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| eb_guy888 |
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Hey guys
I dont know much about turbo's and that apart from the basics. I was recently talking to a friend who has a turbo subaru bug eye, last yrs model. Its running over 200kw. He was telling me that he was racin a guy, and they were side by side then his boost shot up and he took off. Im wonderin, what is boost? what causes it and what does it do exactly? |
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| smiley235 |
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Well, the turbo has a turbine that is turned by the exhaust gasses coming out. This turbine is connected by a rod to another turbine which (as it starts to turn faster) sucks air in like a vacuum cleaner. Now this air is then forced into the engine at a higher pressure than what it would normally go in (cause its been forced) thus, the engine can mix more fuel with it and you get more explosive power in the engine. Now as the car accelerates, it takes a while for the exhaust gasses to get the turbo spinning, so the turbo spools up enough speed, then when it gets fast enough to start forcing air into the engine, you get boost (and you should notice a very substantial increase in acceleration that makes you go weeeeee)
_________________ 178.3 rwkw
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| 4.9 EF Futura |
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A turbo or supercharger compresses the air going into the engine.
Boost is how the pressure of this air is measured. For example - 7psi boost means the pressure in the intake manifold is 7psi higher than atmospheric pressure.
_________________ I promise..... I will never die. |
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| eb_guy888 |
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ah I get ya
so once the turbine spins fast enough it will boost you like nos or something would I get ya now I wondered why his boost wound up b4 it shot him off. A boost guage tells u when its winding up so u know when ur going to get that extra shot of power yeh? |
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| smiley235 |
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yeh, the needle starts off in the negatives, below 0, then as the exhaust gasses get faster and the turbo is spinning fast enough, you've got positive pressure so you boost and the boost gauage needle and your rpm shoot up. And yes, similar concept and feeling to nos.
Heres a little video to see if u want. http://videos.streetfire.net/search/boo ... d614c2.htm
_________________ 178.3 rwkw
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| Rmyers |
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4.9 EF Futura wrote: A turbo or supercharger compresses the air going into the engine.
Boost is how the pressure of this air is measured. For example - 7psi boost means the pressure in the intake manifold is 7psi higher than atmospheric pressure. I was told that atmospheric pressure is up around 14.5psi??? |
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| 4.9 EF Futura |
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Rmyers wrote: 4.9 EF Futura wrote: A turbo or supercharger compresses the air going into the engine. Boost is how the pressure of this air is measured. For example - 7psi boost means the pressure in the intake manifold is 7psi higher than atmospheric pressure. I was told that atmospheric pressure is up around 14.5psi??? Correct Mr Myers. It's somewhat dependent on altitude and the weather... but atmospheric pressure at sea level is generally regarded as 14.7psi. 14.7psi is 1 bar. i.e. atmospheric pressure is 1 bar. So if you're running 7psi boost in the intake manifold, its actually 21.7 psi at sea level... bit 14.7 of that is atmospheric pressure 
_________________ I promise..... I will never die. |
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| smiley235 |
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yup, 101kpa which = 14.7psi
_________________ 178.3 rwkw
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| ebs_4l |
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4.9 EF Futura wrote: 14.7psi is 1 bar.
well, close, its technically 14.50326psi lol
_________________ EB 4L, 8.4:1, R154, GT4202r, 4in exhaust, Greenslade Engineering exhaust manifold, plenum chamber, 90mm throttle, Garrett W2A cooler, Surecam custom, autronic SM4, Bosch 120lb, Crane HI-6, LX-92, LM-1, Turbosmart Reg, 2x bosch 044, turbosmart 48 gate. 470kw+ @ 18PSI |
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| 4.9 EF Futura |
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ebs_4l wrote: 4.9 EF Futura wrote: 14.7psi is 1 bar. well, close, its technically 14.50326psi lol Lol - good call! Thanks for the clarification
Must have my pressure readings and stoichometric ratios mixed up
_________________ I promise..... I will never die. |
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