Tuesday, Aug 27, 2002 at 00:00
Hi again,
Very similar result overall in both super or turbocharging once cruising speed has been reached, infact with the vast majority of forced induction systems be it diesel or petrol once this speed has been reached and the "acceleration load" on the engine levels out, boost actually decreases.
Boost in Supercharged (both types turbo and mechanical) engines is a result of the engine not being able to use the "charge" available to it in the intake manifold.
In supercharged(mecanical) engines the level of boost is controled by blower speed ver's engine revolutions, intake opening and engine consumption(Camshaft, displacement etc).
In turocharging the boost is governed by intake opening, engine consumption and exhaust flow but most importantly exhaust temperature.
You may have heard a diesel truck coming to the bottom of a
hill , then when the truck starts to come under load as it starts to go up you can hear the turbo starting to wistle.....a result of not an increase in engine RPM or but rather an increase in exhaust temperature.
My point here is that turbos tend to be a more "self governing" thing, they don't have the response of a supercharged(mechanical) engine, they take a while to build up pressure (hence the term turbo lag). As a result of this they are regarded as being easier on the engine.
Super charging (mechanical) tends to be much more responsive and that is why it is used in competion.
Neither is ideal but I think in the everyday application a turbo wins hands down.
Manufacturers are now starting to supercharge vehicles as a result of the unpopularity of turbo lag and turbo cool down times.
Either system has the ability to harm the engine if the engine hasn't the mechanical strength to cope with the new horsepower is will produce as a result if the boost level is to high.
You will notice huge performance increases if you can pressurise the manifold around 6-8 psi,...any more is asking for trouble without bottom end mods to increase strength.
Sorry for the long post
John
AnswerID:
6060
Follow Up By: John - Tuesday, Aug 27, 2002 at 00:00
Tuesday, Aug 27, 2002 at 00:00
Just one more thing....
If ou keep the pressure down to around the 6 psi or so you will not have to many problems....Just keep the oil changes regular because the poor old oil in a turbo engine is the coolant for the turbine shaft as
well as the lubricant......bad oil....that is what will increase engine wear, be warned.
Cheers again
John
FollowupID:
2654