Turbo Vs. Super

[454Casull]

Originally Posted by krebs128

supercharger or turbocharger, they both produce friction which equals heat, now which one produces more heat? idk-i'll just have to take your word.

If there was enough friction to produce heat that wasn't in negligible quantities... well, there isn't enough to friction to produce a lot of heat.

[Hypsi87]

As you all probabally can tell I'm a turbo nut. Something about superchargers I just don't like. ( they rob too much horsepower.)

Here are some other little tid bits on turbochargers.

Everyone always says "If a turbo is so great then why don't top fuel funny cars run them. The anwser is....In the NHRA rule book it states that they are not allowed to use any other type of forced induction.

A turbo will not increse the ammount of accuall air that your engine flows. That is because a turbo is a pressue multiplier not a preessure adder. for example lets say that the room you are sitting in has 1000 cfm of air in it. Well a turbo will take that 1000cfm and stuff it in the soda can you have sitting next to your computer. It's still 1000 cfm it is just more dense.

A turbo can spin 150,000 RPM's or faster depending on the size and boost level.

Boost is accually the ammount of air that your cylenders don't use. If your cylenders used all the air that was supplied by your turbo then how could pressure be built in the mainafold???

You can not build boost just by simply reving your engine ( I.E. building boost in neutral.) the turbos need exaust to spin and a engine under no load does not produce the exaust to spin the turbo fast enough.


Thoes big redneck tractor pull tractors have four to six turbos on them hooked up in sequence and they produce 100+ PSI

[SaabJohan]

Boost pressure is the pressure above atmospheric.

A turbocharger will increase air mass flow (but not volume flow) into the engine. 1 bar of boost means approx. twice the mass flow. Air mass flow is what makes power.

Maximum turbo speed depends on the turbo size, smaller one can use up to 300,000 rpm but larger only 100.000 rpm, this is because they are limited by blade speed.

The turbochargers compressor has a very high adiabatic efficiency, this means that very little heat are produced and that the power consumtion of the compressor is low. Adiabatic efficieny is infact higher than most belt driven centrifugal compressors.

Turbochargers last very long if they are used correctly. They usually last longer than superchargers.

[454Casull]

Originally Posted by Hypsi87

As you all probabally can tell I'm a turbo nut. Something about superchargers I just don't like. ( they rob too much horsepower.)

Here are some other little tid bits on turbochargers.

Everyone always says "If a turbo is so great then why don't top fuel funny cars run them. The anwser is....In the NHRA rule book it states that they are not allowed to use any other type of forced induction.

A turbo will not increse the ammount of accuall air that your engine flows. That is because a turbo is a pressue multiplier not a preessure adder. for example lets say that the room you are sitting in has 1000 cfm of air in it. Well a turbo will take that 1000cfm and stuff it in the soda can you have sitting next to your computer. It's still 1000 cfm it is just more dense.

Boost is accually the ammount of air that your cylenders don't use. If your cylenders used all the air that was supplied by your turbo then how could pressure be built in the mainafold???

You can not build boost just by simply reving your engine ( I.E. building boost in neutral.) the turbos need exaust to spin and a engine under no load does not produce the exaust to spin the turbo fast enough.

Do you know what cfm means? It's an acronym for "cubic feet per minute"... How can you use a unit for fluid flow for volume? That would be like saying a lawnmower engine makes 20lb-ft of power...

Next - boost increases the density of the air, so the cylinders actually do use the boost.

</me owned>

[SaabJohan]

To build boost we will need load (the amount of exhaust increase much more by load than it does by revs), by revving the engine in neutral the only load we have is from the crankshaft and flywheel inertia, and that won't do that much. To build up boost in neutral we will need an anti lag system.

CFM, cubic feet per minute is a volume flow unit, this is usually measured before the compressor in a turbocharged engine. But if we instead measure it after the compressor we will find that if we turbocharge a NA engine the turbochargered one will have the same volume flow as the NA one, but its mass flow have increased due to the higher density. However, if we measure before the compressor the volume flow into the turbocharged engine is higher than for the NA engine.

To build up boost the compressor must deliver more air mass flow than the engine consumes. To maintain boost the compressor must deliver the same air mass flow as the engine consumes but a higher volume flow.

[disco192]

I just wanted to address the issue of turbo lag:

Turbo lag is a thing of the past. It used to happen because engineers put heavy turbos in cars with insufficient backpressure. Drive an old Saab or an old Volvo and you will know what im talking about. And when everyone says that superchargers are better of the bottom, i say bullshit.

Low end torque is also a thing of the past. New turbos with ceramic fins and extremely sophisticated bearing systems have almost NO lag when put in the right configuration. Read up on turbonetics ceramic ball bearing turbos, they are sweet.

And on the topic of low end torque, with todays transmissions you dont need power in the bottom half of your powerband anyway due to gear ratios. In a 6 speed you spend the whole time in the top 75% of your powerband while racing. Back in the day of 3 speed autos and 4 speed manuals, you did need power in the bottom half. But cars have 5 and 6 speeds now.

People need to grow up and realize that cars change with technology. Turbos dont have lag and you dont need low end torque (eliminating superchargers "advantage").

[9ball]

http://www.superchargersonline.com/content.asp?ID=19

Here is a good article on this subject.

[beef_bourito]

maybe a little off topic but why dont you just add a supercharger and a turbocharger, wouldn't they compensate for eachothers downsides?

[454Casull]

Quite complex...

[Sluttypatton]

Its been done, I beleive it's called "dualcharging", but 454's right, it's tricky.

[beef_bourito]

yes i know it's tricky but what would be the advantages/disadvantages of dualcharging as opposed to just super or just turbo?

[Polygon]

Originally Posted by beef_bourito

yes i know it's tricky but what would be the advantages/disadvantages of dualcharging as opposed to just super or just turbo?

Simple, none.

[454Casull]

Originally Posted by Polygon

Simple, none.

None? Relative advantage? Or no advantages whatsoever?

Can you elucidate?

[MustangRoadRacer]

there are also centifgal superchargers. not all are roots type.
anytime you compress the air it heats up, which is why intercoolers are used because with cooler air you can compress it more and run more advanced timing for more power.
more superchargers now have intercoolers. I know Vortech offers one they call the "aftercooler" which helps.
the only bonus to belt driven superchargers is that you have almost all of the boost available at VERY low rpm compared to a turbo.

[Neutrino]

My personal preference is still the turbo

main reasons

easy to tune boost levels and response even on the fly...on super you have to change the puley

turbo will put out boost depending on rpm and load...super will put boost based only on rpm

turbos will cause backpresure but its negative effects are minor compared to the parasitic loss of a super