Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Turbo thoughts

ok, I finally have a minute to think about how to explain this. Here goes.

Don,

let me start with this statement, Boost does not make power. In reality, all the boost pressure is, is a measurement of the resistance to the flow from the turbocharger into the cylinder. The reason you get more power when you raise the boost pressure, is because you are flowing more air into the engine. This is also partly why, after a certain point increasing boost pressure will give less gain for each psi, the engine can only flow so much air, and you get to a point of diminishing returns.

I will go on to say, a turbo does NOT make boost. A turbo pumps air, and in order for boost pressure to exist, that air must be pumped against some restriction. The more restriction, the more boost pressure. This is why, for a given amount of airflow, an SVT contour will have less boost pressure than a regular contour will. This is also why, for a given boost pressure (regulated by a boost pressure referenced wastegate) an SVT contour will flow more air than a regular contour.

Try this, take a stock SVO, and measure the airflow going into it at a given amount of boost (and a particular rpm), then go get an Esslinger head or somehting like that, with improved ports and whatnot and put it on the car. w/ no other changes, I gurantee that the new head, at the same boost pressure and rpm will be flowing a lot more air. or you can take the wastegate setting and play with it until the two airflow measurements are the same, and then look at the boost guage, and it will be noticably less than the stock head.

This is just plain wrong. Where do you think the airflow from the turbo goes? (ignoring a blow-off or bypass valve)

You know what, I just completely re-read your post, and you are close, but quite mixed up. It would take more time than I have now to cover it all. I guess I will have to come back to this.

ok my re-wording is necessary, lol. i shoulda said "CFM flow of the turbo..."

the turbocharger *obviously* can only push so much air. reading any compessor map will tell you that. hence the reason there are so many different types/combinations/modificatons of compressor wheels.

a turbocharger has its range of efficiency that it must operate in in order to produce positive power. i made it sound all ****ed up with the "not related" issue. so lemme rephrase.

the turbocharger itself will not push more air just because an engine is larger. a larger engine will help bring a turbo to its range of efficency quicker, and past. a larger, efficient engine will produce more exhaust flow *obviously* and this will change the characteristics of the turbochargers power-making ability.

The T-3 that i use will be much too small for a larger 5.0L engine. supposing that both engines have a similar intake/exhaust cfm to displacement ratio, the T-3 will not be up to the task of powering the 5.0L like it will power the 2.3L.

heres a quick analogy: blow thru a coffee straw and try to fill up a beachball. now, blow as hard as you can. your head aches, your cheeks hurt, your lungs strain. and that damn beachball isnt very full! now, pick up a paper towel roll. blow thru it. your lungs are not taxed hardly at all, and for the most part you couldn't wear yourself out blowing thru it. also, that beachball is filling up nicely. a turbocharger works like this. the same size turbo will not power something that requires a larger compressor.

did i clear up anything i said???

/me goes to papertowel, and starts blowing, to try and understand better. Blowing makes me faint, now just more confused

wut i do know is that turbo = good thing

Don we weren't talking about a completely mis-matched compressor. We are talking about two very similar engines, only one has less restriction in the intake path.

btw, I've got two T3s sitting on my bench that say they will do wonderful things for my 5.0L (of course, it will take both of them, but who cares, right?)

I've seen him run a number of times at route 66 man it was kind of funny to see a guy with a early 90's LX with a 5.0 get beat by him...

Rara-

You called me out on my opinion of Ford's concern for their customers, and I replied. I'm honestly curious about your thoughts on how Ford handled my situation. I think that it is rather conclusive proof of Ford's attitude. I'm not saying that Ford is any worse than the rest of the lot, as they would likely do the same.

:p lucky you

I'm sorry, you're gonna have to point me to this, I can't seem to find it in this thread, and don't recall it.
Thanks

No, thats..... AWESOME AWESOME AWESOME AWESOME AWESOME. Its okay, I'm sure it was just a typo. Happy to correct you though! :p

Bah, damnit, wrong thread. Lol, that's what happens when you have 20 IE windows open and don't pay attention to which one you are replying to. It's over in off-topic, in the What Cops want thread. Sorry for the confusion.