Life has been very uninteresting lately, it’s winter and that uncomfortable kind of cold that can’t be dressed properly for. I’m either still cold, or sweating because I have too much on, or both because the temperature can’t figure out what it wants to do. I still have to pay my property taxes now that I found out that at least one of the offices does not accept debit cards and I managed to track down my checkbook that I hardly ever use except to void a check when someone prefers to pay by direct deposit.
So I have my checks for whenever the weather improves to the point I can do the walk between the three offices on State St. in Garland. In good weather it’s a nice walk from 5th to Garland Ave, less than a mile. And there are bus stops on both ends but it is only a short walk from Downtown Garland station to the first tax office, less than a quarter of a mile.
And at some point I really need to stop at a CVS or other store that carries butane to fuel the torch that heats the bender for the plastic rod I’m using for the frame of the Mini Sprint-T. And while I’m on the subject of cars I found a really good intake manifold for a SBC to use should I wind up running a SBC on the 1:1 Sprint-T. This manifold is an evolution of the TPI GM intake from the late ’80s early ’90s, that produced prodigious low-end torque but ran out of breath above 3000 RPM partially because of the state of the art for EFI at the time. Well this version breathes all the way up top, with “top” depending on displacement but generally higher than a factory cast crank will live with. The tech person I was in chat with says for a 383 the “top” is above 6000. The tech manual advises against using E85 but the only thing I can find that might not be compatible with the fuel is possibly the fuel injectors or the rubber injection lines supplied. Those are all easy to replace with alcohol rated devices or materials. The crank and piston kit I’m looking at has a max continuous of 5200 RPM or a short-burst redline of 5500 RPM.
Finding a kit to build a 383 that runs on 87 octane NA is another problem entirely. Most of them are too high a compression ratio for 87, or built for forced induction and cost too much because they are designed for higher HP than a NA engine can make on either 87 octane or E85. Sure that makes for an engine that is unlikely to fail even during racing, but I could buy a kit not made for boost that would be just as reliable and a bunch less expensive if they would use the same parts they use for 93 octane except for the extremely dished pistons in the hyper eutectic material instead of forged used in the boost-capable kits. Locally the difference between 87 and 93 octane is $0.30-0.50/gallon, or about 20-30%, and E85 is about a penny more than 87. Depending on tune it might be cheaper to run on E85 all the time using the 93 octane kit if I wasn’t concerned with availability for long trips. But for that I have the possibility of running a storage tank in the tire trailer to extend the range enough to get between E85 stations on the Interstate when driving between races, and there are plenty of places to refuel locally.
I finally got some sleep today after staring at the wall until ~0700. I went to bed about 0300 and tossed and turned trying to find a comfortable position to lie down. Then I had to get the brain to shut down and let me sleep. But good news Mrs. the Poet went out to do some things and got me my new scrip for anti-depressants filled. Now I just have to wait until I build up enough in my tissues to hop the blood/brain barrier and start anti-depressing me.
I never got too depressed to stop thinking about my engine in the TGS2. Like I posted a few days ago I did some research and reverse-engineering to determine I had 55cc combustion chambers on the head side. That means I probably won’t have to angle-mill the heads to get the combustion chamber in the head down to 44cc, but I probably will just to keep as much material on the deck surface as I can for stability. As much as I would like to believe it to be otherwise, aluminum heads are not rigid structures and flex under the loads of combustion, causing them to loosen over time and eventually blowing head gaskets. Leaving the deck surface as thick as possible helps reduce this flex, which is why I’m going to angle-mill instead of straight milling the head surface. Ideally I would fill in the combustion chamber to make it smaller and stiffer, but this requires access to materials and machining processes that I don’t have access to. The reason why I would do this over milling the heads is adding to the combustion chamber makes it stiffer, and I can move things around to improve intake and exhaust flow while reducing the chamber volume. But as I said I can’t get to the machines I would need to do this so I will angle-mill instead.
Something else I have been thinking about is moving the injectors to get more fuel cooling of the intake charge. E85 fuel has a very high latent heat of evaporation that can drastically reduce the temperature of the intake charge, but it has to have time to work for that to happen. What I was thinking about doing was moving the injectors from right next to the head surface of the manifold to the top of the intake plenum aimed straight down into the ports with the manifold changed to a more vertical plenum on top rather than the bent over runners and plenum on the side on the stock manifold. This would still keep the same mixture distribution as the stock injector position next to the head in the middle of the port, but gives the entire length of the port for the fuel to evaporate and cool the charge before it enters the cylinder. This would improve both power and economy as a cooler charge can work with either more compression or more spark lead, either of which makes more power at WOT and better economy at low throttle openings. The fact that working on combustion chamber design and mixture distribution improves WOT power at the same time it helps part-throttle economy is a big reason why we have 300 HP cars that deliver 40 MPG highway these days. It’s a combination of aero and engine efficiency reducing the amount of power required and getting more power out of the fuel used.
I’m from the days when knowing how to change jets and power valves was required to tune a modified engine, now you need to know how to alter a fuel table in a computer to do the same thing. I can understand why some of us fogeys are upset at the change negating hard-won knowledge, but TBH changing fuel tables in a computer is just better. For one it’s a lot cleaner than changing jets and power valves, besides being more precise. But there is still one old skill I’m going to need when I start working on the TGS2 engine after the conversion to E85: I can read spark plugs for heat range. And E85 at 14:1 compression requires a lower heat range than 87 Octane at 9.8:1, but nobody knows exactly how much lower. I’m going to start with stock and give them a read to see how much lower I need to go to save buying an extra set of plugs. Or I could buy 6 individual plugs at 6 different heat ranges and give them all a pull at the same time and go buy the full set of the one that reads closest to perfect. In fact I think that is the solution. A fast cheap solution to finding the best heat range for the E85 conversion.
And My Goodness I have been wordy today, 800 words to be semi-precise. Feeling better makes me write better and writing better makes me feel better. Yay!
I don’t know how closely you follow Twitter or the news but there were two garbage fires in DC today, the one that was “elected” by negative 2.8 million votes, and a Parks Service garbage can that was set on fire in front of the working press.
What does this have to do with this blog about bicycle safety and a guy turning junk and discount parts into a hot rod? Damnifiknow. And my spell checker says I spelled that portmanteau correctly. Excuse me a moment while I check to see if either of the cats is hugging a dog… Clint is sleeping in a chair and Clyde is somewhere outside, so … maaayyyyybee? And that was a media ref from the OG Ghostbusters in case you didn’t catch that.
Firmly taking my mind off that subject, I’m still debating trunk space in the mid-Bucket, as a compromise between usefulness as a daily driver and handling/acceleration as a race car. I have a trailer kit in the garage that I can use for trips to the grocery and hauling luggage on trips to longer than overnight stays, but do I want to go to those kinds of lengths just to get a few thousandths of a second quicker lap times on Solo and AutoX races? Especially when I will probably need the trailer for carrying support equipment and supplies for Solo events anyway as I will be using race-only tires and wheels for the SCCA events and very probably swapping springs and shocks at the track for both Goodguys AutoX and SCCA Solo events. On the other side I have to install a pickup bed to meet the rules for Goodguys anyway, it is not that big a deal to make it functional as a luggage or grocery carrier. The problem is I have to decide pretty early in the design phase for the rear clip if I make the pickup bed functional because many structural members will have to be moved to make room for the trunk and make the rear clip structurally sound. Mrs. the Poet says she doesn’t care because she’s not ever going to ride in a car that doesn’t have doors or a roof. So I could carry my stuff in the passenger side of the car except for the wheels and tires.
On the other thing, the retuning of the ECU to run E85, research has drawn a blank on how to increase fuel to compensate for the much higher amount of fuel needed to reach stoichiometric ratios while still being able to run 93 octane premium without doing a complete rebuild of the fueling system. If I want to just run E85 all the time I can change to a much bigger fuel pump and run more volume at a higher pressure and stay within the metering limits of the stock injectors, but switching back and forth requires knowing beforehand the exact ratio of ethanol to regular gas…
And I need to put this to bed and be thinking about the car some more.
PSA, Opus the Unkillable