We all know that generally a larger turbo on the same boost will make more power, but I doubt that many people actually know exactally why... I'm trying to get my head around it.

Let's say there is a modest 50hp difference between two motors identical except turbo size. Now that 50hp can't solely be lost to the motor trying to push a huge ammount of exhaust through a tiny turbine housing? Does having a smaller turbine housing that restricts you up high, decrease volumetric efficiency due to exhaust in the combustion chamber due to much higher exhaust manifold pressures causing the loss of power? Or are both engines running at similar cylinder pressures?

Tuners: Based on past tuning experiences, how do injector pulse widths vary between two motors similar in every way (boost, peak power rpm, a/f ratio, timing etc) except final power output?

Thanks.

 

smaller turbine = more backpressure = bad= more heat= less power=shitty so dont use em

 

more reversion

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">smaller turbine = more backpressure = bad= more heat= less power=shitty so dont use em </TD></TR></TABLE>


hahah

 

Its quite simple. a bigger turbo will move more air(volume) at the same boost(psi = pressure). pressure and volume are 2 different things. its like this : if i slap u with 1 hand, this equals a smaller turbo, but when i slap u with 2 hands (at the same force mind u), this is the bigger turbo. pls dont laugh at my analogy...

 

jep, no you are very wrong. I started this discussion because too many people think like you do.

nickromeo: So reversion is the effect of exhaust being pushed back into the cylinder? i.e. lowering v.e?

 

define volumetric efficiency

 

yes running a larger turbine housing is gonna increase your volumetric efficiency. Running a larger turbine housing is the key to making more power and at the same time decrease reversion which helps prevent knock. Your engine will breath much better. At the same time running a larger turbo with a larger compressor will give you more efficient air. The less efficient your compressor the hotter your post compressor air temps will be.