ptuomov

We're running JDS's supermaf software in EZK. We're not using the WOT spark timing vector. Old school, the EZK WOT wire gets cut. New school, you set a radio putton on Sharktuner 2. Superstitious, both.

Why MAP instead of MAF load for EZK?

PorKen

Sorry, typed without thinking. I did already consider the MAP sensor, but was stymied by there being no unused input for an air temp sensor. (Although, coolant temp is not used much in the EZ, so I suppose you could switch it with an air temp sensor.)

MAP is more immediate/boost sensitive? MAF load relies on frequency counting back and forth between the two boxes, RPM<->load, which is susceptible to error.

ptuomov

In my opinion, if one is going to use MAF to measure load for fueling it's more efficient to use MAF to measure load for ignition. The same for MAP, I'd use it for both if I'd use it for one.

A digression: For modern systems, I think the advances have been in trying to better understand the driver intent. Throttle position in this context is an excellent indicator of driver intent. That can then be combined with engine conditions, which are relatively straightforward to take into account as of 2014.

ptuomov

Still improving the data collection. John's doing runs that peak at about 680 rwhp and we're trying to fully understand the strong and weak points of the system.

We've now got a fast EGT sensor that should pick up very close to the total temperature:



The old sensor was shrouded and the new sensor has an exposed tip. (The photo quality isn't great. If you want to help us improve on this dimension, the +1 800 328 7448 comment line is open.) Exposed tip = faster response time + measurement closer to total temperature.



That swap should improve the precision of the turbo inlet temperature measurements, and therefore enthalpy calculations.

We're also installing a higher resolution, lower range pressure sensor in the compressor inlet. The inlet itself is designed by Honeywell/Garrett to accelerate the air to 200-400 fps velocities, depending on which part of the compressor map one is operating. 200 is closer to 15 psi and 250 rwhp per side and 400 fps is closer to 30 psi and 500 rwhp (scientific wild a$$ guess, didn't do the math on the boost and power, just on the velocity). But the later one can accelerate the inlet flow to those speeds, the lower the pressure loss. We need to know exactly how much we're leaving on the table there.


Here's an extreme example. The Williams-Honda F1 engine needed very high compressor inlet air speeds. But to reduce the frictions, they accelerated the air at the last possible moment. See how large the inlet pipe is until the very last moment and then how dramatically the CSA shrinks:




Of course, in turbo engines it's always about packaging, packaging, packaging: how to fit the largest inlet duct in there while running power steering, air conditioning, high-amp alternator, etc. Here's an interesting solution for a boxer motor. They need all the efficiencies they can get, after all they are down two cylinders to start with:



Making that sort of inlet duct the right way may not be the cheapest project one could contemplate, however.

ptuomov

The in-cylinder pressure measurement system finally shipped, we should get it late next week. The intake and exhaust port pressure sensors will be tricky to install, so there will be many weeks of head scratching ahead of us.

Alan

Tuomo how are you plumbing these? I know you say you haven't got it all figured out but general plan to start with?

Alan

ptuomov

It'll be a lot of head scratching. Honestly, I have no precise plan. We've got to look at the dimensions and consider how much of the engine needs to be torn apart for each option. The first thing we'll likely try is fitting intake pressure reference to the flappy valve pipe or the plenum side cover, the intake port pressure to the intake manifold runner, the cylinder pressure sensor is easy as it is integrated to the spark plug, the exhaust port pressure we'll try in the manifold primary runner, and the exhaust reference pressure probably at the turbo inlet. But we'll have to first mock it up and send photos to the company selling the system to see if they agree the measurements will be valid with those locations.

BC

We will need the pictures of the cylinder pressure sensor that is integrated into the spark plug

ptuomov

This is going to be a head scratcher to get installed on the hot-rodded low-compression engine. The first thing to check is whether the sensor-equipped spark plug will fit in the S4 spark plug tower. And then whether to drill the heads or the intake manifold to resemble Swiss cheese.

ptuomov

John's remapping the stock engine with new map points below.



This is in anticipation of the needs of the hot rodded, low compression engine. The stock engine can't use the extreme load and rpm cells, but we want to get everything that can be tested completely tested before swapping the engine.

ptuomov

The stock engine pissed its pants. This is after some hours of tuning and ambient temps coming up to 93F:




Now, before anyone gets too excited and congratulates me about reaching a milestone, I am disappointed to report that the fluid on the floor is not oil. It's coolant from a hose that blew out. We'll pour over the data logs for any smidgen of evidence of overheating, but I am not optimistic we'll find anything interesting. The stock engine is taunting us.

Ducman82

you have not broken it yet? :-P

ptuomov

Neither me nor John have succeeded in breaking the stock engine with boost yet. I am holding out some hope with the 7100 rpm maps and 7300 rpm rev limit, but I've been disappointed often enough to not count my chicken before they hatch. It might be that we can't fully compensate the S4 cams with boost to make the engine do anything interesting at 7300 rpm.

Rob Edwards

Tuomo-

Have you managed to log any data in any of the cells that John added at high rpm? When you pull the data log file into Sharkplotter, do the rpm and MAF load axes show those values?

I'm hoping to be exploring the 6 to 7K range with Alpha-26 on the engine dyno, just curious as to how the modded rpm range data behaves with SP.

ptuomov

The answer is I don't know. Will post more when I know. Off to Niagara Falls now with the family, more next week.