I kept getting woke up by noises and pains. And the odd twinge and muscle spasm.
At least now I’m not bothered by engineering problems I can’t solve without access to a computer for parts information and a calculator for other problems. As in there are multiple OD ratios available for that T5 gearset upgrade and one I think might be too tall for the Sprint-T. That would be the 0.59 ratio that comes standard with the upgraded gearset. With the difference in diameter between the race tires 23″ and the street tires 27″ is like throwing in another gearchange so the top gear spins the tires at like 235 MPH at redline in 5th and dividing that out to convert it to a RPM/MPH and then multiplying by cruise speed gets me below idle RPM until 33 MPH.
I think I’m getting EGT sensors and tuning 200° lean of peak at cruise, for gas mileage. And changing the A/F ratio until I get best average power as determined by idle to redline pulls in 2nd gear. Which means to 61 MPH because that’s what redline in 2nd works out to. So since I don’t need a precise number I can just put the car in 2nd rolling onto the onramp of a freeway and time how long it takes to get to redline from idle in 2nd a few times on the same onramp and change the fueling a bit and try again in a few minutes and see if I’m quicker or slower to redline. I’m sure the people living close to that onramp are going to love my tuning sessions. I should probably make sure I install an effective muffler.
On the frame changes, I think the most structurally efficient way to get the diagonal braces installed is to let the intersection with the hoops curve at the same radius as the bend in the hoops so the diagonals fall in the same plane as the uprights.
And just as I was finishing that thought my computer locked up for about an hour. I couldn’t get the browser to change tasks, or anything else like shut down, or open a file, or pretty much anything except be shiny. And now I’m pretty much about to shut down myself having spent all my spoons trying to get the computer functional I think I’ll finish my beer and take a nap since it’s about 0600 which is functionally like roughly 2200 to me on my sleep schedule. but before I do that I’ll publish this post.
I got a text about my TV antennas, but the tracking ID in the text sends me to the website I bought the antennas from, not tracking my order. The e-mail I got lets me track my stuff, but my first notification was by text and that one doesn’t let me actually do anything except shop for more stuff.
I checked on that unlimited 5G data deal and it has ended before I could take advantage of it, the deal is now $40/month unlimited data, still way less than what I’m paying for internet now. Basically I get a new phone and use it to set up a hot spot next to my laptop and I get 100 Mbs internet which is more than good enough to watch YouTube videos and since it’s bidirectional also more than enough to post to this blog with no problems.
Also still working on that manual transmission in the Sprint-T thing, and it looks like the upgraded T5 is going to cost $2300 no matter which way I come at the problem unless a junkyard sells me a Camaro T5 for scrap value, and I install the Gforce gearset in my garage, in which case I’m still looking at $1800±.
Also I have been making sure I have the arm strength in my left arm to work the hand clutch, by doing wall pushups with my left hand. At this point I’m not doing good pushups because my shoulder is (still) messed up. But I’m getting better as my shoulder gets stronger. Still hurts, but I’m getting better. Looks like I’ll be able to build that 1500 pound race weight car after all.
What we discussed was we are paying $257/month for the bundle, and we could live without it. Like I just got an offer for 5G with unlimited data for $25/month, we could buy an antenna/tuner for way less than $257 for both TVs in the house. I mean sure, we would have to buy two of them but still less than $257 and once we pay for the antenna, that’s it, no more ongoing costs.
So I went to the web site for a local electronics chain and bought antennas for both our TVs for $75. with tax and shipping. We currently spend $257/month for the bundle of internet, cable, and land line we get from our local supplier. We’re going to $25/month for internet via cellphone with slightly slower download but significantly higher upload speed. The upload speed we are paying for now is super slow, barely more than dialup. But since I’m not a gamer I can live with slow uploads. The most bandwidth I use uploading is posting to this blog and leaving comments on webcomics.
I spent most of last night staring at my eyelids or looking at my phone. What happened was I stumbled on a website selling upgraded T5 transmissions that could be shifted without using a clutch or lifting throttle.
Now they didn’t give a torque rating on the upgraded clutchless transmission, just “stronger” than the factory 300 foot-pound rating, and reading about the fragility of the transmission proves that’s a hard limit. Since the engines I’m looking at are much higher rated for output than that the stock T5 is never going to work, but this company sells parts and complete transmissions that claim to greatly increase that throughput.
Sales page for the T5
Of course I had to see how this 75 pound transmission would work for my application including figuring out cruise RPM and how fast the car would go with the “40MPH in 1st” final drive gearing in 2nd (about 70). My mind wasn’t working right when I tried to figure “40 MPH in 1st” to “RPM at 70 MPH cruise in 5th”. I mean I know it’s just comparing ratios, except there are several ratios and I couldn’t get the equation to work out. There is the ratio between RPM and speed, the ratio between the street and race tires, and the ratio between 40 race and 70 MPH cruise. When I’m awake, that’s not a problem, but last night my brain was sleepy and did not work to let me calculate that it would cruise at 1850 RPM at 70 MPH in 5th and not being able to figure that out wouldn’t let me sleep.
But as I was looking for upgrade parts from other manufacturers I found this that has been track-tested at 550 ft-pds without breaking on slicks with a significantly heavier vehicle than the Sprint-T.
G-Force upgraded T5
But anywho I was looking for manual transmissions and stumbled on this: Strong 5-speed transmission. The super low 1st gear option only supports 500 foot-pounds but also only weighs 99 pounds (well all of them weigh the same, but the one with the lowest 1st only takes up to 500 foot-pounds without breaking). And that low ratio 1st gear turns 1860 RPM at 70 MPH in 5th with the same final drive that turns 6000 in 1st with the same final drive. Also tops out in 2nd at 66 MPH with the race tires. Obviously strong and light are not cheap at approx $2600 plus freight and taxes.
We get about 20 or more calls a day on the land line but very seldom are they from actual people. Yes I know this isn’t about building the Sprint-T, or building bicycles, or about getting hit while riding a bicycle. It is about an annoyance plaguing these times: the robocaller.
Seriously, our landline costs us $19.99/month and every time it rings (multiple times a day) I have to hear Mrs. the Poet complain loudly about not wanting to buy the product or support the charity. The noise from Mrs. the Poet is almost worse than the robocalls she complains about.
Now to dump the landline would require some changes, we have had the same phone number since 1996 when they changed us from 214 to 972 but the same 7 digit number since we moved to Garland. So many discount services are tied to that number that would have to change to one or the other of our cell phones.
But thing is both Mrs. the Poet and me have cells, her since she can’t remember when, at least since 2012 when she gave it to me to take on my trip to take care of my Dad after his wreck, and she had had it for over a year or maybe two before then. So, despite her almost never turning it on, she’s had it for ages.
My cell dates from 2012 when I took over the burner phone my elder daughter left behind after visiting from Scotland just before my Dad died. I kept that number until late 2013 when I had to replace that phone and didn’t have the documentation to keep the number on the new phone and ended up with the number I have now which is about to go to its third carrier.
But anywho, it’s not like we don’t have established long-term places of contact, so just changing the numbers our discount accounts are linked to and we save $20 every month. Plus we don’t get multiple robocalls every day. We just need to call a few people we still want to talk to about the change and we’re set.
Yep, I’m still thinking because I can’t “do” because my money is getting spent on other things, like buying windows I can actually see through, and health care. Yes, we are replacing the opaque thermal windows that have degraded so bad that one corner is almost like the insides were painted over. Also paying for seeing a doctor who is not the Lab Rat Keeper.
But that’s not what I was thinking about today. I was thinking about the frame, about how I can make it easier if I make it in bolt-together sections with bolt-in braces that keep the sections rigid, and allow for different suspensions for real A-B-A testing. Like I could build one front clip with the straight axle, and another front clip with independent front suspension, and swap back and forth between the two to get a true comparison. Like swap in a few hours from straight to wobbly.
But the first part will be building the roll cage with the two hoops that are exactly the same size as the body and barely clear it as the body passes through the halo opening in the top of the cage with the bolt-in brace removed. The thing is to route the bracing so that as little needs to be removed as possible to get the body inside after everything gets painted but still braces everything against torsional flexing. What I have is a full cross brace all the way from the left to the right but split to unbolt and allow the body to get through. Then the diagonals run from the corners to the transverse brace in the middle to where the brace is removed for the body to get through. There is not that much vertical thickness to the body so most of the opening can be blocked by the diagonal bracing and still allow the body to get fed through sideways from the top. Just spin the body through the roll axis and let it fall through the halo by overlapping the diagonal bracing.
Don’t forget I have to get through that hole to get in and out of the car. I have been thinking about that and the motions required, where I have to grab and brace my body. From inside getting out is easier than from the outside getting in. Getting out is a matter of bracing my feet against the transmission crossmember on the floor, grabbing the cross brace of the cage and using my legs to push me up against my arms and sitting on the top of the cage and swinging my legs over the side and sliding down until I’m standing outside the car. Getting in requires climbing until I can sit on the side of the cage and swinging my legs over the side and into the car and using the bracing to lower my body into the seat. Anyway I have to get two 12 foot sticks of roll cage material (the 1.5″ diameter 0.120″ wall) and get two legs bent at right angles 46.5″ apart, centered on the stick so I have lots of material to work with to set the height of the cage. The top part of the upper frame rail and diagonal braces are also part of the cage, so they have to be made from the same material. But the front clip can be made from 0.060″ wall tubing which saves a few more pounds.
And I didn’t get good sleep last night, so I’m nodding off at the keyboard. I’ve basically spelled out the changes in the new design, so I’ll put this post and me to bed.
The biggest problem I have now is I lack funds to buy tools and raw stock, or to buy the parts I can’t make. And this frustrates me no end. On the plus side I have time to think about how to do it better, like I recently did by going from a fabricated steel panhard rod to a straight piece of aluminum that weighs less than half as much by moving the frame out of the way.
“Think before doing” is a good maxim to live by, but I have reached the point of “Do something even if it’s wrong!” Or more accurately, “Do something before you can’t do anything!” as my infirmities multiply and grow worse.
At the rate things are going I won’t even be able to get in and out of the Sprint-T after I finish it because I won’t be able to bend at the hip far enough to get past the roll cage. And then I would have a true Greek Tragedy, all that planning and work but unable to harvest the fruits of my labors.
Moving on from self-pity, I’m still trying to find a transmission that will work for the mission of racing around in first gear and hitting redline at 40 MPH but getting good freeway mileage, but still not weighing anything or having to change gearing between racing and highway, and not coming up with any good answers. So far the best (lightest) solution was the 2.43 1st gear Super T-10 and swapping the gears in the quickchange rear to get stupid tall final drive in 4th from the 40 MPH in first ratio. The next best I have found is the Super Street 5 speed with OD that comes in at 35 pounds heavier but has a 3.33 first and a 0.77 5th. No need to swap spur gears to go from redline @40MPH in 1st to cruising at 2068 in 5th @70MPH.
[squirrel!]Excuse me a moment my music app just played The Song That Must Be Played As Loud As Possible (Won’t Get Fooled Again by The Who) and I had to crank my headphones up to 11. Now I have to stuff cotton in my ears to keep the blood from running out.[/squirrel!]
Getting back to the post, one has simplicity in its favor, and the other has lightness on its side. Neither has anything for cost, the cost of buying an extra spur set for the quickchange and the ongoing costs of buying rear end lube for changing the spurgears easily offsets the higher cost of the 5speed. And as I don’t have funds for either one at the moment it’s mox nix. (Or macht nichts in the original German). Also the torque limits on the Super T-10 are so low that even a stock tune L33 will stress the transmission to its limits, except the 2.43 ratio 1st gear model’s 375 foot-pound torque rating is comfortably inside the L33’s 335 foot-pound rated output.
Everything else is marginal to “ain’t no way”. 2.64 1st is 325 foot-pounds (iffy) and the 2.88’s 300 rating and the 3.42’s 266 rating are both “grenade city” except when you pull the pin on a grenade you have a pretty good idea of when it’s going to blow, about 2.5 to 3.5 seconds after you throw it. The 3.42 ratio might last until you floor it or a few seconds after, but the 2.64 is the real question mark. It might last for a season or 2 or blow up while you’re hundreds of miles from the shop and spares with no way to get there. No, if I go with the T-10 the only way to go is the 2.43 1st gear. But that 35 pound weight savings looks sooooo goooood. It’s the difference between 1490 pounds empty and 1525 which is 2.3% and all I have to do is crawl around under the back of the car a few minutes to half an hour before a race and the same amount of time after. It’s tempting as hell.
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.
And it kept me awake until nearly dawn thinking about getting an overdrive for the T-10 by swapping in an OD for 3rd and changing the shifter to allow it to be the new 4th.
In doing my research for this I discovered that the OE 3rd gear is already a slight OD as the ratio between the input and cluster shafts is 1.28:1, while the output from 3rd is 1.23:1, which means the ratio of the gears on the 3rd position of the transmission is already an OD just not very much of an OD, 0.96, probably just a tooth larger on the cluster than the main shaft. It’s looking like I will have to order a custom cluster with a custom gear for the main shaft that is as small as will fit. This is not an inexpensive alternative.
And it’s not like I could amortize the costs by selling duplicates at a profit until the tooling costs are covered. This application is very niche, not many people are in the market for this combination of light weight and OD top gear, and can live with only 4 speeds. Also I have been looking at the ratios in use on the transmission and most of them are not actually useful in making 3rd OD. Swapping the gear for 2nd gives an OD that is not even enough to make the output OD, the gears are 1.25:1 as they are before swapping which is less than the 1.28:1 of the input gears. So basically I’m looking at finding the smallest gear that will fit the output shaft and designing a gear to machine into the 3rd position on the cluster and hoping the resulting ratio is enough to be more overdrive than the underdrive ratio of the input shaft to the cluster. Also most of the different ratios available are just from changing the ratio of the input to the cluster, the 2.43 S cluster, and the 2.64 W cluster are the same ratios except for the input/cluster gear. In fact checking the spares list shows that most of the ratios are shared with common 2nd ratios for the S, W, CC, and Z clusters, common 3rd for S and W, and common 3rd for X, CC, and Y. So yeah, I will have to order a special cluster and gear for the main shaft if I want to hang an OD 3rd on my transmission.
And I have been going back and forth between the PDF of the spares list, the calculator app, and this post for like 4 hours, it’s time to put this one to bed.