big power rev2

[Andy F]

I had a crap Christmas but it was expected, could have been worse though so can't grumble
When are you back at work Mich?? i still have another week If you fancy a video day, (just got me a 42" plasma and Cyrus AV) let me know!!!

[michael]

Not back until a week today - you can demonstrate the TOTB DVD to me at your cinema seen as mine hasn't turned up!

Flash git

[Andy F]

What ya doing tomorrow??
Krista's back at work, its great
Can pick you up if you want a beer.
any time is good.....you say

[michael]

No plans at all sir, free all day as far as I can remember

I'll probably have a lie in but otherwise all I need to do is go to the Post Office in the morning.... some time early afternoon?

[Andy F]

Pick you up at 1 then

[michael]

See you tomorrow!

[MR2Mania]

See you tomorrow!

love you...

[michael]

love you...

I'm blushing now!

[Andy F]

Meet new friends join
imoc dating agency

[gtschris.com]

get rid of the afm? Why ?

Going with the all new Andy F style posts, "AFM's are crap, junk it".

More usefully - AFM's have a limit on how much pressure they can measure, I *think* rev2's hit this at about 15psi?

.. Hmm, you're thinking of the Rev2 boost pressure sensor perhaps? That does top out at 16ish psi, but the ECU will have put a normal car until fuel cut well before that.

People usually junk the AFM as they see it as a restriction in the intake, limiting boost.

But its not been a problem for me

The AFM is a limitation not due to actual air flow (but yes this is an unwelcome restriction in the turbo intake system) but the limit of load it can calculate before hitings maxing output 0.36 volts (high voltage = less load). The ECU uses AFM load input signal and RPM to calculate boost, higher up the rev range the ECU will dump fuel into the engine at 100% duty cycle at 14/15PSI on a stock motor.


This actual data should prove to the most hardened “I am gonna keep my AFM brigade” how totally unsuitable the stock ECU/AFM set ups is with a modified 3SGTE, had this sort of data been on IMOC a few years back it would have certainly saved me a lot of time and effort learning the hard way, the rev3 is is better but still very limited.

Here a screen shot from greddy emanage, this shows the limitations of the AFM’s load output signal. Turbo is a ball bearing GT25r .86 A/R, free flowing exhaust, HKS 264 cams, Spearco Intercooler.




The screen shot is a dump out of the emanage software’s dataloging, here is what’s happening as I blasted up the road 18.2 seconds in.

6233 RPM
Airflow adjustment 0% this is because this run was done with the emanage correction map zero out.
Throttle position 40% its actually 100% but I got the TP input to the emanage hook up to the map sensor instead of the throttle position sensor (enabling adjustment to be made against boost rather than throttle position)
Airflow meter input 0.36v voltage to the emanage from the AFM
Airflow meter output 0.36v voltage to the ECU from the emanage (this can be changed to adjust fueling).
Greddy sensor 2.25V = this equals 11PSI Boost
Total Injector duty cycle 100% so the 440cc injectors are open all the time flooding the engine with fuel and running very very rich.

So there we have it AFM maxing out at a mere 11psi boost on a mildly modified MR2 Turbo…

[MR2Mania]

The AFM is a limitation not due to actual air flow (but yes this is an unwelcome restriction in the turbo intake system) but the limit of load it can calculate before hitings maxing output 0.36 volts (high voltage = less load). The ECU uses AFM load input signal and RPM to calculate boost, higher up the rev range the ECU will dump fuel into the engine at 100% duty cycle at 14/15PSI on a stock motor.

Chris is right, the AFM will max out in terms of what it's reading for maximum load. Also, the MAP sensor will max out too at some point, as Ben mentioned. The people that experience the latter are those that are raising the boost. Let's say someone has a Unichip fitted, if they do not have a turbo module with integral MAP sensor installed, then it won't see loads higher than the 12.5-odd psi that fuel cut occurs at. If they *do* have the integral MAP sensor, then this instead will be able to read the higher than fuel cut load points, and so the Unichip can kinda be used to try and control fueling and ignition at these points (assuming that it still has the plus/minus range to do so).

Having said all this, it still can't help with the situation if you've reached the max load point that the AFM can read. What's needed here is something that will allow the mapper to use a difference device to calculate load - either a device like the HKS Vein Pressure Convertor (gets rid of the AFM and allows the mapper to use a MAP sensor instead). NOTE: I've been told that the new Unichip that will be coming out soon will allow a tuner to fit a MAP sensor and use this MAP sensor to emulate an AFM, so the ECU still stays happy and you can ditch the AFM completely. Don't know when this will released though, but it's got other nice features, like being able to deal with larger injectors.

With regards to the Rev3 onwards, since they don't have an AFM, the only restriction is the fuel cut point. But, if you use a Unichip with an integral MAP sensor, you can still tune finely for load points higher than the fuel cut point, so I don't consider the Rev3 as anywhere near as restrictive as a Rev1/2. I've seen a Rev3 producing over 340FWHP on the stock ECU (with the help of a Unichip) without much hassle.

[bodleytunes]

So if u dump the afm what do u buy to replace it ?

[MR2Mania]

So if u dump the afm what do u buy to replace it ?

Ideally, you want whatever ECU you'll be using to be making use of an air temp sensor and MAP sensor to do away with the AFM. All standalones can do this, but you'd need another type of device if you're doing it in conjunction with the stock ECU.

[gtschris.com]

The AFM is a limitation not due to actual air flow (but yes this is an unwelcome restriction in the turbo intake system) but the limit of load it can calculate before hitings maxing output 0.36 volts (high voltage = less load). The ECU uses AFM load input signal and RPM to calculate boost, higher up the rev range the ECU will dump fuel into the engine at 100% duty cycle at 14/15PSI on a stock motor.

Chris is right, the AFM will max out in terms of what it's reading for maximum load. Also, the MAP sensor will max out too at some point, as Ben mentioned. The people that experience the latter are those that are raising the boost. Let's say someone has a Unichip fitted, if they do not have a turbo module with integral MAP sensor installed, then it won't see loads higher than the 12.5-odd psi that fuel cut occurs at. If they *do* have the integral MAP sensor, then this instead will be able to read the higher than fuel cut load points, and so the Unichip can kinda be used to try and control fueling and ignition at these points (assuming that it still has the plus/minus range to do so).

Having said all this, it still can't help with the situation if you've reached the max load point that the AFM can read. What's needed here is something that will allow the mapper to use a difference device to calculate load - either a device like the HKS Vein Pressure Convertor (gets rid of the AFM and allows the mapper to use a MAP sensor instead). NOTE: I've been told that the new Unichip that will be coming out soon will allow a tuner to fit a MAP sensor and use this MAP sensor to emulate an AFM, so the ECU still stays happy and you can ditch the AFM completely. Don't know when this will released though, but it's got other nice features, like being able to deal with larger injectors.

With regards to the Rev3 onwards, since they don't have an AFM, the only restriction is the fuel cut point. But, if you use a Unichip with an integral MAP sensor, you can still tune finely for load points higher than the fuel cut point, so I don't consider the Rev3 as anywhere near as restrictive as a Rev1/2. I've seen a Rev3 producing over 340FWHP on the stock ECU (with the help of a Unichip) without much hassle.

What i would add to this is:

the rev1/2 map sensor is only used for fuel cut circuit and in car boost display, the ECU does not use the map voltage input for any fueling or timing maps.

the rev1/2 map sensor will ready boost upto 17psi 4.94V+

the rev3 may have a map sensor and its a much better ECU but is limitation is still the load level the ECU will go 100% duty cycle, i have studied this with emanage dataloging.

I had 22% load being pulled of the rev3 map at 17psi boost 5500rpm so the ECU was fueling for 13psi boost and still maxing the 540cc injectors out.

340fwhp is possible with a rev3 on piggy back tune but a less than ideal arrangement as you have no idea what actual ignition advance is being applied. The more you move away from toyotas ECU timing/fuel maps by playing with signals to the ECU the harder it is to tune the car some would agree imposible safley.

[bodleytunes]

gredddy e-manage & some replacement ?

[gtschris.com]

gredddy e-manage & some replacement ?

no emanage is a piggy back.

you want a full EMS system i.e stand alone.

apexi pfc
Hydra Nemisis etc

[bodleytunes]

sounds expensive

[gtschris.com]

sounds expensive

if you want to play you got pay.................

a well setup EMS is cheaper than poping pistons all the time (trust me)

[bodleytunes]

what about a bigger air flow meter? Im getting a z32 one for my datsun and its good for 600hp.

[gtschris.com]

what about a bigger air flow meter? Im getting a z32 one for my datsun and its good for 600hp.

Hint.........
read my post again and try and get your head around what happening with the AFM.