Santa brought something I’ve wanted for decades, a proper DSLR camera, a Nikon D750. I’ve played with it some and already wish I had it 10 years ago – it makes me want to become a better photographer. Hopefully this means better pictures and videos for you as well!
My brother said there’s a Fontana event on the same weekend as the Willow Springs event. I’m torn; I’d like to do the Willow Springs event simply because I haven’t really run the car there yet. The catch is that we’ve been having really cold weather (I found sheets of ice in our yard this morning) and overnight temperatures at WS have been in the mid-20s (last night got down to 19 F). There’s how I’d cope with it (read: how to get a good night’s sleep because we’d camp there) and then there’s how the car would cope, given that antifreeze isn’t permitted. Fontana is about half as far away and I could run one day and avoid an overnight stay. We’ll see; it’s not helping that I’m coming down with something, but since the events are three weeks off, that shouldn’t be an issue.
Merry Christmas, everyone! Doing a lot of family stuff but should have more time later to prepare the car for a planned track event at Willow Springs on January 16-17. My brother’s also planning to attend in his LS-powered Stalker, so that should be fun. We typically camp at the track so hopefully it won’t be too cold overnight (it was down into the 20’s recently… ugh). Most track organizers run rain-or-shine, which means waiting until the last second to sign up, but doing so also risks having the event sold out.
Things are happening, they just aren’t real entertaining. Thanksgiving, shopping, and family stuff consumed much of the time, though a few car things did slip in.
I’m not convinced the alternator bracket is really fixed; even when tight, it’s possible to rock the alternator slightly, probably due to the mounting hole in the broken segment having elongated somewhat. It’s not entirely bad to redo it because it may have always been slightly out of alignment right from the start. A straight edge had been placed across the face of the crank pulley in order to determine the plane of where the alternator pulley needed to end up. What I didn’t check was whether the shoulder of the crank pulley and the alternator pulley were the same, not sure they are. As a result, the alternator may have always been slightly offset even before it broke.
In other news, over the last couple weeks, more test runs were made to better dial in the VE table, which was off a fair amount. Getting it closer to reality allows much better closed-loop air/fuel control, so that’s working pretty well now. (This was another task that the tuner was supposed to have handled, yet another I had to figure out on my own.)
Closed-loop boost control always looks like it can be better refined… tuning never ends. Boost has slowly been advanced to its current 250 kpa, or 22 psi. On ethanol there’s still no knock, and while boost at this level is fine for brief pulls, track events are probably a bit risky, as heat-soak may invoke knock. The ECU is configured to pull boost if incoming air temperature gets too high, and it’s also monitoring knock, but it’s still a concern. In addition, third gear is good for 120 mph, and while there’s no wheel spin, it’s getting close, so more power isn’t “necessary.” I’ll probably drop boost a bit for safety and reliability, at least for track events. Once everything is finally dialed in and working well with ethanol, Midlana may be switched back to gasoline for the street, just for practicality. Boost would be dropped to ~14-16 psi, but the chief benefit is that fuel mileage will increase by 50% (from ~20 mph to ~30 mpg).
Lastly, if you’re thinking of getting yourself a copy of the Midlana book, better hurry. The printer always runs discounts during the holidays, though the discount amounts seem to be somewhat random (they don’t inform authors what they’re planning), so it pays to check. Order now to get yours before Christmas!
Yesterday morning I drove Midlana to a “secret” car show, held in a well-off part of town. Not realizing that it was by invitation, I just showed up and parked – it’s on public streets after all. They were very welcoming and there was a little bit of everything; check out more pictures on my Instagram page (#midlana). I finally got an up-close look at an Ariel Atom 3S and while I’m well aware of Ariel, I don’t keep up with their product line, so it was surprising to see a turbo Honda K24 in it. The driver was very friendly and explained that he brought the car while in England. He had a slight accent, which oddly always seems to go together with being able to afford nice things – the 3S starts at $89,750.
That afternoon the boost controller duty cycle map was tuned, so with that working well, closed-loop boost control was reenabled. Next on the list was to better tune the Volumetric Efficiency (VE) table. The tuner was supposed to have done this, but with air/fuel feedback disabled, it showed that the VE values were off. A few runs provided data points for correcting the table, so the new values were entered and the table smoothed. The plan was to load up the new VET table Sunday morning and see how close I was. Alas…
Sunday morning – the car started making a new noise… sigh… Really? What now? The alternator belt started squealing and it turns out that I underestimated the forces on the alternator bracket, which looked as though it fatigue-failed. In hindsight it really needed a stiffener, so one was added, the car reassembled, but by then my car time was up and it was time to visit mom.
The rear suspension rod-ends were upgraded and like the front, the job took all day. Before starting in and with the car on blocks, the tires were pulled back and forth, side-to-side to see how much play there was… there was a lot, maybe 5 mm* or so. Due to how the toe-control links tie into the uprights, any amount of play gets mechanically magnified out to the surface of the tires. This is the prime reason they were replaced, them loosening up so fast. I can’t blame anyone but myself for having used such poor quality parts in the first place. The first picture below shows the enormous difference; not only does the part on the left have specifications, its wider housing is about twice as strong, but also, the wider housing allows a wider Teflon bearing surface which has higher ratings and will also last longer. The difference in price is substantial, but given their task, I no longer trust the cheap ones. For background, the cheap ones were about $3, mid-range U.S.-made parts are about $11, and the good ones are around $26. The highest-quality parts were used selectively in the highest-loaded positions, and the mid-range parts used everywhere else.
I briefly considered selling the used joints to someone who would use them in non-critical applications, but thought better of it and into the trash they went. I don’t need that on my mind.
A few readers pointed out that since I twisted the steering arms, it shortened the steering rack to upright distance – that’s correct – and they wondered whether bumpsteer might now be an issue. I pointed out that bumpsteer, while a quantifiable and measurable value, is subjective to the driver. If the driver can’t tell the difference between “X” and “Y” amount of bumpsteer, it doesn’t matter. (I should have driven the car with the Miata tie-rod ends, but when I saw that there was some bumpsteer, I set out to eliminate it. In hindsight, even though there was some, it may have been fine as it was.)
The car was taken out for a test drive and I couldn’t detect any bumpsteer, but than again, it was Friday traffic and impossible to do any handling tests. During the drive I was heading downhill toward a traffic light… well, let me back up a bit and explain something. When driving, especially sports cars, we program ourselves to be hypersensitive to certain things. Just getting a glimpse of a black-and-white car is enough to make people back off the gas. There are other things as well, like smelling melting plastic, or coolant, or brakes that gets immediate attention. Such was the case slowing down toward the traffic light at the bottom of the hill, a definitely strong smell of really hot brakes. When I pulled the calipers off the rotors, a tiny bit of the brake pad broke off along the bottom edge; apparently the brake kit I used allows the brakes pads to hang slightly over the inside edge of the rotors. Smelling hot brakes made me worry that a piece might have gotten jammed somewhere and was causing the brakes to drag. Then I looked over and there was an old truck pulling a very overloaded trailer full of concrete debris – what a relief… for me, not so much for him!
In the last picture – it’s kind of hard to see – is a bunch of tiny white specs. Those all are dried-up bug goo, or more specifically, dried up locust goo from when I ran over all of them. That stuff is really hard to get off and just getting it wet doesn’t seem to do the trick. If anyone has some wonderful stuff they use, let me know.
*I’m making an effort to start using metric values. I’m already getting heat for not using metric values in the drawings, so I have to start somewhere!
I had put off upgrading the poor-quality rod-ends, guessing it was going to take a lot of time – it did. It took all day to get the front suspension done. What made it take longer was also twisting the steering arms to move the steering rod ends away from the brake discs. When Midlana was first assembled, I ground back the rod end housings to make them fit, but it always bothered me about how much they may have been weakened. I really wanted to use unaltered rod ends for the safety factor if nothing else.
It’s been years since I used the gas welder. The last time, the acetylene regulator failed, so bending the arms didn’t happen. With the regulator fixed and some time to myself, it went okay bending the first one. (Using a large rose bud tip with high gas flow is intimidating… it’s a ton of energy to be pointing about!) Twisted the arm to where it seemed about right, let the upright cool in still air for hours, and when reassembled, found it had been twisted a bit more than necessary, but it’s perfectly usable.
Heated up the second upright and got it twisted nearly to where it needed to go, and then the gas torch gave me a scare. The blue inner cones denoting the hottest part of the flame started getting smaller, which meant that either oxygen flow was increasing or acetylene flow was decreasing. About the same time I heard a loud pop, looked over, and the oxygen gauge was pegged (I’d set it to about 15 psi, and now it was off the top end of the gauge at over 100 psi). The loud pop was the pressure relief valve, keeping it from rising to tank pressure, which was around 1000 psi! Apparently the oxygen regulator has failed, probably the same way as the acetylene regulator did. I wasn’t bright enough to guess at the time that if one failed, the other probably wasn’t far behind, but no knowing what failed, it wasn’t obvious. Anyway, the good thing is that the arm had been twisted enough that it’s good, though it’s not quite twisted the same as the other side. Oh well.
I haven’t measured bumpsteer but hopefully it won’t be enough to bother messing with. I’ll probably just drive it and see if it’s detectable. By the way, the rust you see is mostly due to doing one track session in the rain. The lesson is to: buy plated rod ends, use stainless parts, paint them, keep they oiled, or don’t drive in the rain!
After last week’s findings, a lot has to be redone. The wastegate spring was changed to 12 psi and the 3-port controller swapped back in, the wastegate spring duty cycle table has to be redone and the volumetric efficiency table checked.
A surprising number of people have asked why the air scoop points aft:
1. When cornering, the inside front tire throws road debris inboard, with some landing in the area of the air filter. With the scoop pointing aft, it shields the filter element from small rocks.
2. If and when the car gets caught in the rain, it eliminates water intrusion (especially when parked).
3. There is a large rotating air “bubble” behind the windscreen. This was made apparent when the oil O-ring failed and oil ended up on the inside of the windscreen. Air flows up over the top edge of the windscreen and circles down toward the engine cover, then forward to the base of the windscreen again. As a result, air is likely flowing into the inlet of the rear-facing scoop.
4. There have been suggestions on cutting open the scoop to fix the issue. While appreciated, cutting back the the scoop any amount exposes the filter to the elements, or opens up a hole into the engine compartment, allowing hot air to get sucked into the filter.
5. At car shows, it keeps troublemakers from thinking it might be funny to pour a drink into the air inlet.
A proper scoop will be made using the moldless-construction technique.
Next week is a short week for me so I hope to check several items off the to-do list. First up is replacing all the low-quality rod ends with higher quality parts. At the same time, I want to heat and bend the steering arms to move them away from being so close to the brake discs.
Lastly, it looks like my brother and I will be signing up for the infield track at Autoclub speedway, one that’s more twisty and more attractive to cars that handle well. Top speed in this configuration is around 130 mph instead of the 150-160 on the big course.
What a bitch… is that crazy or what? In hindsight, it explains virtually everything that happened during the months of fruitless troubleshooting:
1. MAP-drop never happened with the engine cover off (when I did my 12 runs in a row and deemed it fixed due to an “rpm limit issue”).
2. It never happened with the car on the dyno because the engine cover was always off.
3. The scoop collapsing shut caused the air filter to get pushed off its mount – it was never an air filter issue.
4. Last week when run without the air filter element, there’s apparently enough leakage between the air filter and engine cover that it can’t develop enough of a suction to pull the scoop shut.
5. Upgrading the wastegate made no difference.
6. Removing the muffler had little effect – if anything it made it worse.
Before realizing what was happening, it seemed like the air filter element was getting sucked down onto the inlet bell. A K&N filter had been used before, but was upgraded to a 33-2135 unit, designed for the 403 hp late-model Chevy truck. That’s close enough in power that it should do fine, and in addition, a cross-support was added across the airbox below the filter. The K&N is roughly 1″ thinner than the enormous Amsoil unit, so that’ll improve air flow heading into the bell-mouth inlet.
I can’t begin to explain how much of a relief it is to FINALLY have this brought to light. Of the dozens of suggestion I received, not one suggested a possible filter or scoop issue. Needless to say, the air scoop is coming off until a real one is fabricated.
The Second Edition is now live on Lulu! Also, for those who’ve been pestering me, it’s now available in both perfect-bound and coil-bound! For those who have the First Edition, fear not, the changes are not large, and include hundreds of minor textual changes to improve readability. The few technical changes are already known and will be listed on the Midlana forum.
First up, a neighbor has had two enormous Ficas-type trees in his yard for decades and never trimmed them. The thing about trees is that they can be ignored for years, but that always comes at a price. Early Saturday morning, a huge branch came down on his house and two cars. The roof on the house is visibly pushed in, one car had its side mirror removed and a large dent in the roof, and the second car had the branch come through the windshield in addition to dents on the roof and hood. A tree trimmer who sized up the situation several years ago said that trimming just one tree would be well north of $10,000 and refused to even bid. Because about half the branch landed in the street – city property – a city crew promptly arrived and removed that portion of it, leaving the poor owner with the branch still sitting on his roof. Did I mention it’s supposed to rain tomorrow? I drove by today and was surprised that he’s done nothing. I’d have at least bought a chainsaw and cleaned off the roof so a plastic sheet could be dropped onto it, but it’s his house…
The wastegate spring was lowered to 15 psi/200 kpa and more testing done. The MAP drop was back, big surprise, but this time, I heard something the instant power dropped from 200 kpa to 150 kpa; that’s never happened before. Removing the engine cover showed that the air filter element had been partially sucked onto the bell-mouthed intake. I wonder… could this have been it all along? Could it be the air filter element getting sucked onto the intake bell and reducing the filtration area by probably 80% and becoming a restriction?
As a quick test, the air filter was repositioned and another run performed. Again, the element got sucked off one edge and again, MAP dropped off. Next, the filter was removed completely, and guess what, not a single issue for the rest of the day. I even drove out to where some high-speed runs could be made to red line, and it worked just fine. Well isn’t that interesting.
The filter only recently started having one edge pulled off its mount, but the MAP issue has been happening for months. Full disclosure: I learned that I’m using the filter element upside down. That didn’t seem to matter at the time, but maybe it’s a big deal. There’s a screen mesh on one side of the filter – the top in my setup. It’s possible that without the support of the screen, the folder paper element can’t resist the suction and gets pulled onto the face of the inlet tube, becoming a blockage. What’s highly suspicious is that MAP always drops to 150 kpa, as it did today, which makes me suspect it’s the same failure mode each time. The only questionable part of this theory is that the filter doesn’t appear deformed like it’s been pulled away from the screen; the glue on the back is in good condition, but there is a dent from the inlet. Even so, I will add a support and see if this has been it all along. There’s a few ways to fix it, some easier than others. I’ll first try an easy way, running a rod or rib under the element to keep it up off the inlet bell.
What’s a little bothersome is that if that’s happening, I wonder about the fairly small air inlet on the scoop; could it be getting sucked shut? Looking at the air scoop, there’s two suspicious pale white marks along the top edge – I didn’t put them there and they didn’t used to be there. It’s almost like the plastic has been deformed. I’ll add a support brace to that as well, which will open up the inlet a bit more. I don’t want to get overly excited, but this is the first time something’s been found that is directly connected to the problem I’ve been chasing for months. We’ll see.
And finally, expect some Midlana news this week, so keep checking here, the Midlana forum, or Instagram 🙂
Finally drove the car to see how it deals with a straight “16-lb” wastegate spring and no ECU control. The figure’s in quotes because the manufacturer states that the rating assumes that intake and exhaust gas pressure are equal. If they aren’t, the actual pressure may be higher or lower. Mine has always been a bit higher (I think that’s a good thing), with it actually running 230 kpa, or 19 pounds; not a big deal but interesting. What is a big deal is that after many acceleration runs, there hasn’t been one MAP drop. This seems to show that the problem is either wastegate float due to using a weaker spring, or the ECU isn’t controlling boost properly (I suspect the former).
The next step is to reduce spring pressure to 14 psi (the maximum I’m willing to run on 91 octane gasoline), then use the ECU and boost control valve to adjust boost higher for ethanol. So – changing only one thing at a time – the spring will be changed but still have no ECU involvement. If there’s no MAP drop, then the boost control valve will be plumbed back in and we’ll go from there.
Separately, I’ve noticed that under hard acceleration, the air/fuel ratio gets a bit lower/richer than it should. Closed-loop lambda control is enabled, but even though the richest target mixture at the high end is 0.78 lambda, it’s dropping as low as 0.69. Anyhow, a question regarding lambda PID has be posted to the ECU forum. Somewhat related, injector duty cycle is maxing out at 89%, right on the edge for being undersized. Once the mixture is leaned out slightly, that should improve injector margin (and/or I can increase fuel pressure).
My brother has been pestering me about doing a trackday event – it has been a long time. The choices are Autoclub Speedway, about 90 minutes away. Further away are Willow Springs, Streets of Willow, Buttonwillow, and Laguna Seca, in that order. I’d like to get a rematch with Willow Springs, but almost as good is Streets of Willow, located next door, which is very twisty, favoring light cars which handle. There’s also a large skidpad there; I want to take Midlana out and do some traction-limit/drifting turns to get an idea of its threshold balance. It’s simply been too dangerous/foolhardy to do so on the street.
I’ve been to Buttonwillow once before, but for whatever reason don’t really like it – not sure why, maybe it’s just a lack of familiarity. Autoclub Speedway is the closest and the cheapest, but it’s also the highest speed course with scary concrete walls, though going off in the dirt at Willow can end as badly if the car hooks and rolls. Than of course there’s Laguna Seca, sort of the holy grail of tracks. I have to run Midlana there at least once, but it’s the furthest away, typically the most expensive, and has a really low noise limit. We’ll see.
Car-related activities took a backseat for a week due to a work-related out-of-town gas turbine class. What I was most impressed by weren’t the electronic controls, but rather the mechanical backup systems, which were the control system before electronics. Even though it’s all electronically controlled today, all the mechanical systems remain in place, standing by in case the electronics fail. I’m in awe of those systems, using springs, rocker arms, linkages, bellows, spool valves, magnets, and very few electrical parts. It’s easy to think that the systems are complicated, until realizing that they are in fact beautiful and elegant mechanical solutions. My hat is off – in a big way – to the mechanical engineers who designed the systems, many of whom likely used nothing but slide rules and a lot of brain power to come up with solutions.
The class answered a question I always had; there’s a scene in the movie “Cast Away” where Tom Hanks swims away from the floating wreckage of his cargo jet as one engine kept running on a broken wing. I thought that was ridiculous, but surprisingly, Hollywood actually got that right. Once lit, all a jet engine needs to run is fuel, and since it’s got an engine-driven mechanical fuel pump, an engine can indeed operate all on its own with no power at all, a tribute to its elegance and robustness.
Somewhat related, when I got out of class on Thursday, out to the west were some seriously huge and mean looking clouds. It turned out those storm clouds were dumping tons of rain on trapped motorists on the roads north of Los Angeles. We got a little rain but avoided the worst of it; I read that some of the side roads will require months to clear.
The only car-related activity I did was to swap in the 16-lb wastegate spring and switch to a purely mechanical-activated wastegate, but haven’t driven the car yet.
Yes, I will admit I gave a bit of thought about getting hold of a used gas turbine auxiliary power unit (APU). The trick is the transmission and how to throttle it. I have some ideas there but it’s just pie-in-the-sky. I’m fine with where I am for now.
The dash oil temperature now reads right, but MAP continues to read low (only) at idle, with it reading 15-20 kpa, while the ECU, which is reading the very same sensor, sees 22-24 kpa. That’s nice.
Anyhow, Midlana went back onto the dyno to see whether the cause of the MAP drop could be found. At first, the tuner felt that the clutch might be slipping, because if it slips even a little, MAP will immediately drop. He said it doesn’t take much slip to cause MAP to drop. Later, he got suspicious of the closed-loop boost control, so it was disabled and the boost run at a fixed duty cycle. Like magic, all MAP variations disappeared, indicating that the PID control loop needs more work. With that “solved”, boost was increased and then the MAP-drop started happening, so he finally saw what I was experiencing.
At the end of the day we had no smoking gun, but do have some things to try. First is to swap in a 16-lb spring and disable boost control completely, running a hose directly from the intake tract to the wastegate. It’ll be run that way for a month or so with logs always running, to see if the MAP-drop still happens or disappears, then go from there. Depending how that turns out, the next thing to try is going back to a 3-port controller. He felt that the combination of a weak (5-psi) spring, 4-port controller, and poorly-tuned PID may have been causing the problem (falling out of boost and being unable to recover).
The tuner told me about one customer’s car with a twin-scroll turbo setup that was impossible to tune because that boost was all over the place, very sporadic and unstable. He said that it wasn’t until the owner switched to a regular T4 turbine housing did the problem go away. When I told him that I’m running a twin-scroll setup as well, he just said, “Hmmm.” I’d love to try some different turbine housings, a 1.0 A/R housing and a non-twin scroll unit, but at $550 each, it’s just too expensive for something that would potentially be used only once.
As a previous post explained, oil temperature is fed into an analog input on the dash, and that the value recently started reading “51 deg C” when cold. The dash allows setting up sensors as either resistance-based or voltage-based. It turns out that the sensor was set as resistance-based, but because the ECU already has a pull-up resistor on the sensor, that’s a voltage, so it has to be voltage-based. How on Earth it worked fine for five months and only now started acting up is beyond me. I don’t touch the dash configuration unless necessary, but today the sensor type was switched to voltage and presto, it started working… again. Very odd.
The other issue which has been going on even longer is that dash MAP reads low. The ECU always sees the correct value yet the dash reads low (only) at idle. As posted earlier, I thought the dash used the MAP value in the CAN packet but I forgot that I had to give up on it because the dash scales MAP as a percent and I can’t change it – percent what!?). I spoke to AiM and they said to check that the dash has the latest code – it does. They also said to connect the sensor ground of the dash to the sensor ground of the sensor, so I connected the two. Got everything buttoned up and started the car, and it idled like crap. I let it warm up and it just kept running worse and worse, so an earlier tune that I knew worked fine was loaded – it ran like crap as well. Then, the light bulb went on, and I remembered having this same problem when I connected the flex sensor ground to sensor ground (imagine that) and it also ran like crap. Sure enough, disconnected the ground and the engine idled perfectly smooth. I tried grounding the dash input signal ground straight to the chassis and it didn’t make any difference to the displayed value. On the other hand, the displayed value was displaying fine, so not sure what’s going on there.
Drove the car some yesterday and if it wasn’t for the MAP-drop thing, it’s running great! Just have to get that behind me!
Well it’s back, the MAP-drop anomaly, which was noticed soon after updating the ECU firmware. I’ve done a lot of runs, logged more variables, but it’s still a mystery and worse than ever. Now it happens nearly every time at a lower rpm, around 5500-6000. The only good thing is that it lowers the speed I have to be going to invoke it (so instead going to jail for a year, it’ll just be a ticket…) Actually, I’m fed up with it so the car’s going back to the dyno next Friday. With it happening now so easily and repeatedly, it should be easy to replicate. The problem will be, once it is replicated… “now what?” I’m just too close to the problem and need a second (and third) set of eyes on the problem. It was fun as a science experiment, until it wasn’t, and now it’s annoying.
I know what you’re thinking, “why not just go back to the previous version of firmware?” Well I could, but since no one else has this same problem, it seems unlikely that it’s root cause. I suspect there’s something specific with my engine that’s causing it. Also, I rather keep the ECU upgrade because they made a lot of improvements; I don’t want to give them up because some are fairly important. Also, because the ECU is fairly new, there’ll be a lot more updates, and I don’t want to be left with an old version because of this. May as well hit this thing face-on and figure it out now.
To quote Yoda, “There is another.” While I fiddle around with ECU and dash issues, congratulations are in order for Jim Langan, who has Midlana #2 sitting on her wheels! Jim chose to go with the traditional Lotus Seven front fenders, which look great. There are currently about half a dozen builds under way, which you can check out on the Midlana Forum.
With the exhaust leak fixed, we need a new problem, and alas, one turned up. The AiM MXS digital dash has been working fine, except for a strange error reading MAP. The MAP value is sent over to the dash via the CAN bus, along with engine speed and several other parameters. They all work fine, but the dash claims that MAP isn’t the usual 22-24 kpa at idle, but instead, something lower. After maybe 30 minutes of run time, it’ll even display 0 kpa, which is a perfect vacuum… not likely. Meanwhile, the ECU sees a correct value for MAP, which is the exact same value being sent to the dash. That’s the old problem…
The new problem started several days ago, when oil temperature started to lie. Unlike MAP, oil pressure is a voltage, read by both the ECU and the dash. As soon as ignition is turned on (like first thing in the morning), oil temperature should be about room temperature, and it is – so says the ECU. However, the dash claims that it’s 51-52 degrees C, which is nonsense. However, as oil temperature rises, it seems like the dash starts reading the actual value once it’s above its false 51 degrees C floor.
Neither problem can be explained by a wire being loose. In the first case, since MAP is in the CAN packet, all other values should be messed up as well, but they’re fine. In the case of the oil temperature, if the wire was broken, the reading should go to max, and if the voltage is shorted, it should read zero. It does neither, and if it was shorted, it would affect the ECU’s reading as well, but it’s fine.
As a hail mary, I updated the firmware in both the dash and ECU – no change. To add insult to injury, the engine now gets limited at a lower rpm than before; I hope it’s my test tune and not some mystery feature of the new ECU firmware. It’s always something.
Replaced the exhaust manifold gasket; yup, not hard to see where the old one was leaking!
Finally took care of something I’d been meaning to finish up for a long time. A spare valve cover had been modified to remove the oil filter and dipstick (both being redundant due to the dry sump). Also shaved off the HONDA logo, which will be replaced by a MIDLANA logo. However, before the newly powder-coated part could be installed, all the blasting media had to be removed… there was more than I expected. I really like how it changes the engine compartment; it makes it look much more integrated and clean.
Finally, the air filter scoop was replaced with another of the same.
So close. The crack in the #4 primary was real, but turned out to not be the main leak. That ended up being down below the flange where the gasket material had blown out. I don’t blame the gasket itself; I knew that I’d been pushing my luck by reusing it several times, so a replacement and spare are on order.
Thought I understand PID closed-loop control, there’s still a lot to learn when controlling the engine. More early-morning testing is slowly dialing in the boost control loop, gradually getting rid of the overshoot while still maintaining fast response. Just as important as determining the P(roportional) and I(ntegral) terms is limiting the integral value to keep it from “winding up” the loop and causing overshoot. A little is okay, but I was seeing 20-30 kpa, which isn’t acceptable; it’s now down to about 10 kpa and I’m trying for a bit better.
Reintroduced throttle-position-dependant boost, which makes the engine act more like a V8 and less like a boosted 4-cylinder.
Also ordered a replacement hood scoop for the air filter. While I plan to someday make a proper carbon unit, the cheesy vacuum-formed unit had melted somewhat and cracked. Time for another temporary replacement.
Went over the exhaust system and found the probable leak hiding in plain sight, on top of the #4 primary at the cylinder head exhaust manifold flange. Maybe I’ll remove the header before welding, maybe not, depending on whether the TIG torch can be maneuvered into position. As noted in the Midlana book, one reason for not coating a header is for exactly this reason – if it’s coated, it can’t be repaired. It looks as though it’s been there a while, gradually growing. The header wrap probably didn’t help, either.
Regarding the oil O-ring failure last week. After it was repaired, the dry sump tank was topped off, with the thinking that it was probably about half a quart low. Added one quart, still low. Added a second quart, still low. Added a third quart, and it still wasn’t quite full. That was rather shocking, because it meant that either I’d let it get low previously, or I’d lost a lot more oil than expected. Regardless, it potentially suggests that the dry sump system may have saved the engine.
In other news, I got called for jury duty. In California, that happens as often as once a year. For the past two times, I never got called. The time before that, I got called but was excused (saying your an engineer usually displeases one lawyer). Before that, I was on one jury and the case lasted just a couple days. This time though, like watching a iceberg looming on the horizon, it was announced that there was a big case coming up that would last for weeks (the iceberg). Groups were first called for more normal cases, leaving a smaller pool of us, then an enormous group called for the major trial… (iceberg, dead ahead)… and boom, I got selected. As many of you know, it can’t be discussed until it’s over, but I’m pretty sure there’ll be a story to tell.
The downside is that it’s going to extend far beyond what our company pays for jury service, leaving me the fine choice of either using up vacation time, or “LWOP” (leaving work without pay). Such is the cost of doing one’s civic duty.