Teufel Hunden
02-20-2004, 08:14 AM
Some common Turbo-related terms defined:
-Boost Threshold or Boost Point
The lowest engine RPM at which noticeable boost (1-2 psi) can be achieved.
-Lag
The difference between a change in throttle and the production of boost when engine RPM is in a range when boost can be achieved.
-Detonation
Spontaneous combustion of the air/fuel mixture ahead of the flame front. When pressure and temperature exceed that required for controlled combustion, the mixture autoignites. The metallic pinging sound is the resulting explosion's shock wave colliding with the cylinder walls.
Note: Ping, knock and detonation are equivalent terms. Pre-ignition is a different issue. It's important not to call one the other.
FAQs:
-How will the turbocharger affect driveability?
Driveability of fuel injected engines will remain the same.
-Will the turbocharger hurt my mileage?
Yes. When not operating under boost, a turbocharger is a small system restriction. This restriction causes a small loss in volumetric efficiency. How much your mileage is affected depends on many factors. Some see up to a 5% drop, while others notice negligable differences.
-Will the turbocharger affect engine wear and maintenance?
Yes. If you drive vigorously but have some respect for the equipment, you can expect 90% of normal engine life. The need for on-time oil changes also increases.
-Do twin turbos offer any advantage?
Sometimes. An engine with flow capabilities greater than 300cfm (roughly 180cid) can benefit from two turbos. Two little turbos can slightly cut turbo lag and lower boost threshold, as opposed to one large turbo, and allow for a better balance of low speed and top end performance. Do not accept the idea that twin turbos are inherently more powerful, as too many other factors are involved.
If you think of anything else that's needed here, send me a PM!
-Boost Threshold or Boost Point
The lowest engine RPM at which noticeable boost (1-2 psi) can be achieved.
-Lag
The difference between a change in throttle and the production of boost when engine RPM is in a range when boost can be achieved.
-Detonation
Spontaneous combustion of the air/fuel mixture ahead of the flame front. When pressure and temperature exceed that required for controlled combustion, the mixture autoignites. The metallic pinging sound is the resulting explosion's shock wave colliding with the cylinder walls.
Note: Ping, knock and detonation are equivalent terms. Pre-ignition is a different issue. It's important not to call one the other.
FAQs:
-How will the turbocharger affect driveability?
Driveability of fuel injected engines will remain the same.
-Will the turbocharger hurt my mileage?
Yes. When not operating under boost, a turbocharger is a small system restriction. This restriction causes a small loss in volumetric efficiency. How much your mileage is affected depends on many factors. Some see up to a 5% drop, while others notice negligable differences.
-Will the turbocharger affect engine wear and maintenance?
Yes. If you drive vigorously but have some respect for the equipment, you can expect 90% of normal engine life. The need for on-time oil changes also increases.
-Do twin turbos offer any advantage?
Sometimes. An engine with flow capabilities greater than 300cfm (roughly 180cid) can benefit from two turbos. Two little turbos can slightly cut turbo lag and lower boost threshold, as opposed to one large turbo, and allow for a better balance of low speed and top end performance. Do not accept the idea that twin turbos are inherently more powerful, as too many other factors are involved.
If you think of anything else that's needed here, send me a PM!