Turbo vs Supercharger
11-05-2009, 02:31 AM
#151
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I would think it is... the Bore is the same... the crank has a longer stroke in the 3L S2... A 2.7L block would probally need different rods -shorter- and the edge of the block inside casing clearanced to allow the long stroke crank to pass... Not sure what would need to be done to make a 3L crank fit in that block...
11-05-2009, 02:55 AM
#152
Rainman
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2.7 8v and S2 have the same block.
the 2.7 was a 104mm bore with the 2.5L crank (78.9mm stroke).
adding the 88mm stroke crank brought it from 2.7 to 3.0L.
an 88mm stroke crank will go straight into a 2.5 block, taking it to 2.8L, however you will need special rods to make it work.
the 2.7 was a 104mm bore with the 2.5L crank (78.9mm stroke).
adding the 88mm stroke crank brought it from 2.7 to 3.0L.
an 88mm stroke crank will go straight into a 2.5 block, taking it to 2.8L, however you will need special rods to make it work.
12-08-2010, 05:09 PM
#153
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turbocharger vs supercharger estimating the hidden costs/break even point....
how far off might i be on a cost-comparison if i sourced a good number of used turbo parts....
for a true low-boost turbo vs supercharger shootout on paper ?
can you all help me adjust the numbers ?
i was posting on the "crack house" thread about the fake e-ram supercharger....
https://rennlist.com/forums/924-931-...ercharger.html
where we concluded that NONE of these FAKE/scam products will ever increase horsepower under any circumstances...
i came up with some estimates.... first, that superchargers work well in:
1. economies with strong currencies (cheap fossil fuels).
2. drag racing / racing where burning 12 gallons of fuel in 4 seconds / or a few minutes is politically/economically feasible.....
3. commercial automotive applications running 5~8 pounds of boost. (see # 1).
there was a comment made in THAT thread (see link above) about superconductors (far and away, the highlight of the thread)..... emphasizing that it would require "superconductor" levels of battery and wiring efficiency on the order of multiple X times current practical limits to be able to store the massive, electrical power required to make a high-efficiency, centrifugal supercharger that works on demand, running an electric motor — workable.
if it was "workable," we'd have seen electric "NOS" a long time ago....
my conclusion is simply, that you have to go big....
(and not-only, because we lack the cheap superconductors/super-batteries required to make an "on demand" product work).
superchargers (centrifugal superchargers) require a delicate balance and are the sum total of several compromises. they can be made to work reasonably well making say, 6~12 pounds of boost, in small to medium displacement engines missing a few cylinders — but even here, it is extremely difficult to hide their glaring flaws in a daily driven car.
in recent years, automobile manufacturers have surely produced some very nice tangible, junior supercars, ranging from the small Lotus' to the Mitsubishi Evo, Subaru WRX and similar competitor's cars, to the Nissan 350 ZXs and Corvettes of the world — and they all deliver reasonably well in the "bang for the buck" context.... but you have to ask yourself one question: how many superchargers do you see running in these same, recent, production cars.
they all run high output n/a engines and turbochargers....
the cars running intercooled turbos are more efficient, and are especially attractive in banana republics where 5, or 6 dollar-per-gallon gasoline may soon become a reality—
of course, turbos require greater up-front costs.... but, if you run a supercharger, the hidden costs keep adding up, and before long, there's a break-even point. and it's likely to happn sooner than you think — maybe, 18~35 k miles down the road — and by the time you get there, you'll have laid out as much $$$$ as just going "turbo...."
here are some estimates i was able to come up with:
low boost turbocharger parts & install (w/out engine blueprinting): $11,500 (this number can vary by $1000s X)
low boost supercharger kit & install........................................... $5,500
difference.............................................................. ..............$6,000
difference in gallons of premium pump gas.......................... 1,900 gallons
turbocharged 968 vs supercharged 968:
fuel mileage with turbocharger: 25 MPG (highway).
fuel mileage with supercharger: 16 MPG (highway).
difference (estimate)................9 MPG
X 1900 Gallons = 17,100 Miles / the break even point ($$$$).
.
for a true low-boost turbo vs supercharger shootout on paper ?
can you all help me adjust the numbers ?
i was posting on the "crack house" thread about the fake e-ram supercharger....
https://rennlist.com/forums/924-931-...ercharger.html
where we concluded that NONE of these FAKE/scam products will ever increase horsepower under any circumstances...
i came up with some estimates.... first, that superchargers work well in:
1. economies with strong currencies (cheap fossil fuels).
2. drag racing / racing where burning 12 gallons of fuel in 4 seconds / or a few minutes is politically/economically feasible.....
3. commercial automotive applications running 5~8 pounds of boost. (see # 1).
there was a comment made in THAT thread (see link above) about superconductors (far and away, the highlight of the thread)..... emphasizing that it would require "superconductor" levels of battery and wiring efficiency on the order of multiple X times current practical limits to be able to store the massive, electrical power required to make a high-efficiency, centrifugal supercharger that works on demand, running an electric motor — workable.
if it was "workable," we'd have seen electric "NOS" a long time ago....
my conclusion is simply, that you have to go big....
(and not-only, because we lack the cheap superconductors/super-batteries required to make an "on demand" product work).
superchargers (centrifugal superchargers) require a delicate balance and are the sum total of several compromises. they can be made to work reasonably well making say, 6~12 pounds of boost, in small to medium displacement engines missing a few cylinders — but even here, it is extremely difficult to hide their glaring flaws in a daily driven car.
in recent years, automobile manufacturers have surely produced some very nice tangible, junior supercars, ranging from the small Lotus' to the Mitsubishi Evo, Subaru WRX and similar competitor's cars, to the Nissan 350 ZXs and Corvettes of the world — and they all deliver reasonably well in the "bang for the buck" context.... but you have to ask yourself one question: how many superchargers do you see running in these same, recent, production cars.
they all run high output n/a engines and turbochargers....
the cars running intercooled turbos are more efficient, and are especially attractive in banana republics where 5, or 6 dollar-per-gallon gasoline may soon become a reality—
of course, turbos require greater up-front costs.... but, if you run a supercharger, the hidden costs keep adding up, and before long, there's a break-even point. and it's likely to happn sooner than you think — maybe, 18~35 k miles down the road — and by the time you get there, you'll have laid out as much $$$$ as just going "turbo...."
here are some estimates i was able to come up with:
low boost turbocharger parts & install (w/out engine blueprinting): $11,500 (this number can vary by $1000s X)
low boost supercharger kit & install........................................... $5,500
difference.............................................................. ..............$6,000
difference in gallons of premium pump gas.......................... 1,900 gallons
turbocharged 968 vs supercharged 968:
fuel mileage with turbocharger: 25 MPG (highway).
fuel mileage with supercharger: 16 MPG (highway).
difference (estimate)................9 MPG
X 1900 Gallons = 17,100 Miles / the break even point ($$$$).
.
12-08-2010, 06:04 PM
#155
.....how do u know gas mileage with supercharger is that number?
my acura rsx is epa mpg 21/28. combined 24. i currently have eaton roots blower on it with no aftercooler. (very inefficient from boosting point of view) the blower has a bypass valve when you're not heavy on the throttle.
i used to average 26-28 before i put the supercharge on. i now average 26mpg doing 80% highway. i maybe lost 1-2mpg going from NA to supercharged....so economics of consumption isn't significant. but economics of fun is definitely significant
my acura rsx is epa mpg 21/28. combined 24. i currently have eaton roots blower on it with no aftercooler. (very inefficient from boosting point of view) the blower has a bypass valve when you're not heavy on the throttle.
i used to average 26-28 before i put the supercharge on. i now average 26mpg doing 80% highway. i maybe lost 1-2mpg going from NA to supercharged....so economics of consumption isn't significant. but economics of fun is definitely significant
12-08-2010, 06:36 PM
#156
It all depends on the supercharger. With a roots type mileage will go down, because its always working. On a centrifical charger it won't be since it operates similar to a turbo. its just belt driven.
12-08-2010, 06:42 PM
#157
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Jfrahm,
in the opening lines of my post, where exactly do i state "this" is anything even close to the "final word" on the matter ?
in fact, the entire post is actually a question. completely expository post.
you remain "mum" on MPG numbers, even after being asked for your estimates.
we don't have a lot of data on centrifugal superchargers for 2.5s, 2.7s, variocams, etc...
feel free to enlighten us.
and one more thing to everyone. my post was talking "centrifugal superchargers."
12-08-2010, 06:43 PM
#158
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Not necessarily, roots type superchargers often have built in bypasses which drop their parasitic loss to 1-2HP when not in use, some are even setup with electric clutches on their pulley to eliminate that loss as well.
12-08-2010, 06:49 PM
#159
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pros and cons to each
more power for a given boost for a turbo
it uses exhaust Q/heat to power the compressor
a sc used engine power (it is generating) to drive it
losses may be 20-25% more with a sc
much less lag on a sc
more proportional boost (depending on type, positive displacement vs centrifugal)
sc may have a wider operating range
more power for a given boost for a turbo
it uses exhaust Q/heat to power the compressor
a sc used engine power (it is generating) to drive it
losses may be 20-25% more with a sc
much less lag on a sc
more proportional boost (depending on type, positive displacement vs centrifugal)
sc may have a wider operating range
12-08-2010, 06:59 PM
#160
Rainman
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here are some estimates i was able to come up with:
low boost turbocharger parts & install (w/out engine blueprinting): $11,500 (this number can vary by $1000s X)
low boost supercharger kit & install........................................... $5,500
difference.............................................................. ..............$6,000
difference in gallons of premium pump gas.......................... 1,900 gallons
low boost turbocharger parts & install (w/out engine blueprinting): $11,500 (this number can vary by $1000s X)
low boost supercharger kit & install........................................... $5,500
difference.............................................................. ..............$6,000
difference in gallons of premium pump gas.......................... 1,900 gallons
12-09-2010, 04:44 PM
#161
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am i high or low ?
Powerhaus will do a low-boost turbo for any 968 (adding a stronger headgasket ?) for about $14 or $15 K.
btw, forced induction threads, the world over, seem to get "heated." thus the need for more intercoolers.
anyway, the crack house got busted.
Powerhaus will do a low-boost turbo for any 968 (adding a stronger headgasket ?) for about $14 or $15 K.
btw, forced induction threads, the world over, seem to get "heated." thus the need for more intercoolers.
anyway, the crack house got busted.
12-09-2010, 05:08 PM
#162
Three Wheelin'
electric turbochargers are not a shameful source of technology to get greater power, and neither is NOS. neither of these options should be ignored if you are presented with the appropriate scenario that might require them.
weight reduction is the best way to get more "power" IMO, though it is obviously limited.
12-09-2010, 05:49 PM
#163
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bonus: i am the second person who posted "it's viable," in that thread....
frahm beat me to the punch by a couple of minutes.... DAM ! (as i was writing).
we were posting the same basic idea, independently.... i had never really thought of a serious, on demand/electric supercharger before, (i'm sure there are many on this forum who have)..... so as i was sort of "gaming" a system as Jfrahm was posting, and estimated that about 3 to 4 X the generating power of your typical alternator and on about the same order of battery capacity could be workable...
with automotive engineers fitting many workable options into cars nowadays, my instinct tells me that if such a system was workable using current battery technology.... we'd have seen it already. (not counting hybrid cars)..... but, our current batteries and alternators are at the mercy of considerable parasitic losses, and as a result, fall several orders of magnitude short on the multiple kilowatts of electricity that would be required....
when i see a stand alone device that adds 15~20 hp, and doesn't destroy your battery stamped on the cover of HotRod, i will be the first person to congratulate the inventor, and i would love to install one on my Ford Escape for all those hills in the war-zone where i love to surf....
so as to the question of such a system being viable.... i said nothing less: it's viable.
but, i'm not buying an eram to install on my Escape.....from page three of the eram thread:
a 3 or 4 psi increase at the intake manifold would REALLY help the cause of any medium displacement engine.
a forced induction system on demand (a closed off system) that would shut down, and via a bypass, default back to your general intake system would be possible, and likely, workable. it would require a real supercharger on the order of say 80 % of the size of an ordinary supercharger, run via a large electrical motor that would require on the order of perhaps 8~12 X 1,000 watts of power AND SPIN VERY FAST.... maybe run for less than a minute, get VERY hot in the process, and run your battery down very quickly....
it could be done. would it be practical ? i say, "to some extent, yes." it would beat having to recharge a bottle any old day, not burn up your pistons, or destroy your head gasket, and might weigh perhaps, 35 or 40 pounds.
would it produce miraculous performance gains ? no. would it hurt the overall performance of the car ? a little (anytime you add weight)....
okay, maybe it turns out that a 6~7 thousand watts will get us there.
nothing against the op, or using "crack" as an analogy... as far as i'm concerned we're cool.
frahm beat me to the punch by a couple of minutes.... DAM ! (as i was writing).
we were posting the same basic idea, independently.... i had never really thought of a serious, on demand/electric supercharger before, (i'm sure there are many on this forum who have)..... so as i was sort of "gaming" a system as Jfrahm was posting, and estimated that about 3 to 4 X the generating power of your typical alternator and on about the same order of battery capacity could be workable...
with automotive engineers fitting many workable options into cars nowadays, my instinct tells me that if such a system was workable using current battery technology.... we'd have seen it already. (not counting hybrid cars)..... but, our current batteries and alternators are at the mercy of considerable parasitic losses, and as a result, fall several orders of magnitude short on the multiple kilowatts of electricity that would be required....
when i see a stand alone device that adds 15~20 hp, and doesn't destroy your battery stamped on the cover of HotRod, i will be the first person to congratulate the inventor, and i would love to install one on my Ford Escape for all those hills in the war-zone where i love to surf....
so as to the question of such a system being viable.... i said nothing less: it's viable.
but, i'm not buying an eram to install on my Escape.....from page three of the eram thread:
Originally Posted by odurandina
a 3 or 4 psi increase at the intake manifold would REALLY help the cause of any medium displacement engine.
a forced induction system on demand (a closed off system) that would shut down, and via a bypass, default back to your general intake system would be possible, and likely, workable. it would require a real supercharger on the order of say 80 % of the size of an ordinary supercharger, run via a large electrical motor that would require on the order of perhaps 8~12 X 1,000 watts of power AND SPIN VERY FAST.... maybe run for less than a minute, get VERY hot in the process, and run your battery down very quickly....
it could be done. would it be practical ? i say, "to some extent, yes." it would beat having to recharge a bottle any old day, not burn up your pistons, or destroy your head gasket, and might weigh perhaps, 35 or 40 pounds.
would it produce miraculous performance gains ? no. would it hurt the overall performance of the car ? a little (anytime you add weight)....
okay, maybe it turns out that a 6~7 thousand watts will get us there.
Originally Posted by odurandina
the thing that gets me is that the posters WERE UNUSUALLY KIND to the op.
amazes me being called names for tongue in cheek, harmless remarks, after it had been so clearly demonstrated by many knowledgable posters, why this particular system WIll NOT WORK AS ADVERTISED.
THERE IS TOOOO MUCH AIR TO MOVE for that little cigarette smoke fan...
amazes me being called names for tongue in cheek, harmless remarks, after it had been so clearly demonstrated by many knowledgable posters, why this particular system WIll NOT WORK AS ADVERTISED.
THERE IS TOOOO MUCH AIR TO MOVE for that little cigarette smoke fan...
nothing against the op, or using "crack" as an analogy... as far as i'm concerned we're cool.
12-09-2010, 07:21 PM
#165
Race Car
