dhof303

Wow, not touching this thread would be the smarter thing to do but I can't help myself. This very subject is the route of a century of performance debates in cars, planes, boats. The bottom line comes down to who has the best setup for the money IMO, anyone can win a race on any given day, making more power on a dyno than anyone else is an endless quest for those with unlimited funds. I say use your money wisely, in a unique way that makes power, if it doesn't then lesson learned and try a different route. Sometimes you get a good combination of parts/car/driver and you can be the winner for the moment. Opinions on what is best it appears sometimes can get out of control when people are face to face much less behind computers. I am interested in helping any fellow enthusiast gain as much as they can from their car, even if I don't agree with the setup.

killo-11

Hey Fordracing200
You have obvisouly confused this thread of mature people discussing 2005 Mustang Tech and performance with some kids chat room. Keep the "male body part and stfu" comments for your self and by the date of you birthday you are barley old enough to own a car let alone one of these. If you look at the title of this page, let me help you "The Mustang Source Forums > Mustang Discussion > Mustang by Model Year > 2005+ Mustang > S197 GT Tech & Performance" it doesnt say anywhere for you to tell us about your daddy's 86 GT. Or to insult people that disagree with you. And by the way this was a discussion about a soon the be released turbo kit for the 2005.

Fordracing200

i said nothing about any fox mustang, u are out of line and i am not gonna waste my time with your useless rants, u have nothing good to say as a comeback so u go ahead and pick on me cuz my age???whats wrong with you? Are you just mad cuz u are losing the agrument? or is it a lack of confidence?

lilbossman

did he say anything about his dads car? i didnt see anything.if you are goin tosay something be sure to make sure its right.

clintoris

OK... here we go again... except today, I'm in a better mood, so I'll try to be more civil.
By the way Michael, with turbos, its actually all the plumbing that makes them spool up faster. It's kinda like an air compressor... you have to build volume. The bigger the compressor tank, the longer you can sustain the air pressure you're looking for. So, ironically, the most efficient turbo system I had ever read anything about was actually mounted in place of the mufflers. That's like 30 miles of plumbing, but its all of that volume that allowed it to run so effectively.

Anyways... I'd like to take this down a notch as far as the attitude. We all sit here in front of a computer screen and know pretty much nothing about each other. We can't sit here and defend ourselves when people start making comments about who doesn't know what... there just isn't enough time in a day to type all of that. So, I'll be the first to admit that I don't know everything, and I'll appologize for my attitude yesterday. But, lets not make comments about other people's intelligence when we really have no idea what people do and don't know. I'll say that I'll be the first to admit when I don't know something, or when I'm wrong (which rarely happens.. just kidding). But there are a lot of people that are trying to learn something from these tech forums, ...... so perhaps we could be a little more informative instead of argumentative.

Anyways.... I'm done being mommy for today. Now let's all play nice.

SurfnSoCal

I think some people here have sand in their vaginas. maybe a whole desert.

Fordracing200

I actually didnt have a problem with you in this thread until the blower me crap. So, lets just walk away from this as civil people.

Fordracing200

you pervs are obsessed with the human body arent you?

RRRoamer

Wow!

Turbos can build boost faster than either roots type blowers OR screw type compressors. Screw compressors ARE more efficent than roots, but they still build boost in a basically linear fasion (given that they are driven by the crank, they HAVE to!). Turbos can produce max boost from a very low rpm. And hold it all the way to redline.

The issue with lag and "frying oil" is VERY old school. They do have a bit of lag, but a super charger does too. You have to spool the engine up to make boost with either of the mechanical beasts, so you can't say they are lag free.

Down side to turbos: complexity. And, if Ultimate Racings experience is the guide to follow, difficulty in programming '05 Mustangs ECU to understand it.

In short, for a given amount of boost (and assuming intercooled or not intercooled across the board), a turbo will give you more peak power and a wider torque curve.

There have been a few experiments published on different boost methods on the same engine at the some boost level. The turbo always made the most peak power (and usually at a lower rpm than the rest) and it always had the widest torque curve as well as the highest peak torque. Take a look at the torque curve from a turbo engine some day and compare it to the curve from a roots or screw blown engine...

Drivabiligy... That is a toss up. Properly set up, turbos can be just as drivable as any blown engine. But it is definitely harder (aka:requires more skill) to do it properly set it up. I have a feeling it will be a LONG time before we ever see a bolt on turbo kit that doesn't require custom tuning to fine tune it on the 05s. I might be mistaken, but...

RRRoamer

Wrong. A turbo is pretty much a pure thermodynamic engine. Gas temperature, pressure, and velocity (well, without velocity, you won't HAVE any pressure...) are what spins a turbo. The engine is MAKING these hot gasses at a pretty fast rate. Having large volume (on either side of the turbo and before or after it) just increases the mass of the air in the system that has to be accellerated, which DOES increase turbo lag. Also, the longer pipes have a negative effect of cooling off the exhaust gases BEFORE they get to the turbo's turbin section. Bad. That's the main reason why turbos are normally mounted right on the exhaust header/manifold. That delta T between in and out on the turbine is the single biggest contributer to the power that drives the compressor. The less T that goes in, the less power that comes out.

killo-11

clintoris,
I am confused about your statement. Please explain how having a larger chamber to fill makes a turbo respond faster? It seems to me that turbos are driven by exhaust flow and pressure, filling a larger area like an exhaust pipe that it long would act like a buffer and slow the time it takes to get a response from the turbo. Also having to fill a long outlet pipe on the compressor side would compound the problem.
What you refer to as build volume I would call lag and lots of. While I will give you the top end would be ok the time to get everything moving would take longer. Please try to explain you opinion as I have.

killo-11

RRRoamer,
That was a good explanation thank you for that. But it seems to me that it also depends on how you measure power. Peak horse power and average horse power across and entire rpm band might be a better way to evaluate performance. While I am not saying that you are wrong but the average power produced from idle to red line might be a better way of measuring and evaluating any system. Have any studies been done this way? And again I must state all my opinions on this thread have been about the system that was presented at the beginning. Not as a debate between turbos and superchargers.

Fordracing200

DUH, ever heard of a Dyno Run? :bang:

killo-11

Read the ENTIRE post before you show your stupidity and igornance. The question was about average horse power across the entire rpm band. Not peak, and also how the average of a turbo system compares to the average of a supercharger. I know the concept of averaging is probably beyond your comprehension but if you do a Google search it will explain it to you. I don't have the time to explain simple math to you.

clintoris

Michael,

when I was talking about volume (and this is how I understand it, so if I'm wonrg here, I'd love to learn something.... so please help me to understand) but here goes.... I'll compair it to an air compressor again. If you have a compressor with a hundred gallon tank on it, and you run air out of it at 10 psi, you can maintain constant 10 psi for x amount of time... if you have a compressor with a 20 gallon tank on it, you can't maintain that constant 10 psi for as long a period of time.
So if we take that principle and apply it to a turbo, because the vacuum of the engine when naturally aspirated is going to consume the charged air in a super short intake tube a lot faster than it can if you have 15 feet of plumbing that will hold a lot more volume.... so the turbo can maintain the desired psi for a longer amount of time.

I may be way off here, so correct me if I'm wrong.

So RRRoamer, I'm not above being corrected, so help me out here, brutha

killo-11

The part of the problem isn't how much air you have stored to cram in to the engine but how long it takes to to to compress it. A large volume pipe will hold a larger amount of air but will also take longer to fill (lag). Then when you shift and the rpm drop the pop-off valve will sense an over pressure (lower rpm = less air consumed) and relieve your built up supply. In the system we are talking about, the mounting of the turbine is far from its source of its energy. So naturally is will respond slowly (more lag). If we had an engine that operated at a constant rpm what you are saying is true but as we know we are varying the rpm constantly.

RRRoamer

That is EXACTLY what I am trying to get to in my previous posts. Not only will a turbo make more PEAK hp than a supercharged engine (again, everything being equal!), but it will make MORE power down low. AKA: wider power band or higher average HP. That's why I said look up some good turbo HP and torque curves and look them over. A turbo builds insane power down low and just keeps building on it as rpms rise. A supercharged engine is more linear and that it builds more power as the rpm rises, but it doesn't start off so high down low (down low in this case is in the 3000 rpm "range").

RRRoamer

Clintoris,

The problem is your analagy (or how in heck you spell that word!!!). I turbo system really isn't like an air compressor system at all. With a compressor, you are trying to fill a bottle with compressed air for LATER use. In this case, a larger bottle DOES give your compressor more time off before it kicks on again. ASSUMING the compressor is putting out more air than your tools are using. Then it just comes on and stays on... Thanks sand blaster...

What really makes your statement worng is when you say " is going to consume the charged air in a super short intake tube a lot faster than it can if you have 15 feet of plumbing that will hold a lot more volume....". The whole point of boost in the first place (be it turbosupercharging or mechanical supercharging) is that the supercharger produces MORE air than the engine can stink down in a given amount of time. The excess air backs up against the "restrictive" intake system and builds higher pressure than atmospheric. The next time an intake valve opens, it has this higher pressure air pushing it into the cylinder faster and leads to a denser charge in the chamber.

And one common misconception: a vacuum does NOT "stink" anything. If you get right down to it, "vacuum" doesn't really exist. What we call a vacuum is really just an absence of matter (generally a gas of some kind, like air...). It's kind of like darkness. It's really only the absence of light (of some kind at some frequency...).

Why a vacuum appears to stink is because of the behavior of gasses. The individual molecules are always zipping around and bouncing off of everything in their path. If there is a lot of molecules around, then they are bouncing off of each other more than they are bouncing off of solid objects (like the back of the intake valve or inside of the intake manifold), so they are constantly pushing each other around.

When that intake valve opens on the lower "pressure" in the cylinder, the gas molecules at the face of the valve suddenly find they do not have anything to bounce off of on that side (but they are still bouncing off of the gas molecules futher up the intake and off the intake sides), so they keep traveling into the cylinder until they bounce off of a gas molecule or perhaps the cylinder wall instead. As more and more molecules go into the intake, the molecules further up the intake starts to push the gas in front of it towards the intake valve. This propogation is the lag that it takes to get the air in the intake manifold moving into the cylinder. It's not very long, but it DOES exist and it does effect how much air gets into the cyclinder before the intake valve closes again.

Things get real weird when you get so few molecules in the container that the gas molecules are hitting the container more than they are hitting each other. This is the "moleculer flow" transistion (-3 or -4 scale if my memory is working). At this point, there are not enough molecules in the container for the mixture to act like a liquid and "flow" like above. Instead, each and every molecule has to bounce it's way through the valve.

Of course, this has absolutely NOTHING to do with automobiles as the best vacuum you will find on car (say the AC system when it is being pumped down before charging) is not really that close to the transistion. But moleculer valuums are just weird. My tools at work (process engineer for Intel) operate in the -8 to -9 scale and some of the newer tools are getting down to the -11 and -12 scale. That is just a few molecules in the entire process chamber.

killo-11

I wish I could post pictures here but I don't know how. Lets try to compare two different systems while not the same they are close.
The new Saleen supercharger claims 430.6 HP and 398.06 TQ @ 4psi.
http://www.modularfords.com/forums/s...ad.php?t=29196
This turbo charger system claims 356.7 HP and 368.98 TQ @ 3.5 psi.
http://www.ultimate-racing.com/Products2/M...tangTT-3PSI.jpg Both were run on a Dynojet, while I don't know the the conditions of the Saleen chart the turbo clearly shows 52.89F. Now we are talking about a .5 pis difference and a 73.9 peak HP difference in favor of the Saleen kit. Also note if you look at the two different graphs that the turbo system is lower in power across the entire run. Let look at a few points. Turbo 2300 rpm 80 HP, SC 2250 rpm 110 HP, Turbo 3000 rpm 175 HP, SC 3000 rpm 205 HP, Turbo 4200 rpm 300 HP, SC 3200 rpm 300 HP, Turbo 5000 rpm 350 HP, SC 5000 rpm 375 HP, Turbo 6000 rpm 355, SC 6000 rpm 420 HP. Look for your self if you think my numbers are incorrect. I will give you that there is a .5 pis difference but I don't think .5 psi will make up the difference in HP here do you?

killo-11

RRRoamer
You are correct in you description of gasses. A better word for a vacuum would be a void. And I also think you meant to mention that you are working on the Torr scale not inches of mercury.