Turbo vs. blower debate w/in

[HAZ-Matt]

<blockquote>quote:</font><hr>Originally posted by Bliggida:
why?<hr></blockquote>

I would not say that Bliggida is an idiot. I do however disagree with a few of his "facts" as posted.

First of all the typical argument that Bliggy uses for almost everything is that if it is used in top fuel dragsters it has to be the best. This is completely false. Please do not use this argument again. Turbos are not legal in NHRA top fuel classes. Remember when Indy cars first started strapping on turbos? They got a hell of a lot faster. And low and behold they were banned because cars were too fast and the drivers couldn't handle them (they have since ben re-legalized).

Here's a real fact. In any race series in which turbos are legal, they dominate.

Now, let's talk about a little thing I'd like to call thermodynamics. Turbos are more efficient compressors than any other supercharger. Centrifugal superchargers are next, followed by screw, and then roots are at the bottom. What does this mean? It means that a turbo will have LOWER intake temperatures than a supercharger at equal boost numbers. Hmmm turbo downpipes at 1600 degrees huh. I'd think I'd need to see some more data on that one. (BTW, the flames shooting out of the exhaust of top fuels is hydrogen gas burning... the extreme heat of their exhaust is enough to split atmospheric water into hydrogen and oxygen and then combust the hydrogen) But, that's ok cause little temperature is actually transfered from the turbine to the compressor. Superchargers make up for that heat with their inefficiency. And it is not only that superchargers are less effecient than turbos, but their compressor design is a large compromise. Look at a centrifugal supercharger. It's compressor is directly linked to the crank, and only sees peak efficiency for an instant. Turbos can stay near peak efficiency longer with the help of the wastegate. As their speed is only indirectly affected by engine rpm and load, it is possible to maintain a compressor speed profile that caries greatly from the rpm of the motor.

Roots and screw superchargers can produce a flatter torque curve in some cases, but they do so at the cost of higher intake temperatures due to lower efficiency. Centrifugal superchargers can in no way create as flat a torque curve as a properly set up turbo system.

Superchargers definitely have their place. In OEM applications, low end torque makes the car seem more responsive and sporty. Ask anyone about the LT1 versus LS1... almost all f the people say the LT1 "feels" faster, when in reality it isn't. So with the added low end punch for OEM apps, we can sell cars more easily. Superchargers also have the added luxury of being easier to retrofit to a car that was originally naturally aspirated. No crazy exhaust routing to worry about. Cam specs are also less importat with a supercharger than a turbo. At any overlap value, air will still flow in through the intake port, and out the exhaust port.

Bottom line, superchargers are easier, and can approach the performance of a turbo system, but they do not offer superior performance.

[ June 11, 2003: Message edited by: HAZ-Matt ]</p>

[Arctc Wolf]

turbo cars have seen 40+ lbs of boost. yes, turbochargers can glow after runs, but this heat doesn't transfer over to the compressor side. the glowing is the exhaust heat building up in the exhaust housing. roots blowers have an average efficiency of about 50%-60%. turbo's can see 65%-80% in some cases.

blowers require torque to turn the compressor, and since "ricers" as u call them, have small engines and make hardly ne torque, this isn't a good idea for them. the reason they make so much top-end hp is because their motors are set up that way on purpose. high reving engines make lots of hp cuz hp depends mainly on rpm, so yes, they're gonna put turbo's on their car's to make power from 3500 to 9000 rpm since that's their main powerband neways.

yes, blowers on big engines get you killer 60 ft. times, but only if you can hook the car up w/ suspension, chassis, and wheel/tire mods. I bet that car had slicks and a full racing rear suspension. not everyone wants to run w/ slicks and back-half their cars. I don't, cuz i don't have the money or the need to do that. also, u could do that w/ a turbo too. get a TC stalled to the lowest rpm that u make full boost at. Radcat said he made full boost at 3000 rpm. a lot fo ppl w/ TC's have 3000+ rpm stall speeds. if he put a 3200 Tc on his car, he'd launch at full boost, and could cut some very low 60ft. times if he could hook it up. And yes, drag racers use auto tranny's.

Bliggida, did I miss anything, or have I just shot all ur ideas out of the water? plz lemme know if I can educate u on ne other points.

[Arctc Wolf]

oh, and haz-matt, centrifugal sc's make more power top-end, so they are a lot like NA. this is why they prefer NA cams. roots blowers make the same boost everywhere, so they need more lobe separation. turbo cam should have dual patterns or favor the intake, or else the turbo kinda stalls out. ask dominic about the last one, he told me that.

[HAZ-Matt]

<blockquote>quote:</font><hr>Originally posted by Arctc Wolf:
oh, and haz-matt, centrifugal sc's make more power top-end, so they are a lot like NA.<hr></blockquote>
Obviously they make their best power at high rpm if the selected compressor is correct. Since centrifugal superchargers are directly connected to the motor, at low engine speed, the compressor is so inefficient that it's power output is not very high. Thanks for the info, although I already knew it. The second part is kind of sketchy... NA powerbands being top-end? Maybe some of the newer engines, but traditionally it has been about low end torque.

<blockquote>quote:</font><hr>this is why they prefer NA cams. roots blowers make the same boost everywhere, so they need more lobe separation.<hr></blockquote>
Depends more on where you want your powerband. I could put a high LSA on a car witha centrifugal and it would scream up top.

<blockquote>quote:</font><hr>turbo cam should have dual patterns or favor the intake, or else the turbo kinda stalls out. ask dominic about the last one, he told me that.<hr></blockquote>
Not that I mean to insult Dominic, cause I know that he knows his stuff, but I truly do not believe that there is one person on this message board that really knows how to set up a turbo cam. Go look at the cams that guys are running on the GN boards. Most of them are favoring exhaust. There are a lot favoring intake, or more accurately favoring intake duration, and I know exactly why they are doing that and what their thought process is... however I do not completely agree with them in every instance, and it is not necessarily true that you need to do that.

[Arctc Wolf]

ok, ppl who wanna put cam's in their MA cars look for higher powerbands since it make a lot more up high. this is why [ppl get 110-114 lobe separation. centrifugal sc's like this too.

I don't know about GN heads, but ours flow well supposedly on both sides. of course porting will help this even more, but if the exhaust is flowing within 10% of the intake, then more intake favoring would be good I'd think on a turbo car.

this about it. more exhaust duration would let air out over a long period of time, making it go out slow and keeping the turbo at lower rpm. more intake than exhaust would get a lot of air in, and push it out over a short period of time, but mroe forcefully, making the turbo spin at a higher rpm. blow in a pinwheel till u can't, doing it over a long period of time. it'll spin slow. blow on it as hard as u can in a short period of time, and it'll spin fast. since u have 6 cylinders blowing hard at different times, it keeps it spooled up quicker, all the time.

[nocutt]

<blockquote>quote:</font><hr>Originally posted by Arctc Wolf:
ok, ppl who wanna put cam's in their MA cars look for higher powerbands since it make a lot more up high. this is why [ppl get 110-114 lobe separation. centrifugal sc's like this too.

I don't know about GN heads, but ours flow well supposedly on both sides. of course porting will help this even more, but if the exhaust is flowing within 10% of the intake, then more intake favoring would be good I'd think on a turbo car.

this about it. more exhaust duration would let air out over a long period of time, making it go out slow and keeping the turbo at lower rpm. more intake than exhaust would get a lot of air in, and push it out over a short period of time, but mroe forcefully, making the turbo spin at a higher rpm. blow in a pinwheel till u can't, doing it over a long period of time. it'll spin slow. blow on it as hard as u can in a short period of time, and it'll spin fast. since u have 6 cylinders blowing hard at different times, it keeps it spooled up quicker, all the time.<hr></blockquote>


You are correct but this is more of a "general consesus"...you always favor exhaust when grinding a cam with TURBOs, especially!...You are forcing in pressurized air...why favor intake duration? well I take that back...better put; more emphasis should be placed on the exhaust. The 3800S2 heads flow wayyy better than stock GN heads...different ball game!

[hou-tex-six]

<blockquote>quote:</font><hr>Originally posted by Bliggida:
why?<hr></blockquote>

I believe HAZ-MATT and Arctic Wolf answered this.

Cp

[Bliggida]

Dominic I have never said anything to the effect that if its top fuel it must be the best thing to use. I mentioned several times the difference between all out racing top fuel cars and street driven cars. If you want to talk about all out racing, the superchargers win. And by the way, the most powerful turbocharged motor allowed to race is Meeny's 422ci Quad-Turbo. It makes 2,200 horsepower, and while competitive he has yet to dominate or win sufficient enough events to put him into contention of the points lead.

Blowers make up for the heat caused by turbochargers by their inefficiency? Since when is between 55% to 75% efficiency considered 'inefficient' especially on a street motor? In race motors they go upwards of 125% percent.

I can show you several examples of 40 PSI blowers. I have yet to see a 40 PSI turbocharger.

Yes I remember the turbo Indy cars. But they were not 'so fast' they couldn't be handled. There are more powerful machines out there than an indy car that are handled just fine. They were banned for other reasons. But be that as it may there are more powerful supercharged cars than an 1800 horse Turbo Indy car.

Allowed to compete in NHRA is immaterial. If they could build a more powerful turbocharged motor, they'd do it. Show me a automotive turbocharged engine that makes half of what is capable on a supercharged engine? Supercharges ultimately make more power.

Any form of racing allowing turbochargers they dominate. Okay, like Trans-Am, GT cup, Touring car championship, Touring II, like those? They are dominated by either N/A engines or supercharged engines like the blown NSX. The only form of racing I have seen dominated by turbochargers is rally racing. And they are using car's that would not have been built otherwise for homologation purposes as to why you actually see them on the streets. You go to build the best rally car, so you go AWD with a turbo, must make a production run to race them, and then you are champ? I'm not impressed. But that's not the point.

Superchargers only see peak efficiency for a moment? Um no, Superchargers also have blow-off valves, and wastegates that will regulate boost too. So you can have it come in a lower RPM and keep it producing boost at full efficiency on into your upper RPM.

A supercharger being easy to install depends on the tools, skill, and the application.

Artic wolf no need to restate something I've already said. That doesn't prove any points other than you weren't reading.
<blockquote>quote:</font><hr>blowers require torque to turn the compressor, and since "ricers" as u call them, have small engines and make hardly ne torque, this isn't a good idea for them. the reason they make so much top-end hp is because their motors are set up that way on purpose. high reving engines make lots of hp cuz hp depends mainly on rpm, so yes, they're gonna put turbo's on their car's to make power from 3500 to 9000 rpm since that's their main powerband neways.[quote/]

after I had already stated...[quote]Reminds me of another point - why would you supercharge or crate low boost on something that has no torque (FWD motors) these engine's don't make torque to begin with so why try to emphasize that when at best and boosted it will only be mediocre? Where as instead, these high end horsepower screamers will get a double dose if you turbocharge them.<hr></blockquote>

Does the car need to be back-halfed with slicks and be a total stripped down drag race car that isn't street legal...no, it doesn't. Nor are you required to do so for that level of performance. It's certainly the easiest way to get there, but not the only way.

I am also well aware what RPM a turbo can produce full boost at. If you were reading my post you would have seen that I already mentioned that very fact...TWICE. In fact I even talked about low RPM turbochargers that could create boost well below the midrange.

Did you shoot any of my points out of the water? No. You made a couple of untrue statements and then copied something I had already posted. If you are not going to contribute anything new to the discussion please refrain from reposting what someone else already wrote.

From an article I came across <blockquote>quote:</font><hr>Because the turbocharger is mounted to the exhaust manifold (which is very hot), turbocharger boost is subject to additional heating via the turbo's hot casing. Because hot air expands (the opposite goal of a turbo or supercharger), an intercooler becomes necessary on almost all turbocharged applications to cool the air charge before it is released into the engine. This increases the complexity of the installation. A centrifugal supercharger on the other hand creates a cooler air discharge, so an intercooler is often not necessary at boost levels below 10psi. That said, some superchargers (especially roots-type superchargers) create hotter discharge temperatures, which also make an intecooler necessary even on fairly low-boost applications.<hr></blockquote> now you combine that heat with the other heat causing factor of how fast the Turbo spins. Speed causes friction which causes heat. A turbo can spin 75,000 to 150,000 RPM, where as a blower may only see 15,000 to 40,000 RPM. That significant RPM means more heat. Heat kills horsepower.

Another article states: <blockquote>quote:</font><hr>Not only is this heat from the exhaust useful to us but it also has a down side, in that temperatures well over the 1,000ºC mark are not uncommon and that plays havoc with the turbine wheel.

As development of turbochargers has continued, the material used for the turbine is now changing from nickel alloy, heat resistant steels to ceramic materials. Not only are they lighter but they can also stand up to those high temperatures very well. <hr></blockquote> and later goes on to say <blockquote>quote:</font><hr>A generally held opinion about superchargers is that they take power from the engine to drive them, so they are not really all that efficient. Without getting into comparative graphs and so on, just let me say that the increased power output from an engine that is supercharged (even lightly), is far and away superior to the same engine without it!<hr></blockquote> Superchargers certainly do require power from the crank to be powered. However, what it actually is and what people make it out to be are two totally different beasts. I've seen some people claim that half the power you could have had with a turbo is being costed by a supercharger. Depsite both motors being built otherwise equally both seem to make the same amount of power, such that it can be negligable on street motors. But if they make the same amount of power and the supercharger is robbing you horsepower from the crank, wouldn't that mean that the supercharger actually makes more power since it overcomes that drag to produce the same amount of power...EXACTLY.

The same point can be made about a Turbocharger making just as much power as a supercharger despite being heated and subsequently heating the air intake temperature to insane amounts it still makes the same amount of power relatively in a street motor.

However, there is a distinction between what we drive on the road and race engines. Ultimately you will make more power with a supercharger. In theory a turbocharger could make more power as the PSI increase until it would blow itself up (thank the wastegate) however, this theory has never been proven to be a more effective way of making power.

And again. The question is not which is better the supercharger or the turbocharger. If that is the question you are asking you are asking the wrong one.
The better question here is "what do I plan to do with my force inducted motor?"
So you can better answer which one will be right for YOU in your SPECIFIC case concerning your PARTICULAR vehicle setup.
There is no one simple answer for a street car.

They both have advantages and disadvantages, the folks who understand that and tell you to leave it at that! They are the ones that are getting the correct picture. It entirely depends on what you plan to do with the car, and what car you have, and how you drive. That will dictate which is a better choice for you in your instance.

As far as reliability and ease of installation, a supercharger will generally have the upper hand but that is totally dependant on what engine you are working on. There are some applications a turbocharger would be easier to install. Though not suffering the heat of a turbocharger, a supercharger could wear out faster which goes back to the third part of the equation "how you drive". A baby'ed turbocharger might last longer than a flogged supercharger.

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by hou-tex-six:
I believe HAZ-MATT and Arctic Wolf answered this.<hr></blockquote>
no, they didn't.

[nocutt]

I really don't wan't to get into the debate of which mod is better...two completly different animals...I do however know that you (Bliggida)are given false info or incomplete info. In other to even out the playing field I think we need to stick to street driven cars and street driven cars that will see strip usage. Wanting power is a testament everyone will attest to. Now, how you get it and how you put it to use is entirely dependent on what you REALLY want.

As for the 40 psi blower you keep on describing, can you imagine how much HP/Tq it will take to drive that thing...SERIOUSLY? 40 psi is really not even worth it on a turbo app. (although you call Ken Duttweiler GN guru he'll tell you different).I have gone to the strip several times and both supra and GN I have seen run an "open wastegate" so we are talking about 25 maybe 31+ psi. And they come back, for more...and this are street driven cars...show me a blower running this much on the street...but in the end what does it really matter? A blower is fixed on what it will displace at X RPM...you need to understand that point. All the other points you have made and attempted to make seems to overlook this point. Efficient or not...on the street, a blown car will see less of its peak power compared to a turbocharged vehicle...light to light. On the strip, this is a little different...and of course very subjective, but we are still bound by physics. Therefore, yes the blower can make more power on tap, but been able to make it to the floor will be another problem given a 3800S2 stock configuration as a good example. With a turbocharged vehicle, equipped with an electronic boost controller you can delay how boost gets into the engine, when and even place specific psi within gears or RPM. Ultimately a turbo can be made to even mimic a Blower's flat torque curve and then this configuration can still change...the versatility is phenomenal to say the least. This is one of the reasons why a lot of folks favor turbos. I love superchargers personally, but they only show the characteristics of their design and not the engine's character...

[hou-tex-six]

<blockquote>quote:</font><hr>Originally posted by Bliggida:

Superchargers only see peak efficiency for a moment? Um no, Superchargers also have blow-off valves, and wastegates that will regulate boost too. So you can have it come in a lower RPM and keep it producing boost at full efficiency on into your upper RPM.<hr></blockquote>

I didnt bother to read the entire last Chapter in your book of unfounded, untrue, misinterpreted, and just plain wrong BS. But I did run into the above little jewel... Where exactly are you mounting the wastegate on your superchargers??? Do you even know what a wastegate is BligGAYda? Again, I didnt read all that nonesense, but I highly recommend you get your information from "articles" that arent biased and one minded. Where are these coming from, because what it looks like is that your reading the wrong information written by dumbasses and guess what this makes you look like? Yeaaaah, I'll let you figure that one out...

Cp

Edit: Just some "Articles" I found on the web. I cannot assure their accuracy, but these are being sold, so I assume they exist:

"TT50 - Capable of over 50 PSI of boost. Race applications for small blocks or modified big blocks. Flows 1400 CFM @15 PSI. Supports 1250+ HP. Large Garrett mount."

From: JEM Performance Parts


And another little article. 48 PSI, Inline 6 Turbo, 730Hp and 1300Tq. Theres your 40 plus psi turbo, getting pretty close to 50.

http://www.bankspower.com/im_tt_july03.cfm#

Cp

[ June 12, 2003: Message edited by: hou-tex-six ]</p>

[V6Bob]

"Any form of racing allowing turbochargers they dominate. [sarcasm] Okay, like Trans-Am, GT cup, Touring car championship, Touring II, like those? They are dominated by either N/A engines or supercharged engines like the blown NSX."

Add-on turbos aren't allowed in Trans-Am, etc. These are all relatively stock-based classes.

"The only form of racing I have seen dominated by turbochargers is rally racing."

Possibly the best example of turbo domination is Formula One when turbos (and supers) were allowed in the 70s/80s. Turbos ruled, even limited to one half the engine displacement of NA engines. Nobody even tried to compete with a super and it wasn't because the Formula One guys are dumb, or lack money, or are not willing to try stuff. Another good example is the Can-Am cars of that period - turbos destroyed the Can-Am's "run what you brung" philosophy. Once again, it wasn't because people overlooked supers.

"Show me a automotive turbocharged engine that makes half of what is capable on a supercharged engine? Supercharges ultimately make more power."

When turbos were banned in Formula One they were making over 1000HP with 90 (nine-zero) cubic inch engines. On gasoline.

For reasons I don't fully understand, in the highest and least limited classes turbos have dominated in road and oval track racing and supers in drag racing. Might have something to do with aerodynamics and weight, or maybe large displacement engines versus small displacement engines, or possibly the fuels used. Or maybe fuel consumption, which is not a factor in drag racing. I just don't know.

"There is no one simple answer for a street car."

On that we agree. Personally I like supers better. I've owned a super, but not a turbo.

But, at the highest levels the racing record is completely clear. Where turbos are allowed they have dominated on road courses and on ovals.

[ June 12, 2003: Message edited by: V6Bob ]</p>

[mattsv6]

if centrifugal and roots blowers are more efficient then turbos and they are better then why dont deisel trucks run them. what about planes??? why did they design a turbine engine after the turbo instead of the blower?? the facts that have been stated dont make any sense to me! i jsut dont no who is posting mis-information for all too see on the net and i hope that these people smarten up a little and take it off.

turbo's also dominate the bonneville salt flats and other "high speed races" among almost all classes of organiz3d racing.

this is a quote that i am taking out of a book:

" what mtoor can be turbocharged?? any motor can be!
how much power can i make with a turbo on my motor? you can make as much as the motor will handle!"

i think that speaks for itself.

<blockquote>quote:</font><hr> Not that I mean to insult Dominic, cause I know that he knows his stuff, but I truly do not believe that there is one person on this message board that really knows how to set up a turbo cam. <hr></blockquote>

we are trying to have a reasonable debate about turbos - blowers and you are flaming people like this? i really took offense to this considering i design about 10 cams per day at my work for the racing motors that i build. i am sure that others "including dominic who you used as an example for no reason" are kind of pissed at that statement.

turbos produce heat the same way that a centrifugal blower does. when you compress air, it creates heat. this is a law of physics so noone cna say otherwise with this.

someone stated that you can intercool turbo's or aftercool blowers??? are you kidding me with that statement? makes no sense to me because an intercooler is actually a mis-statement. if you introduce a cooling medium "after" the means of compression, that is known as aftercooling. you can say that i am wrong and my knowledge of this subjects is wrong. but me and all the other people that no alot about turbos will agree with what i jsut stated.

blowers being MORE efficient then a turbo? in some cases yes. but it is only when a turbo that is mismatched to a motor is compared to a proper sized blower. you can have a turbo with a max efficiency of 80% if it is run the right way and on the right motor. this is why i asked if anyone new where i could see some compressor maps for the centrifugal blowers and compare them. i no for a fact that a roots blower has a max efficiency of about 55%, so that it not even close to a turbo. and i am estimating roughly about 60-70% max efficiency for the cetrifugal. so the turbo definitely comes out on top there.

now lets look at placement. where can you mount a blower?roots, only on the intake manifold. centrifugal, somewhere that you can grab the belt to turn it. turbo(s), hrmmm, i think they can go anywhere in the car. that must be a plus there. i have seen the turbo inside the car where the passenger would normally be and i have seen them UNDER the gas tank in an f-body before. this has to be a plus for the turbo's agrguemnt.

[Arctc Wolf]

I am tired on trying to show u why u are wrong. Those of us who know about car's know that I am right. I think u need to read books on turbocharging andf supercharging, and learn it for urself.

Thanks to those of you who know what I'm talking about and are trying to teach Bliggida something.

[slacker69]

yall will see how much turbos own when me and tiago finsh my car wih t64 turbo and you will say blower what. You just wait.