What turbo to just extend the powerband

[CnoTataymo]

A GT35r only making 327whp? Sounds low.

 

[mazdaspeed32007]

Dude, LaDouche and his car were both fail. End of story. If you think not then you don't know jack s*** about our cars or the mazda forums (all of them).

Hell he was even banned off of MSF for his douchebag attitude and negative posts even after he gave up on his MS3 and parted out. Now he is a laughing stock on the BMW forums. Good riddance, they can have that POS.

hahahahahaha. you da man

 

[toaofallen]

wow i just read all of this in my pipefitting class and for the first time in this class i learned something lol what a wast of 1k
but ya reading this made me think twice on how im going to mod my car thx

 

[240ka]

The k04 is too small for our motor.

That's why vw/audi guys with 1.8 and 2.0 motors get better gains out of the k04 compared to us. There motors are quite a bit smaler than ours so its not maxing out the turbo like it does on our 2.3 liter motor

That's what guys with bigger turbos on our stock bottom end aren't sending rods through the block. The k04 is creating way too much load and tq under the hp curve.

Id feel more comfortable with a bigger turboo on my motor than the k04

 

[Darth Vader]

aww but, I bought this car for it's agro V8 torque!

 

[vin0410]

boost pressure is directly related to how much air the engine can breath in at any given rpm vs how much air the turbo can move.

Assuming 100% volumetric efficiency

Air flow rate = (displacement)(rpm) / Strokes * conversion factor

MS3 - 2.3 liter @ 5800rpm

AFR = 140ci*5800* / 2*1728 = ~235 ft^3


GTI - 1.8 liter @ 5800rpm

AFR = 122ci*5800 /3456 = ~205ft^3

They do not push the same amount of air at a given rpm

To go one further:

again assuming 100% VE

boost = (max cfm of turbo/AFR)*14.7 - 14.7
MS3 - (X/235)*14.7 - 14.7 = 15.7psi..... x= 486cfm
GTI - (X/205)*14.7 - 14.7 = 15.7psi...... x=424cfm

the x values are how much cfm the turbo is required to push to achieve 15.7psi

again they are not the same. This does not account for the engine volumetric efficiency, engine design etc. which in either case will not be the same for both engines.

so 15.7psi is not always the same cfm. This further proves that the K04 is undersized for the 2.3.

and to show it is in fact still making power above 6k please see attached dyno chart and datalog. power is beginning to drop at 6100rpm, but that is due to flow limitations of the engine itself, the turbo is still pushing 18+psi at 6200 in the attached datalog

Yes after 6k the turbo is still building 18+ psi, but the engine is not breathing much either. The see how much the turbo blow is not just the pressure. We should take into account both the pressure and the flow per revolution, as torque is proportional to pressure times flow. From the graph it is also possible the turbo is maxing out AND the engine flow diminishing (a lot, more than turbo). For example, if we improve the engine flow at high rpm (high cams or so), can we be sure the current pressure can be sustained?

Yes the engine flow is diminishing and I tend to think turbo is also maxing out. if you ever compare it with other turbos say TD05, you will certainly feel K04 small for 2.3L. A turbo good for mid to low torque.

Strange though...the head and the manifold look like great flow stuffs.....maybe the throttle closing by ECU is the reason?