Tag Archives: Sprint-T

Sorry again for no updates

Still nothing much happening beyond another huge burger and a sundae on my Birthday courtesy of Red Robin and their loyalty program. Oh and the reward card I got for doing an online thing that was mostly good for buying things online but I could also spend at Red Robin was mostly drained right before my birthday, it went from $75 to $3 before I could even spend it.

I’m still thinking about the Sprint-T, and entering any free engine give-aways I can find, a free engine that runs beats an engine I don’t have. It might not be the engine I wanted, as almost all the give-away engines are iron block with aluminum heads, and I’m hoping for aluminum block and heads, but they’re all better than no engines. I’m also thinking about the transmission, as some of the give-away engines are set up for an automatic or exceed the torque limit for the T5 by a substantial margin. So, I’ll need to buy the appropriate transmission for the engine. The “appropriate” transmission being the lightest thing I can bolt up that doesn’t break and has a high enough overdrive for driving on the freeway without excessive fuel consumption, or that has a low enough 1st gear that I can install a final drive the same as what I would have with a more normal final drive and a really tall overdrive. Racing will be mostly in 1st gear until about 40 MPH, above that I can use 2nd. And the only time I’ll use 3rd or higher is on the highway getting to race venues.

Mrs. the Poet is getting better, her digestive issues are working their way out. Our other problems are also working their way out. They’re not fixed yet, but progress has been made. My major problem with her is her insistence that I adhere to her sleep schedule. I usually end up with about 5 hours of sleep and wandering around in a daze until sundown, when my normal sleep schedule tells me it’s time to wake up. I will be so glad when she gets well enough to sleep in a bed and not need someone to change her diaper. I will be even more glad when we can sleep together in the bed.

And speaking of bed, it’s past time to put this post to bed.

I managed to think last night

Nothing to panic about, I’m still trying to come up with a way to make that manifold with the materials and processes I have at hand. Now I don’t have access to any 3D printers, much less anything that would allow making compression molds for intake manifold runners. But what I DO have is sheet metal, and hammers and dollies for shaping that sheet metal, and a torch that I can use to heat metal so it can be formed without wrinkles or tears.

So what I thought about was making a sheet metal mold that would mimic the actual part, then making molds from that sheet metal positive, with lots of reinforcement so they don’t collapse under the forces of compression molding. By using sheet metal to make the positive I wouldn’t have any problem with making the positive mold absolutely smooth, that’s a process I mastered decades ago. But yeah, sheet metal positive for the inside and outside molds, I can do this. It would also work for the plenum molds, especially since to swap left to right all I would need would be to turn the plenum over so the throttle arm of the throttle bodies would be closer to the center than the outside on both plenums.

The plenum will have 3 sides and 2 ends for its mold, the bell mouths for the runners will meet to form the 4th wall of the plenums. The inner finish for the plenums is not critical at all except for the entrances to the runners, which will be molded into the runners.

And I need to eat and it’s almost 2200 so I’ll have to find something I can throw into the microwave, then go to bed.

I’m getting almost excited

I’m not bouncing up and down, but I’m almost that excited that I’m about to get the parts and materials I need to build the front fenders for the Sprint-T. It has been a long time since I have been able to get something done on the car, and now that I can it’s almost more than I can stand. The only thing I don’t have is the mold to make the clear headlight fairings, but I can’t make that until the front part of the fender is built. So, I’m going to build the fender first, PTEG vacuum-molded headlight fairing later.

I have been having strange dreams about building a composite intake manifold from a 3d-printed mold and carbon fiber composite materials. It was quite detailed with the printed molds of the inside of the ports of the manifold getting assembled from 3 pieces that were separated to be removed from inside the part after curing, and the bleed ply was used both to get the part off of the mold and to get an “as cast” surface finish to energize the boundary layer of flow inside the manifold. Anywho the printed mold was in 3 pieces with a large center of the port being removed so the outside mold parts could be peeled away from the inside of the port, with tons of mold release applied to the center part to make it eas(ier) to remove. The manifold was a cross-ram configuration with the injectors in the plenums aimed at the opening to the ports opposite the plenum from the injectors, and the runners getting attached to the plenums and the face that bolts to the head by lengths of CF tape and the same resin used for the runners and plenums. The dreams even included the size of the throttle bodies used on the plenums, 78mm so as to flow the same or more than a single plenum manifold with the 105mm throttle body many manufacturers offer. And I looked it up and the actual equivalent throttle body for running 2 in place of a single 105mm is 75mm which is a factory Ford part for a 4.6L 2V pickup truck engine. Which means this is a relatively cheap part compared to the 105mm for a single plenum manifold. The actual number was 74.24mm to be exactly equal but 75 is close enough for government work and hot rodding. Anywho, the 75mm throttle body is $50 each plus tax on the jungle site. Anybody feels like sending one or both would get their name in the blog and my deepest gratitude. The 105mm at Holley was $699 to $715 depending on finish and machining, so two of the 75mm throttle bodies is both better for performance and cost. And nevermind because I just bought them. I got paid for a gig I did a couple of months ago but never got paid for until today. Or at least I was never told about it until today with the deposit and balance with today’s date on it.

And while I was describing the literal dream manifold, I was using spare processor cycles in my brain to come up with a way to support the front of the fender and also mount the headlight fairing/cover, cut a piece of aluminum sheet to the profile of the front fender and weld a strip of aluminum to the edge and drill and tap the strip so that screws could hold the headlight cover between the fender material and the headlight cover. This would mean the headlight cover would need periodic replacement as the screw holes fatigued but the material would be scratched and UV deteriorated by then and would have to be replaced for the headlights to work as intended. The holes in the strip could be Riv-Nutted instead of threaded for a more durable threaded hole with a lighter strip of aluminum. I would need to get these parts done at a shop because I don’t have the equipment to weld aluminum in my garage. I might make them out of light gauge steel that I can weld, or I could use a hammerform to make them out of annealed aluminum without welding. This is a process I have done in the past with the equipment I have at hand. I need to use a lot of hand work to get the edge of the hammerform right, but I have the tools to make it, plus the tools to anneal and beat the aluminum to shape.

And I have rambled on enough for today, time to put this post to bed.

Progress is being made, of a kind

Bits and pieces are coming together to build the lights and fenders for the Sprint-T, in the form of a turn-signal/marker light that can be mounted over or under the headlights on the backing bracket for the buckets that hold and aim the headlights. It’s not much, just a strip of amber LEDs in a weatherproof housing with a 3 wire hookup, ground, high, and low light output to cover all the functions the light has to perform.

How I hook the lights up depends on how the low and high outputs function. If high power overrides low power inputs then I will drive around with the low power and ignition switch on the same inputs, but the other way around, low power overriding the high power input I have DRL and I connect the turn signals to the low power to make them blink at low power and cause the DRL to flash. It all depends on how the light reacts to inputs. And to know that I had to buy a power supply and test leads. My old 12V power supply burned out about a decade ago when I was building high-output bike lights and taillights, and apparently my test leads went with it in the trash. The new power supply is big enough to test all my 12V lights, just not at the same time.

I bought other 12V power supplies/battery chargers between when my previous one burned out and now, but they only function/supply power when there is a 12v SLA battery connected to the outputs unlike the previous versions I bought. And I no longer have any 12V SLA batteries I can plug into the circuit, if I did I wouldn’t need to buy another power supply. Fortunately this power supply is built to support large chains of LED lights, or higher power LED spotlights or landscape lights. It will power one of the headlights, but not all 4 of them at one time. The 5A limit will only handle one headlight. But I just need to test one light at a time.

I got a new part for the Sprint-T yesterday

I bought an assembly from the jungle store, that was intended for semi-trucks that holds 2 4 x 6 headlights. It’s a bit wide for the Sprint-T, but I can trim it down to fit better. It was serendipity that I found this as I was just looking for the headlight buckets to fit the lights I already purchased, expecting to have to fabricate the backing plate and the adjusting screws and springs, now all I have to do is assign wire colors to the headlight pins to connect the existing harness to the rest of the car because this is buckets, adjusting screws and springs and backing plate all together in one inexpensive assembly. That and make the structure to mount these assemblies to the fenders. Also I won’t need to make a waterproof structure to protect the wiring because the bracket already is a waterproof structure that I just have to seal against water from the tire inside the fender.

The assemblies have the three-wire headlight harness but the wires aren’t pinned to the included sockets, so I’ll have to decide which color wire goes to which headlight pin. I have black, red and green wires to assign, the black is easy, that’s ground. The red and green are less easy as I want to make this repairable but any klutz with a pair of wire pliers and a soldering iron who knows the automotive color code. And from what I can find there is no universal color code for headlights beyond making the ground wire black the rest of the wires are of any and all colors and some with white or black stripes. So future mechanic trying to repair a broken Sprint-T the low beam positive is red, the high beam is green.

Now as I was saying the big bracket that holds all this mess is a heavy injection molding about 15.5″ wide by 6.5″ tall with all the wiring inside the bracket, while the usual street tires I’m going to be running are a bit more than 10″ wide (255/60R15), meaning there’s going to be some excess width either to the outside or inside of the tire, or split to either side. Actually I was going to trim this mess so that the fender sides just clear the adjusting pivots on either side of the headlights, and the top was just clear of any adjustment screws. That makes it “only” 14.5″ wide by 6.25″ tall. It’s important to make this as small as possible to minimize frontal area of the tire fairings. The other consideration is the bottom of the headlights has to be 24″ from the ground at rest to pass inspection in Texas. If this was an airplane I would make the fenders only as tall and wide as needed to cover the tires because there would be nothing else to take into consideration, but on a car they’re an ideal place to mount the headlights because they’re both the widest and most far forward places on the car. So I have to make the top of the fenders tall enough to make the bottom of the headlights 24″ high, where if I was mounting the headlights anyplace else I would just have to make the fenders so that the tire would just kiss the inside of the top at extreme jounce travel.

The problem is there isn’t anyplace else to mount 4 headlights and still make them far enough apart to pass inspection in Texas. If I mount them in the only other logical place on the front of the car they would be practically a solid light bar on the front of the car 31″ wide across the nose, because that is how wide the nose of the car has to be to clear the tires at full lock and cover the radiator. In the fenders they have enough separation to make 2 distinct lights and also make it possible to determine how far away the car is at night to allow pedestrians to estimate speed and distance before trying to cross the road in front of the car. Headlight mounting width was a problem with the first Baja Bug conversions, because some states didn’t approve of the 2 lights in the nose that were even closer than the early Jeeps. I’m not sure about if Texas was one of those states, but a Google search says it was as it requires headlights “on either side” of the motor vehicle. (TXVC547.302) And after measuring the bracket and doing some quick arithmetic of the wheel travel and diameter I can say the bottom of the headlight will definitely be above 24″ from the ground at static ride height if I make the top of the tire just kiss the inside top of the fender with the headlights mounted as high as possible in the fender and the ride height at rest of 6″, or 3″ at full bump travel. Woo! Still legal at minimum frontal area!

I’m not dead yet, this time

The radio silence has not been due to death nor illness, I just lacked anything I could say civilly. As you might have heard we had a major school shooting here in Texas and the major cause is letting hormonally-addled teens have access to just-short-of-military-grade-weapons and unlimited ammo. And both our Senators are blathering about everything except letting hormonally-addled teens have access to high-powered semi-automatic rifles and all the ammo they could afford on their spanking-new credit cards. One even famously blamed doors for the heavily armed teen getting in, and not the laws that allowed the teen to be heavily armed.

Something else that happened that I didn’t want to write about was I fell over backwards the other day, fortunately with no lasting damage other than to my ego. But the efforts I had to make to get back off the floor had me questioning if I would be able to get in and out of the Sprint-T when I finished it. I had planned on climbing the outside of the roll cage and lowering myself through the top of the cage to get in, and the difficulty I had in standing up made me question my ability to perform those acrobatics. Seriously the struggle to stand back up had me wondering if I could get in and out of my dream car. I mean, what good would it do for me to build the car if I can’t even get in it to drive it, plus the balance issues that led to the fall might also be an issue with driving it. I get mistaken for being drunk often enough that it might be a problem when I’m driving.

Another issue that is ongoing is my inability to connect with members of the opposite gender and engage in mutual cuddles and satisfying my need for touch. It’s affecting my ability to concentrate and form sentences. In fact I think I will finish this paragraph and toddle off to bed because I have mush where my language processors should be because of my having touch hunger. I need more hugs and kisses than Mrs. the Poet is capable of providing given her problems with her back and it’s effect on her mobility. And I almost face-planted into the keyboard, I’m also sleep deprived to go along with touch deprived. I’ll catch you later.

I’m on my third pair of underwear tonight

I’m having hip problems that keep me from side-stepping quickly which is how I get from behind my computer. The muscles I need to move my hips from side to side are not functioning to specs the last couple of days, and that keeps me from getting up and going to the toilet as quickly as drinking lots of fluids to prevent kidney stones combined with diuretics to keep my BP down and also not get kidney stones sometimes requires. Basically I’m trapped in a bentwood rocking chair with tall arms and I need to completely stow the keyboard shelf and my laptop under the desk to have room to slide sideways out from under my desk, and sometimes there’s a bind in the sliders and I can’t get everything out of the way in time before the dam breaks and I have soggy underwear. So far I’ve managed to get my pants off in time, but my underwear doesn’t clear the waterworks before the dam bursts, and I have to put on fresh underwear. This is embarassing, but it’s a fact of life when you have hip issues and calcium metabolism issues and blood pressure issues all at the same time, so I just live with it and try to not get caught in places where someone could find out about it.

I’ve been watching YouTube videos related to building the Sprint-T and getting hopeful I might get this thing done before I won’t be able to get in and out of the car because of my hips not working, maybe. Even though I’m still missing an engine, transmission, frame, and all that kinda stuff I have to either buy or build yet. Anyway, I’ve kinda figured out how to make the clutch work so I will be able to make the car start and stop without stalling, but I really wanna know how Indycar makes the clutch on the steering wheel work, because they can slip the clutch or dump it as required from a paddle on the steering wheel where I’m looking at using a handbrake lever to do the same thing. If I could get it done from a paddle on the steering wheel, I could granny shift with the same paddle instead of having to buy a special gearset for the transmission and jam the car into gear without the clutch just lifting the throttle and sticking in the right gear. Looking at the way it’s done by Indycar, I don’t think it’s a viable method for the Sprint-T. Indycar uses an electro-pneumatic system, which has a system not on the Sprint-T to power the clutch declutching, the pneumatic system also used to operate the airjacks that are also not on the Sprint-T. I can’t find anything more than that about the system but as it allows the gradual engagement of the clutch I’m assuming there’s some kind of linear sensor in the paddle on the steering wheel that controls the clutch, and probably a PWM (Pulse Width Modulation) signal to the controlling device for the pneumatic cylinder that drives the clutch to declutch the transmission. As I stated I’m having to exercise my imagination on this because there’s nothing on how this system works beyond “electro-pneumatic clutch” “operated by a paddle on the steering wheel”, in two separate articles, but I can’t figure out any other way for it to work than as I have posted it.

As it stands I’ll have to use both hands to get the car in gear then lift throttle and jam the gearshift either up or down to get the car in the right gear, because I’ll need to use my left hand to work the clutch and my right hand to shift into gear and if the car is moving that leaves no hands to turn the steering wheel, which is illegal in some states and not recommended in most if not all of the rest. Although these same states allow putting critical engine and HVAC controls on a touch screen that requires taking eyes off the road for an extended time so apparently not having a hand on the wheel is a bigger thing than not having eyes on the road.

And I’ve been awake over 22 hours now and I’m getting clumsy at the keyboard and having to fix typos repeatedly, so maybe this is a good time to put this post to bed, and me shortly thereafter.

Another case of nothing to write but a compulsion to write something

The tl;dr version of this post is I feel the need to write, but I don’t have a topic springing to mind at the moment. I think I wanna write about the Sprint-T, but I don’t have anything to say about it, except for how frustrating it is to not have a budget for building this thing.

I have been thinking about also the dedicated A-Mod racer with the aluminum block LS engine sitting next to the driver for the lowest possible polar moment of inertia, because if you can’t do anything with the main project distract yourself with a different project that has even less likelihood of completion than your main project. The idea driving the LS A-Mod is offsetting the engine and transmission to one side and putting the driver next to it but offset the other direction so that the two moments balance out. The exhaust will run over the driver’s legs, and the driver’s butt will be right about even with the rear face of the block. This will mean the engine will be offset about 10″ away from the driver because of having to clear the physical parts of the engine specifically that bellhousing, but the driver could be offset more than the engine. Like I already know how far to move the engine when the driver sits completely behind the engine and there is some left-to-right overlap, it’s just basic algebra to use when they’re side by side. Basically the engine has a moment relative to the driver, the driver has a moment relative to the engine, and the two moments have to add up to 0 when the car is built. This kind of stuff is what I do for fun and relaxation, and I’ll say it first: NEERRRRRD! I’m literally doing a word problem, for fun. Sioux Geonz teaches remedial math to college freshmen and I’m told sometimes links to my blog posts as examples of real-world applications for what she teaches. If it helps, I’m happy with it.

Anyway part of the reason the engine is beside the driver is another moment problem. If the driver is in front of the engine like most formula race cars, it stretches the car out and results in a larger moment than if they are side by side, and for this particular style of racing this makes the car with the larger moment slower than the car with the smaller moment because the smaller moment lets the car change directions quicker. And if your car can change direction quicker then you can cover the distance the direction change has to take place in faster. And as in everything about cars this results in a tradeoff, the driver is exposed to more heat sitting beside the engine than if they are in front of the engine and not under the exhaust. There’s also the location of the cooling system to consider in the heat loading situation, in that there is a greater likelihood of the radiator blowing on the driver with the side-by-side driver-engine configuration because the cooling system is literally hung off the front of the engine and is easier to plumb if the radiator is in front.

And I’m writing right now because I’m trying to not think about the Ukraine, and dinner is ready, so I’m going to put this post to bed now.

Forcing myself to actually care about something

I think that’s something old people have a problem with, finding something to actually give a shit about as they get older. Also I’m dealing with something that’s making my damaged hip hurt, so there’s that, too.

What I have been thinking about for something to do is looking up stuff that might be useful for building the Sprint-T. The price of that upgraded T5 transmission is $3600, this week. But it only weighs 77 pounds, 2 pounds more than the stock T5. That’s pretty good for a 67% increase in rated torque capacity from 300-500 pound-feet. Most of the increase in capacity comes from upgraded materials, with the rest from slightly larger gears.

While I was it it I also looked up the weight difference between the straight axle and the independent front suspension. Actual weight on the tires is about the same, but the ratio of sprung to unsprung weight change is huge, mainly because each wheel only has half of the unsprung weight as opposed to both wheels having all the unsprung weight with the straight axle. If I got my sums right the independent suspension is 5 pounds more than the straight axle, with most of that in the frame where the suspension attaches, brackets and bracing not needed with the straight axle.

There’s also a bit more weight for the moving parts in my design because I like to have the lower arm almost a center pivot with pretty much no change in track with suspension movement. That means there will be some bump steer as the instant center moves during suspension travel and the tie rod can’t point at the point where a line drawn between the upper and lower control arms intersects so it has a different arc than the place where it attaches to the spindle. That also means the lower control arm goes halfway across the car, which makes it heavy. I’m still thinking I want to make the lower arm shorter than that just to reduce weight because it doesn’t make that much difference for the geometry of the front wheel travel. But I’ll have to buy some suspension CAD program to play around with the suspension arms to see where the crossover point between long and short control arms is for the Sprint-T.

And for everybody who reads the tags, the weather today has been wonderful, warm enough to not require heat, but cool enough to not require AC. We get about 2 to 3 weeks like this twice a year here, and we just bask in it. The electric bill is almost nothing as we only have to pay for keeping the water heater going for showers and dishes and washing hands.

Still thinking alert, take cover immediately

J/K there’s no imminent danger. I was thinking of ways to improve the front of the Sprint-T. Also still thinking about the drivetrain with a possible manual transmission.

Starting with the front suspension and related things I decided it might work better if the panhard rod (AKA track bar) was straight. That requires redesigning to the front part of the frame so there is nothing that the panhard rod has to go around to get from the driver’s side of the frame to the passenger side of the front axle. I did this by moving the front diaphragm that carries the loads from the coilovers to the rest of the frame from in front of the axle to behind the axle. This requires moving the steering behind the axle as well as the steering box back to the kit location. This also means the radiator has to be moved back and up to clear the steering shaft from the steering box to the steering wheel. This is how designing a car goes, you can’t just change one thing, it cascades across most of the car. And I forgot to mention the complete redesign of the bumper support structure because the top and bottom frame rails stop at the front axle.

The other thing I was doing was trying to find a lightweight transmission with overdrive, and basically what I found was the Super T-10 couldn’t be made to have an OD without basically redesigning the transmission because the cluster was a solid hunk of steel. Now if it had followed the path of the sister/progeny transmission that used to be called the Nash 4+1 which uses a cluster with replaceable gears, then I could just have a replacement 3rd gearset machined and installed instead of a full replacement cluster. Anywho, the mentioned 4+1 is now the Super Street Five Speed with much higher torque capacity compared with the Super T-10, and extra weight from the structure to resist loads from the increased input.

The 5 speed handles 600 ft-lbs, compared to the 300 to 375 rating for the T-10, and also has a much lower 1st gear (actually several options that are as low or lower than the lowest 1st gear on the T-10). The price for gearing this low and higher torque handling is weight. The 5 speed comes in at 105 pounds compared with 70 for the T-10. Still lighter than any of the self-shifting transmissions with overdrive, by 60-80 pounds, plus it takes up less room inside the car, especially since on the Sprint-T the inside of the floor is also the top of the bellypan and nothing hangs lower than the bellypan, that’s another design paradigm for the Sprint-T.

The top of the bellypan is attached to the bottom of the bottom frame rail, and if there were no bellypan the bottom of the bottom frame rail would be the lowest part of the car except the wheels, because that lets the car be as low as possible without dragging the road if a tire goes flat. Theoretically all 4 tires could go down and the only thing touching the road would be the tires. This requires the road to be pool table flat, but even on normal pavement I can still get both tires on an axle going flat without anything touching anything except tires. I picked this one up from off-road trucks that need to be able to keep going with flat tires.

Anyway, going from a bent panhard rod to a straight one allows a smaller size rod and also allows changing from steel to aluminum, and the combination allows for the drastic reduction in weight of about 2/3, and as half of the panhard rod is unsprung a reduction in unsprung weight as well. This results in a slight increase in grip on bumpy roads and courses as less unsprung weight improves the ability of the tires to follow bumps without leaving the road. This is why I try to reduce unsprung weight every chance I get.