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standard fuel preassure and max boost on 660cc

Discussion in 'Problems, Fixes, Tips...' started by superspat, Oct 16, 2014.

  1. superspat

    superspat Copenworld Regular

    Joined:
    Jul 1, 2014
    Location:
    borunemouth
    Car(s):
    ford cmax
    daihatsu copen
    hi all
    can any 1 tell me what the standard fuel preassure on idel is for a 660cc, i need this so i can set up new fuel reg

    i need to know it with vac hose dissconnectded

    also can any 1 tell me what is the max boost you can safely run on a 660c engine, im thinking around 1.2/4bar max before the headgasket will give way
     
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  2. threepot

    threepot Copenworld Regular

    Joined:
    Oct 8, 2014
    Car(s):
    Copen, Hijet, Celica, and Yaris!
    I have not measured it on a Copen yet but on other Daihatsu's with the same fuel pressure regulator design, rail pressure is about 45/50 psi without the vacuum pipe attached. And then at idle with the vac pipe it drops to about 35psi.

    Bear in mind, that they all behave a bit differently, some i've measured have been higher or lower than others. They are a very crude diaphragm and spring setup inside.

    Also the ECU will tweak its LTFT% and STFT% values depending on how its lambda values are sensed. So cranking your fuel pressure up does make a slight performance difference for the first couple of miles, but then the ecu tweaks the injector pulse duration (via the LTFT% value) to counteract the pressure difference.

    You can check you Copens fuel trim as per the diagram I have attached (taken from the Copen manual) or with an obd2 scanner.

    Cranking up your fuel pressure is a handy bodge if you are getting to 100% injector duty cycle under boost conditions and leaning out.

    But keep in mind, 10/20% is reasonable, but the higher you go the more likely you are to stop the injectors from being able to open due to the pressure behind them, and the harder you are making the coils work in the injectors.

    ( matt rant over! )
     

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  3. threepot

    threepot Copenworld Regular

    Joined:
    Oct 8, 2014
    Car(s):
    Copen, Hijet, Celica, and Yaris!
    As for your second question about the head gasket and max boost....

    Firstly I have never cranked up the boost on a copen! But I have a certain soft spot for all these silly little Daihatsu's.


    There is no golden figure.

    It all depends on cylinder pressures and temperatures, and how good the coolant system is.

    If you think about a crap cast manifold, and the stock minging "down pipe" canister.... the shape and restriction in that will trap heat into the exhaust manifold - the ports - the valves - the spark plug tip.... etc etc etc

    Keeping you cylinder temperatures low is the key. And at the same time by reducing the drag in this exhaust manifold/turbo/downpipe area you will vastly increase the volume of gas you will get through the system.

    When you measure "boost", you measure it at the inlet manifold. So the more restriction you put in the system after the inlet manifold, you will see more "boost pressure" but you would actually loose performance.

    So if you want your copen to zing harder, think beyond excessively cranking the boost up, and popping head gaskets. That 15 psi to creeping 18 psi zone is the max you really need to push the limits.

    And if you haven't tried it already, at 23ish psi Daihatsu's go really really well!!!! But they just don't last very long!!!!!


    What have you done to your copen so far?
     
    Last edited: Oct 17, 2014
  4. superspat

    superspat Copenworld Regular

    Joined:
    Jul 1, 2014
    Location:
    borunemouth
    Car(s):
    ford cmax
    daihatsu copen
    ive had 5 kei cars and my last l200s mira was runign 1.5bar on a hybrid turbo, that was fun.

    if going by daihatsu 660 engines and what i have pushed them to and the advice ive got from my maylisians friends then 1.2/3 is safe on the older engines, but the copen engine is stronger so 1.2/3 bar is going to be safe in my views, onyl weak point is the head gasket but will swap that out foa 1.5 metal one next year when the clutch dies on me

    ive already got got fitted a decat, 2" straight through exhaust to help the gasses get out quickly and custom built fmic and induction kit to help it breath and keep the temps down,
    will have a hybrod going on next week, and by hybrid i mean larger inlet wheels and larger machined housing and larger exhaust wheel with about5mm machined out the exhaust housing so the hot gasses will b escaping at a much quicker rate that standard turbos
    also have a blitza spec r boost controller fitted, sard bov and will be fitting a apexi safc2 that ive got lying around and ether a jam or turbosmart fcd to boost past the fuel cut of 0.98bar (that the fuel cut on mine)

    will be porting the cast manifold as much a possible aswell when fitting the hybrid
     
  5. threepot

    threepot Copenworld Regular

    Joined:
    Oct 8, 2014
    Car(s):
    Copen, Hijet, Celica, and Yaris!
    Make a decent downpipe. They always make a massive difference :)

    Those cast things are like a brick wall to the gases coming out of the turbo.

    Something with a nice tubular 90 degree elbow, and a little bit cut in for the waste gate port flap.

    Sounds like you are in the right ball park as 1.2 bar is about 17psi.

    I actually find those triple layer metal gaskets are not as good as the old style graphite gaskets. Normally it is due to the graphite gaskets seal the cylinder head machining imperfections better than the multi layer steel gaskets. The worst ones are those perodia nippa ones people put on the 3 cylinder engines, they are totally the wrong size and don't work very well. Considering you can buy a proper graphite one if you look in the right places I just don't get why people use them, they are like 2mm too big on the cylinder rings.


    I can't emphasise enough how much difference a decent down pipe makes, it doesn't have to be anything special, just some mild steel elbows welded together to some flanges made by a local laser cutting place hits the spot every time.

    The Apexi SAFC is a pretty rubbish bit of kit, it just modifies the MAP signal which if you have an FCD then its not going to help matters at all. Modifying the MAP signal will also alter the ignition timing, and in the wrong direction at full boost. The last few vehicles that have been in my hands, I have ripped them out and told the owner to sell it on ebay.

    Porting the manifold is a good idea though, as getting a tubular one made up can be quite pricey.
     
  6. superspat

    superspat Copenworld Regular

    Joined:
    Jul 1, 2014
    Location:
    borunemouth
    Car(s):
    ford cmax
    daihatsu copen
    I had a perodua nappa gasket on my zato and it was a cheap uprated headgasket that worked/ is still working very well, just helps to get it skimmed first,

    The safc is only going to be used to take fuel away, I've never used them to add fuel and have been ok on my old starlets I've had

    But a down pipe is on the cards, all daihatsu downpipes/ catalyst converters are a shocking design that in no way is designed for a smooth airflow and they make a big difference on the charade gtti,

    Don't suppose you know a place we're I can get a down pipe from and that would post to the uk
     
  7. threepot

    threepot Copenworld Regular

    Joined:
    Oct 8, 2014
    Car(s):
    Copen, Hijet, Celica, and Yaris!
    Just make a down pipe lad. It's just some bits of tube welded together!

    Take a turbo gasket and the exhaust gasket to a local laser cutting place and they will make you some flanges for about £20 or £30.Then buy some mild steel exhaust elbows off ebay.

    Cut them with some slitting disks in the grinder, mig weld it up. Jobs a good'un !

    If you live local-ish to Cheshire maybe come and spend a saturday afternoon in my workshop and we can knock something up if you bring the materials.

    Owning a Daihatsu isn't about buying the same off the shelf parts like the Ford or Vauxhaul or Honda scene. Modding a Daihatsu is about getting in there and making it happen!

    Think about what that negative fuel correction on the SAFC really does - it reduces the map sensor signal, so the ECU will shift to the next column to the left on the fuel and ignition map - so it will advance the ignition timing - which is your worst enemy when turbo tuning as it pushes your cylinder temperatures up. That is why a mapping rule of thumb is 1 degree of retard per 1 psi of boost.
     
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