I think I am saying that the flow map of the same turbo with lower VE on the same engine as compared to a flow map with the same turbo with higher VE .. should have lower max boost...
I think you are saying with identical setups ONLY CHANGING THE VE of the engine. Yes, with higher flowing (VE) engine you will have lower top manifold pressure preasure. Think of your manifold pressure (boost) as being a meter of how poory your engine flows at any given RPM and load. Airflow is what we are looking at here. The problem it it is so ingrained in our minds that boost pressure = airflow. This is true with an all stock internaled engine compared to another. So it is a good way to compare all our cars UNTIL you start doing things like: EXHAUST MANIFOLD UPGRADE HEADWORK THROTTLE BODY UPGRADE Even simple things like getting your intake manifolds extrude honed, and using higher lift cams will increase your VE. Once any of those things is changed your flow (VE) is increased and your boost level (and thus your intake charge temperature) should be lower, at the same power levels.
...assuming the surge line is above the efficiency island that the turbo operates in this example.
And since RPM is independent of the flow map...more power should be realized at the same RPM band on the higher VE car ..assuming the surge line is above the efficiency island ...
I'm sure you didn't mean to imply it but it is obvious (as Kenny stated earlier) the compressor flow map is static and is not in anyway effected by any change in the motor's VE. The engine's VE will DRASTICALLY change those lines that have been plotted over that flow map in an attempt to help us better understand how to interpret them given an engine with 1.5l of displacement per turbo.
if the turbo is producing more boost and is below the surge line, EGT's will increase due to the increase in wheel rotational speed from the improvement in VE
EGT's increase with power output but not directly with increase in VE, only insomuch as VE effects max output power. At the same power levels EGTs should be LOWER on a better flowing engine.
I just wanted to make sure that all the above was correct thinking or wrong thinking ...
Dee, I hope I have helped you better understand this stuff and if I am wrong on any of the above (very possible) that this can be a nice learning experience for both of us.
m a g l i t o
parts are FINALLY here - engine is going back together NOW
sig photo by me effects by ZXRider(SoCal)click here for latest build update post
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