Mabus

awd would be sick!!

SmokenDSM

I've been reading these forums for some time, and this is by far the dumbest post I've read, which is why I decided to register and reply

First off, how can you possibly estimate what kind of boost the supercharger will be running? Don't make such bold statements about something you know nothing about.

Next point. You're basing the amount of boost that the engine can take from a CENTRIFUGAL SUPERCHARGER on the displacement. Again...stupid.

Now, what is this "15psi blowoff" you speak of? Do you realize that the rate at which the supercharger is spinning is proportional to the rpm of the engine? I don't think I even need to mention the fact that boost depends on how fast the wheel is turning. You can't "blow off" a supercharger if your foot is still on the gas. As a matter of fact, the boost is controlled by the wastegate on ALL TURBO CARS, and engine RPM on s/c.

Next.. you're estimating power gains by the volume of the engine. Again..

Your buddy runs 17psi on his audi. That's a 1.8t with a closed deck, not to mention the fact that its turbocharged and not supercharged. Apples and oranges here.

To the guy mentioning the evo motor. No ____, that's another excellent example of a block with a closed deck. The scion motor will ever top that without resleeving.

To the guy who said this engine was built for boost... Does that mean all camrys and rav4s are built for boost too? No engine with an open deck classifies as "built for boost"

I think I've said everything I wanted to say. Now stop breathing through your mouth and read before you make another post as dumb as that one.

619AKIRA619

well my block is a gsr, with a type r tranny w/ lsd. enjo stg 2 axle. my block is some what build but not totally yet. i guess it helps that my reaction time is getting better. usually get around .2.

davo345

Could someone clarify what an "open-deck" and "closed-deck" is? I found the above post very informative just wasn't sure about those terms.

jmiller20874

The STi motors are open-deck and they're classified as built for boost.

Someone didn't do their research

toastbox

A "Closed" deck has bridges between the cylinder walls to secure the top of the cylinders to the deck where the head is mounted. So both the top and the bottom of the cylinder are fastened to the outside of the water jacket. In an "Open" deck setup, only the bottom of the cylinders are secured to the block, the top is completely free from the outside of the block or waterjacket.

If you looking at an "Open" deck from the top, it looks like the cylinders are joined together, side by side, placed in a cavity in the block surrounded by coolant.

The benefit of the "Closed" deck design is that under severe conditions, high turbo boost or extreme combustion pressures, it is more stable and less prone to breaking a head gasket and other important parts by moving around.

jmiller20874

open deck - The engine block is die-cast, usually aluminum. The casting process used requires that the water jackets surrounding the cyclinders be "open" to allow the block to be cast in one piece. This type casting allows for more precise machining of the cylinder walls and other internal areas of the block. As a trade-off, the metal tends to be thinner.

closed deck - The engine is sand-cast meaning that sand blanks are used to pour the molten metal over to form the block. Once that is complete, the sand is washed away leaving the cavities to the engine. This process allows for thicker cylinder walls and the water jackets surrounding the cylinders are "closed".

toastbox

Here's a good pic, if you still don't understand:
http://www.cardomain.com/memberpage/807137/2

engifineer

SomkinDSM: A little of your info is correct, but much of it makes no sense. First, the info he is stating on the output of the supercharger was probably based of what scion reps have been stating. I have heard from three different sources that it will produce around 6psi most likely and no more than 9psi. No one was making assumptions based off of anything other than the best info we have so far from scion. So on that point you are obvioulsy just trying to start an argument. Second, I hate to tell you, but supercharging and turbocharging has the same end result. You treat them as two completely different things. The difference is in the way that they are powered. There is some difference in the output due to turbo lag and the linear response of a supercharger, but that is it! They are still compressing air, period. And this engine has already been proven to handle more boost than was expected, so that is not in question. Now, when making your point about basing the amount of boost on the displacement, I thought you were going somewhere there... but you capatalized CENTRIFIGUL SUPERCHARGER as if that made a difference in what you were talking about, which it absolutely did not. A couple of others have hit at some of your other mistakes, so I wont go into those.

SmokenDSM

Alright.
Here's all I have to say about the sti motor: Pictures speak a thousand words so I'll just leave it at that.


Now onto engifineer. I'm glad at least some of it made sense. Let me clarify more because I was too groggy to think yesterday.

Turbo- and superchargers are the same in that all they accomplish is boost. That's about as descriptive as saying a ferrari and a civic are the same in that they get you from point a to point b. With a name like engifineer, you should know alot more of their differences than the ones you listed.

Yes I realize the engine has been proven to handle boost, I won't dispute that. But saying that its BUILT for boost because of a low compression ratio is very incorrect. I would really like to know how much longer that 400+hp tC will last before something goes horribly wrong. I do give them alot of credit though.

Now as for my volume comment. Here's what I was referring to

"The 2.4 liter engine in our Tc's can handle so much more than that, a good turbo running on just 15psi blow-off (maybe not even that much), would raise the BHP up to about 300hp just by sheer volume. "

Will that be 300hp peak (needless to say, right before the rev limiter? - which is sorta low) Will there be a decent powerband? Is the transmission geared for this powerband? You can't just change pulleys without upgrading fuel delivery. That's how you blow up motors.

I capitalized centrifugal s/c for emphasis so that there's no more confusion about the whole "15psi blowoff" ordeal.

I still stand by my mouthbreather comment. Moderators should have deleted that post before the masses read it and became even more misinformed..

engifineer

ummm I pointed out some pretty major differences in short form... was that hard to understand? If so:

A supercharger is driven mechanically, off the crank. There are three real types of SC: the roots, screw and centrifugal. The tC unit is supposed to be a centrifugal design, which provides less boost at low rpms than the other supercharger types, but also creates less charge air temperature increase. Although less linear than the other two types they are typically more linear than turbos. Superchargers create a parasitic load and thus waste some power. Turbos do as well, but tend to be more efficient because of where they draw their power.

Turbos are driven off of exhaust gas. They use some "wasted energy", but still add restriction to the exhaust and are not 100% efficient (as nothing is). The turbine in a turbocharger typically spins at higher rpms than most superchargers, and produce more boost. A balance must be chosen between high end boost output and lag. Larger turbos are capable of high amounts of boost, but typically spool up higher in the rpm band. Smaller turbos spool up more quickly but produce less boost. Some systems use a twin charged design to provide boost throughout more of the power band.

Turbos create higher charge air temps than superchargers typically.

And intercooler is used to drop charge air temps. The idea is not to simply create higher pressure in the combustion chamber, but to introduce a denser charge (more oxygen molecules per sq in. )

Now, there is enough detail to back the argument I made.... do you need more?? Or is that enough to satisfy you? You never really answered my post.. you merely tried to state that I did not know enough about the two. Nice diversion from the real conversation.

Giravani

Good post! I've done a bit of reading on turbochargers but I will admit that I have little to no knowledge about superchargers. In relation to the boost vs. lag problem, couldn't that be corrected with an effective wastegate? I've read about some turbo setups being able to run high boost with little to no lag, all because of the ability (whether by wastegate or actual turbine manufacturer - neither was disclosed) of the turbine and wastegate's ability to quickly adjust blade-speed and synch up with the throttle's demand. Admittedly I'm a noob when it comes to FI, which is why I come on here in hopes of learning new things, like most of us (I would like to think).

engifineer

Proper sizing is one of the key points. With a properly sized turbo, you can create better low end performance and still produce a decent amount of boost, which is ideal on the street. Now, if you are all out drag racing, then you can sacrafice some low end without much issue obviously. So it defintely depends on the application

toastbox

That's a horrible comparison. a better descriptor would be to say a "rotary engine and an internal combustion engine are the same in that they both power your car". You're comparing brands in one statement, whie engifineer is comparing types of forced induction.

I'd be careful about talking sh*t in rgards to engifineer; he's a pretty well respected member of this board, and to boot, he has shown several times he know's what he is talking about. You're likely to get Pwned, saying stuff like that, but I suppose that is your business.


I'd agree with the parts you said regarding built for/handling. Two different things.

bringing gearing into your argument here has no place.... you're changing what you are arguing about. Are you talking about the engine, it's capacity, and it's ability to handle that stress, or are you talking about how to make sure the car runs as fast as possible, to take advantage of the available output. Stick to one argument at a time.

You do have some vaild points, but you're arguing them emotionally, and pulling cheap shots. Don't do that, at least not if you want people to see your point of view. Take a deep breath, write what you think, read it over first, and then think about what you're writing, and if it is personally attacking someone without provocation.

toastbox

seems I was a little late posting this warning

SmokenDSM

engifineer: I have read your post twice and have not found a single question mark. I guess that's why I didn't answer any questions either. You said that you weren't sure where I was going with my comment, and I have shown what I was referring to.
Oh and I didn't say you didn't know what you're talking about. Go read that part over again. And as far as I could tell, that's the only thing you pointed out in my post, while you claim there's alot of it that doesn't make sense.

As for the other guy, who wants to so called "Pwn" me. My comparison is equal to his. That's why it's called a comparison and not a direct relationship. But I'd like to comment on your comparison too. A rotary engine is still an internal combustion engine, so it's overall a much worse comparison than mine.

Moving on to your next point
"He has shown several times he knows what he's talking about." He has, no doubt, has proven to everyone here he knows the difference between the different FI methods. Great. You can get that kind of information on how stuff works.com and should be common knowledge in a forum dedicated to hunger for power.

Again, I comment on his 300hp claim as "worthless". I'll leave it at that.

toastbox

Wow.... I am speechless. Either you are clearly disregarding what people post and changing it to somethign else (I never said *I* wanted to pwn you, I was stating that if you kept talking smack about people, you'd *get* pwned), or you are incapable of comprehending what people are saying.



You're right...a rotary engine engine is still an internal combustion engine...I should have referred to it as a conventional piston engine. It doesnt change the fact that, in one argument you are discussing *methods* of forced induction, and in another argument *brands* of car manufacturers. As you are so fond of saying:
Comparing means of a process in one argument, and then comparing brands of a process in the next is just plain stupid.



I really don't have anything more to say or comment about you or your posts...clearly, you're incapable of treating anyone with any kind of respect, having a rational conversation, or even sticking to subject matter in your arguments.

SmokenDSM

Please do tell me a synonym for the comparison of a turbo- and a supercharger.
And I really don't care for any "pwning". I'm just trying to cut down on the heresy.

Giravani

Ok, before this turns into an all-out flame war, I would like to step in to try to bring a little rationality to both parties.

First, attacking one another's character doesn't accomplish anything other than flood useful posts with anger-directed commentary and non-productive garbage. We all know this and yet everyone continues to engage in it. But I will say it again in hopes that SOMEONE will absorb it and move on as a better person.

Second, both parties have logical points of view, but I believe that SmokenDSM may have expressed his thoughts differently than he originally intended them to be expressed. That's my rational side that gives everyone the benefit of the doubt by default. Although it needs to be said that there is a very clear line between thorough, rational, investigative, and diligent comparisons between two or more things, and flat out uninformed misinformation.

So, with that little blurb, I'm hoping that we can bring this to an end and get back on topic. I didn't see anywhere in the subject header for this thread that SmokenDSM is an idiot and engifineer is a genious, nor am I suggesting that this is the case for either person. The topic under discussion here is superchargers and turbochargers, and the pros and cons of both.

Without further adieu gentlemen (and hopefully with a little more maturity than before) I return to the original conversation.

-Adam

jmiller20874

Still waiting on those pictures you spoke of (reference STi) or was that another argument with no merit? Sorry Giravani, I had to do this but stating that "no open-deck engines are built for boost" and then once an example is given to dispute this fact, SmokeDSM made a clever dodge move.

Do you know something Subaru engineers don't or can you comfortably speak for all production turbocharged engines?