I'm just curious as to what is better and why? Is it that turbos are cheaper? It seems that supercharging is way simpler to set up.
Supercharge Or Turbo?
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turbo66valiant
Well-Known Member
I prefer a turbo but the real question is why did you throw the Slant away for the BB in the Valiant? Put the Slant back in a turbo it!!! Later
Ryan
Ryan
The engine was seised, thats one reason why I'm not using. But I still have it.
PanGasket
has cork sides
Turbos aren't powered by sucking power from the crank, they use wasted exhaust energy which is the big + there. The + of the supercharger is the ease of setting it up. Theres alot more to it than that, but, I'd go turbos as you wouldnt suck down nearly as much gas as a supercharger
Rice Nuker
Let the Coal Roll!
Look up the evolution of supercharging and turbo charging in aircraft engines. The effects and benefits are realized over the years. It is amazing how much energy is shooting out the exhaust pipe. Very interesting reading if you are info forced induction. My opinion is ditto what DarTT said.. Also I have no first hand experience.
It's certainly true that superchargers use engine power to turn them and also true that we're talking about engine power that never makes it to the rear wheels.
But turbocharging extracts its own pound of flesh from the engine, to create boost. It does so by creating increased back pressure in the exhaust system; if your engine is enjoying. say, 20 pounds of boost, you probably have something like 30+ pounds of back pressure in the exhaust system up-stream of the turbocharger. Overall, it's a good tradeoff, because turbos tend to be more efficient than superchargers, but don't think that turbocharging is "free." It's not...
This is something I have been saying like, forever.
Current hair dryer super chargers use...??? ... 5 hp to turn at high speed?
Current hair dryer super chargers use...??? ... 5 hp to turn at high speed?
Rice Nuker
Let the Coal Roll!
Copied from Wikipedia. Interesting no matter if it is redundant in my opinion. Immediately speaks to energy consumption of the supercharger. Also interesting is the additional fuel required to power the supercharger due to its parasitic behavior.
A mechanically driven supercharger has to take its drive power from the engine. Taking a single-stage single-speed supercharged engine, such as the Rolls Royce Merlin, for instance, the supercharger uses up about 150 hp (110 kW). Without a supercharger, the engine would produce 750 hp (560 kW); with a supercharger, it produces 1,000 hp (750 kW), a total increase of 400 hp (750 hp 150 + 400), or a net gain of 250 hp (190 kW). This is where the principal disadvantage of a supercharger becomes apparent: The engine has to burn extra fuel to provide power to turn the supercharger. The increased charge density increases the engine's specific power and power to weight ratio, but also increases the engine's specific fuel consumption. This increases the cost of running the aircraft and reduces its overall range.
As opposed to a supercharger driven by the engine itself, a turbocharger is driven using the exhaust gases from the engines. The amount of power in the gas is proportional to the difference between the exhaust pressure and air pressure, and this difference increases with altitude, helping a turbocharged engine to compensate for changing altitude.
The majority of WWII engines used mechanically driven superchargers, because they maintained three significant manufacturing advantages over turbochargers. Turbochargers, used by American aero engines such as the Allison V-1710, the Pratt & Whitney R-2800 were larger, involved extra piping, and required rare high-temperature alloys in the turbine and pre-turbine section of the exhaust system. The size of the piping alone was a serious issue; the Vought F4U Corsair and Republic P-47 Thunderbolt used the same engine but the huge barrel-like fuselage of the latter was, in part, a result of the necessary piping to and from the turbocharger in the rear of the plane. Turbocharged piston engines are also subject to many of the same operating restrictions as gas turbine engines. Turbocharged engines also require frequent inspections of the turbocharger and exhaust systems for damage due to the increased heat, increasing maintenance costs.
Today, most general aviation aircraft are naturally aspirated. The small number of modern aviation piston engines designed to run at high altitudes generally use a turbocharger or turbo-normalizer system rather than a supercharger driven from the crank shaft. The change in thinking is largely due to economics. Aviation gasoline was once plentiful and cheap, favoring the simple but fuel-hungry supercharger. As the cost of fuel has increased, the supercharger has fallen out of favor. Equivalently, depending on what monetary inflation factor one uses, fuel costs have not decreased as fast as production and maintenance costs have.
Rice Nuker
Let the Coal Roll!
deleted duplicate post..
cudavert
DARTAHOLIC
I say turbo, as long as you don't mind doing a bit more fabrication (intercooler piping etc) and the oil drainback provision to your oil pan. Turbos are somewhat cheap now and are pretty efficient.
Well, that's a very good question. I have called both Paxton and Vortech and nobody is willing to commit to a figure,
But my Vortech S-trim, V-1is driven (360 Magnum; 10 pounds of boost) by a 6-rib, serpentine belt.
How much horsepower can you put through one of those???:read2:
Nice read on Bill. The only problem I see there is the super chargers mentioned are very old on a huge engine. Those engines produce alot of power without the supercharger.
I had read somewhere (Allways taken with a grain of salt of course) that to power a current hair dryer supercharger required 5hp. While this may be accurate, it is something I think was tested while NOT powering a engine.
I would love to see an engine supercharged but NOT powering the supercharger itself. 1 test with the engine turning the s-charger and one with it not. It would need another engine/motor driving the supercharger and matching the PSI rpm for rpm, psi for psi during the test.
Same with a turbo if possible.
I had read somewhere (Allways taken with a grain of salt of course) that to power a current hair dryer supercharger required 5hp. While this may be accurate, it is something I think was tested while NOT powering a engine.
I would love to see an engine supercharged but NOT powering the supercharger itself. 1 test with the engine turning the s-charger and one with it not. It would need another engine/motor driving the supercharger and matching the PSI rpm for rpm, psi for psi during the test.
Same with a turbo if possible.
Awhile back, I read somewhere that a Vortech centrifugal on a 360 at 15 pounds of boost, required about 15 HP to drive, but I can't verify that number at all... sorry.
5 hp sounds a little low to me....
5 hp sounds a little low to me....
LOL, I agree. Like I said, "Grain of Salt" when reading. Maybe I missed the 1 infront of the 5. :toothy10:
turbofreek
batcrap crazy racing team
Difference starts at about 3200-3600rpms. A turbo will be at its full boost setting creating a ton more torque then a centrifugal supercharger that still isn't half way to making its full boost setting. That's right, superchargers don't reach full boost till your shifting. Where as a turbo reaches it before peak torque. Also a blower tends to eat 18-30% power loss or engine drag on the crank to turn it. That is just another reason why turbos always make more power at the same boost levels.
I'm sure that every car is different, but my 360 Magnum that is equipped with a Vortech V-1, S-trim centrifugal supercharger, is at full boost (10 pounds) about 3,600 rpm; maybe it's too small for the engine, and that''s why it never goes above the desired 10 pounds, but it's still at 10 pounds when the car goes across the finish line.
Go figure...
Additionally, I wonder where the information came from that a centrifugal supercharger has a parasitic drag of 18-to-30 percent.
Let's use my engine as an example:
My engine produced 445 rear wheeel horsepower on a chassis dyno. Most calculatiors I have seen contend that the rear wheel figure is 85-percent of the flywheel horsepower (15-percent drivetrain losses with an automatic,) That would peg my engine at 524 flywheel horsepower using the 85/15 numbers. The numbers I got were 524 and 78 for the drag.
My supercharger is driven by a 6-rib serpentine belt. My max RPM is 6,000.
I don't have any hard information regarding just how much horsepower can be delivered through a 6-rib serpentine belt, butam skeptical that it would be as much as 78. Using the other end of your formula (30-percent,) it would be 157 horsepower.
If someone on this board has information as to how much horsepower can be transmitted at the rpm's I am turning the belt (max of 6,000 rpm 7" pulley = 10,995 feet per minute, belt speed, I'd be interested to see it.
Thanks in advance,,,:read2:
PanGasket
has cork sides
Holy crap. Thats some serious numbers right there Bill!
fstfish66
Well-Known Member
turbos have recently come a long way since the new technology in the waist gate,,,,but there no eye candy like a roots blower, i may be a little bias,,,,,
I so disagree with that. And I have a knife in a gun fight in this section.
Heres a flip side for ya.
Being a turbo needs exhaust to spin the whole system to create pressure, how much HP are you loosing to drive the turbo and create pressure.
The exhaust must be slowed down since the turbo is creating pressure and will need more pressure to drive it. Bottleing up the exhaust inorder to drive the turbo can't be good for HP. So I wonder what kind of losses are there?
Thanks for the kind words. 8)
I bought a used 360 Magnum out of a 1999 Durango and did a tiny bit of porting (and, I mean "tiny"... all I did was knock off the rough edges in the valve bowl area) and put a very mild Hughes cam in (214/218-degree @ .050"-lift) and added the blower.
It went from 260 RWHP unblown to 445 RWHP, with the same size carb (750cfm Holley) by adding the blower and a set of TTI step headers. I also went from an M-P 180-degree, water-heated intake manifold to a Professional Products Air-Gap style intake.
It IS a different car, now... from 13.35 to mid-11's in one swell foop... lol!
I'm including a copy of the dyno test result sheet and pic of the blower installation.
Thanks ffor your interest.
superchargeddrt
Well-Known Member
Well I guess you know where I'm gonna go. Honestly turbos are the more efficient way to go but they are tricky to set up (turbo lag etc). And then there's all of the under hood plumbing to deal with. Personally I just prefer the ease of installation of the supercharger along with the easier tunning. But to each his own. Good luck with what ever you choose.
Mad Dart
Nothing to see Here!
N/A, Supercharged, Turbo'd, On Juice...........whatever trips your trigger, I say do it!
turbodart68
Well-Known Member
Yep! They all have their advantages. Pick your poison. By the way I think 20% is possible for a high boost centrifugal.
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