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Engine Specific Info and Questions => IDI Engine => Topic started by: Benjamin on March 14, 2008, 02:29:10 pm
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guys, i have a small idea,
i think the main problem with making big power is not feuling, but getting that big turbo spooled up... (exept if you pay big money for ballbearing hybrid turbos) diesels cant make so great power gains like gasoline engines do, and feul is a restriction, becouse off the pump, but we havent seen a 12mm feuled out with IDI, and we still have the 14mm, but it also have limits becouse you do need to inject it fast enough and it need to burn fast enough also, but i dont think we have seen the limits!
i think there are several thoughts about building a G40-G60 on a diesel with many pro and contra's...
i have the idea to build a compressor, as you know there are several compressor.
roots
(http://users.skynet.be/fa344132/fotokes/auto/techniek/Roots_Blazer_ZW.jpg)
dont know the name in english...
(http://users.skynet.be/fa344132/fotokes/auto/techniek/Twinscrew_process_white.jpg)
G-compressor or Scroll compressor
(http://users.skynet.be/fa344132/fotokes/auto/techniek/G-lader%20open_03.jpg)
Comprex wich is a nice system, but simply not good cause you dont have high power outputs in no any way, and its also pretty complex
(http://users.skynet.be/fa344132/fotokes/auto/techniek/comprex.jpg)
and than, you have the centrifugal compressor, for those who dont know, the centrigugal compressor is the intake from a turbo, and the shaft is (mainly) connected to the engine.
those compressors make about 40.000rpm
(http://users.skynet.be/fa344132/fotokes/auto/techniek/Centrifug.jpg)
the good and bad thing about this one is, its very small and very efficient, but this type is rather for cars with peak power and just a little torque, this is thee reason why you dont find them on normal cars.
Now i was thinking about taking a pretty big turbo, take the turbine off, and build a centrifugal compressor myself. but this time not pushed by the engine, but with an electrical engine or so!
Anyone have an idea or so, what kind of power need the electric engine be, how to make fast rpm trough reductions, what about the bearings, or is it better to push the compressor with another engine than electric, i dont know if its possible, but can a turbine from the turbo be turned on when you add feul to it, some kind of JET system, only you dont use the compressor, just a thought.
Greetz, Benjamin
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theres actually a guy that did exactly that, he sells a kit too
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theres actually a guy that did exactly that, he sells a kit too
With a centrifugal, what kind of power gains did he make? He did it on diesel?
Greetz, Benjamin
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he did it on a beetle, there was a post in this forum a little while ago for it. pretty neat but it was only good for short bursts of power, and the powergain was relatively weak imo.
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link to forum
http://vwdiesel.net/phpBB/viewtopic.php?t=10210&highlight=electric+turbo
link to example
http://www.turbomagazine.com/tech/0406tur_knight_turbo_electric_supercharger/index.html
i dont know if this is centrifugal compressor, its my understang its not, probably becouse this one makes 4x less rpm
(http://images.turbomagazine.com/tech/0406tur_knight02_z.jpg)
Greetz, Benjamin
/edit:
T: When did you develop the idea of using three motors?
TK: About 10 years ago I developed a program to determine the horsepower requirements for electric compressors. It was a very difficult program and it took me a long time to get the parameters correct. I found that flowing 780cfm at 15 psi required 80 to 100 hp. I went smaller on engine size and lowered boost requirements until I reached 450cfm at 8 psi, which required 18 to 22 hp, so I looked for a 20-hp dc motor. All I found were 50-plus-pound motors, which were too large to use in my intended application. Three years ago I realized if I used multiple motors, I could get to the 20-hp mark.
T: Why a Roots-type supercharger?
TK: I designed many different models and applied for the patents. I also have patents pending on screw, roots, centrifugal and sliding vane-type electric superchargers. The centrifugal design is in the works, and the screw is simply too expensive to use. The sliding vane is great but quite large, so the Roots is cost effective, reliable, simple, durable, and provides the quickest boost response.
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I had started this thread a while back! i still would love to see it put together
http://vwdiesel.net/phpBB/viewtopic.php?t=8398&highlight=feeler+thoughts+g60+supercarger+diesel[url]I balieve a supercharger would create a lot of low end power that a diesel engine is lacking with a turbo! twin forced induction units could be employed with this configeration? I have just about every thing to do the project! but no time because of all the overtime i'm working at work!Duanehttp://vwdiesel.net/phpBB/viewtopic.php?t=8398&start=0&postdays=0&postorder=asc&highlight=feeler+thoughts+g60+supercarger+diesel[url]
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so, any other idea's to make the turbine flow, without taking power from the engine like exhaust gasses, mechanical on a belt, or electrical wich is also mechical becouse of your alternator.
Need a 5th injector and a sparkplug to make that turbine spooling, or what?
Greetz, Benjamin
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Have a second alternator and battery dedicated to the electric supercharger. Have the alt run off of a magnetic clutch pully from an AC compressor so that when full throttle is applied the clutch is disengaged so as to not drain power from the engine when you need it most.
You could wire it so that during normal driving the alt would be engaged, charging the battery and have the gas peddle wired as a potentiometer to controll the speed of the supercharger.
Yes I have put some thought into this in the past :roll:
PS. Speaking of twincharged engines...
HKS once made a turbo kit for the superchaged Toyota MR2 and VW now makes a TSI 1.4L twincharged gas engine.
Many old Detroit 2 cycle diesels are supercharged and twin turbo.
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here is a link to a topic i started involving a twin charged mercedes diesel.
http://vwdiesel.net/phpBB/viewtopic.php?t=11908&highlight=mercedes
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i finally found the answer to my question click here (http://images.google.com/imgres?imgurl=http://www.vwvortex.com/artman/uploads/016_001.jpg&imgrefurl=http://www.vwvortex.com/artman/publish/volkswagen_news/printer_1496.shtml&h=400&w=600&sz=83&hl=en&start=1&tbnid=ynU7dNxaUYF_2M:&tbnh=90&tbnw=135&prev=/images%3Fq%3D100%2Bmpg%2Bdiesel%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN)
vw did a twin induction kewl!
Duane
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That's why they developped VNT turbos.
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dont know the name in english...
(http://users.skynet.be/fa344132/fotokes/auto/techniek/Twinscrew_process_white.jpg)
Twin Screw compressor, the new air compressor at work is that type
Always wondered about bolting an Atlas Coppo screw compressor to an engine from a pneumatic drill/jack hammer compressor
(http://www.trident.on.ca/atlascopco/rotaryscrews.jpg)
in fact why fit a turbo or supercharger when you can just tow one of these behind you :roll:
(http://en.red-dot.org/rd/img/360/2006-05-0679-b.jpg)
its a bolt on towable twin screw supercharger :wink:
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wouldn't it be easier to use a set of compund turbo's ?
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guys, i have a small idea,
i think the main problem with making big power is not feuling, but getting that big turbo spooled up...
Interesting subject B
My own crazy idea is that the design of combustion engines including diesel IC needs to be revisited from the ground up. When we look at performance we do not differentiate between "continuous duty" and "discontinuous on demand type of duty" the way most machinery is normally rated in the industrial sector.
On cars I see a need for cruising and a need for passing (or impressing). The latter is rarely ful time and the engine does not need to be designed for it.
In other words we should make engines capable of storing energy and this I think can be done either in the form of DC electricity fed supercharger, or by storing high pressure air to be injected in a diesel intake without turbo or supercharger.
This is what I am looking at. An air compressor with a magnetic clutch ran by the alternator belt, a high pressure air tank, a throttle link type of control, some sort of a cooler and a hose to the intake manif.
Here is my supercharger...please don't laugh.
Haybayian
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My thinking is that any engine uses about 1/3 of the energy it makes to power the car, 1/3 is wasted in aerodynamics and the other 1/3 is lost in exhaust heat. Why not use the 1/3 of the exhaust heat to power a fan *turbo* and use a little of that wasted heat...your making it anyway.
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My thinking is that any engine uses about 1/3 of the energy it makes to power the car, 1/3 is wasted in aerodynamics and the other 1/3 is lost in exhaust heat. Why not use the 1/3 of the exhaust heat to power a fan *turbo* and use a little of that wasted heat...your making it anyway.
Offcorse, i like turbos more than any other perfomance product.
but for high perfomance outputs on our diesels there are some problems.
on TDI engine's you have the limited feul, 12mm cant rev to high becouse it can break the plunger wich can give a total engine failure.
but on our IDI we dont have problems with plungers so we can feul on, maybe even with 14mm heads.
A stock T2 or T3 is a cool turbo, but what if you want more?
the cheapest way i think is going for a VNT turbo and on a 1.9 the VNT25 is the biggest you can get spooled up, if you want any bigger you are idmediatly on a VNT30 or VNT32.
There are also ballbearing turbos, wich are more expensive, and as far as i know, you can get almost the same spool up with the same output as the VNT25 does.
bigger turbos dont spool quick enough or you need to shift above 5500a6000rpm, this bring some problems, for the internals, but maybe also for the feuling!
In that way i am looking forward for bigger powers.
i believe 250hp is possible with a vnt25. but what about 300 or +400hp?
With wich forced induction can you make this happen.
Gasoline can, and diesels cant, why, i dont think the problem is the burning proces or the injection time is to long, i think we just need a better forced induction
Greetz, Benjamin
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I think we will run out of internal engine part strength before we run out of options for forced induction. The crank, rods, pistons, block and cylinder head would all have to be strengthened to get 250hp out of a precup 1.6- 1.9L diesel. head lift would be a serious problem with extremely high boost pressures. Looking at the aircompressor trailer made me think of a funny scenario. The us airforce used to use a horizontally opposed two cylinder fourstroke engine running a roots type supercharger to start jetengines with compressed air. Why not use a small motorcycle engine running a supercharger mounted in the back of a caddy to feed the engine and avoid parasitic losses from the supercharger? granted it would add weight and complexity and it would burn gasoline or better yet methanol and you could inject the methanol into the diesel as well. that way you would have boost on demand. Electric start ont he supercharger engine and a twist grip on the shifter or a servo to control the throttle controlled by a potentiometer on the go pedal. ha. Oooh I know you could build a very light chromoly tube chasis say 1000lbs and then you wouldn't have to do much to the motor, power to weight. supercharger and turbo
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Owwww my brain hurts from reading that...... I believe an easier way would be called Nitrous or compound turbo..... Or VNT if you want beautiful response from your turbo
guys, i have a small idea,
i think the main problem with making big power is not feuling, but getting that big turbo spooled up...
Interesting subject B
My own crazy idea is that the design of combustion engines including diesel IC needs to be revisited from the ground up. When we look at performance we do not differentiate between "continuous duty" and "discontinuous on demand type of duty" the way most machinery is normally rated in the industrial sector.
On cars I see a need for cruising and a need for passing (or impressing). The latter is rarely ful time and the engine does not need to be designed for it.
In other words we should make engines capable of storing energy and this I think can be done either in the form of DC electricity fed supercharger, or by storing high pressure air to be injected in a diesel intake without turbo or supercharger.
This is what I am looking at. An air compressor with a magnetic clutch ran by the alternator belt, a high pressure air tank, a throttle link type of control, some sort of a cooler and a hose to the intake manif.
Here is my supercharger...please don't laugh.
Haybayian
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My thinking is that any engine uses about 1/3 of the energy it makes to power the car, 1/3 is wasted in aerodynamics and the other 1/3 is lost in exhaust heat. Why not use the 1/3 of the exhaust heat to power a fan *turbo* and use a little of that wasted heat...your making it anyway.
Offcorse, i like turbos more than any other perfomance product.
but for high perfomance outputs on our diesels there are some problems.
on TDI engine's you have the limited feul, 12mm cant rev to high becouse it can break the plunger wich can give a total engine failure.
but on our IDI we dont have problems with plungers so we can feul on, maybe even with 14mm heads.
A stock T2 or T3 is a cool turbo, but what if you want more?
the cheapest way i think is going for a VNT turbo and on a 1.9 the VNT25 is the biggest you can get spooled up, if you want any bigger you are idmediatly on a VNT30 or VNT32.
There are also ballbearing turbos, wich are more expensive, and as far as i know, you can get almost the same spool up with the same output as the VNT25 does.
bigger turbos dont spool quick enough or you need to shift above 5500a6000rpm, this bring some problems, for the internals, but maybe also for the feuling!
In that way i am looking forward for bigger powers.
i believe 250hp is possible with a vnt25. but what about 300 or +400hp?
With wich forced induction can you make this happen.
Gasoline can, and diesels cant, why, i dont think the problem is the burning proces or the injection time is to long, i think we just need a better forced induction
Greetz, Benjamin
research compound turbo's ..... very , very fast spool up , and more than enough boost presure to blow the very best combintaions of headgaskets , o rings/ fire rings , and huge head bolts/ studs .
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In that way i am looking forward for bigger powers.
i believe 250hp is possible with a vnt25. but what about 300 or +400hp?
With wich forced induction can you make this happen.
Gasoline can, and diesels cant, why, i dont think the problem is the burning proces or the injection time is to long, i think we just need a better forced induction
More intelligent minds than my own have said repeatedly that the performance barrier in diesels is their rev limit, and the rev limit is a directly affected by diesel's combustion speed and injection duration.
Typically even highly fueled diesels operate in an incredibly lean situation; when you see black smoke coming out of the back of a diesel, it's more often a result of too-long of an injection duration or very poor atomisation of the injected fuel: either way, you don't have enough time to vaporise and burn all the fuel charge before the exhaust stroke.
Gasoline engines produce massive horsepower through their ability to rev very, very fast. The homogeneous nature of the fuel/air charge and gasoline's very rapid combustion rate combine to allow them to burn their fuel in a very, very short period of time, which can be aided by adding additional spark plugs to the chamber to provide additional ignition points.
Diesel, with stratified in-chamber injection, must both inject the full fuel load and fully combust it in a duration only slightly longer (At higher RPM) than the full combustion event of a gasoline engine. The air-fuel mixture immediately surrounding the injected spray of fuel is over-rich, which limits combustion speed. Turbulence in the cylinder works to increase combustion speed by rapidly spreading the burning fuel around and combining it with fresh air, reducing or removing this over-rich condition.
This, by the way, is the reason given to me why an IDI diesel will rev a bit faster than a DI diesel; the prechamber port's restriction promote more turbulence inside the "Swirl" chamber in the head, so the burn is faster.
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quote
More intelligent minds than my own have said repeatedly that the performance barrier in diesels is their rev limit, and the rev limit is a directly affected by diesel's combustion speed and injection duration. (quote)
Thank you for these points. This sums up my current (limited) understanding of how diesels work. As I was reading last night about two V12 diesel engines the K10 Audi and Peugeot 908 Le Mans I found that for instance the K10's engine is designed to rev at up to 8000 rpms but that the engine's power band for both torque and HP is between 3000-5000 rpms and the the rev's limiter has been set accordingly. The type of fuel combustion/oxydation that is taking place in a diesel engine is slow, problematic and yields a slower rpm power band. This suggest that pursuing higher rpms may not be the way to better performance unless spectacular new ways are found to improve diesel combustion. I understand that multiple staged injection is now the state of the art. But I also understand that the most promising area is in the actual "fuel" being burned. I am thinking of mixed combustion involving for instance ethanol, water and God knows what else. The point I am making is that the way to diesel performance is probably not just in mechanical changes but rather in the chemistry and electronics.
Haybayian
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HCCI seems to be the way things will go in the internal combustion field.
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HCCI seems to be the way things will go in the internal combustion field.
Indeed...look up Benz's Dies-Otto...pretty neat!
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I don't know too much about the diesel combustion, but all I do know is that in my 1984 Rabbit the electrical system is a nightmare. I could add a turbo to it easier than I could an electric supercharger, but that is just me. My car is a piece of ---- and I wouldn't want to add anymore tax to the wiring in that car. I am glad you are thinking outside of the box though. I hope it works for you eventually. Who knows maybe my next project in 10 years I'll be using something exactly like what you have here....but no way will I be with this car. :D
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HCCI seems to be the way things will go in the internal combustion field.
If they can figure out how to get it to work under a wide variety of load conditions. HCCI is turning out to be very, very difficult to control, requiring the addition of a lot of complexity.
On the topic of electric superchargers, has anyone figured out the size of the 3-5hp electric motor those things are going to need powering them to generate appreciable boost? It'll be like stuffing a Briggs and Stratton under the hood! The B&S might even be smaller! :D
Edit:
Also, some numbers.
A typical supercharger takes that 3-5hp to generate their boost, right? Seems to be about right from what I know of superchargers, their boost isn't "free" like a turbocharger's is, they have to draw power off the crank to accomplish the same task.
3-5hp is 2235-3725watts. We'll go easy here, and go with the lower 3hp figure, so 2235w to power this supercharger electrically. Staying with 12v to avoid the need for a transformer (efficiency loss, more space), this comes out to 186.25 amps, give or take a small bit. Time for an alternator upgrade, for one!
We'll say you run this thing off a battery rather than straight off the alternator. A 550 amp-hour battery, if you wanted to totally discharge it, would provide power to run this monstrosity for almost three hours. Not bad, but this is only a 3hp supercharger, your boosting potential is going to be limited.
You've exhausted your battery, now you get to recharge it from your engine. Assuming 90% efficiency for the alternator (Mechanical->Electrical conversion) and the same for the battery (Electrical->Chemical, Chemical->Electrical), you end up with this:
2235w/.9=Power stored in the battery=2483.33w Chemical
2483.33w/.9=Power demanded from the alternator=2759.259w
2759.259w/.9=Power drawn from the engine=3065.844w
Means your supercharger's total system efficiency would be 2235/3065.844, or 72.9% efficient. This is not counting the efficiency of the supercharger itself, just the drive and recharge system that supports it. This is also best-case scenario, as I am given to understand battery efficiency is more around ~80% and alternators ~85%, rather than the ninety I gave them each.
A good turbocharger can easily net that exact same efficiency, including the efficiency of the compressor and turbine setup.
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A VNT works darn well for me. It moved my torque peak from 3200rom to 2000rpm.
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A VNT works darn well for me. It moved my torque peak from 3200rom to 2000rpm.
i have a bigger turbo on a smaller displacement, but i think this is almost the limit. as said before, how to get high powers like +200/liter from a diesel.
I did some research, URL the electric compressor from thomas knight (http://images.turbomagazine.com/tech/0406tur_knight02_z.jpg) do have 3engines from 5hp. (to drive the roots)
In 1996 Knight looked into a 90-hp DC motor, but it was bigger than a car engine and weighed 1000 pounds. He decided to lower the engine size to a reasonable amount. Even a 2.0-liter engine making 15 psi at 8000 rpm required a 30-hp DC motor. Knight looked into smaller motors, which were still too big and heavy.
centrifugal:
"In 1998," says Knight, "I remembered the model boat multiple motors, and realized I may have a solution. Two or more motors; three or four. Why not?" So he applied for patents and researched motors. The 4kw brushless model plane motors were $1,000 each, and each supercharger unit cost $4,500 to make. He made one with three model motors drawing 3,500 watts each at 60 volts. This one used a centrifugal supercharger with gears, then belts, etc. Gears were parasitic, and belts were destroyed in a short time.
you can also read other items but no any application takes a low-power engine.
turbo is not free power
Turbos are not free power, as some will claim. A turbo is a turbine-driven supercharger and to drive something requires horsepower. The turbine needs velocity, volume, heat and pressure to operate. The first three won't make any boost. It's pressure that makes boost. The first three help with greater efficiency. The pressure in a turbo is measured by the difference in intake manifold pressure and exhaust manifold pressure. This is referred to as the exhaust-to-intake pressure ratio. Most turbos operate at a 2:1-to-3:1 ratio, meaning that if 10 psi is in the intake manifold, the exhaust manifold will see 20 to 30 psi. (The GN operated on a 2.5:1 ratio and the 300ZXTT had a 2.7:1 ratio). Some racecars make PR better than 1:1, but they're still making backpressure. Backpressure is a restriction, and a restriction is not free power.
A turbocharged JET with the shaft connected to a compressor would be an idea. Alltough, its also not realy so practical. But forget electric drived compressor at all.
Greetz, Benjamin
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A typical supercharger takes that 3-5hp to generate their boost, right?
Wrong. A typical supercharger takes 18-22hp to produce 450cfm @ 8psi boost or 80-100hp to develop 780cfm and 15psi boost, have a look at the previous page. A lot of people underestimate the power necessary to pump the volume of air required by an engine. I like the triple starter motor setup pictured, nice bit of machinery, if a bit silly.
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I can see it now, all those Merc guys digging frantically through their trashcans to find the VW nozzles they took out. :P :lol: :P :lol:
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A typical supercharger takes that 3-5hp to generate their boost, right?
Wrong. A typical supercharger takes 18-22hp to produce 450cfm @ 8psi boost or 80-100hp to develop 780cfm and 15psi boost, have a look at the previous page. A lot of people underestimate the power necessary to pump the volume of air required by an engine. I like the triple starter motor setup pictured, nice bit of machinery, if a bit silly.
So I was really erring on the low side. I was trying to take into account lower volumes for lower displacement engines, and I guess I overcompensated a touch.
Still, 18-22hp required just makes the overall efficiency, size and now cooling problems that much worse.
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turbo is not free power
Turbos are not free power, as some will claim. A turbo is a turbine-driven supercharger and to drive something requires horsepower. The turbine needs velocity, volume, heat and pressure to operate. The first three won't make any boost. It's pressure that makes boost. The first three help with greater efficiency. The pressure in a turbo is measured by the difference in intake manifold pressure and exhaust manifold pressure. This is referred to as the exhaust-to-intake pressure ratio. Most turbos operate at a 2:1-to-3:1 ratio, meaning that if 10 psi is in the intake manifold, the exhaust manifold will see 20 to 30 psi. (The GN operated on a 2.5:1 ratio and the 300ZXTT had a 2.7:1 ratio). Some racecars make PR better than 1:1, but they're still making backpressure. Backpressure is a restriction, and a restriction is not free power.
Thus why the word "free" in reference to the turbocharger boost was in quotations, to indicate that I was simply referencing, not laying claim.
I fully realize that you can't get something from nothing (Which would be the full application of the term "Free" in reference to boost generation), but the turbocharger is still more efficient even if only by sheer virtue of a reduction in the number of state changes that must be made to supply the desired output.
It is also "Free" in that it tends to avoid a great many of the parasitic loss points associated with mechanically driven forced induction setups, such as the belts, pulleys, gears, chains, or whatever else you use to drive the setup. Yes, you have the increased exhaust backpressure over a mechanically driven supercharger (which places no restriction in the exhaust), but this is offset by other factors which increase the turbocharger's efficacy over the supercharger under the conditions where the turbo is more desirable (typically, mid-range and top-end power. I don't think I've ever seen a turbo used to boost low-end power specifically).
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I don't think I've ever seen a turbo used to boost low-end power specifically
Have you driven any turbocharged VW/Audi product gas or diesel lately?....1500rpm torque peaks, VNT15's and K03's FTW :roll:
Seriously I think VW has a tiny turbo complex or something.
Now my 1.6td with a T3 on the other hand.....I think....maybe...possibly...ok waaaaaaiiit....oh theres some boost.
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I don't think I've ever seen a turbo used to boost low-end power specifically
Have you driven any turbocharged VW/Audi product gas or diesel lately?....1500rpm torque peaks, VNT15's and K03's FTW :roll:
Seriously I think VW has a tiny turbo complex or something.
Now my 1.6td with a T3 on the other hand.....I think....maybe...possibly...ok waaaaaaiiit....oh theres some boost.
Actually... no, I haven't. I've driven a K24 1.6TD, which was just like that. Never been in a TDI, never been in a car powered by a 1.9TD with a K03.
Now, was the turbocharger on a TDI put there to increase low end, or to increase top-end power with the added effect of increasing low end as well? I've driven NA diesels that were torque peaking @ 1500rpm out of 4k RPM; that's just a diesel talking, not the turbo's function.
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Even the VW gas engines like the 1.8T...tiny turbo. I think what the OEMs are going for is making a small fuel efficient engine feel like a bigger engine with low end torque by fitting a tiny turbo. People hate small engines and turbo lag...at least here in America we apparently do.
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TDi turbo is small and driving it feels like driving a V6. Instant torque and lots of it. but about the time it gets really fun, it's time to shift. Could also be the 1.9 not so high red line motor. In traffic drivability is better with small turbo compared to a biger one, even tho the bigger one can net you more power.... eventually
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"people buy horsepower but drive torque"
thats why a 90hp old tdi is more enjoyable to drive as a daily driver than a vr6. the 110hp with that tiny vnt15 is even better.
basically everybody needs small turbos in their golfs, but always want the bigger ones, then *** around because of the lag, and smoke on low revs, and lack of power when off boost...