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Q45 Differences

pommey barstard

By pommey barstard,
in Engines & Forced Induction

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paulr33 Grand Master

paulr33

Posted
Posted

yes but 300rwkw on an rb25 is different to 300rwkw on an rb30

it will flow different amounts of airflow for a given RPM

and i believe he was using ap eng RB20 which i think possibly the airflow ramps were a bit of out spec, ie: in the newer 5.10 RB25 PFC i think the ramps are bit better

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mokompri Community Regular

mokompri

Posted
Posted (edited)
yes but 300rwkw on an rb25 is different to 300rwkw on an rb30

it will flow different amounts of airflow for a given RPM

they may flow different amounts throughout the rev range, but if peak power is the same and if it doesnt max out on one, it wont on the other either.

Edited by mokompri
Bl4cK32 Grand Master

Bl4cK32

Posted
Posted

I was running it off the rb20 base map to start, then we flashed the pfc over to the rb25 base settings (which work better) and we had a play with the datalogit adjusting :

the numbers in the voltage ramp which are visible in datalogit, fc pro and power excel only control how it is placed on the load map, that is it wont control when it hits 5.1v but more determine where certain voltages hit the load axis.

as well as something else to get the load points down to a tunable resolution.

dont ask me specifics, i just pay fer the tunes :P Cubes may remember exactly what we did...

cameron Mentor

cameron

Posted
Posted
they may flow different amounts throughout the rev range, but if peak power is the same and if it doesnt max out on one, it wont on the other either.

In my expierence's with the Q45 (one that works) I've tuned 2 different RB25's with 2 different turbo's same Q45 AFM... Sorry didnt look at the number on it.

Engine 1: rebuilt engine, GT3540 turbo - running 30psi making 500rwhp maxing AFM 5.1vlts @ 5000rpm - engine was reving to 8k - peak power was made at 7500rpm

Engine 2: stock engine, HKS 3037s turbo - running 25psi making 430rwhp maxing AFM 5.1vlts @ 5500rpm - reving to 7k peak power made at 7k

We did not check these AFM with a multi-meter to see for sure that they were maxing out, these readings were from the apexi PFC.

The cars drove fine etc, had no troubles with tuning the AFR's

I know boost pressure does not = air flow through the meter.

The z32 is a much better afm for tuning the only thing you could do is to put it into a bigger 90mm pipe.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Doesnt a z32 have enough resolution for 300rwkws?

:S

369rwkw/24psi on my ole RB25 & Z32

peak power the same for both motors, wont mean the same airflow for both motors (if different capacities) if im not mistaken

mokompri Community Regular

mokompri

Posted
Posted (edited)
peak power the same for both motors, wont mean the same airflow for both motors (if different capacities) if im not mistaken

power is determined by how much fuel and oxygen is burnt ie mass of fuel and mass of oxygen/air

afm measures *mass* of air, so regardless of engine capacities a 2L and 3L both producing 100kw at whatever rpm, are both consuming the same mass of air.

Edited by mokompri
cameron Mentor

cameron

Posted
Posted

Wolf3D... great step up :lol:

mokompri: What are you trying to say? If 2 differnet engines make eg: 300rwkws and if the AFM does not max on one it should not be max on the other becaues they have the same peak power.

You'r claim eg:

Car: Make 300rwkws at 7000rpm - None Maxed AFM

Car: Make 300rwkws at 7000rpm - None Maxed AFM

How do you know its not maxed, regardless of the peak power like I said AFM's generally max at peak torque point or close to it in the engine, whether its 5000rpm or 7k a MAX voltage of 5.1 is the limit.

Too many variables,

Were talking turbo's not superchargers!

Let me know how you go adrian! :)

mokompri Community Regular

mokompri

Posted
Posted

doesnt matter whether its a supercharger or a turbo..

what im saying is, that afm's measure mass of air

the peak consumption of mass of air is at max power, not at max torque (unless that rpms also has max power), for any given period of time.

so yes, 2 engines making 300rwkw will show the highest voltage on the afm at peak power, and since they both make 300rwkw peak neither will max or both will max.

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