Electric Turbo

[public]

Perhaps I am a little out of the loop on the numbers. It has been a while since I built any forced induction motors but I do recall that we had this discussion in the mid to late 80's. On equal boost pressure the blower had a lot more to it but these were carburated engines. We did not have computers that could follow the turbo to do fuel injection. I do know that blowers respond to RPM changes instantly due to being belt driven. Turbos do not. The centrifugal blowers and turbos do fit under the hood a lot easier. Anyway, Forced Induction of any kind was allways a blast. The only thing more fun was my old 413 cid wedge N/A with dual quads and a 383 crossram. About 10 MPG. ahhh, memories. Good Luck.

[SaabJohan]

Originally Posted by Reed

yeah a roots blower is less than 70% effecient whereas a turbo can be upwards of 90%. if you really want a supercharger then go with a centrifugal one. it has a compressor just like a turbos but obviously with different blade angles, sizes, and numbers. they are far more effecient that a roots blower.

A roots supercharger is usually less then 50% efficient, the turbochargers compressor is usually 70-80% efficient if it's matched well.
Since the turbocharger also is driven by a turbine it doesn't take any power from the crankshaft.

Turbochargers also allow the use of higher boost pressure on lower revs than on higher, this is used on many turbocharged road cars today and in a bit more extreme version on the WRC cars which use such high boosts on low speeds that the power outpur is above 200 hp at 2000 rpm, above 300 hp at 3000 rpm all the way up to the engine speed limit of about 7000 rpm with a peak of about 330 hp at 5500 rpm. On these cars the turbocharger spools up so fast that the driver can't notice it.

The centrifugal compressor isn't of positive displacement type, this means that its boost will increase when engine speed do.

The turbochargers started to come during the seventies, first with mechanical fuel injection, under the eighties the electronic fuel injection systems took over. In USA for example the turbocharged Porsche 917 competed, the 917 won every race and the turbochargers was later banned. In the late seventies Renault started to work with a turbocharged 1.5 liter engine for F1. The engine had at first many problems and people laughed at it. But when it runned it was fast, and then it didn't took long until the 3 liter NA engines no longer had a chance. Of course this also resulted in restriction, but the NA engines still didn't have any chance. The speed and the cost increased and resulted in another ban of the turbochargers.

[longlivetheZ]

SaabJohan is correct. Turbos will have the potential to outperform any S/C in any application if properly thought out and designed. Turbos do not rob the engine of power (screw type S/Cs take as much as 30 hp per 100 crank hp), have very little lag when properly designed, and are much more efficient, among many other things. The pros for turbos greatly out weigh the pros for S/Cs. Why do you think that turbos have been outlawed or moved to seperate classes in most types of racing?

Read the "Turbo vs. Supercharger" thread in the Forced Induction section of the Cars in General forum...you'll never think about using S/Cs again.

[public]

A turbo does add a load to an engine. It may be more efficent but it does restrict your exhaust to some degree. But I think we can all agree that it is well worth it. Now if gas prices would just come down.

[Sluttypatton]

Meh, screw gas. It's time we moved on to alcohol.

[public]

Forced Induction and alcohol. Now that sounds like a party. Nitro Methane anyone?

[Auto_newb]

Originally Posted by longlivetheZ

SaabJohan is correct. Turbos will have the potential to outperform any S/C in any application if properly thought out and designed. Turbos do not rob the engine of power (screw type S/Cs take as much as 30 hp per 100 crank hp), have very little lag when properly designed, and are much more efficient, among many other things. The pros for turbos greatly out weigh the pros for S/Cs. Why do you think that turbos have been outlawed or moved to seperate classes in most types of racing?

Read the "Turbo vs. Supercharger" thread in the Forced Induction section of the Cars in General forum...you'll never think about using S/Cs again.

30 hp per 100 HP is a quite exaggerating especially for the screw types which are the newer ones. Turbos DO rob the engine's power at some degree, just not directly, it uses exhaust gasses as a medium transferring energy from the exhaust stroke of the piston to the blades of the turbine.

They have been outlawed because turbos give so much power compared to s/cs unless you run on a course with nothing but low speed turns and sharp turns with little to none straightaways, but obviously none of this would happen, but I think it is a stupid idea to outlaw turbos as they are just denying the inevitable and the companies that make s/cs will never be ambitious to find a way around the turbo and neither will the racing teams.

BTW, I read that thread, and it hasn't changed my way of thinking... I still like s/c's

[SaabJohan]

Originally Posted by Auto_newb

30 hp per 100 HP is a quite exaggerating especially for the screw types which are the newer ones. Turbos DO rob the engine's power at some degree, just not directly, it uses exhaust gasses as a medium transferring energy from the exhaust stroke of the piston to the blades of the turbine.

They have been outlawed because turbos give so much power compared to s/cs unless you run on a course with nothing but low speed turns and sharp turns with little to none straightaways, but obviously none of this would happen, but I think it is a stupid idea to outlaw turbos as they are just denying the inevitable and the companies that make s/cs will never be ambitious to find a way around the turbo and neither will the racing teams.

BTW, I read that thread, and it hasn't changed my way of thinking... I still like s/c's

How much power a supercharger is robbing depends much of the boost pressure. So in a small high boosting application the supercharger takes more than on a larger low boost application.

Turbochargers DO NOT use the exhaust gasses like some sort of medium to transfer energy from the exhaust stroke, I don't know why people tend to believe this.
As we know turbines work by the same principle as the piston engine; expandning a gas mass lower its enthalpy and this energy can be converted into motion. When the exhaust valve opens the temperature is still high and the pressure is well above atmospheric, this means that the gas can be further expanded and energy otherwise lost can be extracted. The turbocharger do not take any power from the crankshaft to power its compressor. The turbine do however add a restriction like a poor flowing exhaust system which restrict the exhaust flow, and this increase the pumping losses during the exhaust stroke. However, when the turbocharger works efficiently it can produce a boost which is as high as the exhaust pressure, or even higher than the exhaust pressure which means that the engine will work as NA in a high pressure environment or even as a supercharged engine but without the powerloss.

With modern technology the turbocharger will probably handle a course with low speed turns even better than a supercharged engine unless the supercharger somehow can adjust the boost pressure with a variable speed drivesystem of some sort, this since a turbocharger easily can use a higher boost on lower engine speed and keep the turbo going even on low engine speeds with the help of antilag or perhaps a variable turbine geometry. This can give the turbocharged engine high power outputs even at low rpm, an example of this is the WRC engine which I mentioned above.

[Neutrino]

Thank you SaabJohan for explaining that. It seems that many belive that turbochargers put out boost only in the high rpm band. However that is complettely false as you pointed out.

Turbochangers are load driven, so as long as the load on the engine is high the turbo will spool even if the rpm is low, making turbos excellent for low speed corners. On the other hand if you drop low in the rpm band and you have a supercharger you'll hardly have any boost.

So in a way with a turbo you'll have an adjustable powerband that changes according to the load placed on the engine.

For two perfect examples of how turbos can boost power even at low rpm lets look at those cars:


mercedes sl 600 Torque lb-ft at RPM: 590/ 1800 - 3600 out of a 5.5L V12 twin turbo

or srt4 wheel TQ lb-ft at RPM 250/2200 - 4400 from a 2.4L I4 single turbo


how can anyone say those cars don't have power at low rpm when they have torque numbers almost resembling diesels.

[longlivetheZ]

SaabJohan knows his stuff. He said everything I was going to say...thanks for saving me some time!

Quick summary: Turbos, contrary to popular belief, mostly use the heat from the exhaust to turn the turbine...not the actual flow of the exhaust. The restriction in the exhaust system is quite little until the turbo gets spooled up when restriction is pretty much none. A high flowing exhaust system will make up the difference.

Modern technology MORE than makes the S/C obsolete. Turbo designs, variable geometry turbos, etc have made turbos EXTREMELY efficient. Check out the design of the new Lancer EVO's turbo...pretty cool shit...

Originally Posted by AUTO NEWB

BTW, I read that thread, and it hasn't changed my way of thinking... I still like s/c's

And this is why you're a 'newb'. Don't worry...you'll learn.

[Auto_newb]

Originally Posted by longlivetheZ

SaabJohan knows his stuff. He said everything I was going to say...thanks for saving me some time!

Quick summary: Turbos, contrary to popular belief, mostly use the heat from the exhaust to turn the turbine...not the actual flow of the exhaust. The restriction in the exhaust system is quite little until the turbo gets spooled up when restriction is pretty much none. A high flowing exhaust system will make up the difference.

Modern technology MORE than makes the S/C obsolete. Turbo designs, variable geometry turbos, etc have made turbos EXTREMELY efficient. Check out the design of the new Lancer EVO's turbo...pretty cool shit...



And this is why you're a 'newb'. Don't worry...you'll learn.

Oh my god, you made fun of my account name, how old are you to make such stupid insults? You must be around 15 years old, because it shows that if someone doesn't accept your opinion you just HAVE to fire back no matter what, either that or you are a 30 yr old grown up with a manhood the thickness of a pencil and the length of an eraser, that needs a BIG MOUTH to compensate for something SO LITTLE.

Modern technology MORE than makes the S/C obsolete. Turbo designs, variable geometry turbos, etc have made turbos EXTREMELY efficient. Check out the design of the new Lancer EVO's turbo...pretty cool shit...

You know what little kid?

Maybe I should keep this name so I can let people like you make idiots out of yourselves.

EDIT**
Ok to make this post have a purpose after reading Neutrino's post... Turbo's from what I have seen have heat problems as they glow a nice red color, now wouldn't this make the intake charge hot as well?

Modern technology also adds more parts and complexity, which makes it less simple. S/c's will always have a place in F/I, from twin-screw to roots style.

[Neutrino]

GUYS....this is a very respectable part of the forum so lets keep it that way.


If you want to fight about something do it using technical arguments and not personal attacks.

[Reed]

the intake charge never comes into contact with the glowy thing (also known as a turbine housing). the only thing that really heats the intake charge is the compression (if you compress a gas it will heat up) this happens in superchargers too, except in a roots or screw blower you cant have an intercooler, and that is another thing that makes turbos better.

not to add to the rediculous argument above but you are calling someone a little kid while using fallic insults. your not making a good argument.

[Evil Result]

hum, if you had the proper cams, couldn't the exhaust pumping loss be reduced if the IVO & valve overlap was long enough where the intake charge would help push the exhause out then EVC and IVC whould hold the charge so as to avoide the power loss....i'm thinking camless technology... you would have no power at the low end for that to happen.

but with turbo charging how much HP loss to gained because of a reduce intake charging?

[rs182]

On the topic of the electric turbos/superchargers: I have two on my 28' Formula boat with twin inboard 350's and they are great for blowing gaseous fumes out of the engine compartment before starting the motors!