28 March

I haven’t driven Midlana because I can’t get the Race Technology (RT) Dash2 dash unit to read the CAN data from the ECU. Without dash data, I think it’s too risky to run the car blind (especially after something as major as an ECU change). The RT dash worked great with the Honda ECU via an ordinary serial link, but for some reason the CAN interface doesn’t work at all. RT has a newer dash unit, one virtually the same in appearance, but with built-in logger, GPS, and CAN interface. However after thinking it over I’ve decided to go with a different brand.

The digital dash market has evolved since I bought the RT unit. Now there are apps that can be combined with a cheap tablet computer to become a digital dash. They’re tempting but I wanted a “real” dash, one that can stand up to heat, dust, moisture, electrical interference, and signal conditioning. Also, I wanted one that wasn’t a fixed format, using screen real estate for variables I had no use for. While there are quiet a few manufacturers has a lot of positive press. Plus, a coworker crews on a race team that’s used the same AIM dash for 7 years with no complaints, so that’s promising. Also, they have numerous U.S. dealers (AIM is based in Italy, RT is in Britain, and somewhat suprisingly, no cool dash units are made here). It turns out that AIM just released two new units, the MXG and MXS. Both offer data logging, GPS, CAN, and built-in WIFI for downloading data. The MXG (I suspect the “G” means gigantic) is very nice but is simply too large for my dash, but the MXS (small?) is virtually the same and will fit fine. Best of all, the displays are full color and highly configurable, not just in what can be displayed, but also the type of data, physical configuration, and color of the layout. And so it came to pass, it should be here next week 🙂

In case you’re wondering why I didn’t go with mechanical gauges, it was considered. However, it reminded me again why I went with a digital dash in the first place. Automobiles have moved on, with ECUs becoming incredibly powerful and are a treasure trove of data. which is good to tap into. Consider the following situation. Let’s say that a mechanical MAP/boost gauge is added to the dash. Meanwhile, the ECU has its own MAP sensor. You’re driving down the road and the ECU’s MAP sensor starts to fail. Meanwhile, the gauge on the dash says that nothing’s wrong. I think it makes sense to see the same data that the ECU is using so that if there’s any problem, you’ll see it, not a copy which may show nothing.

Lastly, consider a variable such as oil pressure. With pointer gauges, the driver may or may not see a problem. Yes, a pressure switch can be added to activate a light, but there’s better way. If oil pressure is read by the ECU, it can take care of the situation right now, not after pressure has dropped to a critical level. The ECU can impose an immediate cut in power, and can have combinational error detection (i.e. if oil pressure is <20 psi AND engine speed is >2000 rpm, flag a warning message and immediately reduce power. We’ll see how it goes!

24 March

Found why the radiator fan quit. Turns out that the plug-and-play harness connected the fan to a duty-cycle controlled output, one without a flyback diode. The electrical engineering speak means that if it’s not configured right, it’ll pulse on and off, drawing a near-constant arc across the contacts due to driving an inductive load. You can see how burnt and melted the relay is around the contacts. Going back and checking how the manufacturer configured it as part of their base tune, apparently the tuner changed the output configuration, resulting in one fried relay. After setting it back to the original configuration, it works fine now.

I have some video of some of the dyno pulls; I’ll post it up eventually. Too bad I missed a picture of the 3-foot flame that popped out when he let off after one of the pulls 🙂

23 March

First, the good news.

The car was tuned on 91 octane gas and 85% ethanol (“E85”) during a 9-hour tuning session – and we still aren’t quite done. Tuning a turbo engine on a new-to-market ECU is very involved because tuners don’t yet have a library of tunes that they can pull from to save time. A baseline Honda K20 tune was supplied which got us part way there, but of course it’s not for a turbocharged engine. A lot of time went into establishing cam and ignition timing before tuning could really get started.

The plots tell the story. The first shows a comparison of gas and E85, where purple is boost, green is torque, and blue is hp. Engine power on 91 octane was 440 hp at about 12 psi. Note that tuning was done at a shop different than previously, but because the same Dynapack brand dynamometer was used, the results were nearly identical; compare the first dyno plot to the black and white dyno plot. The previous shop’s dyno read about 20% higher than drum types – the type that most people use to compare values, so figure 440 hp on this one is about 350 whp on the other style. That said, the point of a dynamometer is to provide fixed conditions for tuning, and because the Dynapack allows holding the engine at a given rpm, it’s superior for tuning compared to the drum style. The point being that the numbers produced isn’t what’s important, it’s the change made from run to run that counts. That said, I find it amazing that in this day of crazy precision, why can’t dyno manufacturers do better than 20% variation?

Anyway, the first dyno plot also shows the change in output when switched to E85; power increased 40 hp with no other changes (other than fuel). The second color plot shows the results of taking advantage of advanced ignition and increasing boost from 12 to 16 psi, 530 hp (~425 whp on any other dyno).

My thanks to Peter and Dardan at Synapse Engineering. They don’t normally tune customer cars as their dyno is used primarily for development of the company’s products, uniquely designed blow off valves and wastegates. They have a very interesting design that I may use in the future!

So what’s the bad news? Sounds like a pretty good day, huh? Well it was. Unfortunately the day finished on a down note due to my own stupidity. It had been a very long day, I arrived home after dark, and there was a car parked in the street that I had to drive around before pulling over to the curb. I was backing the car off the trailer and right at that moment, a car came around the corner, blinding me right as Midlana rolled off the trailer – and BAM. Yup, I backed Midlana into the parked car… 🙁

The damage to their car was slight, the right corner of my car hitting their left front bumper. Damage to my car was more substantial, with the rear corner pushed in at least an inch. I felt terrible and very disappointed at myself, and for what I’d done to someone car. I wrote up a note and went to put it on the car, right as the neighbors pulled up. Turned out that it belonged to a relative and because we were friends, they refused to “press charges.” While I was relieved (I’m still going to buy them an Amazon gift card) I was now faced with fixing the body damage on Midlana. As you can see, it’s done, but it wasn’t anything I enjoyed doing. I learned that I don’t like repairing tube frame cars with riveted body panels. No matter how hard you try, the chassis and panel rivet holes will never ever line up again. Some were so far off that after cheating the holes, the rivet heads barely cover the indiscretions – good thing they aren’t structural. Other than a badly damaged ego, after a full day of repair it was deemed “good enough.” Midlana has her first official battle damage – it just didn’t happen on the track (which is probably a good thing). It was also good that Midlana’s tire wasn’t hit, so the suspension points weren’t messed up. Also, while the rear bodywork was bent, the external green panel wasn’t damaged to a point that it couldn’t be bent back into shape. I was just glad to avoid having to repaint it since the simplest paint job is about $500.

With the bodywork complete, the car was taken out for a drive and it’s definitely faster, and surprisingly there was no wheel spin in 3rd gear. That’s the huge difference between this engine being in Midlana versus in a FWD Acura RSX. Under full throttle, much of the weight on the RSX’s front tires goes away, resulting in impressive smoke clouds but not much acceleration. With Midlana it’s just the opposite, traction increases the harder the acceleration.

There are still a few issues to iron out. Pushing the clutch in when coming to a stop frequently allows the engine to stall. During idle sometimes the engine will start oscillating, but neither of these are a big deal. On the hardware end of things, during tuning the radiator fan quit working for some reason. During the brief drive I couldn’t see coolant temperature. That’s because the flat dash needs its serial interface adaptor configured, but the dash manufacturer still uses RS-232, remember that? The problem is that neither my PC nor laptop have RS-232 ports, so I bought a USB/serial converter, which of course didn’t work. The dash manufacturer recommended a particular brand of converter, so that’s on the way. If that doesn’t’ work then maybe I got a dud, because I know the ECU is outputting CAN data because the scope shows it.

Oh yeah, last week I was checking that everything worked before tuning. When I tried to have the ECU read the flex fuel sensor, it read zero, which was odd because the scope said the sensor was working. I double checked that it was wired to the correct input, then posted a question on the manufacturer’s support forum. Hearing nothing, I called them and right off the bat, the tech said, “no one’s ever had problems with this.” That comment wasn’t necessary, and I couldn’t help but think “dude, you’re going to eat your words.” We went into the documentation and sure enough, they had a pin assignment error. Went back out to the garage, switched to the correct input, and presto, it started working. I updated my post with that information, figuring it would help others who might run into the same issue. Later I wanted to add another note to my post and was surprised to find it gone. I sent them a separate email asking whether they really meant to delete it – no reply. Okay, then I’ll post their goofs here.

15 March

Wow, long time since an update, but a lot (of work) has been happening, it just doesn’t seem that way by looking at the car. However, the new ECU is in, the wiring re-do is nearly finished, along with various new sensors. With the car due to be tuned soon, I eventually had to cross my fingers and try starting it for the first time. I was really nervous due to all the changes made at the same time. The biggest fear was some spectacular mis-wiring that would blow up the ECU, but all the worry was unfounded 🙂