Geez Paul, I hardly know where to start on this, you seem to have a kernel of knowledge that is fouled up in misunderstanding and misinformation. I'll try . . .

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My compression ratio has already been changed once, I half expect to have to do something about it anyway even if I don't go FI. Is a gasket such a big deal??



And how much, dare I ask, was your CR changed by changing the gasket? Not too much I would venture. Further, changing gasket thickness enough to alter CR an appreciable amount is so the wrong way to do things its not even funny. On a forced induction engine, the HG often acts sort of like a fuse, when you go to a thicker gasket to reduce CR, you've just dropped the rating on your fuse, often to far below where it should be. Its begging for a blown head gasket. The proper way to change CR is typically with new pistons, and sometimes is acceptable to modify the head deck thickness or the combustion chamber to alter the CR, but such changes should only be even attempted by someone knowledgable, or someone willing to risk the entire engine for the sake of learning by trial and error.

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Octane must come into this somewhere.



Yeah, a little, but are YOU going to swing by the airport for AvGas every time you need a fillup? I think not. Depending on where you are in the country the max available octane at your local gas station is 91, 93 or 94. Even on 94, on my bone stock 5.0L the difference between stock timing and knocking can be as little as 5 degrees initial advance (10 deg base timing vs. 15 deg base timing) and becomes more critical on forced induction, and even more so on a non-intercooled setup.
You also seem to be completely missing the point that air charge temp plays just as important of a role as octane, if not more so.

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nd the degree of this problem is proportional to how much excess you're stuffing into it, right? So the more ambitious you are with your power goals, the tighter that squeeze would be, not so?



True, in some sense, but it really isn't the power goals its how you reach the power goals, and what steps you take to ensure things run correctly.

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Great, you just invalidated most of the serious NA modders on CEG. Who limits themselves to 10% gains around here?



Who exceeds 10% gains? not too many, and certainly none that don't make significant mods across the entire engine system. For the most part, the contour engines are not bottlenecked anywhere and require significant mods throughout the ENTIRE system to see major power gains. Its designed that way on purpose from the factory . . .

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All I know is that people keep telling me that a tour ATX is way more at risk above 200 HP than a tour engine or tour MTX is. Are they wrong?



So, what you are telling me, is you want to half-ass your upgrades? You are willing to pay to upgrade the engine, but not the transmission? And because you aren't willing to upgrade the transmission, you are willing to accept a poorly conceived forced induction system? Just because you can buy something, and it fits, doesn't mean its a good idea to use it.

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(I believe there was a recent article somewhere about a Focus project where they put on more and more boost with stock zetec internals until it finally blew up, and it got well up into the three hundreds.)



And your point is? Its not power loads that usually kill your motor. With a proper fuel and timing tune, you might be very surprised at how much power a particular engine can withstand for a short period of time. BFD, its the day to day stuff that's hard. if you don't design your street car system with some sort of cushion in its design for unexpected events, like a particularly hot day, or a mislabeled gas pump, or whatever, you will kill your engine, due to detonation or to high exhaust temps.

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Besides, I just don't foresee wanting any more than 200. I might well be happy with 175, for that matter. Which means that this project is not going to justify the kinds of expense associated with a full balls-out turbo job.


Who said anything about a balls-out turbo system? I'm talking about a properly designed one.

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You don't know what my priorities actually are, or what my overall purpose with this is. You seem to be saying it's something nobody should even be interested in pursuing. That's not your call to make.



No, I'm saying you are trying to do things backwards.

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Um, you just said I'm messing up my motor by LOWERING its power. That makes lots of sense.



No, I didn't, you apparently aren't paying very close attention. You are jumping all over the map with your comments, and none of them really tie together, except that you apparently want 200hp because you think yur transmission will explode the instant you exceed that, and you don't want to pay for an intercooler to get to that power level. I'm saying that an intercooler, even at a given power level, will make things much healthier for your engine, with increased cushion against detonation, and lower overall temps in the engine. Unless you are running ~5psi or less, which is almost pointless to go through the effort and money on a small displacement engine to setup up a turbo for that.

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It sounds like you would argue that there is no such thing as a legitimate forced-induction product that isn't intercooled. Nobody should ever use, say, an Eaton supercharger, or a non-cooled factory turbo. Is that your position?



Can you name any recent (and decent) OEM forced induction vehicle that doesn't use any form of intercooling? The last one I can think of went out of production in 1989 and was the Merkur XR4Ti, and at that was in desperate need of an intercooler, especially considering the other two applications of the same motor in fords line-up got one (the SVO mustang and the T-bird turbocoupe). IMHO, anything over 6psi in boost should seriously consider some form of charge cooling, and further, should require it, except in extreme cases with other mitigating circumstances.

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Well, this is genuine new information. Do factory turbos really run super-rich? They must pollute like hell if that's so...



Now, see, this sums up most of your posts and comments on this subject; This isn't new information. It is common knowledge amongst anyone with some reasonable familiarity of forced induction systems on internal combustion engines. Granted, some of the details and particular numbers, etc. may be up for debate, but the principles are sound and proven.




Balance is the Key. rarasvt@comcast.net