i read a little about that V2, and im goin to think about it, ill might be interested in that one.
Nice 1Hope you can get a good tune on your engine... Have you had any power figures for your engine ???
nope over here we dont have 4wd dynos, but i think my car its runing really good, the other day i race a 2004 m3 smg transmition, and i beat it for 2 leghts.
Thats a good resultOriginally Posted by ARPN
nope over here we dont have 4wd dynosBut as to be expected to
Back to the topic as such -
I've always understood (and sold) the FCD, in fact almost any kind of fuel cut defender, to be a device which stops a signal exceeding a given VOLTAGE value, nothing more.
Works fine on anything MAP sensored - RX7's, most turbo toymotas etc
Mitsubishis use an air flow meter which puts out a FREQUENCY - all this is doing is clipping the tops of your voltage waves isn't it? Nissans, mazdas, toyotas etc put out a voltage signal from their AFM when they have one, we got the bung end of the stick here
Its not doing anything to the AFM signal except butchering it, as opposed to doing anything actually productive.
If I'm wrong there, correct away. Haven't ever personally used them, would rather an S-AFC if a quick fix is needed.
Not quite sure that's right Ako. Pretty sure the MAF works on a 'hot wire' principe in our cars, so it's a voltage that's sent to the ECU rather than a frequency.
In basic Terms, the VR4 works on frequency Hz, Mazda works on the hotwire route(voltage)
And FCD is blocking the ECU on our cars by limiting the signal from the MAF, from seeing any higher frequency than it is pre programmed within the ECU.
The reason this is bad, is that we can then Add more air through Boost than our MAF can read, but the problem is our ECU and Fuel Pumps may not be able to match the right amount of fuel to the amount of air that is being inputted.
What this means is there is a great chance that our engines will then lean out(Not the correct Air to Fuel Ratio,AFR) meaning to much air and not enough fuel. ( A bit like not enough Vodka with your Tonic)This will then overheat the pistons and in extreme cases cause failure through the melting of piston rings or the pistons themselves!!
The only way of being certain this is not happening, is by the monitoring of the Air Fuel Ratios(AFR's) via a Wideband 02 sensor/controller, such as the LC-1( www.innovatemotorsports.com/products/lc1.php ) This way, you can be sure that the engine is not going to be damaged...
But as above !! Correct me if i'm wrong
Last edited by Wodjno; 25-02-2007 at 01:49 AM.
I get the whole "too much air not enough fuel = new engine" idea...
What I was getting at was I thought the FCD only is a voltage clipping device, i.e won't go over 6V / 5V / whatever you set it at. So that a car which is MAP or hot wire sensored and has a fuel cut at say 5V, you set your FCD to 4.95V, no more boost cut on cold nights or whenever. I had one in my turbo honda city of all things
Since mitsi's work on a frequency not a voltage, think of it this way - you have your sine waveform coming out of the AFM. Varying from say, -5V to +5V. If you put in a FCD which is only clipping voltages, all your doing is butchering the top of that waveform, making straight edges along the line of whatever voltage your FCD is set at. Imagine someone bouncing on a trampoline and the path they would take - now put a roof just above their heads
Unless of course it CAN stop a certain frequency - it kind of explains why most have limited success if any with the HKS FCD's on these cars. Any time I ever had customers wanting to tune around a fuel cut in a subby or mitsi, I'd sell some kind of AFC device - there's a few of them around the $400 mark. Also used to be one of the NZ distributors for the LC-1.
Not trying to be negative, just chucking this out there since I see a lot of people on here use them and not many of them having much use.
I'm quite open to anyone who can show me otherwise - I've always understood the above, as have most of the workshops I deal with. Just seems a bit dodge when there are much better ways to solve the issue, that work better - and are cheaper into the bargain.
I agree with the aboveI get the whole "too much air not enough fuel = new engine" idea...
What I was getting at was I thought the FCD only is a voltage clipping device, i.e won't go over 6V / 5V / whatever you set it at. So that a car which is MAP or hot wire sensored and has a fuel cut at say 5V, you set your FCD to 4.95V, no more boost cut on cold nights or whenever. I had one in my turbo honda city of all things
But the reason the factory fuel cut is there, is to stop the engine from leaning out.. You set you FCD to 4.95v so there is no longer any fuel cut ! This then allows you to cram in as much Air as your Turbo's can handle and stil no fuel cutBut how can you be sure your Fuel Pump is adding enough fuel
Great it maybe that you can now max out at 18psi
You might not damage them straight away(but you also might) but the long term affect could be catastrophic
Fuel Cut is the best and quickest way of ensuring your Pistons won't melt.. Cos if there is no fuel, then theres no explosion in the cylinders, thus meaning no excessive heat that can damage them
It works fine... as long as you know your limits. I did consistent 13,7 passes with only FCD and HKS EVC3 fitted, all day long... on only 0,8-0,85 bars of boost, in a full weight Legnum.
However there is a limit to what your fuel pump, injectors and turbos can handle...
I think we're on different wavelengths here - I'm questioning whether or not the FCD is actually achieving anything at all!
What I was saying is all you are doing is butchering the signal to the ECU, not limiting it. The frequency can still go as high as it wants, how thew ECU interprets the modified waveform is another story altogether.
The FCD does achieve something and can be a valued MOD.. But only if used correctly(preferably in conjunction with a wideband 02 sensor).
Our cars need FCD K (that is the only one that will work with Karman signal). It works by limiting Hz signal from MAF.
I agree with the sentiments of the guys here in the post.
An FCD, of whichever type, simply limits the maximum airflow value the ecu can see to stop it peaking out and hitting fuel cut.
Why fitting an FCD can be a bad idea:-
Fuel cut is the ECU's last ditch attempt to save the engine. The ECU is seeing so much air that it knows it cant deliver the fuel (in terms of injector pulse width) to burn it at a reasonable afr. Essentially the ECU knows you are running lean. It cuts the fuel so as to stop the airflow. At the instant you hit fuel cut it feels like you just hit a brick wall- the same feeling as hitting a speed limiter in a j spec car.
If you datalog a car accross a period of fuel cut, you will see a massive knock spike (like it will peak the logger out) at the instant the fuel is cut and you get that mega lean condition as the last bit of fuel is burnt.
I have known owners of cars who have continuously smashed their car into the fuel cut from running too much boost who have unwittingly blown their engines simply from the knock generated at fuel cut. Many of them thought they simply had a bad miss.
That said, if you can monitor afr and ensure you are not running lean, you can use an FCD to maximise performance and get that bit extra woof out of the turbos, whilst still stopping the pottential damaging cut occuring.
Even so, an FCD simply clamps the maximum value for airflow, so once it is operational the ecu will not see any more air, and will not legthen pulse width accordingly. So the 'deeper' you go past the FC value, the leaner you will run.
Cheers,
Ben.
Thanx for the Input Ben
And i think you have confirmed exactly what i have said
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