Guru_Del

iTrader: (5)

well in the spirit of the thread my opinion is go turbo. reason being this video

Right click and save

http://www.sclc.net/roadrace.mpg

Viciouz

iTrader: (6)

I don't know... I am feeling the Supercharger, but I need to see numbers and Dino's in order to believe it. Also, isn't there a way to make a supercharger give your car that sudden boost feeling of being thrown back into your seat?

Satori

I’ll have to vote for the turbo over the supercharger.

Superchargers are either less efficient (make more heat during compression) or they don’t give you full boost until redline (linear increase in engine speed = nearly linear increase in boost).

The roots type can hold an almost even boost regardless of engine speed but they have compressor efficiency around 50%, causing an increase of intake temps about 40% more than a turbo. This results in bad MPG, high engine heat and not a very good power increase.

The centrifugal types are typically more efficient than turbos (about 80%), but you have to deal with the fact that the boost pressure rises with the square of the engine speed. So a supercharger that puts out 9 lbs. of boost at 6000 rpm only puts out 3 lbs. of boost at 3000 rpm, whereas small turbos – like the T25 – can give full boost by 2500 rpm and will maintain that boost level to redline. Centrifugal types are also heavier than turbos and they take up more space under the hood.

The only advantage I see in supercharging is it would be a bit simpler to retrofit it to a normally aspirated engine than a turbo system. But the best way to go overall would be a turbo.

I did note that somebody pointed out that turbos aren’t a free lunch in that they increase “backpressure” (I hate that term) in the exhaust system. This is true; however, the pressure resistance caused by the turbine wheel is more than made up for by the reduced engine breathing effort once the turbo is spooling. IOW, the engine doesn’t have to waste power trying to “suck” the intake charge into the cylinder because it is being force fed. The reason it doesn’t increase exhaust manifold pressure very much is because the turbo isn’t powered by the exhaust pressure as much as it is powered by the exhaust heat. The drop in exhaust temps of up to 300 F represent the heat energy that drives the turbo – without which, all that potential energy is being wasted out the tail pipe. Turbos may not be a free lunch, but they are the next best thing to one.

NOTE: sorry if this post is repeating previously stated information, I didn’t read through all twelve pages.

Raptor

Superchargers are dead set easy to fit, they do take up a little more room than a turbo but are not heavier, well at least mine isn't. Don't forget to add that exhaust manifold to the turbo when calculating the weight, you will be suprised at the total weight increase.

Supercharger also negate the breathing effort making up for some of the power losses that are talked about.

No problem with coking bearings from overheating and improper shut down techniques with an S/C and no extra problems due to a massive lump of cast iron at incredibly hot temperatures.

S/C is the easiest way to make power bar nothing, no need to knock a hole in the sump for oil returns and the like either, really there is quite a few things that make T/C somewhat more effort and the extra power over a S/C (if any) won't be worth the effort.

My bit

Boeturbolancer

iTrader: (26)

Raptor... you say no need to knock a hole in the sump??? Are you sure... i've had to do this on quite a few SC installs including RIPPS. So where are you returning your oil from the SC?

Satori

Well, Raptor, if you’re looking for ease of install as the primary factor, NOS is by far the easiest way to make power -- easier than superchargeing or turbocharging. It’s just too bad that it’s a very temporary solution. A few runs of high power before having to refill the bottle make it impractical for street use on a daily driver.

I see quite a few people that have NOS setups on their daily driven cars and I’ll never understand why. I’d never put a car on the bottle unless it was a track only vehicle.


EDIT: spelling.

Raptor

Our S/C doesn't need or used oil for lubrication. Was designed with ceramic bearings from the outset and with ceramics and internal belt together with ported transmission cooling the unit needs no umbilical connection to engine.

We just bolt on and in 5mins its a goer, the blower is designed for the smaller engines.

Viciouz

iTrader: (6)

raptor, do you think your superchargers are applicable with the us lancers? and if so, what mods would have to be made in order to prep the car for a supercharger?

DEVOTED

iTrader: (1)

Now this thread is funny as hell. I've been droping into these SC, Turbo threads and it just amazes me what some people do. Its like me setting up a poll whether to use 91 octane or convert my car to a fuel cell and run on hydrogen. We know that 91 octane is avaliable and works great. We also know that hydrogen works great but how many lancers are really running on hydrogen... hmmm.... what should I spend my money on... ???

Boeturbolancer

iTrader: (26)

--->Devoted

Raptor... thats cool... i'd like to see that SC... who makes it?? That is what you'd think would be on the RIPP kit... maybe it is??
Cool info though!

sdhotwn

iTrader: (2)

Not completely correct. There are cases where the supercharger is as or more efficient than the turbo. A centrifugal shaft driven super charger is one example. It spins at lower speeds so has less loss due to rotational friction and so forth, and also produces lower temp charge air. It is equal to or slightly more efficient than a turbo typically.. But it's a pretty hefty tossup at that point. an IC'ed turbo will create nearly the same charge temp

Quote:

The roots type can hold an almost even boost regardless of engine speed but they have compressor efficiency around 50%, causing an increase of intake temps about 40% more than a turbo. This results in bad MPG, high engine heat and not a very good power increase.

The centrifugal types are typically more efficient than turbos (about 80%), but you have to deal with the fact that the boost pressure rises with the square of the engine speed. So a supercharger that puts out 9 lbs. of boost at 6000 rpm only puts out 3 lbs. of boost at 3000 rpm, whereas small turbos – like the T25 – can give full boost by 2500 rpm and will maintain that boost level to redline. Centrifugal types are also heavier than turbos and they take up more space under the hood.

You point out what I said above here...

Quote:

The only advantage I see in supercharging is it would be a bit simpler to retrofit it to a normally aspirated engine than a turbo system. But the best way to go overall would be a turbo.

I did note that somebody pointed out that turbos aren’t a free lunch in that they increase “backpressure” (I hate that term) in the exhaust system. This is true; however, the pressure resistance caused by the turbine wheel is more than made up for by the reduced engine breathing effort once the turbo is spooling. IOW, the engine doesn’t have to waste power trying to “suck” the intake charge into the cylinder because it is being force fed. The reason it doesn’t increase exhaust manifold pressure very much is because the turbo isn’t powered by the exhaust pressure as much as it is powered by the exhaust heat. The drop in exhaust temps of up to 300 F represent the heat energy that drives the turbo – without which, all that potential energy is being wasted out the tail pipe. Turbos may not be a free lunch, but they are the next best thing to one.

NOTE: sorry if this post is repeating previously stated information, I didn’t read through all twelve pages.

This section is the reason I had to respond to your post. The turbo is very much powered by the exhaust pressure and not by heat. The heat drop you see is purely a result of the reduced energy of the exit gas that results from conduction to the turbo body as well as the fact that work is being done and therefore energy is removed from the medium. Energy isn't free. If you disagree with me then explain the wastegate operation. Is the wastegate there to pull temperature from the exhaust to make the turbo produce less output? No, it vents off excess exhaust gases so that there is less overall volume to spin the turbo up.

The 300F drop is not heat energy that is driving the turbo, it is simply overall energy loss from the exhaust gas during the turbine operation.

Another argument against the heat doing the movement on not the exhaust gas... think of power plants. If the steam's heat was doing the work, then why run high pressures?? Turbine's are driven by moving fluid. A result of the use of that fluid's pressure to rotate a turbine is that energy is removed from the system. So yes the temperature drop seen is indicative of the energy used to turn the turbine, but it is not the heat that does the turning.

sdhotwn

iTrader: (2)

A few pounds here or there doesn't matter, but I do have a hard time believing a centrifugal setup with that huge mother of a shaft while leaving the stock header and so forth in place is going to be any lighter than a turbo.

But you forget to mention the near 20% loss a supercharger generates in the effort it takes to turn the super. Yes it makes that power back, but the fact that the charge is eating 20% of the power in the system is MONSTROUS compared to the parastic effects of a turbo.

You still have a hot exhaust manifold no matter what. Yes it doesn't have hot spinning parts I'll agree. Yes S/C is a lot easier for maintenance and shut down etc.

But supercharger can't make the same kind of power that a TC can. Especially on a small 4 banger where every ft-lb of torque counts. The fact that a SC add's nothing on the low end in comparison to a fast spooling TC is a massive drawback. a SC only further amplifies the overall top weighted power band that is common in a 4 cylinder. A SC is also more parasitic to the engine. The amount of power made at 10 psi on an IC'ed TC is a fair bit more than at 10 psi on a standard SC. This is being masked to some extent with methanol and water injection like on the RIPP kit. Also, a centrifigul system still has drawbacks with having piping that can mandate use of a BOV and still cause inaccurate total MAS readings that can still result in "stall" conditions for the engine.

Both are great technologies, but there are aspects to both that lend themselves more to one situation or another and to one form of tuning or another.

Not to mention the nearly fixed boost levels that happen with a SC system. You have to alter the system pretty heavily to changer your boost levels.. not just turn a spring on a wastegate like on a TC.

Boeturbolancer

iTrader: (26)

Damn...sdhotown... remind me never to get in a battle with you

Just kidding but your comments are great learning tools for all keep it up man

sdhotwn

iTrader: (2)

What matters to me is trying to provide good accurate information and trying not to be biased and at the same time making sure I'm not a jerk when I do it. So as long as I accomplish that and it helps someone that's what matters to me! The more knowledge there is in the community the better off we all are!

IILANCERII02

iTrader: (1)

wow steve your a beast! How can u improperally shut down a car with a turbo?