many, many a warehouse and beyond.

Dead eye was only partially correct... I think I got the HIV as well as the Cancer from this thread

turboed350z

So basically you got nothing intellectual to contribute so your close mind goes on a flaming spree...

How about you stick to the topic at hand. Yes increase in pressure adds stress, but lets factor in elevation and climbing hills. Will a FI engine STILL be more stressed when the NA has to do 2x the work?

Nexx

iTrader: (41)

Will a huge ***** strain a vagina more than a smaller one? I mean with enough lube can the vagina tell if its getting screwed with a big or small one?

turboed350z

Technically speaking, when aroused, the vaguna expands 2x its normal size. So if youre screwing an unaroused vagina with s little pecker, it will think youre big. However, if the womab is aroused, the big pecker may seem inefficient.

Zivman

iTrader: (19)

you continue on and on showing how little intelligence you have....

please take another look at this again and again and again till it makes sense to you->

Higher cylinder Pressure = more stress


raise elevation, you still are force feeding one and that equals more cylinder pressure...

climb a hill, you are still force feeding one and that equals more cylinder pressure...


and if you want to go even further... given the engine is in the same vehicle and climbs the same hill at the same rate they are doing the same amount of work... move 3000lbs over a set distance over a set time period is doing the same work. it doesn't magically become 2x the work for an engine because it lacks boost.....

I now have full blown AIDS with my cancer.. thanks for that

turboed350z

Actually, its proven that FI engine performs better at higher elevation than NA. And NA engine needs to spins more to produce power needed to pull a 3k lb car up a hill than a turbo will.

And towing, the best towing truck is the ram 3500, a TURBOed desiel engine. Towing puts a strain on an engine, so wouldnt it makes MORE sense NOT to add extra stress on an engine? Yet ford, dodge and chevy all have turbo u der the hood of their work truck. I wonder why that is? Possibly because its more stressful for an engine to tow 10,000lbs NA than it is for a turbo engine to. But what do i know right? I must be so dumb to ask a question that forces people to think before they reply.

Zivman

iTrader: (19)

You don't even know what point you are trying to argue for or against. You bring in random factors that don't have any relevance to the discussion and try to use that for your argument...

Now you want to discuss a ram pickup ? And turbo diesel?

With towing and climbing hills you are reaching into a territory of is it more stressful to run an engine at 100% of its capacity vs less than 100%...

You've trolled me long enough... I'm thinking you must be related to my brother in law. He's the only person that would instigate a 'discussion' like this

iideadeyeii

iTrader: (6)

Seriously stop posting

MicVelo

OK, everyone, please stop.

If anyone wants to read or contribute something useful to this, go for it. If one is not interested or has nothing to contribute, move on to the next thread. Flame wars are counter-productive and pointless and everyone loses.

iideadeyeii

iTrader: (6)

He's clearly trolling. There's nothing to contribute.

MicVelo

OK guys, whether or not OP is trolling is up to you to decide/believe.

But here's a constructive answer based on current round of questioning:

The basic question T'bo (OP) asks:

Turbocharging performs better at elevation, that much has been agreed on. But, how much better? And when compared side-by-side with an identical car (same cd, same weight, same mechanicals, aside from the powerplants, let's say, a 3.5L turbo engine versus a bored, stroked, cammed, etc. 3.8L V6 - but both producing identical horsepower to the ground), will the engines have the same stress LEVELS at elevation?

Simple answer: BOTH engines will be stressed MORE because of oxygen depletion at high elevations. Another fact.

However, the NA V6 running at elevation in this example will have proportionately more stress placed on it (relative to when it was at sea level) to make equal horsepower than the turbo engine because it has to physically work harder to attain the same level of power necessary to maintain speed and/or torque.

But why?

An NA engine will typically lose an absolute ~3% power with EACH elevation gain of 1,000 feet. Note the emphasis on the words "absolute" and "EACH". This is a known fact.

Example:

A hypothetical 100bhp normally aspirated engine will lose 3 hp at 1,000 ft or 100 x .97 = 97hp.

Then at 2,000 ft, another 3% (again, absolute) or 97 x .97 = 94.09 then...

3,000 ft, another 3% power loss or 94.09 x .97 = 91.26hp

And so on with this geometric progression. This is a given and without the aid of forced induction and the only variable being atmospheric in nature, the losses are pretty much constant.

So, if you think about this through this example, the NA engine is now down 8.74hp (8.74%) at +3,000ft above sea level. Carrying out this thought process, if said hypothetical car requires 100hp to maintain a steady rate of, say 100kmh but only has 91% of that, the car will THEORETICALLY only be able to get up to 91kmh. (Note that these numbers are just examples because other things like parasitic powertrain loss and such are not factored in for this example - but are useful for understanding the concept.)

But lets assume, said engine is able to rev higher into the power band and attain that extra 9% (rounded) it lost, well, obviously, the engine is working harder (higher rpm to attain the same power it had at sea level) and seeing an increase of 9% in stress levels at 3,000 ft. (Again, this stress level isn't hard and fast as the this depends a lot on the overall efficiency and strength of the engine.)

-------------------------

A TURBOCHARGED engine, on the other hand, also suffers power losses but not quite at the same dramatic rate simply because the turbo - through boost pressure - helps the engine to maintain a higher level of volumetric efficiency at most engine speeds.

Or, more simply stated, the cylinders are seeing almost as much air/fuel at elevation as it had at sea level (assuming a properly sized fuel delivery system, e.g., higher volume fuel pump, bigger injectors commensurate with the turbo).

So while the turbocharger itself is working harder and the engine is also, in running higher revs to produce more boost, the engine is seeing relatively less increase in stress placed on it as it's still operating at peak volumetric efficiency at a lower relative RPM than the NA engine needs to be at to produce equal power.

Make sense?

It all boils down to this: It all depends on which components are having to work harder. And how MUCH harder. Turbo at elevation, less relative stress increase on the engine but the turbo may be stressed higher. NA at elevation, more relative stress on the engine overall.

Next logical question: Will the increased stress on a NA engine at elevation ever equal the stress placed on a turbo engine, in general? Do not know the answer to that without doing a lot of calculation of the actual engines and their components. Depends on the level of prep.

-------------------------

Note: You'll notice that I said "turbo" a lot. That's by design as superchargers are a whole different ball game, being mechanically driven, introducing another whole concept called parasitic power loss, which isn't important (or....too complex) for the sake of this general concept discussion.

turboed350z

alway learns something ewhen mic has a wikia post. my next question is with towing. can the same concept/theory, with elevation be put into towing when answering this question?

specifically, both car, one NA and one turboed, are towing a 5000lb load. since the turbo works off of the load of the engine, wouldnt it be less stressful than the NA car?

MicVelo

Not necessarily. Building that much torque - required for towing - in a turbo engine takes more boost and there's a point of diminished returns when the turbo is spooling at it's maximum speed design point.

Add in other things like torque curves, more heat everywhere, more mechanical chaos is likely.

Turbo engines (except diesel) are not as good for towing due to this. You want to tow, get a V8 or diesel with a torque curve as flat as Kansas.

Gee, we haven't even started to talk about hybrid/electric power at elevation.... hahahahahahaha.

Zivman

iTrader: (19)

Please move to off topic

iideadeyeii

iTrader: (6)

but what if the NA car somehow received more air and has the same cylinder pressure as the turbo. Wouldn't stress be the same?

What about if both cars were under water and theoretically they could both run off water instead of air, but exhausted air into the water. Would stress be the same?

One last question. If both cars ran off a cliff(with no bottom. . .theoretical of course) and bounced off the rev limiter in 1st gear would stress be different? What about 2nd through 6th gears? How do you think electrical system would handle the limiter the same on a turbo vs na car? Would one electrical system be more stressed than the other?
What about if they both had 54" wings producing 80lbs of down force at 120mph?

Gawd this is soo confusing guys