what supercharger? please help
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CobraRed_96_GT
Active Member
Piping isn't really a problem (unless you consider some lag inefficient) since turbo set-ups have all kinds of piping and are the more efficient form FI due to basically no parastic loss. You need to factor in the parastic loss (s/c being driven by the crank) and the design of the supercharger itself. Roots is a very old school form of air compression, twin screw is a much improved design of this - and the centri is basically a turbo powered by the crank instead of exhaust pressure. Some centris are more effcient than twin screws, many better twin screws are more efficient than centri's. Though from my understanding centri's are easier to cool off the air supply than positive displacement s/c'ers (could be wrong). Yet all, basically, are more efficient than roots style.
the98stang
Active Member
!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!I paid $2,000 for my used kit and did the install myself. Plus another $500 or so for a tune. Done.
You need to be careful how you define “efficiency”. The modern roots style blowers (which are now actually defined as hybrid-roots blowers) are probably the most efficient out of any supercharger at lower blower speeds. They move more air than a centrifugal and make less heat than a twin screw over the first few pounds of boost. So in that respect, they’re probabl the most efficient. It’s only when increased blower RPM moves them beyond their rated adiabatic efficiency levels that their efficiency takes a nose dive due to excess discharche temperatures and increased horsepower consumption.
That being said, the new TVS series Eaton’s (optined on the kit you quoted) actually seem to be the best out of all of them. Designer testing has shown they’re actually approaching the efficiency level of a turbo. Which is pretty impressive.
deftsound
Please ask me how much my supercharger cost
CobraRed_96_GT
Active Member
You need to be careful how you define “efficiency”. The modern roots style blowers (which are now actually defined as hybrid-roots blowers) are probably the most efficient out of any supercharger at lower blower speeds. They move more air than a centrifugal and make less heat than a twin screw over the first few pounds of boost. So in that respect, they’re probabl the most efficient. It’s only when increased blower RPM moves them beyond their rated adiabatic efficiency levels that their efficiency takes a nose dive due to excess discharche temperatures and increased horsepower consumption.
That being said, the new TVS series Eaton’s (optined on the kit you quoted) actually seem to be the best out of all of them. Designer testing has shown they’re actually approaching the efficiency level of a turbo. Which is pretty impressive.
yeah, i've heard good things about those. But the stock eaton IMO is pretty damn poor. And usually you judge efficiency at max load, or max requested load - not just from 2k-3k. It's hard to race a car in the 2-3k range
jivepepper
Founding Member
Prochargers are fine blowers. I just think the P1SC is weak and proned to leaking.
The vortech S-trim is the best entry level Sc made right now. When I see a P1SC come even close to making 600 rwhp on a 4.6l 2v without nitrous I'll change my mind.
The vortech S-trim is the best entry level Sc made right now. When I see a P1SC come even close to making 600 rwhp on a 4.6l 2v without nitrous I'll change my mind.
True, but when you think about it, that level from off idle to about 3,000RPM is where 98% of your non aggressive daily driving is spent. It's kinda nice to make that little bit of extra power at part throttle that you wouldn't with a centrifugal, without heat soaking the system before those WOT runs like you would with a twin screw.yeah, i've heard good things about those. But the stock eaton IMO is pretty damn poor. And usually you judge efficiency at max load, or max requested load - not just from 2k-3k. It's hard to race a car in the 2-3k range
The modern Hybrid Roots blower really isn’t bad at all. You’re just judging them based on WOT performance evaluation you’ve seen on the '03-'04 Cobra's or GT500's. Which in reality, from a maximum power perspective the M112 and M122 units for chose really are not really sized appropriately for the applications. Why do you think anytime Kenne Bell compares their blower to an Eaton, they always compare a larger Twin Screw to a smaller Eaton in question? It's because if they were to compare the two heads up, the difference between the two of them power wise would actually be a lot closer that Kenne Bell would like.
CobraRed_96_GT
Active Member
This doesn't make much sense to me (no offense).
efficiency (in%)=
Po
---- X 100
Pi
so, your your efficiency is judged based on power input, not just rpm. So yes at WOT from 1.5-3K a hybrid roots may show to be very efficient and heat regulating given the load. But as you put it "non-aggressive" driving you're in that rpm range - but your power input isn't anything near WOT. So who's to say it's being efficient at all - especially from the standpoint of only needing 130hp to go across town when you're making 200 instead. May be nice to have going up a hill, but if i was driving around town from A to B i wouldn't want to be pushing 1-4 psi for no reason - a centri and turbo are there for when you need it, and not pushing boost and using more gas when you dont (along with constant strain - although minimal)
On a street set up, centri's won't start making boost no matter how hard you push them until about 3,000-3,500RPM. They don't begin moving enough air below that point to pressurize the intake, thus you don't benefit from an additional unnaturally aspirated airflow during something like a “spirited” pull away from a traffic light, or low speed merge into traffic. Your acceleration relies solely on what power and torque the engine is able to muster based on natural airflow through the engine under vacuum.
The Twin screw compressors although they’re able to pressurize the system much more quickly than a centrifugal are always compressing the air no matter what RPM your engine is running at. This creates unwanted heat under all forms of driving, not just under boost. Increased ACTs mean you're making less power and increasing fuel consumption. It may be ever so slight, but when you're running about 98% of the time under those conditions, it begins to add up.
Eaton’s don't compress the air within the unit itself like a twin screw. The air is paddled back and forth throughout the unit and pressurization takes place in the intake manifold itself (not compressed within the unit), much like a centrifugal, thus keeping ACT's cooler at that level. When the airflow isn’t needed, the bypass valve reticulates it back into the system until the demand for additional airflow is called for and discharge temperatures remain lower.
And since all modern supercharger systems utilize bypass valves, you're not going to see any boost unless the system demands it. I can run all the way up to redline without getting out of vacuum if I choose to.
