My day at the dyno - the long version
So, I got to the dyno with a plan written down and everything checked and double checked. I took a load of tools, hoses, hose clips etc. While the guys at the shop were putting the car on the dyno, I had some time to take a look at the software for the dynapack. It is pretty straight forward, I was expecting it to be more complicated to be honest. I also got my laptop and headphones all set up ready to start.
First job is to dial in the dyno RPM with the engine speed, you do this by adjusting a gearing ratio in the software. Basically set the dyno to hold what it thinks is 2000rpm and then adjust the ratio until the engine is at 2000rpm. Since 4th is pretty much 1:1, no surprise that the setting came out to be about 4.3 (ie the final drive).
There are also some other vehicle and run setting that need looking at, obvious one is the rev limit. There are also settings that control how the dyno behaves when doing WOT runs, you can set the start rpm (2000rpm), how long to hold the start rpm (2 secs) and the pull duration (10 secs). So basically the dyno does some magic so the revs raise at a steady rate when doing WOT. Again not massively complicated.
Job one is to check/tune the lower rpm. First thing I notice is that my wideband is about 1.0 off the sensor at the dyno. So auto tuning in tuner studio goes out of the window. I start manually tuning, all the time with my det cans on. I basically had the VE, AFR, Spark tables all open as reference. Since I don't do this everyday, it was useful to have the target AFR table open to see what AFR I was aiming for at a give load site. The AFR was a whole load more steady then tuning my ITB engine, so I was please about that. It is pretty crazy holding you motor at 5000rpm on full boost while you dial in the fuel. You tend to just get up there and hold for a couple of seconds and then back off a bit, then go again. There is a lot to keep an eye on, temps, AFR, listen for knock and adjust stuff. Once I got up into the higher rpm ranges, I had to pause for about 30 seconds between loading the engine, just to cool things. This type of tuning is harder on the cooling system than WOT. The cooling system managed well and I did not see coolent temps above 90C and intake above 32C, so I am super happy with that, and I think my shrouding must have worked. I was a little worried about the cooling system, given that I have fabricated many of the parts from alloy, it is hard to know that you have a good solid none porous weld.
So far so good - next is setting up the boost controller, so that I can load the engine a given MAP and then do WOT pulls to tune the fuel and spark. First I set fuel and spark to safe setting and I did a WOT run on waste gate pressure to check my settings. All good, I think from memory it made about 160whp on that run. One thing I noticed is that waste gate pressure is not constant, was not really expecting this, not sure why - this is not my first FI car. Basically the boost increased all the way through the rev range, up to about 8psi at the limiter. I wanted to use closed loop boost control (close loop is where the ecu takes feedback from the MAP sensor to figure out what to do with the boost solenoid). I set the boost map to be just above 8psi and set the over boost to be just above that. So here goes the first attempt, I was expecting a boost spike, but it did more than spike, i just kept going into over boost cut. It did not seem to matter what setting I put in ECU, i got the same result. I move back to open loop - I was able to get some results with this, but still got increases at various parts of the rev range. At this point I am burning up time, so I decide that the boost controller will have to wait for another time or later and the best thing to do is focus on getting a good tune for waste gate pressure, so I can drive the car at least. The boost increasing through the revs will make the tuning a little harder, but the dyno graphs have rpm and MAP on them, so you can figure out what load site you are in.
At this point I start getting the odd miss fire. I checked the plugs and they look ok, the dude at the shop suggests using some BKR7 SE plugs gapped to 0.6mm rather then the iridium ones. He says he uses these over the iridium ones all the time and at $4 a plug, it is worth a shot. The guy at the shop suggests that the iridium ones get fouled up to easily. Unfortunately, still getting miss fires. In conversation with the owner of the shop, we check the coil dwell and it is 4ms, which is too high, it should be 2.0-2.5ms. I think I must have reloaded the diyautotune 250whp map again at some point and forgot to change the dwell - fried coils
Basically, it is home time. Driving onto the freeway, the coils seem to be ok and the car feels so much better to drive, the acceleration is so much smoother. I am probably not reving over 3500rpm, but the difference it very noticeable. As they say there is no substitute for a proper dyno tune.
I am cruising down the freeway and about 1km from exiting, the miss fires are starting to get worse, I am gradually slowing down - I don't really want to load the engine up with the miss fires beings so bad. 80kmh.......60kmh..... 50kmh I managed to get off the freeway and limp home through the suburbs at about 30kmh.
It is 3pm at this point, so it is time to get on the web and find some coils. I am wanting to compete on sunday in the clubs autotest, so I am a bit strapped for time. Best option I can come up with is some 2nd hand Toyota OEM coils from a wreckers. I collect those tomorrow and hopefully I have an option to go the evoluation R's dyno on saturday.
Mean time I need to get some base boost controller settings and do some set up of that. I also, need to think about my wideband - the current one is of no use
The End
I might have to go back to the place I went last time and hope I get a better experience.
