Jump to content
SAU Community

Recommended Posts

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

  • Replies 46
  • Created
  • Last Reply

Top Posters In This Topic

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

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...

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.

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

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

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! :)

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • They're so beautiful 馃槏
    • Early last week, I became concerned that the car was feeling....slow. Most of my driving is commuting to/from work and there are few opportunities to get up it and convincingly make boost/power. It drives in vacuum almost all the time. But when you do occasionally get an opportunity, and.... it takes a little longer to start making power, and then there's not as much as you'd expect, and then you run out of road anyway and have to bottle out - it can be hard to be convinced that there's something wrong. But by the end of the week I was pretty convinced. Made an effort to get a decent test run. Took bloody forever to come up on boost and when it did it would only make about 50 kPa of pressure. There was no black smoke, no noise of a boost or exhaust leak, no evidence anywhere of an intercooler hose clamp being sloppy enough to let air escape. So.... not that sort of problem. Brainstorming led to thinking that the boost controller's solenoid might have failed in some way. No active boost control would just give wastegate pressure, which I was more or less getting, and the laggy behaviour could just be "normal" shitty boost response from an uncontrolled highflow. But a little extra 3rd party brainstorming led to the thought that the actuator circlip might have jumped off leaving me with a bluetooth wastegate. So, on Friday, off comes the stock heatshield (which is an annoying enough job on its own) to reveal - yup. WG is wide open. And.... it won't come back. It is jammed in the dump. Put the rod back on with a new circlip and tried driving it to get it hot in the hope that the capture was from thermal effects having been blown into the dump when hot and since cooled. Nope. Won't move, even with screwdriver mediated force when hot. Ran out of time to play. Came back to it yesterday. Unbolted the dump. Was lying under it with the dump jammed up against my guts undoing the bottom 2 bolts. Got them most of the way out and gave the dump a serious heave. It didn't noticeably move, but there was a satisfying "plink" noise from up to. Shuffle out and sure enough, gate is now closed. Nevermind that there was still the better part of an hour after that required to put it all back together. f**ken cars.
    • For your application, where you'll be at that 1/2" size or perhaps larger, yeah, excellent. Although not if you need a tight bending radius anywhere, because the corrugated stuff is not anywhere near as flexible as rubber/teflon cored stuff. But for turbo oil lines? No. Too big. They just don't do the corro stuff down at the ~1/4" ID size that you'd want, and if they did the OD of it would probably be a bit too fat for fitting it into the tight spaces available. I use hoses like that all the time for fuel gases (LPG, NG) and liquid fuels (HFO, diesels, waste oils). When we did the London Olympic cauldron, with the 204 individual burners on it, we had miles of the stuff (although a lot of that was teflon core). A bunch of that crap is still cluttering up the workshop, more than 12 years later!
    • Would something like this be an option  https://processhose.com/products/configurable-metal-hoses/1-2-in-t316-stainless-steel-annular-corrugated-configurable-flexible-metal-hose-assembly-with-ends-t304-single-braid-masterflex-af5550.html I'm looking at this for replacing the OEM EGR when installing a aftermarket intake plenum 
    • The once piece tail shafts with cv type joints on either end are the ones that end up vibrating and the vibration is caused by the cv joint binding as it turns, I鈥檝e also seen them explode from the binding 
  • Create New...