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Turbo 101

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Old 08-15-03, 03:51 PM
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Turbo 101

After all the reading and research, I'm still lacking the knowledge of understanding the detail workings and functions of the turbo. So many terms and jargons that I can't relate to... Boost Master, your Padawan learner awaits. Teach me the ways of the turbo

Old 08-15-03, 03:54 PM
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http://auto.howstuffworks.com/turbo.htm

This site is GREAT. It has visuals & demos to really show you what goes on....
Old 08-15-03, 04:46 PM
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Originally posted by r0t0r-rooter
http://auto.howstuffworks.com/turbo.htm

This site is GREAT. It has visuals & demos to really show you what goes on....
Been there, done that... what about controlling boost, boost creep, blow-off valve<~~>wastegate...
Old 08-15-03, 05:34 PM
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Available from most online book sellers:
http://www.amazon.com/exec/obidos/tg...l/-/0837601606
Old 08-15-03, 06:42 PM
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I'll add what I can.

Lets start with terms. Blow off Valve, or BOV. When you accelerate and the turbos build boost, it all gets fed into the engine. When you let off the gas, theres still some pressurized air on it's way from the turbos to the engine, and it needs somewhere to go. The throttle butterflies are closed, so it can't go there. Ther turbos are pushing it out, so it can't go there. It goes out the BOV, which basically just vents it off. The stock BOV vents it (the compressed air) back into the intake box, to suppress the noise of it. Most aftermarket BOVs vent it to the atmosphere, so you get that cool pfffsssssst sound.

Wastegate. This is a flapper door type of thing, thats controlled electronically by the ECU. The exhaust gasses that pass through the turbos first need to go through this. It is fully open until you reach the maximum boost pressure (10 psi when stock) and then it starts to close to send some of the exhaust gasses around the turbos, which slows them down and keeps them from building more boost. It is actively duty controlled, meaning that the ECU is contstantly monitering boost pressure and adjusting the wastegate as necessary to keep the pressure at 10 psi.

Boost creep. This goes hand in hand with the wastegate. When the engine is modded, there is a point where too much air is going through it for the stock wastegate to handle. Its opening is only so big, and if the volume of air/sec coming out of the engine is greater than its opening will allow, some of the gasses will start going back into the turbos, and they'll spin faster and faster, creating a slow building of boost over the desired level; a creep, if you will. This is remedied by boring out the wastegate, which makes the hole larger.
Old 08-15-03, 06:49 PM
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Now tell us exactly how the RX7 twin turbo system works in detail.
Old 08-16-03, 01:06 AM
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Originally posted by satman
Now tell us exactly how the RX7 twin turbo system works in detail.

good luck
Old 08-16-03, 06:30 AM
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Originally posted by 911GT2
I'll add what I can.

Lets start with terms. Blow off Valve, or BOV. When you accelerate and the turbos build boost, it all gets fed into the engine. When you let off the gas, theres still some pressurized air on it's way from the turbos to the engine, and it needs somewhere to go. The throttle butterflies are closed, so it can't go there. Ther turbos are pushing it out, so it can't go there. It goes out the BOV, which basically just vents it off. The stock BOV vents it (the compressed air) back into the intake box, to suppress the noise of it. Most aftermarket BOVs vent it to the atmosphere, so you get that cool pfffsssssst sound.

Wastegate. This is a flapper door type of thing, thats controlled electronically by the ECU. The exhaust gasses that pass through the turbos first need to go through this. It is fully open until you reach the maximum boost pressure (10 psi when stock) and then it starts to close to send some of the exhaust gasses around the turbos, which slows them down and keeps them from building more boost. It is actively duty controlled, meaning that the ECU is contstantly monitering boost pressure and adjusting the wastegate as necessary to keep the pressure at 10 psi.

Boost creep. This goes hand in hand with the wastegate. When the engine is modded, there is a point where too much air is going through it for the stock wastegate to handle. Its opening is only so big, and if the volume of air/sec coming out of the engine is greater than its opening will allow, some of the gasses will start going back into the turbos, and they'll spin faster and faster, creating a slow building of boost over the desired level; a creep, if you will. This is remedied by boring out the wastegate, which makes the hole larger.
Well, what would cause sporadic boost patterns?
Old 08-16-03, 12:16 PM
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Originally posted by 911GT2
Wastegate. This is a flapper door type of thing, thats controlled electronically by the ECU. The exhaust gasses that pass through the turbos first need to go through this. It is fully open until you reach the maximum boost pressure (10 psi when stock) and then it starts to close to send some of the exhaust gasses around the turbos, which slows them down and keeps them from building more boost.
The wastegate starts out fully closed, which keeps all exhaust gas flowing through the turbine. It opens to vent exhaust gas away from the turbine in order to maintain the set boost pressure.

Originally posted by HDP
Well, what would cause sporadic boost patterns?
Bad wastegate, bad gas, bad injectors, bad blowoff valve, bad vacuum lines, etc. You should take your car to a qualified mechanic for proper diagnosis.
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