yes the SC "uses" Hp to make hp but when I am driving with the bypass valve open I do not notice it at all. Probably uses less power to drive than a AC system.

 

Yeah this thread is beaten to death...
the fact is that, from a theoretical standpoint, a turbo is and always will be better because the power input required to spin the turbine and connected compressor wheel comes from the exhaust stream, hence the "free power"... A supercharger requires a belt drive to spin it's compressor, making it less efficient...

That being said, it really comes down to what you want...
IMO though, because it is difficult to cool the compressed air down with a supercharger, (a temp increase is inevitable when air is compressed) and it is easier with a turbo, because you can use an air/air intercooler, placed in the air stream at the front of the car, (air/air is also more efficient than a water/air intercooler on Vortech and the likes), it is better to use a turbocharger...

One reason why I chose to go turbo is because of the many options you have available...
- Boost control is far easier than replacing pulleys
- ability to significantly lower the charged air
- etc...

 

Actually, a real water/air intercooler filled with ice water will cool well beyond ambient temperature making it much more efficient at cooling the charge temps than an air/air intercooler. One that is cooled from engine coolant will become heat soaked and very inefficient at normal operating temperatures.

 

Well I know that...
I was basing my answer off of engine coolant, as this is what is used in a water/air intercooler...
Who's gonna go through the labor to put ice water into their Intercooler, LOL that is just hilarious, could you imagine...
Water can soak up alot more heat than air, but it isn't practical in any situation, other than a track run, after which it will have melted and have to be replaced with more ice...
So turbo is always better

 

Well, not everyone daily drives their 10 second heavily boosted cars. I am talking about track runs.

 

Alright, I'm going to rant about my pet peeves for a minute:upset:

1) A centrifugal supercharger is a poor choice for a Honda, as it makes top end power only, as you have to spin the snot out of it for it to boost. So it's not conducive to a small displacement engine, as you still have little bottom end and you have to wait for the revs. That's why these are used on a lot of V8's as they already have the low end to spare.

2) A roots/positive displacement is a good match for a small displacement engine as it boosts the low end as well as the high end. Also, instant boost people. In cruising it's still spinning and making boost, it's just being bypassed, so the instant you hit the throttle, there's already boost waiting.

3) Turbo's are not free power! This drives me crazy, yes they are more efficient than superchargers, but they are by no means free. If you didn't have the compressor end of a turbo, do you really think you'd make the same horsepower with a big obstruction in your exhaust than without? Of course not! They lose power by blocking the exhaust, but more than make up for it by creating boost. Same thing with a supercharger, robs power from the belt, more than makes up for it with boost. Same idea, different efficiency is all.

4) Air/water intercoolers are much more efficient that air/air as Das Schmoo stated. Also, there are air/water intercoolers available for the jackson racing setup, and most have shown great results with it. It is very practical, you don't run ice daily, just when you're doing a drag race. And you don't use antifreeze, you use mainly water, as water has a higher heat capacity. Unless of course you're out in the dead of winter, then maybe you want a little more antifreeze.

5) A positive displacement supercharger usually sees a gas mileage increase when cruising. Of course in town with a lead foot, it'll go way down, but that is something particular to the driving style, not the forced induction.

6) No one setup is more reliable than the other, it all comes down to the individual. If you're some back woods bobo, halfassing it the whole way, it's not going to be reliable. If you're smart about it and use your whole ass, it'll be much less hassle.

You just need to figure out what you want. Autocrossing? Roots type supercharger is a good way to go, with the instant boost and all. Drag? Turbo is a better choice usually, easy to make alot of power, and you're on the gas continuously (well for those 10-17 seconds hehe). Only want a huge HP number? This is about the only place a centrifugal supercharger would be good, but it's just soo not for Hondas.

Personally, I'd go with a nice intercooled JRSC setup, aiming for 250whp max. I like the instant on (although I have owned and still love turbo cars), and would like to try something different. That's not to say a properly sized turbo kit couldn't make 250whp with almost no lag, but it's not instant either. But hey, I'm going H22 in my EH2, so what do I know! :thinking: Ooh, maybe I'll beat the tar out of my firewall and stuff a JRSC in there too!!! :crazyr:

 

what all are you basing your information on?

Without explaining all the ins and outs of it--No, turbos do not cause a parasitic loss in HP...there is no belt to drive the compressor...only the exhaust gasses that are already there flowing out of the engine hence the term "free" hp...put your hand up to my exhaust and tell me that the turbo restricts airflow...

You sound like a "performance handbook"--any one I've ever read says SC over turbo...

turbos have a greater potential for realized horsepower...( boost controller ) supercharger boost is limited by the pulley

superchargers are limited by the engine's rotating speed...

you auto cross much? a supercharger that didn't come factory puts you in a different car class all together...

So, where did you get all this info?

 

Don't get me wrong, I do agree with you for the most part. A turbo is more efficient, has higher power capacity, and is not limited by engine speed, and in most cases is preferrable to a supercharger, I completely agree. However, turbos do restrict exhaust, and it is not free horsepower. Sure, the flow is nice at your muffler, but that is after the fact, the restrction is the turbo, once past that it should flow quite well. The turbo has to be a restriction, othewise the turbo wouldn't move, as they are driven by the pressure differential (or temperature differential, but that's just splitting hairs really). Just think, that's why you put the best flowing exhaust on after the turbo, to maximize the turbo pressure differential. Yes, they make up for the restriction certainly, but they do restrict exhaust and thus cause a loss in power. Takes power to make power, there is no such thing as "free" energy.

I don't claim to know much about autocross, that comment was from a friend of mine. He autocrosses quite a bit, and has repeatedly seen that sc are easier to use (although I guess not necessarily better?) on a course than a turbo. I have no idea if it changes classes or not, but I would assume a non-factory turbo would as well, correct? I had made the comment more in the turbo vs. supercharger idea of the thread, but if it's better to stay NA, which what I assume your suggesting, by all means do that.

 

I'm sorry but I couldn't let this go unsaid. First things first, both forms of forced induction put alot of strain on any engine. Whether the engine was built and tunned propperly will help determine the life of the engine as well as how its driven. Secondly superschargers "DO" require the same amount of tunning as a turbo does. Your using a mechanical means of forcing more air through the engine and without more fuel and propper timing, detonation and damage occurs. Super chargers should be intercooled just as much as turbo chargers should. When you compress air it heats up! Don't mean to beat it up just had to be said....

 

^^most of what you have said is true, however a turbo does not cause as much of a loss in horsepower before compensating ( boost ), not by a long shot...sc takes more HP to run the pulley than a turbo restricting exhaust ( I've never heard that )

any modification to a car other than drop in air filter, fluids, and driver changes your race class

if it has a sc/turbo stock, then bully for you...

No, I'm not saying stay N/A...hell, I had a 100 shot nitrous before my turbo kit...where the fack did you get that idea?