Roman

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Roman last won the day on December 12 2017

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About Roman

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  1. ajg193's 1983 KP61 Sprint

    Great work on the graphs this makes me happy. Sweet economy too! Better than my Echo. Cant beat a light car. Does your FPR reference intake manifold pressure? If fpr is not not intake referenced the pressure difference between fuel rail and intake manifold increases with vaccum. So at a given pulsewidth you get more fuel than expected. Might account for your 10% perhaps. Maybe check what your fuel model in ECU thinks the fpr is doing.
  2. Romans COD piece

    Plumbed in near the end of the 2-1 section, as this is where the standard narrowband sensor was positioned. I really just think the issue here might have been that the lines were too small and the pressure scale of the sensor too high. For the moment I've retired it, but will give it a rethink later on. Having the MAF back in is proving interesting enough so far.
  3. Okay so after I finished building the MAF curve, and drove around to collect some data with it, and then I started building a fuel table using MAF as load axis. After plugging away at this for a while, I noticed something interesting - The fuel map becomes just a straight slope all the way across haha. So this is what my basemap looked like: And the car drove awesomely on it! After a few tweaks to the overall shape it's still pretty similar. Definitely a lot more linear than a MAP or TPS based tune. Which makes sense. With a MAF based tune you really do need some decel fuel cut, as when you shut the throttle the MAF value momentarily climbs and you get pops and bangs out the exhaust... Oh the humanity! In less awesome news though, this new gearbox seems stuffed. The synchros in 3rd seem non existent and I think I heard it break something when I hoofed it into 3rd today haha. So no OS drags for me in this car, and no trackdays this year either. sadface. WTB (non fucked) Altezza gearbox if anyone sees one for sale. EDIT: Also I ran over something with my AD08Rs on which put a big gash in one of my tyres as well. Blargh.
  4. Romans COD piece

    Trust me I'm surprised as well. I've confirmed that the sensor reads higher pressure fine, and when the engine is off the signal is the same as barometric pressure. I can only think that either the diameter of the line is too tiny for it to work effectively, or, there's a venturi type thing happening even at idle. But its definitely weird. Might try again with a bigger diameter line for starters.
  5. Romans COD piece

    The cam timing advances through the midrange, and pulls back towards top rpm. There isnt really a pressure trend that follows this, or at least it's not evident from the resolution available with this sensor. With a 1 bar absolute map sensor or using a differential pressure sensor this might be more evident though.
  6. Phew, finally finished a big wiring tidy up and car back together. So now my car can go back to doing what a car is supposed to do... MAKE SOME GRAPHS! Firstly, I wired up a MAF sensor, but having no calibration for it means I need to compare to existing logs to work it out. So for starters I was just logging raw MAF voltage output, 0-5v to ECU. My ECU currently has one of the values it logs as part of its calculation is "Grams of air per cylinder Estimated" So we need to turn this into a grams per second, so some maths to create a custom field in Megalog viewer and now I've got Grams per second which I can compare to voltage: Which I can then use as an axis on a scatter plot, which shows me a very rough outline of a MAF curve starting to form... So I rough out a voltage vs grams per second to put in the calibration in Link And then go for another drive and do same thing again in megalog viewer... Starting to look better! A few more iterations of refinements should clean up the "messy" signal at the low end. If not, I will just switch to map or alpha N based tune around the areas where it sucks. But from here, once the MAF sensor data is accurate I'll build secondary ignition and fuel tables which have MAF as the load axis. Then I can start experimenting with cam timing at part throttle some more, without my load axis going bananas (map sensor value changing a lot) Then from here, hopefully further improved fuel economy because that's fucken awesome. Alsooooooooooooooooooo I wired in an exhaust pressure sensor, and wtf'd at the results hahaha. When there's more air flowing through the pipe, the pressure goes down: I think it's creating a venturi at the entrance of the pipe, so if anything this reading is more an indication of airspeed than pressure I guess! This new gearbox has been a little hard to get into gear / has kinda jammed once or twice so I'm hoping its not a lemon. But my car is still making the same sort of rattling noises as before so its possible that my other gearbox is still good which is cool. But the test will be whether this one pukes all its oil onto the floor and onto my exhaust every time I drive it haha. Fingers crossed it's good otherwise I'm out of contention for OS drags / might have to bring the yellow Carina instead
  7. OS drags is coming up rapidly so I thought I'd better swap out this rattly gearbox. I got it all swapped over easy enough, and then I thought I'd wire in a MAF sensor again at the same time, as well as an exhaust pressure sensor. And then things escalated and now all of the car's interior is back out hahaha. But MAF/exhaust pressure sensors will give some interesting insights into tuning VVTI angle at part throttle for best economy. When using the MAP sensor as the load axis for the tune, advancing the cam gives strange results. When you advance the cam enough that you start getting overlap, since the manifold is low pressure and the exhaust is higher pressure, you get some of the exhaust gas coming back through into the intake manifold, before it gets sucked back into the cylinder again as the piston starts to go down. This means that the measured MAP pressure goes up, (By 60% in one case!) so the engine adds fuel and pulls ignition timing. Which is the opposite of what you want to do when youve got EGR gas in there. So you need to redo these two things each time you change the cam angle, which isn't really practical. So I'm going to set MAF as load source for these tests instead, as it will stay more constant and wont be measuring the "dead" air from the exhaust which has no oxygen in it anymore. Since I need a MAF to do some testing, which means I cant use my airbox thingy for the moment I'm gonna experiment with something else as well. I saw an article where someone had varying results by tuning the length of the intake pipe ahead of throttle body. Presumably by making it a tuned length for reflecting waves back down the pipe. So I'm gonna start with the longest pipe I can fit and then slowly cut it down more and more and see if fuel requirements change at all. It's also handy having a long straight pipe for best MAF readings as well, while I am testing this. To be honest I've got no idea whether this is going to be any better or worse, at any length. But it'll be interesting to see if there are any noticable harmonics happening in this first part of the pipe. If not, it just confirms my previous idea that aiming for maximum mass flow is better than having a tuned length. (as per airbox thingy) Either way, one or the other is gonna get thrown in the bin and I'm all about that!
  8. Cool to see this all finished and in action! How do you find your dash, in terms of latency / lagginess?
  9. Ash's A6 Carina Coupe (Lyfe)

    You replaced the wheel bearing six times before thinking perhaps it's not the wheel bearing? hahaha just giving you shit but thats pretty funny
  10. Truenotch's BEAMS AE86 racecar discussion

    Hey @Celica RA45 here's a question... Since the manual engines run TI valves which are obviously lighter, does this mean they run a softer valve spring as well? Compared to auto engine with steel valves.
  11. Romans COD piece

    Yeah well its been proven to work by others, its also possible that it just wasnt fuelling evenly between cylinders on mine as the runners arent exactly the same. But either way, in my case the benefits werent worth the downsides. Also if you have a quad throttle setup where it's at the same temperature as the head then you'll probably have a better result as the fuel evaporates a lot quicker. Something interesting, I saw someone post a factory inlet manifold for an SR16VE N1 and it has staged injection from factory. The other 4 injectors are in the head.
  12. TOMSTAMENT'S ULTIMATE CARPI

    Great progress lately Tom! Keep it up.
  13. Okay soooooooo as awesome as it was living in a beautiful place and having a cool Automotive related job, life in Cromwell/Queenstown wasnt quite right for me. It was awesome fun working at HPA, made some friends and great memories which will last a long time. But, it just didnt quite feel like somewhere I wanted to settle down and in some ways it wasnt the career direction I wanted to take. So for a variety of reasons I ended up coming back up to Auckland. Being landlocked so many hours away from the ocean just didnt feel right! It was a bloody awesome experience though and it felt like it reinvigorated my life and got me back on track after some hard times lately. But anyway! It was good that I never got to the point of attempting to drive the Carina down, as the new driveshaft combination wasnt good. It took a bunch more mucking around after I got back to get this right again. But sadly it looks like the previous incident may have stuffed the bearings in the gearbox as it's pretty noisy now and leaks fluid out the rear main seal even after replacing it. Pooz. But it was great to get back home and be able to go drive it around again! The R888s are on my normal wheels so I've been driving around with a 15x6 running 205/50/15 and have noticed no negative effects to handling. Possibly because the sidewall of the AD08R is so stiff. Since I've been back, I started with a fresh sheet of paper on the tune file in the ECU. As it had some old junk in there, as well as some stuff that I setup when I ahhhh knew less than I do haha. The staged injection seemed to work well enough in terms of delivering the right amount of fuel and blah blah... But it was always a bit crappy in transient conditions. I decided I would turn on the outer injectors 100% of the time and try tune the car using just those, and get the accel enrichment and so on working as best I could. But it just felt boggy. When I reverted back to 100% inboard instead, holy moly the throttle response difference was amazing. And so the pull out of corners was much better and it felt like you could more accurately mash the gas and know what the car was going to do. So I ditched it and put a standard manifold back on. My theory is that since my intake manifold is thermally isolated from the head, it is not able to use the heat of the runner walls to evaporate the fuel so you have massive fuel pooling issues... Which means you lose control of your fuelling as some fuel you squirted in several cycles ago is only just entering the combustion chamber as it evaporates. So fuel you add at say 5800rpm only enters the cylinder by the time you get to 6000rpm and so on. And so if you tune your car with the acceleration rate of say 3rd gear fuelling isnt right for 1st gear anymore. Just lots of headaches that you cant really address well enough with the accel enrichment available on a G4+ In the documentation from Toyota on their wall wetting experiments they note that on a cold port (engine cold starts) fuel can take over 1.5 seconds to evaporate and contribute back to fuel in the engine so even if it was only half as long on the runner walls. It's a massive surface area covered in fuel which is always going to be a ball ache to compensate for. Going back to a standard manifold looks to have cured a vaccum leak or two as well, haha so the idle and so on is much better too. I've been playing around a bit with a few variables such as injection timing and VVTI advance as well. I have found that changing the injector timing so it's injecting fuel as the intake valve is open helps a lot with cold starts, and results in a lower fuel consumption when the engine is hot too. Since it's been cold I've also spent a bunch of time getting the cold idle really nice, closed loop lambda adjustment works really well if you set the adjustment rate to 1hz so its only slowly adjusting it. Otherwise it makes the idle surge if you try to run closed loop at say 20hz like you could if you were doing 4000rpm or whatever. Under cruising conditions it seems that advancing the intake cam at all just means worse economy. This may relate to the tuned length of the primaries and secondaries of the exhaust causing some undesirable something something at cruising rpm compared to a standard exhaust manifold... But for whatever reason, it isnt beneficial to advance the cam. And at high rpm low load, rather than retarding the cam I figure I may as well keep the cam advanced so when you stab your foot back on the throttle the cam is not having to "catch up". And this seems to have made the throttle response even better as well. So the engine response is better than ever! I picked up a cheap Altezza engine, planning to give it a freshen up and at some point swap it over. I'll be losing the fancy ported head of my current engine, but will be gaining: -Exhaust side VVTI -Higher compression ratio -better alternator position -Better water line setup -Better engine mount setup -Better PCV valve arrangement -And a few other minor advantages so I think it's worth the trade but will be interesting to see. The state of the oil and colour of the coolant in the altezza engine though is bloody disgusting though so it'll need a strip down and hot tanking or whatever before doing anything with it. So might be a while until it's ready to swap in. But looking forward to having a play with the exhaust side VVTI. I think I'll wire in an exhaust pressure sensor when I do an overhaul of the loom to suit some of the changes needed. Will be interesting if this will show anything relating to tuned lengths of the primary and secondary pipes. In the immediate future however I'm just really enjoying living at the start of Scenic Drive in Titirangi now and being able to go for some awesome drives on some backroads making doort noises again
  14. Truenotch's BEAMS AE86 racecar discussion

    Sorry but yeah this is a sign that your engine is completely dead.
  15. Truenotch's BEAMS AE86 racecar discussion

    Haha never seen a bucket failure before at all... Then just saw this on FB today.