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Davidv last won the day on January 28

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About Davidv

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  1. Davidv

    Supercharger whine - Hermholtz Resonators

    In that case a helmholtz resonator wont really help. You would end up with some rpms being dampened, and some with the noise increased. Also worth noting - Apparently the AMR500 is the little brother is the little brother of the Toyota SC12 and SC14 superchargers. With AMR500 apparently being the TX10 listed below: So you might find that the clutched pulley from an SC12 or SC14 will fit to your setup? Then you can just have the supercharger turn itself off when not at full throttle or whatever. Also - I assume you're running V belts? If you've got Gilmer drive belts, that could be where the noise is coming from. Not the supercharger itself. And it's also a really small supercharger, do you know what your pulley ratio is? You might be overspinning it in order to make boost... Even with an SC12 or SC14 people dont make that much power (like 220ish hp?) before it just starts becoming a heat pump.
  2. Davidv

    Supercharger whine - Hermholtz Resonators

    If you're based in Auckland flick me a PM if you like as I've got some good recording gear and so on. And this sounds like a fun challenge haha.
  3. Davidv

    Supercharger whine - Hermholtz Resonators

    A Helmholtz resonator only really works at one frequency, which in your case, means 1 particular rpm range. The first thing to do though is quantify the frequency that you are trying to cancel out. So record the noise as best you can, isolated from other noises. So maybe try hold the engine at the rpm where your car normally cruises at. Then save it as a .wav file and load it into this program http://www.artalabs.hr/download.htm Then you can load one of the analyzers which will show you what the main frequency of the noise is. Then you can calculate dimensions for a helmholtz resonator that will be able to cancel out this frequency. An easy way might be to get one 3d printed so you can experiment. Generally the higher the frequency the smaller the resonator needs to be.
  4. Davidv

    Megasquirt to Link questions.

    Hahahaha no trust me, once you're used to it you'll not want to go back. It's a lot better than tuner studio. And as mentioned the fuel equation in megasquirt is very simplistic by comparison. And just take a browse through the help file, possibly the best help file I have ever seen for any product. I will say this though - I still use Megalog viewer sometimes because PClink doesnt currently support custom/maths channels which is a pity. It's the only reason I stray outside of the Link system though, and only occasionally.
  5. Davidv

    Using different ECU for injector dead time testing

    Here's a more detailed post about how I tested deadtimes: https://www.hpacademy.com/forum/general-tuning-discussion/show/calculating-deadtimes-with-a-link-g4-and-injector-test-bench I made an extension lead for injector 1 so I could use the ECU in my car, the fuel pump thats in my car, the FPR that's in my car, etc etc so every variable is as close to actual use as possible. Then I just made the ECU vary supplied voltage by using a battery charger connected to battery, and used different combination of accessories on and off to get the voltage to where I wanted to test it.
  6. My arduino based canbus box thingy has escalated into a digidash haha. So 3d printing a housing that will mount up to standard points and accept the standard loom plugs for power supply and so on. Lots of work left to do, but will be cool.
  7. Davidv

    MAF Sensor setting

    +1 to this, a non linear scale is especially useful for MAF.
  8. I've had a bit of a side project going on, I've wanted to learn about canbus so I bought an arduino and a canbus shield. Using some of the examples of code found on the net, managed to get frames both sending and recieving. I've never coded anything before so I had a few blunders like using = where I needed == and so on haha. I'm using another shield on top of the canbus one that runs a screen, and have put together a box for it all. The goal is to have the 4 pots control trim tables for goal AFR, ign timing, cam timing, and injector timing. So when I have cruise control turned on, I can quickly go through a lot of variations and have a graph showing fuel economy on the screen. I can also write a fuel economy value back to the ECU as well, and then have that log into the ECU's logs so that's cool. Currently my car gets around the mid 7 litres per 100km mark, and I'd like to see if I can drop it into the sixes. I'm most of the way there to finishing this thing so hopefully not too long till I can have a play around. I am thinking that for version 2.0 instead of pots I will have rotary encoders and then build an array which will act like a load vs rpm based trim table for each of the different areas. So it will hold the values in that area without affecting the others. It's a bit more complicated though so I'll just get this running as is for now. Since I run 98 octane and MBT is quite far away from knocking I have also been thinking about using a feedback loop where the arduino adds a few degrees timing, see if this positively or negatively impacts economy, and then either reverts or keeps change. Then repeats, and maybe hones in by a smaller change each time. But I think that might work best once I've got some arrays setup, rather than just blanket applying a trim table to everything.
  9. Davidv


    Have a look here
  10. Davidv

    Can protocol sample

    @CamB you can set the byte order to MS first or LS first to swap the order when setting up incoming frames (In G4+ at least)
  11. Davidv

    Closed Loop fuel trims

    That's really interesting Mapper, I've been meaning to have a play with that CLL gain table but havent yet. I think you've just piqued my interest however! I'll try those other numbers for a starter and see how it differs.
  12. I've got an injector timing table set to 240deg BTDC end of injection all the way through rev range. With some changes to cam timing I decided to test 400deg btdc above 2200rpm / redo some testing at different angles. And as soon as I make this change, when my car gets to that rpm where the injector timing advances a lot the car bucks and lurches and stutters. If from here, I set all of the timing to either 240 degrees or 400 degrees, its fine again. But when it's on that transition point, things get weird. It seems more prominent at low load, I'm guessing because its an issue if start of injection is beyond a certain point? I suspect that an injector event gets skipped, the car hesitates and rpm drops and same thing happens again. (It's a really aggressive lurching of the car, and definitely not just caused by the effect of different timing) If I set the table to all 400 deg or all 240 deg the car drives smooth and fine. I can supply logs and a basefile as an example if needed. Thanks David
  13. Davidv

    Modelled fuel + MAF questions

    Thanks for the detatiled answer Adam! Appreciate that you took the time to test this, thanks.
  14. It doesnt seem to, but it may be that the change is so small that it isnt able to be seen with a map sensor of this scale. And possibly because my copper line is too smaller diameter as well. I've parked this idea for now, I'll revisit it later on when I can redesign the pipes a bit better. But I'm just about there with my MAF based tune, might need a test driver at some point while I tinker if you're keen!
  15. Davidv

    Modelled fuel + MAF questions

    Hey guys, I've recently gone back to using a MAF sensor, and I notice that with modelled fuel there is the option to have as a load axis "Air per Cylinder Measured" Which is awesome. Since this figure comes directly from the MAF sensor I am assuming that a lot of the calcs for modelled fuel get bypassed. I also notice there's a seperate category for "MAF IAT" Rather than regular IAT, I assume this does the IAT calculation differently too. However I have a few questions. 1. Options for load axis in the fuel calculation are either MAP, BAP, or Off. I've set this to Off. Would that be best option? 2. Which of the modelled fuel settings now get ignored, since you're measuring air directly? I get the feeling that it air per cyl measured is used as part of the calc which then still generates "air per cyl estimated" which is what the fuel calc runs from? I realise that MAF isnt the suggested option but it offers some benefits while I'm doing some experimenting with cam timing, so I'd just like to get it setup to "best practice". So any advice/info on how it calculates would be appreciated. Thanks David It's pretty cool having grams/cyl as a load axis because the values are quite linear... This was the MAF basemap that I put together based on observation of my MAP based tune, and car ran awesomely on it! It's now changed shape a little after the first iteration of tweaking it but it's still very linear.