how is this supposed to work?

[kev_mono72]

saw this on one of the ads on this site

http://www.spiralmax.com/index6.htm

Just curious as to how it does what it says it does...

Some pics of it

 

[59 bhp is more than enough]

it doesnt believe me. its a piece of pipe with a fan inside it. they try and confuse the customer with jargon. a car will never run 100% efficient. if it made any difference it would go in standard. it bears no resemblacne to a supercharger and will not give 35% increase in power. its the equivelent to shaving your head completley to save weight. technically it will save weight but it will make no noticable increase.

 

[Andrew]

Put simply, it doesn't.

I think the gist of the thing is that it makes the airflow more turbulent, which should make the fuel vapourise better.

2 problems with this... firstly, most engines don't have a problem with unvapourised fuel. Secondly, it's a restriction in the intake side of the engine, which you don't want.

It's all rubbish really, just like those fuel line magnets and electric superchargers and air flow meter resistors.

Andrew

 

[kev_mono72]

ok, cool, so this is fairly useless too then???

 

[Titch]

ok, cool, so this is fairly useless too then???

yes it is
:kungfu:

 

[Andrew]

ok, cool, so this is fairly useless too then???

They are even worse. They cost more, and the theory is utter (slight mispelling of) bullocks.

It's just not possible for a fan like the one in a PC to produce any level of boost. They can move a lot of air, without any restriction. But as soon as there is any restriction, they stop working.

Then there is the power issue. Take a really small supercharger which consumes 4HP of the engines output. 1 HP = 750W (ish), so that is 3000W. At 12V, that's 250A.... which your car cannot provide.

There are electric turbos and superchargers that appear to work - though they need their own power supply and can only run for short periods:

http://www.turbomagazine.com/tech/0406tur_knight/index.html

 

[Pink Princess]

A car can onli ever have at the most 85% - 90% volumetric efficiency its to do with the method of intake and how the strokes over lap, if you understand what i mean, as exhaust gases are expelled in comes new air but some will escape with the exhaust emissions. that cannot be prevented.
u can onli ever have 90% max of thermal efficiency, or rarely you will be able to increase that, if you have the money to spend
then you have forced induction kits, they are good, cheap for the slight performance that they increase
You could change the manifolds, bore it out, change the pistons, skim the head, and this may improve the performance,

then obn other hand you could supercharge or turbo, this would improve performance, efficiency and a lot more...

however nah that spiralmax is a load of ****e

 

[Ed]

Engines waste over 60% of their output via heat (cooling and exhaust). That makes them very very thermal inefficient. You will never get past 40% thermal efficiency let alone 90%. Also by careful design of the intake manifolds, it is entirely possible to EXCEED 100% VME on a NA engine. Infact race cars will all exceed this in the RPM range it is designed for, I would also expect that there are motorbikes that also exceed this. It is true to say however that a normal car will not pass 100% VME, but they will be quite high (upto 95% for modern car) And finally maxium VME is the point at which the engine developes the most torque.

Adding a turbo or supercharger does not make an engine more efficient. Superchargers (the roots type) are typically only around 50% efficient. Turbos are upto around 75% efficient.

 

[Pink Princess]

oh yeah, **** lol, i meant compression efficiency, sorry darling, thanks for picking up on that, thermal efficiency will yeah be around 35%

---

You sure about the 95% on normal cars? I would have expected lower because thats what i have in my notes.. but hey i am willing to change ma mind on that.

Turbos use the wastage and can allow a higher output, however i was under the impression that supers took energy from the vehicle to boot out more, therefore you would need a high performance well powered vehicle to feel the benefits of supercharged, i was purely giving ideas...

i admit i dont kno all, and admit i mssed up on the previous post, purely for fact i got me head in a tis lol...

i will find out the notes for ya darling on engine performance if you like

---

i might just get out of this thread because what i say gets taken wrong. anyways good luck on ya micra, ignore my advice as it seems to be wrong in the instance...

 

[Andrew]

u can onli ever have 90% max of thermal efficiency, or rarely you will be able to increase that, if you have the money to spend

On a 10:1 compression ratio engine, the maximum thermal efficiency you can get, using the Otto cycle (which ignores the intake and exhaust strokes) is about 60%. The Otto cycle ignores pumping, friction, mechanical and parasitic losses. They take off another 30%.

The easiest way to make an engine more thermally efficient is to increase compression ratio.

 

[Pink Princess]

yes i kno i realised after i said it, i admitted i got it worng.........

 

[bobee]

ive seem things like them on sum defenders,
when looking and found this http://www.4x4web.co.uk/4x4-equipment-tests.html - the first review,

they seem to say it helps with lowend grunt..

 

[Ed]

Feel free to speak your thoughts. Dont feel intimidated either. Andrew and I are farily blunt but dont take it as offensive its certaintly not ment. My quote of VME may be a bit higher than in the true sense. But cars are now much more efficient than a few years ago, and often the course information your taught is quite out of date by the time it gets to you.

Back to turbos, they are not free energy. You have to lower the compression ratio to use them, this makes an engine less efficient, and also they place a restriction on the exhaust again reducing efficiency. Often this is ignored in explanations just for the sake of simplicity.

 

[clyde]

spiralmax, free with cornflakes!

the idea is there, as with many similar items such as the foresaid electrical supercharger and inline fuel magnets. however, they just dont prove themselves. But, combined with a giggle band, an underground exhaust, and some rat trap brake pedals, can equate to some 100 plus brake horse power! lol!