|
I live vicariously through your engineering and noodling. I know we are in the same general local and would be up for talking poo poo about cars in person over a beer or something since we travel near the same circles. I was in Waukesha two weeks ago for a wedding and spent most of my day at Veloce waiting for the event to get going. It was well worth the money spent and really got me charged for working on car stuff over the winter.
|
#
?
Oct 11, 2018 00:29
|
|
|
|
| # ? May 10, 2024 18:43 |
|
|
I'm totally game. Out of town for work until Monday though - down in Florida by Okeechobee testing railway maintenance equipment on a customer's rails. Heat and humidity aren't that bad but boy what an interesting smell the cane fields have.
|
|
#
?
Oct 13, 2018 21:04
|
|
|
So, new portable workstation laptop thing showed up. https://www.userbenchmark.com/UserRun/11633355 Yeah, I'm pretty OK with this. Now to get all of my stuff on it.
|
|
#
?
Oct 23, 2018 01:14
|
|
|
OK, what the heck. Been almost a month. Started on a GT-3 revision of the chassis. Anecdotally, someone commented about their chassis being in the 150 pound range, whereas I was about double that... so doing a bunch of recalibrating for where I want to be. No, I don't know that the lighter chassis is properly designed etc, but I don't want to have an overweight car and I'm an overweight driver so that goes double.  Work trip starting tomorrow... will get some personal design work done in the hotel room, likely.
|
|
#
?
Nov 13, 2018 02:44
|
|
|
 So there's the lightweighted version. The darker colored tubes are the required safety structure with is 0.095" wall tube, the rest is thinner. Managed to cut about 200 pounds out of it. Stiffness is down by a third, but I figure that's OK.
|
|
#
?
Dec 26, 2018 16:30
|
|
|
Stupid question time: Why the door bar laterals, x-bracing, plus the anti-intrusion? ... and the v-braced windshield area?
|
|
#
?
Dec 28, 2018 19:43
|
|
|
That's not a stupid question at all. The "NASCAR" door bars are the actual side impact protection - the diagonal X inside them is for stiffness. The driver's right arm will actually go outside the plane of those X bars so the side impact stuff is important. The windshield V is huge for stiffness - dropping those tubes alone cuts stiffness by something like 20%
|
|
#
?
Dec 28, 2018 23:14
|
|
|
mekilljoydammit posted:The windshield V is huge for stiffness - dropping those tubes alone cuts stiffness by something like 20% I'm genuinely interested in what lead you to here given the field of view tradeoffs. Care to say what that 20% means in terms of chassis flex? Is it a safety rating thing?
|
|
#
?
Dec 29, 2018 19:21
|
|
|
Well, there's already a rules requirement to have stuff to keep the windshield from coming inwards if it's not glass. It's a bit of an obstruction but for me anyway, I'm pretty confident that I'll just end up looking past stuff at that distance. I went to the Trans Am pro race at Road America this year and poked around the new Weaver Challenger that Boris Said was driving and that's what got me thinking about that style, but I've seen a bunch of other attempts at triangulating the windshield. The chassis stiffness point is a performance thing not a safety thing per se. See, if you think about it, the suspension and chassis are basically two springs in series. Unlike the suspension though, the chassis isn't damped by shock absorbers and it's not flexing in any useful way so having too flexy of a chassis can end up with a lot of weird effects. As a rule of thumb, you want the chassis about an order of magnitude stiffer than the suspension - theoretically it's still flexing but its contribution to things can be ignored. The point is you want enough stiffness without too much weight. Big openings are inefficient because they can just fold over so you want to triangulate them wherever you can - so the V across the windshield ties the shock mount diagonals that go up to the dash bar to the upper safety structure.
|
|
#
?
Dec 29, 2018 20:42
|
|
|
Suppose I should get off my rear end and stop going to the old stuff races and check out some of the new stuff races. Looks pretty interesting and that there is a lot to learn.
|
|
#
?
Jan 2, 2019 03:24
|
|
|
Trans Am was fun - I try to go to the June Sprints and the BRIC (er, the WeatherTech® International Challenge with Brian Redman presented by HAWK or whatever it's called next year) in addition to the Council stuff where I'm hopefully driving. The big thing is that if you start thinking about load paths and stuff... well, OK. Design of tube structures follows from aircraft principles - the best practices were figured out in the 30s even if it took Chapman (OK probably a bunch of others but nevermind) to bring it in a serious way to cars. How seriously car frame designers pay attention depends based on sort of cars. Formula cars caught on really fast, GT-style cars it sometimes took longer. Trans Am is the biggest budget venue for tube chassis silhouette roadrace cars in this country, so I look at what they do. I have a directory where I've compiled every frame picture of every post-86 (when they went to tube chassis) Trans Am car I can find along with some other well executed tube chassis cars. There's a bunch of little subtle differences between say, an early 90s Riley & Scott and a 2018 Meissen or Weaver chassis, though part of that's the fact that they made some compromises to the R&S back in the day to be able to affordably make a lot of them. The Roush cars seem ahead of their time in taking an effort to triangulate stuff, for example, probably because they were an inhouse effort and not trying to sell the cars at a profit.
|
|
#
?
Jan 2, 2019 03:58
|
|
|
The Mustang GT cars from the BRIC Hawk Redman Challenge in group 10 are always rad as hell. The Morgan +8 GT-R was an aluminum monocoque development mule and while I got to see it up close and personal for years the only thing that had tubes about it was the cage. I'll keep you posted this year on what events I'll be attending. If we are doing council weekends it's always wheel to wheel. Typically the VSCDA/Council weekend at Blackhawk, BRIC, Fall Festival.
|
|
#
?
Jan 2, 2019 19:42
|
|
|
I'll see how much I can actually afford to drive, given kid's scheduled to show up in the middle of April.
|
|
#
?
Jan 3, 2019 00:22
|
|
|
Oops, fixed link. Cnc router so far. Cool thing is design is easily expandable once we prove it out. One proposed use is feed it 4x8 sheets of foam to carve bodywork in 2" slices. mekilljoydammit fucked around with this message at 01:45 on Jan 5, 2019 |
|
#
?
Jan 4, 2019 15:11
|
|
|
gently caress yes, that is going to be sick when it's finished.
|
|
#
?
Jan 5, 2019 02:33
|
|
|
Well, because I'm nuts... started digging into what the Ferrar 308 V12 guy was doing for engine management and it's really clever - the background functions are programmed and tested plus the hardware's tested (I mean it's used in AEM Infinity) but you can go define algorithms used to define everything. The big thing I want to do is start having closed loop no lift upshift but for education purposes I think I might go implement the Subaru 16bit algorithm.
|
|
#
?
Jan 26, 2019 19:40
|
|
|
Heh, saw you in the thread. That ecu is intriguing, from the description. I haven’t gone to actually look at it yet, though. Sounded like it’s some sort of block programming? You don’t have to “code” per se, but define inputs outputs and conditions, and chain all that together?
|
|
#
?
Jan 26, 2019 20:46
|
|
|
So what it basically works out to is that everything is built up in terms of channels, physical or virtual. So say, you define "this channel is MAP and from this sensor with such and such calibration" and "RPM comes in here" then have a channel "VE" where it's a 2d lookup table, then feed that into an channel "fuel to inject" which has an algorithm with however many variables. So you kinda proceed with stuff like that and in the end you end up feeding an answer to some basic functions that exist - "OK, such and such msec of injector at so and so crank angle" It's cool because it lets you think in terms of "OK, at each step I'm going to calculate this value from these other values" in whatever way makes sense to you, without dealing with the underlying code to do basic stuff like calculate crank angle from whatever trigger wheel you defined or have code to accurately schedule when stuff happens.
|
|
#
?
Jan 26, 2019 22:16
|
|
|
That sounds pretty neat. Kind of a flow chart, really. Cool. Will look into that, just for curiosity’s sake if nothing else.
|
|
#
?
Jan 26, 2019 23:48
|
|
|
Anti-archives bump... been doing hot sauce stuff to keep busy since funds are tight. Narrowing in on a hot chipotle recipe inspired by Cutino's Chipotle sauce but different. And then decided to grow some peppers. This afternoon's project. 12 different varieties planted. A lot of jalapenos of a couple different varieties plus two varieties of Scotch Bonnet, two of Habanero, Serranos, Aji Colorados, Aleppos, 7 Pot Browns, Chocolate Scorpions and because gently caress it, Carolina Reapers too. I'm narrowing in on my first recipe, which is supermarket based but tasty - got the idea for Cutino's Chipotle but diverged significantly. Chipotle, pineapple, habaneros, all sorts of good stuff. Working on figuring out some hard parts for the dyno; that's a big thing I want to get done this year. But kid's due on April 21st so we'll see how much that gets done.
|
|
#
?
Mar 4, 2019 00:23
|
|
|
Another bump. Kid due in about a week - scheduled c-section. Excited as heck. Decided to take a step back to an EProd car... it helps I have a lot of the stuff. One thing though is that there's not a lot of options for good 1st gen RX-7 struts. See, it's one of those old styles where the tube is pressed into the knuckle forging, and too small to take advantage of stuff like good inserts. My solution? I'm finally starting work on a development project I've wanted to do for years - linear bearing guided inverted monotube with a hybrid of Bilstein and Penske parts. KW does the same idea on their really high end struts - basically if I make custom shock pistons (relatively simple to have CNC'd, I already have done piston designs, or I could honestly even manually machine them) and a few other little bits, I can fit off the shelf Penske adjustable shafts (I can't make them due to needing gun drilling) with Penske adjustable canisters (I can't make them for what Penske is charging so screw it) into Bilstein strut tubes (precision honed tube with hard chromed outer - I can't make that either) and attach the whole thing to a 1st gen RX-7 knuckle. Going on with that is refining the cambered floating rear hub I knocked out a while back. There's kind of two big things about why setting the GT chassis aside... GT-3 isn't a healthy class in terms of participation numbers, and EProd is, and I already have unibodies I stripped down for EProd... which would require caging but I have the stuff, it just takes putting time in here and there. Does mean I have to go carbureted though, ugh.
|
|
#
?
Apr 14, 2019 19:29
|
|
|
mekilljoydammit posted:Another bump. GL! And  about those race car plans taking shape any time soon now. (but still sounds neat)
|
|
#
?
Apr 15, 2019 13:02
|
|
|
Suburban Dad posted:GL! There's a reason it's going from "thing where there's parts that need doing in big chunks to be even car shaped" to "thing where I can get smaller parts knocked out every so often". I can do cad stuff in hotel rooms while traveling for work, every so often fab something, and maybe slowly get there. No idea on what "slowly" works out to but I go nutty without technical projects.
|
|
#
?
Apr 15, 2019 18:33
|
|
|
mekilljoydammit posted:Another bump. OK, this is stuff I want to see. I may have the last set of new-in-box Tokico Illuminas in existence, and I only have the front set. And I may not use those, since I have a line on a roller FB and a mess of parts if I can sell of the AE86 I don't want.
|
|
#
?
Apr 16, 2019 21:33
|
|
|
We put a couple of those fancy sets of KWs on some evo race cars back in the day. They're neat. It looks like an inverted shock but that big shaft is actually just a reinforcement sleeve that rides on the bearings and comes right out. It's a standard non-inverted monotube (not twin-tube like the variant series and clubsports) underneath. And then exe-tc does this with actual big rollers  I assume that must need a big boot over the whole thing to not just have dirt and rocks get jammed up in it. And stiction is real and significant. Drive an sti with inverted struts or ride a mountain bike and you can feel it. My fork feels completely different and much smoother right after a service when the bushings and air shaft have fresh grease all up in them. jamal fucked around with this message at 22:19 on Apr 16, 2019 |
|
#
?
Apr 16, 2019 22:15
|
|
|
The EXE-TC style solution is plan B; honestly I think for circuit racing I won't beat the hell out of things to the same extent rally does. The rollers and sourcing bearings are really kind of a pain for a 40mm-ish inverted strut. I really don't know why KW does things like that unless maybe it's just to have the reservoir there vs coming out the strut tower somewhere, but if you can avoid having the oil and reservoir being unsprung weight I don't get why you wouldn't. If I had infinite money to throw at things I'd just spring for either Ohlins TTX46 MT struts, or Multimatic's spool valve equivalent, but good lord that's a lot of money. One nice thing about DIY piston/valving is I can violate patents as long as I'm not selling things - the Penske regressive valve, for example, isn't actually that complicated. edit: Oh yeah, while I could just sit and do my own version, just throwing money at http://www.raceproducts.net/mazda-rx7-400-series-bolt-on-camber-kit/index.html is kind of tempting in a "it will definitely work" sense - especially since all machining said and done it's probably not that much more expensive than making my own if I put any value on my time.
|
|
#
?
Apr 16, 2019 23:22
|
|
|
mekilljoydammit posted:edit: Oh yeah, while I could just sit and do my own version, just throwing money at http://www.raceproducts.net/mazda-rx7-400-series-bolt-on-camber-kit/index.html is kind of tempting in a "it will definitely work" sense - especially since all machining said and done it's probably not that much more expensive than making my own if I put any value on my time. OK, that's pretty cool right there.
|
|
#
?
Apr 16, 2019 23:54
|
|
|
Yeah an inverted strut where the insert rides directly on linear bearings would be simpler and drop unsprung weight a good amount. But that huge sleeve does offer more rigidity. These were a rally thing and it could be they wanted the canister attached so there was no hose to get torn up. I don't think they make those anymore, that was like 10 years ago and there were only like 2 sets around that I know of. My question is if you would go through this much effort with a strut, could you just convert to double a-arms instead? There's a guy on the brz forums who is grafting rx-8 front suspension onto his, I think he got the idea from the hks car. I had a plan to do something similar on a subaru a long time ago, just by mounting an upper a-arm to the chassis rails and keeping the upright and LCA although I didn't ever model it all out to see if it would work decently. I think that is how the factory five 818 stuff works- just a big bracket that bolts to the strut mount on the upright and holds a ball joint pin. jamal fucked around with this message at 02:57 on Apr 17, 2019 |
|
#
?
Apr 17, 2019 02:43
|
|
|
jamal posted:My question is if you would go through this much effort with a strut, could you just convert to double a-arms instead? Within the scope of the rules, no. It would be so very much cheaper and easier if I could.
|
|
#
?
Apr 17, 2019 03:02
|
|
|
Kid was born this morning via scheduled c-section. Audrey Maya *redacted*; 7 pounds 15 ounces, 21". She and my wife are recovering well.
|
|
#
?
Apr 22, 2019 23:41
|
|
|
*cue overly complicated designs for baby stroller powered by a insane fusion of rotary and EJ20* Congrats mate and I hope it all continues to go well
|
|
#
?
Apr 23, 2019 00:49
|
|
|
Congrats! Goodbye time and money  .
|
|
#
?
Apr 23, 2019 00:52
|
|
|
Congrats dude!
|
|
#
?
Apr 23, 2019 01:58
|
|
|
Congrats!
|
|
#
?
Apr 23, 2019 22:12
|
|
|
Congrats!
|
|
#
?
Apr 23, 2019 23:12
|
|
|
Congratulations!
|
|
#
?
Apr 24, 2019 01:49
|
|
|
The next generation of rotary enthusiasts has a new queen. Congrats, glad it went well.
|
|
#
?
Apr 24, 2019 12:20
|
|
|
mekilljoydammit posted:Kid was born this morning via scheduled c-section. Audrey Maya *redacted*; 7 pounds 15 ounces, 21". She and my wife are recovering well. Congratulations! That first birthday cake better be a rotor!
|
|
#
?
Apr 24, 2019 14:58
|
|
|
sharkytm posted:The next generation of rotary enthusiasts has a new queen. Congrats, glad it went well. Hey now, I'm not going to push her into this insane path I'm walking... if she is into any other sort of high revving engine I'll accept and love her all the same. (or honestly if she's not even into cars but I can always hope)
|
|
#
?
Apr 24, 2019 15:06
|
|
|
|
| # ? May 10, 2024 18:43 |
|
|
Congrats! And yeah, I was a trifle disappointed when my daughter proved to be excited by mechanical things, but expected it. She did at least "help" me with a few projects when she was a toddler. My favorite baby picture of her is from when she stuck a lug nut on each finger and held up her hands. also, I want to believe that your actual last name is *redacted*. edit: 
Darchangel fucked around with this message at 23:13 on Apr 26, 2019 |
|
#
?
Apr 26, 2019 23:10
|
|