15 October 2018

I’ve been catching a bunch of abuse about not posting… I didn’t know you cared so much!

After getting abuse for posting non-Midlana material, I thought, okay, I won’t, which has led to the aforementioned periods of, well, nothing. I haven’t posted because I feel a bit guilty about not having anything worthy. There are a couple track events coming up, but they’re scheduled out far enough that registration hasn’t even opened yet. There’s also a Laguna Seca event, and while part of me wants to go, I’m too afraid until the car has wings. Why?

I used to drive my old Datsun 1200 at that track and loved it, coming up over the rise past Start/Finish, with the car getting just a little light as it crested the hill and the track curves left. It drifted over toward the right edge of the track somewhat, but no problem.

Fast forward to running the Mini there, which had probably 3X the power/weight. The first time I crested that rise I remembered thinking “oh crap”, because I was carrying way more speed and at the same time, the front end got really light, so the car floated way over to the right edge of the track and there was nothing I could do about it (lifting abruptly can cause a spin). After that “clincher”, I had to let off slightly as I got to the top of the rise so that weight transferred forwards onto the front tires, allowing it to turn.

Fast forward to now, where Midlana has 2.5X the power/weight of the Mini, with even less weight on the front end. Unless I let off, probably a lot, before the crest of the hill, I worry I could do a “Mercedes Backflip” (jump to 0:32). Could that really happen? I don’t know, but suspect Midlana would be at around 120 mph at that point, and with no down force at the front and air getting under it, so I don’t want to find out. So, wings are in order before running there. I’m not entirely imagining things. Two friends, after hearing my plans for the weight and power of Midlana back during the design phase, staged an intervention, saying that they seriously recommended I not track the car without wings, especially if there are any rises or drops.

Another annoying issue with Laguna Seca is, of course, the sound limit, which is 90 or 92 dB. Even some OEM cars struggle to reach that, and I have no idea how loud Midlana is at 50 feet. Yes, it’s got a muffler again, but 90 dB is really low. I’d hate to pay the high track fee, drive the 450 miles there, only to get black-flagged after a couple laps for sound (which did happen with the Mini).

Back to wings for a moment, my brother found another source of extruded aluminum wings, these being about 50% larger chord than the ones I already have. Haven’t decided to switch to these for the main elements, available from Nine Lives Racing.

14 Sept 2018

The hoped-for car event – the Virginia City Hill Climb – was indeed cancelled, the rumor being that they were unable to obtain the necessary city permits. I’m skeptical that next year’s event will happen because once a city starts weighing the liabilities versus benefits, it’s a small step to permanently cancelling the whole thing. Guess we’ll see.

Was going to take the car out and glanced in the engine compartment, only to see that again, the alternator bracket broke. As some of you may recall from earlier diary entries, this has happened several times with both my bracket and a commercially-available part–there must be some really nasty resonances going on. My solution, like last time, was to add more reinforcing. Eventually the failures will stop, or another unit will be produced out of much thicker material.

During repair, one thing crossed my mind that might not have helped things: I may have dunked the hot bracket in water to cool it off after welding. That’s a great way to harden metal–making it much more brittle. This time I let it air cool so we’ll see how that goes.

 

26 August 2018

I was going to add an update, but after checking the previous entry, it says pretty much what I was going to write: being too warm to work on the car, and that I visit Midlana Builders’ Forum several times a day. The only new development is that there’s a big-deal driving event coming up, but as of right now it’s unclear whether it’s going to held. More as the time nears, or maybe I’ll just drop the video after the fact, hopefully with the caption, “It went well!” 🙂

 

24 July 2018

Ugh, too warm and humid to be do much, but I visit the Midlana Builder’s forum several times a day. Progress is being made on several builds there, but as warned of in the book, Life gets in the way now and then–it’s just how it goes. Several of the builders are getting closer though, and hopefully that’ll ignite some urgency in the others, hah.

Speaking of motivation, I keep getting told that I don’t promote myself, the car, or the book enough. I understand, and even agree, but it’s because I really dislike pushy ads and salespeople, so I don’t like to do it to others. Nothing shifts me to the opposite tact faster than someone pushy selling something. I had a guy  selling a bottled water service show up at the door, and when I opened it, said “uh oh.” For a second, I thought he was going to take a swing at me – he got really angry. I was curious how he planned to transition to asking for money, or maybe he planned to demand it. I suspect he realized no sale was going to happen and kinda went off the rails after that… but I digress.

So yeah, I do plan to do some promotional stuff, more shows and videos – when it cools off, which around here is October or so. There’s also all the other stuff: cold air inlet, new engine cover, wings, and so on.

16 June 2018

Finally swapped in the Inconel turbocharger mounting studs. Hopefully this stomps out that failure mode for good.

I also had the pleasure of again meeting Martin Waide at a dinner party, ex-Lotus engineer from back in its heyday.  To talk to someone who worked for Colin Chapman himself,  and with Graham Hill and Jim Clark, is just, wow, expanding my world while at the same time making it feel a lot smaller. It’s like finding a little window through which to peer back into history, marveling at the golden age of racecars.

He asked many questions about Midlana and not unexpectedly, surrounding guests rolled their eyes and moved away as we went into suspension design. Since car design is such a niche, I don’t discuss it much because I know that it’s not at all interesting to most people, but, get me in the same room with someone who works in the field and off I go.

I’m going to meet up with him again so that he can check out Midlana; not as “look what I did” but to get a real engineer’s perspective on its design.

7 July 2018

Still here – building a cover over the pond filtration and wiring it with proper GFI outlets instead of the spider web of extension cords I had before. That’s done, but work on the car is postponed due to the first heat wave of the season; it’s currently 101.8F outside and high 90’s in the garage. Just before dawn it was 75F, hah.

On the car, the cold air (hah) intake, wings, and engine cover remain to be done. There’s a driver’s school in September which got my interest because they claim they’ll be running a large-diameter wet skidpad, something I’ve always wanted to run Midlana on (though it means me and the car getting drenched). With all the recent changes (engine, turbo, tune, transmission ratios, differential upgrade, shock settings, and new tires), Midlana’s capabilities cannot be  legally and safely tested on public roads. I say they “claim” they’ll be running it because having water trucked in for the purpose is reportedly around $800, so I want to make sure they’re really going to do it before signing up. An inquiry was sent but I’ve heard nothing back – what a surprise*.

Other odds and ends: Adding the engine tray has aerodynamic advantages but carries with it other consequences. The most striking is that both oil and coolant temperatures increased roughly 4 deg C after adding the undertray, so convection cooling through the engine compartment was measurable. I imagine it’ll be even worse once a new engine cover is installed because the only cooling air will be coming in the side vents (the right-hand vent is currently non-functional but will be cut open). There is some concern that convection and ram-air effects may not be enough to keep things under control, so Plan B is being considered: an engine compartment cooling fan. I remember reading something interesting about the development of the McLaren F1, where they had similar engine compartment temperature issues. The most interesting aspect was where they mounted them: flat on the floor, sucking air upwards into the engine compartment. This had the double effect of moving air in the direction it wants to go anyway (hot air rises), but most importantly, lowered the pressure under the car by a measureable amount, thereby increasing downforce (or decreasing lift) at the same time. That’s pretty clever. The downsides I see are that dust and dirt kicked up by the front tires is likely to get sucked up, plus, the highest ambient temperatures is located closest to the ground. Granted, it’s (probably) cooler than the air around the engine, but I’m not sure whether it would work as well here in Southern California as it might at McLaren’s home of Woking, UK! Effectivity aside, finding space for it could be a challenge, as there’s just not that much open space anywhere in the engine compartment – whoever designed this didn’t oversize things much!

*This is a continued irritation with me, vendors that sell a product yet make it difficult or downright impossible to give them money. I’m currently designing a new pond filter which uses “feather rock”, a volcanic stone with interconnected pores. We have a local distributor of the stuff and I’ve called or walked in four times now, trying to get them to tell me if they can get the stuff – I know they can since they already sell the boulders, which come from the same mine, but I want the 2″ stuff, but the vendor just won’t answer my questions. As a last try, I’m contacting the mine directly and will ask them if they can kick their local distributor in the nuts to make them answer me. Best of all would be for the mine to offer and sell it to me and ship it with the boulders next time they make a shipment to my local outlet, then I pick it up there. I would enjoy walking in and asking for status, and after they give me another non-answer, I say “I’ve done all your work for you; here’s what’s going to happen.” Apparently business is so good these days that vendors just don’t want to bother with special orders – fine, but they could at least say so!

18 June 2018

Had a brief dream of backing Midlana off a trailer and realized there’s a problem, in real life as well – that unless the angle is very mild, there’s a fair chance the diffuser will drag. Have to take some measurements before that happens.

On a related note, I found an unintended airflow experiment has been going on. Back when I replaced the turbocharger studs (more on that in a moment), the turbo oil feed line and feed adaptor had to be removed. It leaked a little and dripped onto the diffuser near its front center. Because of the way the diffusers attaches, some of that oil ran to the forward edge and got caught up by the air flowing under the car. The cool part – which looks better than the picture – is that the air flow remains well attached as it flows aft. What’s hard to see is that near the front edge, the air flows in and sort of “funnels” into the center channel of the tunnel, showing that the strakes are working as well. Also, along the top edge of the picture, you can see how the air flowed up onto the frame/Gurney flap, which would be expected if it was doing its thing. Good.

Regarding the turbo studs, after doing some more reading and getting some helpful hints on the Midlana Builders’ Forum, it was decided that they’re being replaced again, with the only type of stud that won’t stretch under high heat – Inconel. Actually ordering them though was a bit of a drama. For whatever reason, they’re fairly common in the aftermarket – in Australia – but not so much here. Testing the waters, I found they wanted about $50 shipping for their $50 parts, so no go there. In short, they were found domestically in a somewhat-surprising-but-shouldn’t-have-been source, Mazda. Seems the factory had such serious problems keeping their turbos attached to the second(?) gen RX-7, that they use Inconel studs. Thanks somewhat to mass production, they’re “only” $12 each, but hopefully once they’re in, that’ll be the end of that.

As an aside, a vendor in the US advertises “Inconel” studs, but reading the fine print, it turns out they’re actually “Incoloy”, which research shows isn’t the same thing. The vendor tried convincing me they were and that Inconel is just a brand name of Incoloy, yet research seems to indicate that Inconel has more nickel in it and is quite a bit more expensive (less profit). We use the material at work for really high temperature applications and use Inconel and nothing else, so there.

Lastly, if someone tries selling you fasteners and claims they’re Inconel, a simple test is that they will look like ordinary steel (not stainless) but are non-magnetic.

9 June 2018

I know how much you guys just love it when I post non-car related stuff. This year a couple of hawks had babies in a nearby tree and have been visiting the yard, looking for mice, lizards, and gophers. Usually I don’t have the good camera handy and by the time I do, the moment’s gone. This time I got a couple really good shots; I like the first one because of the glint in his/her eye, and the second one, I’ve definitely been spotted!

 

8 June 2018

The aluminum strakes were swapped in; notice how the aluminum end plates are now tucked under the body panel instead of on top. Because it’s cantilevered out behind rear axle centerline, it means that its vertical motion is mechanically amplified. I knew this and plan to trim back the strakes if necessary, and it didn’t take long to learn it might be. Backing out the car with the diffuser for the first time, when it rolled from our slopped driveway onto the level street, the rear suspension compressed just a little and I heard a brief scrap. I couldn’t help but laugh that the new diffuser had lasted all but 15 feet before being scarred. If this happens more frequently, it’ll be trimmed.

After finishing the diffuser, I happened to glance at the engine – never a good idea when in a good mood – and spotted that a stud holding the turbocharger had backed out. If that had been it, I wouldn’t be telling you, but it turned out that two were loose, with the second one being a pain because the turbocharger compressor has to be removed to get at it – you may remember the big Circlip pliers bought just for this. Sigh, when one thing gets fixed, it always seems like something else pops up.

New locking studs and nuts were installed and we’ll see how they last. Drilled-head bolts were not used for two reasons. One is the tight clearance, it wasn’t certain whether they could even be maneuvered into position to drop into the turbine housing mounting holes. The other reason is, being bolts, there’s a fair chance that the threads will get frozen in the stainless exhaust manifold, possibly breaking during removal. For now I want to stick to studs and see how they hold up. If they loosen again, safety wire will probably be involved one way or another. Stainless fasteners were not used because they thread into a stainless manifold. I learned the hard way – several times – that screwing together stainless parts is a recipe for disaster. Even spinning them together by hand often results in the metal galling and basically welding itself together. That said, there is a new stainless alloy that would be great in this application: Nitronic 60. The problem is that it’s so new, bolts made of it are really hard to find. Most vendors who handle it just advertise, “we can make whatever fasteners you want out of this material”; yes, I’m sure they can.

Let’s see, what else… wings. Based upon the references regarding diffuser design, placing the rear wing above the diffuser outlet makes a large improvement in downforce, so that’s the plan, but there are consequences though. Much like how the diffuser’s proximity to the ground is mechanically amplified by being behind axle centerline, so too is the downforce provided by the wing. Given how fast the car is, there is some concern that with a rear cantilevered wing, cresting a rise at high speed could allow enough air under an already-lighted front end to lift. For that reason, I think it’s wise to build both front and rear wings and install them at the same time. Hopefully the front wing will produce enough downforce to keep the nose planted.

In other news, one quirk of this WordPress blog template is how it arranges posts. First, they’re always in descending order, meaning that in order to read a multi-entry chronology, you have to read from the bottom up. That’s not a big deal, but it’s got another quirk of how past some number of posts, it places these additional entries on a second page. If you don’t notice the page selection buttons at the bottom of the blog and just start reading from there, you may miss entries hiding on the second page. I just changed the maximum number of displayed blog entries from “10” to “20”, so hopefully hidden entries are no longer an issue.

2 June 2018

Had the week off so between honey-dos and being on-call, the diffuser was built. As background, the vertical strakes were going to be aluminum, but later, because there’s a fair likelihood that at some point they’ll drag on the street, I switched to HDPE (high-density polyethylene) because I had it, and because it seemed like it would wear more gracefully, unlike aluminum that would bend and stay bent.

Having made the decision to go with “wearable” plastic, the vanes and end plates were initially going to extend lower, such that there’d be only 2.5″ of ground clearance. The idea was that they’d “self adjust”, but after thinking it over, that seemed like a recipe for disaster. Images of having the leading edge(s) catch on something and having the entire assembly pulled off the car didn’t seem impossible. For that reason they were trimmed back so they’re even with the bottom of the car. Anyway, on with the pictures.

There was an aspect of HPDE that I casually considered, that it’s rather heat sensitive. Since there’s a lot of air flowing past the exhaust where it exits into the left-most tunnel, how hot could the air really be? The answer is illustrated in the last picture – “hot enough” (and this was a casual drive, I imagine on-track I’d be dripping melted blobs… sigh – they’ll be replaced with aluminum.

I’m sure you’re wondering whether the diffuser works – good question. My imagination thinks so*, and I can offer that leaves fly up behind the car. But, sometimes leaves flew up behind the car before. My thinking is that it can only improve airflow and at track speeds, will very likely be doing its thing. Oh, and the rear wing will be placed above the trailing edge, which enhances diffuser flow even further. There’s simply no easy or safe way to test it out on the street.

* Of course, after I change the oil on a car, I swear it runs smoother, so there’s that…

26 May 2018

Over on the Locost forum, someone built a diffuser using 1/8″ (3mm) ABS sheet, doubling it on the strakes. I’ve got some left-over black 1/4″ (6mm) HPDE sheet which might work well for the strakes due to being potential wear items. I’ll have to make templates and see if there’s enough material on-hand. Given how diffusers work, it’s tempting to extend the end plates lower than the floor, though that makes them the lowest point on the car…

20 May 2018

Worked on two projects: the cold air intake and the diffuser.

Unlike how I normally do things – scratch-building everything – this time I wanted to see if I could find something “off the shelf” to serve as the air filter enclosure. After wandering around half a dozen stores, a stainless double-wall ice bucket (complete with woven bamboo weave) looked “promising”, mostly because nothing else in the kitchen sections was even close. Removed the bamboo, then used the “death wheel” to cut out the inner wall. It was pretty amazing how perfectly it fit the conical air filter – though I did test-fit it in the store. What still has to be added is a 5″-diameter extension to pick up the duct hose. At the other end, another fabricated duct will feed air to the hose from the side air inlet next to the dry sump tank. It’s either going to be composite due to the oddball shape, or a rather curvaceous aluminum assembly.

Diffuser: after reading that excellent article, given that the bottom of the car is flat from front to back, the diffuser might actually have a chance of doing something. It’s a 24 x 48″ (609 x 1218mm) aluminum panel, with a lot of mockup work. The forward edge will be captured by the aft edge of the engine tray. Right now I’m thinking of aluminum angle below to support the strakes (yes, that’s the term), and another piece across the rear edge to prevent bending and to (very optimistically) perhaps even act as a Gurney flap. That should make it rigid, but it’s still has to be supported, either off the side panels or via tubes or cables off the inboard chassis. Mostly because of the muffler, the diffuser angle ended up being 13 degrees. Yes, I know, everyone says the maximum divergent angle should be 7 degrees, but as the article notes, diffusers run at lower speeds and with larger ground clearance can handle bigger angles. In any event, something will close off the current open area around the exhaust, probably screen just like above, though the shape needs some thought to not totally mess up the appearance.

There is a bit of concern about the nearly 2-ft extension behind the rear axle. For example, going over speed bumps, not currently a problem, could become so at certain speeds, where as the rear of the car passes over and down, the suspension compresses somewhat below ride height as the shocks compress, so the speed bump could end up kissing the bottom of the strakes. I’m trying to plan for that possibility, so that the worst that happens is a bit of aluminum gets bent, rather than it hooking on the leading edge and ripping the entire assembly off the car!

18 May 2018

The wings – not yet fabricated – will only be mounted for track events. I’m not impervious to what people think (partly because it can affect book sales) but also because I’d feel silly driving on public streets with them. While technically functional at all speeds, they’re realistically pointless at legal road speeds, so it’s sort of a lose/lose proposition. I mention this now because to a somewhat lessor extent,  the same applies to the diffuser.

The diffuser will be a 24 x 48″ (610 x 1220mm) panel with the forward edge attaching to the rear-most cross tube. Due to the muffler, it’ll have a small angle toward the front, then a larger angle behind it.

This Racecar Engineering article and Willem Toet article were both very helpful (though the latter was obviously not proof-read!). Before reading the articles, I was going to leave out the strakes (the vertical vanes always seen on diffusers, but the figures graphically show why they’re a good idea. The articles were found while doing a Google search to answer whether a flat or curved diffuser works better. While neither article answers this directly, it appears that the sudden slope change at the front edge is necessary to initiate the spiral air currents drawn in from the sides. (On a related note, most forum discussions about diffusers are very inaccurate, go figure.)

Getting back to the question about street use, I’m sort of on the fence concerning the diffuser. Like the wings, even if it works, it’s of little to no practical benefit at legal speeds. Unlike the wings though, it’s not quite as “in-your-face”, being mounted down low. Also, there’s the practical issue of where to keep it when it’s not on the car. The wing assemblies will be tall and slender, and can be stored against a wall out of the way. Not so much with a large three-dimensional diffuser assembly. As of this writing I’m leaning toward leaving it on the car and putting up with the increased boy-racer look. That said, if I can drive down a leaf-covered street and kick them up high in the air behind me, that’s so totally worth it 🙂

Before anyone says “well what about the pretentious air intake on the roof?” Unlike the wings and diffuser, cooling the intake charge is of benefit whenever the engine’s in boost, which is often, so it stays.

12 May 2018

I’ve had enough – don’t worry, it’s not about the car.

Visiting various websites, I’ve had enough of the increasing number of ads and the extremes to which some website owners will go to in order to increase ad revenue. Click-bate – and more and more regular sites – are turning into thinly-wrapped delivery systems for Google ads instead of actual content, which is being relegated to less and less screen space. What content is left has been calculated to be the bare minimum required to get people to click the next page. So to twist a saying, I’m putting my mouth where my money was and am removing Google Adworks from this site.

I know many people didn’t mind, but what they may not realize is that when webpages appear to hang while opening, it’s because Google gives priority to all the sidebar, header, footer, and embedded ads, ahead of the actual content. I don’t like them deciding that their revenue is more important than the content people came to see in the first place.

To be honest, Adworks never made much here, so I’m probably being a hypocrite; I probably wouldn’t be as righteous if it was making $10,000 a month. But it isn’t, and no longer feeling a bit like a prostitute is worth more than what their system was paying.

6 May 2018

Cleaned the bottom and rear of the car, though it was impossible to get at all the oil. I didn’t want to use any sort of sprayer that drives water into the wiring or chassis tubes, so I’ll wait for the oil to absorb dust and fall off…

After that, it was time to install the new exhaust, this time with a Borla muffler, mostly because it’s stainless but also to test the claims of great muffling and low back-pressure. The exhaust is set up so that it disconnects downstream of the flex coupler with a V-band for track events, and a short right angle extension can be swapped in, much like how the exhaust was before today. Both wastegate outputs are also fed in upstream of the muffler – no point cruising quiet(er) but attracting the wrong type of attention while under boost.

The muffler works really well (Borla PN 40359), I’m pretty happy with it. The picture from the rear shows how it’s leaned forward, to miss the future diffuser. This leads into something I’m working on, to solve how Midlana’s been looking a bit “unkept.” One issue (in addition to the engine cover) is the chopped off lower rear panel (crunched when the car backed off-course at Willow Springs then cut off because it wasn’t repairable). The plan is to fabricate a one-piece engine tray/diffuser of aluminum or stainless. Whatever the material, the nearly 48″-wide sheet has to be thin/soft enough that it can be curved upward to form the diffuser. At the same time, I’d like it thick enough that it can serve as structure under the engine, something of a contradiction. A middle ground might be to have a shop roll the curve into it for me.

As mentioned before, the air filter’s being changed to pick up air from the side inlet instead of sucking in hot engine compartment air (now hotter because of the muffler below it). The ducting and different air filter element is on-hand; the new filter is better suited to being enclosed and fed via ducting. After finishing the muffler, the new filter was installed without the ducting just because, the large hose clamp tightened, and I headed out for another test drive.

During the drive on my newest favorite road, I saw two Alfa Romeos GTVs (my favorite model) pulled off to the side, the owners chatting. Further on were another 3 or 4 more, one with its hood up. I stopped and asked if they needed any tools. They laughed and said “we drive Alfas, of course we have tools!” We chatted some about Midlana and then I was on my way – thankfully not trailing a stream of oil like last week!

With the muffler working so well, new sounds are detectable now, and unfortunately, one sounds like engine knock under full boost. What’s unclear is whether it’s always been there and I couldn’t hear it, or if the (assumed) added back pressure from the muffler caused it. I’ll log a drive to see what’s going on; maybe it’s just something that sounds like knock. If it’s the real deal though, boost will be dialed back a bit :).

Stopped for gas on the way home and half way through filling the tank, I saw something move out of the corner of my eye – the air filter had just fallen off the turbocharger, hah. How it managed to stay on the vibrating engine through the entire drive and only fall off right then, I don’t know, but I was happy to see it happen. The hose clamp worm screw housing had contacted the compressor housing, giving a false indication of being tight – fixed.

No oil leaks on the test drive, though there’s still oil from the original leak coming out of the woodwork. What didn’t help the oil leak situation was the engine tray being off the car. Not only did this allow the oil to be blown aft, but the open rivet holes allowed some of it into the chassis tubes, only to later drip out when it feels like it.

Lastly, alternator output remains at 14..0-14.5V during the entire drive, so no issues there.

Oh, ran across this pretty cool looking (and free!) PC application for designing mechanical linkages. I haven’t used it yet but it could be useful for future projects :).

 

 

30 April 2018

Once the weather warms up, the engine compartment will be cleaned with soapy water – the oil’s everywhere.

Parts are on the way for the muffler, along with hose for the revised intake.

I forgot to mention that the alternator behaved itself through the entire drive, staying between 14-14.5V the entire time. Hopefully this will be the last mention of it for a long time.

29 April 2018

Did another long back country drive, finding new and wonderfully twisty roads off the beaten path. Even on a Sunday, when motorhomes and pickup trucks with dirt bikes clog the roads heading back from the desert, there are still a few roads to be explored. About half way through this drive, the little voice in my head asked, “Do you smell something?” Me: no.

A bit later, “Are you sure, it smells like oil.” Me: Yeah, but it’s really faint and probably isn’t even coming from my car. It could be a truck and I don’t see any smoke. As I neared home, however, the oil smell had become unmistakable.

Pulled into the garage and the line of oil down the street delivered the message in no uncertain terms that something was up. The bottom and back of the drivetrain, and all the suspension and the rear of the car were covered in oil, so the immediate goal was finding the source.

Started it up and there it was, coming from around the oil-to-coolant heat exchanger. After cleaning up the mess to get under the car without taking an oil shower, a closer look found it was coming from the inlet fitting on the oil cooler. The -12 AN fitting wasn’t loose; it was the bolt-on adaptor it was screwed onto that was leaking. Oddly, the Torx screws were tight, so it seemed like the gasket must have given way after, what, five years?

After removing the fitting, it turned out that it’s sealed with an O-ring and it seemed like it had gotten pinched – or so I thought. It wasn’t until I pulled it out of the groove that I found there were two O-rings! The only thing I can think of – given that there’s only room for one O-ring – is that the assembler must have reached into a bag of O-rings and not noticed that two were stuck together. Amazing that they remained sealed for as long as they did.

I’m going to call the seller to see if they’ll give me a free replacement gasket set if I casually mention that the only reason I didn’t trash this engine was the 8 quarts of oil in the dry sump system. When the tank was drained before removing the fitting, it was a bit shocking to see that only about two quarts of oil were left. I think the leak started very gradually which is why it didn’t become suddenly obvious. Seeing the solid line of oil down the street, I doubt it would have lasted another 20 minutes. Yes, the ECU should catch the low oil pressure with a rev-limiter and a warning message, but I don’t want to test that. Close call though.

26 April 2018

While looking at the broken exhaust, the brace from the engine block that supports the turbocharger was found broken as well. I think I know when this happened. I was leaving a driveway and accelerated hard and may have caused a “PIO” (Pilot Induced Oscillation) with my foot inadvertently getting on and off the gas due to the car accelerating and decelerating so hard. The result was a violent back and forth action similar to ignition cut. I say I may have because the ECU failed to log it (again). Anyway, the turbo support bracket was repaired – though I noted that some bonehead had left it tack-welded, no surprise it failed.

As a temporary fix, the failed stainless bellows was welded back together instead of being replaced. That’s because even before this happened, there’s been a plan afoot to adding a muffler (again). The intent is to both reduce noise and unwanted attention, and to just be more pleasant. Besides, the car has so much power that if I lose 10 hp by adding it, so what. It’ll be installed so that it takes about a minute to remove for track event.The downside is more weight and heat, which will likely lead to something else that been on the back burner, a cold air duct running from the side vent to an enclosed air filter. As it is now, the open air filter sucks hot air in straight from the engine compartment, decreasing power and increasing the chance of preignition. Adding the duct may well make back whatever power the muffler takes.

In other news, a bit more information was found regarding CS-130D alternators. Apparently they contain a temperature sensor, though it’s unclear what for. It might be to reduce output to protect the alternator as it warms up, or maybe it’s to maintain output instead of it dropping off with temperature – I suspect the former.

Also alternator related, it was noticed that at idle, the alternator vibrates some. Suspecting something was broken, it was disassembled again but nothing was found, so the mount may simply be flexing. Might have to make a new one using thicker material, or double up the material that’s there now. It was reassembled with a new bolt and after putting it all back together, turning the alternator pulley now turns the engine (apparently it had to wear in) so belt tension’s off the list of suspects.

Right now I suspect it’s just how these alternators work, varying the output with temperature. An experiment would be to warm up the alternator with a drive, then while idling, cool it with compressed air to see if the output voltage jumps back up. My brother reminded me of something I intended to do, measure battery voltage with a good DVM instead of taking the dash/ECU’s reading as fact. Good idea, because the dash reads about 0.2V low, further lessening my drive to fiddle with this issue much longer.

22 April 2018

Well, it’s better, I guess…

Took the alternator out and found it’s a CS130D model – I thought it was the previous generation, the CS130. The “D” version has more output, larger bearings, and better ventilation, though it is a bit larger.

It appeared to be in good condition so a cable connecting the alternator directly to the battery was fabricated, in addition to connecting the previously-unused “sense” wire to make sure the voltage is monitored directly at the battery.

At initial cold-start, battery voltage immediately went to 14.5, higher than before, but like before, after about 30 minutes of driving, it had decreased to 13.5-13.7V. The odd thing is that later during the same drive, sometimes it would go back up to 13.9-14.0V. If it slowly sank and leveled out, I’d think it was a temperature-sensitive voltage regulator and that would be the end of it, but this, huh.

A possible contributor might also be belt tension. Some sources claim that a serpentine belt is tight when you can just turn the longest span 90 degrees. Another source says that the belt should be tight enough that the engine can be rotated by turning the alternator pulley with a wrench. If it’s the former, I’m fine; if it’s the latter, I’m not. If the belt is slipping though, I’d expect it to get worse when a big load like the radiator cooling fan is switched on, yet when I did so when the alternator output was 14V, it didn’t drop much, implying that belt slip isn’t the issue.

The alternator might be defective, or maybe they all do this. The belt might be slipping, or it might not be. The alternator is mounted in the only place it can go due to the required reverse-rotation of the water pump. Because of the mount’s geometry, mechanical leverage increases as the belt is tightened. This would be a good thing if there was more space but there’s a chassis tube not far away, so there’s only a limited range to get it tight, and the next shorter belt won’t fit. Another possibility is to switch to the slightly smaller CS130 (though it’s only about 0.3″ smaller) but may still not allow getting the next shorter belt on.

Yet another variable is the pulley ratio. An aftermarket alternator manufacturer claims their alternators are good to 18,000 rpm, though I’m not sure whether  OEM units are the same. The ATI crank damper is 5.5″ diameter and the alternator pulley is 2.7″ (68.6mm) – an odd size regardless of units. Alternator speed is scaled by pulley diameter, so if the engine’s spinning at 8200 rpm, the alternator’s spinning at (5.5/2.7)*8200, or 16,700 rpm, so there’s a bit of wiggle room left. The math says that the alternator pulley could be reduced to 2.5″ to increase charging at lower speeds. The thing is, the belt routing is sort of like the letter “B”, such that it nearly touches itself as it passes over the water pump pulley. If the alternator pulley diameter is reduced, the belt surfaces may touch and greatly accelerate wear. Maybe a pulley could be added to increase spacing, but messing with pulley diameter is sort of besides the point since sometimes the voltage output is fine. Further muddying the waters is how sometimes, when I’d rev the engine up, battery voltage would increase, implying it’s a pulley ratio problem – yet other times it wouldn’t make any difference. Ugh.

Summed up, I’m not sure where to go with this, leave it alone and keep an eye on it, or chase it down until root cause is identified.  Lastly, this article is really helpful in understanding alternators.

In other news, I was wondering why my exhaust pipe was suddenly pointing off to the side. Turns out that the flex joint in the exhaust has completely cracked through. That’s nice, but it didn’t ruin my 100-mile drive through the back roads!

16 April 2018

Whether or not the alternator gets swapped out, it looks like its wiring needs revisiting. The alternator connects through the fuse box to the battery. The catch is, I added a battery cut-off switch upstream of the fuse box and bad things can happen if the switch is opened with the engine running. At best, the engine quits as it should, though I now think it won’t. Since the alternator feeds in downstream of the switch, it would likely self-power the system and the engine would keep running. At worst, not only would the engine keep running, but with no voltage reference, the alternator could generate voltage spikes high enough to damage the ECU. I’m too chicken to try it and find out.

The alternator feed-in point needs to be moved directly to the battery. As a related issue, the wire connecting the alternator to the battery is way too small (I blame the Painless Wiring kit but should have known better). It’s 10-gauge but needs to be much larger; the PowerMaster site claims that a 7-ft wire running 125 amps requires at least #6, if not #4. Yes, 125A is extreme, but having everything on in stop-and-go traffic with a flat battery could get there, albeit briefly. Wire size doesn’t seem like it could be the sole cause of the voltage drop, but it can’t be entirely ruled out either. Copper has a positive temperature coefficient, meaning the hotter it is, the more resistance it has, which causes voltage drops with current (this is why a hot starter won’t crank an engine). Still, air temperature rising only 20C wouldn’t be enough to account for the problem… only there’s more to it. The alternator wire runs down the center tunnel, sharing space with the coolant pipes. There’s a fair chance that it’s seeing around 60C or so, increasing resistance by around 16%. That still doesn’t fully explain the situation because the wire temperature in the center tunnel likely doesn’t vary much. Guess I just have to try it to  see; right now I still think there’s still a good chance the problem is an overly-sensitive voltage regulator in the alternator. Regardless, the alternator wire needs to be upgraded no matter what alternator is used, so this is a cheap experiment before spending money on other things.