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InitialDave posted:The video itself is somewhat underwhelming in how it's shot, but Jesus loving Christ, this Texas Mile run: Dang, what you can hear of that thing sounds fantastic. Oddly enough, I used to live in Victoria, '80-'84. Humidity is even worse than Houston, if you can imagine. At least I know how to get back if I want to attend one of the races.
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Mar 27, 2019 00:17
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| # ? May 31, 2024 01:49 |
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RE: measuring lol horsepower. I was in college trying to start up an FSAE program (long story short, school didn't want to cough up the dough despite incredible profitability potential) and needed a way to measure horsepower on a shoestring budget. The cheapest Dyno we could negotiate was still north of $8k so that was out. We ended up coming up with two solutions. The first was replacing the engine mounts with load cells to measure the torque directly. With engine rpm you could get real brake horsepower. The second was using the ionization of the spark plugs during combustion with a secondary ignition circuit (lower voltage, extremely high frequency) to calculate the actual ignition temperature to plug into a thermodynamic model to measure the power. Both of these are scalable to godly power levels, just need to implement it.
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Mar 27, 2019 00:51
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Both of those methods sound like a huge pain in the rear end.
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Mar 27, 2019 01:29
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In a purpose built race car you probably tear down every other use? Not really. The engineering on the plug ionization current is a little more engineering related but all of the theory is well established. It works on the principle that a flame is conductive. It's conductivity is proportional to it's temperature. If you can send electricity of a known voltage and measure the current, you can determine it's temperature. You then use the temperature as an input for T3 in the Otto cycle. You can directly measure the other 3 temperatures with more direct methods. T1 uses the IAT sensor. You can calculate T2 with adiabatic heating minus the heat removed through the vaporization of fuel. T4 is a measurement of exhaust temperature at the port. You could insert a probe to measure current to get T3, or you can use something that's already there. The spark plugs actually makes things much easier.
um excuse me fucked around with this message at 01:59 on Mar 27, 2019 |
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Mar 27, 2019 01:34
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BMW has used that ionization stuff to measure the speed of the flame front or something for knock detection in the past, I wonder if there is raw access to that data
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Mar 27, 2019 01:42
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You'd want to talk to Delphi. They developed it.
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Mar 27, 2019 01:43
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Right or wrong thread? https://www.autoblog.com/2019/03/25/smyth-performance-vw-beetle-truck-conversion/?ncid=edlinkusauto00000021&yptr=yahoo 
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Mar 27, 2019 04:14
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AEM made a driveshaft dyno you could buy for awhile https://www.aemelectronics.com/files/pr/102811_Dyno-Shaft/Dyno-Shaft_PR.html
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Mar 27, 2019 04:25
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Applebees Appetizer posted:Right or wrong thread? Wrong thread for sure
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Mar 27, 2019 04:31
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Ion sensing gets you cylinder pressure though, which is more useful anyway. It's on my todo list for my dyno.
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Mar 27, 2019 12:24
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jamal posted:AEM made a driveshaft dyno you could buy for awhile I'm not finding a whole lot, but is there some reason why this didn't catch on?
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Mar 27, 2019 14:45
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Applebees Appetizer posted:Right or wrong thread? Seems more Ute than Pickup IMO
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Mar 27, 2019 15:41
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Applebees Appetizer posted:Right or wrong thread? God help me, I don't hate it. And there is historical provenance, apparently: https://www.thetruthaboutcars.com/2010/03/1946-vw-beetle-factory-pickup-with-fifth-wheel-car-hauling-trailer-discovered/  Someone posted a nicely done New Beetle ute a while back. The Smythe one looks on par. edit: found it, I think. The Smythe one is better, but I like this one, aside from the fake patina, somewhat unfortunate wheels and ugly tail lights (all things that are relatively easy to change.) https://www.carscoops.com/2014/12/is-this-one-of-coolest-vw-new-beetles/#lg=1&slide=14   I particularly like the edit edit: nifty tailgate, and the quarter window treatment is useful.  triple edit: Are those reverse lights built into the bed rails? 
Darchangel fucked around with this message at 16:24 on Mar 27, 2019 |
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Mar 27, 2019 16:06
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mekilljoydammit posted:Ion sensing gets you cylinder pressure though, which is more useful anyway. It's on my todo list for my dyno. You can calculate pressure once you have temperature since you know the compression ratio. But the actual mechanics is directly as a result of temperature.
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Mar 27, 2019 16:59
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um excuse me posted:You can calculate pressure once you have temperature since you know the compression ratio. But the actual mechanics is directly as a result of temperature. Your cam is going to have an effect on what the actual cylinder pressure you're seeing is, possibly enough to throw off your numbers. Darchangel posted:God help me, I don't hate it. I kinda like the rusted look, since the rest of the vehicle looks clean. I don't like the artificially-rusted stuff when the rest of the vehicle looks like garbage, I guess it's kind of a going-for-a-specific-look thing versus a I-don't-have-the-ability-to-do-this-well-so-I'm-going-to-make-it-lovely-on-purpose thing in my eyes. I agree with you on the wheels, and also don't like the bright shiny filler cap.
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Mar 27, 2019 18:19
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Time for a masterclass driving video https://newsroom.porsche.com/en/2019/products/porsche-911-gt2-rs-production-car-lap-record-michelin-raceway-road-atlanta-17314.html 173mph down the Road Atlanta back straight in a stock production car. Nah. gently caress that.
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Mar 27, 2019 18:42
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boxen posted:Your cam is going to have an effect on what the actual cylinder pressure you're seeing is, possibly enough to throw off your numbers. Well compression ratio is an over simplification of figuring out cylinder pressure. You do have table in the ECU that reference the volumetric efficiency which take into account cam angles, rpm, intake temps, and head loss. You take that and multiply it by the cylinder volume, then you calculate ignition pressure from there using the compression ratio. When I was doing FSAE development we had an electrical engineer who specialized in integrated circuitry designing an ECU that measured all of the intake variables instead using the look up tables found in most ECUs. The proposed DAQ was very advanced for the time. Half of the tech we developed wasn't in cars yet but can be found in a lot of cars today. um excuse me fucked around with this message at 19:26 on Mar 27, 2019 |
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Mar 27, 2019 19:24
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BlackMK4 posted:Time for a masterclass driving video https://newsroom.porsche.com/en/2019/products/porsche-911-gt2-rs-production-car-lap-record-michelin-raceway-road-atlanta-17314.html Pobst’s balls clank when he walks.
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Mar 27, 2019 21:38
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MrYenko posted:Pobsts balls clank when he walks. I enjoy that it doesn't even get to 7th gear 
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Mar 28, 2019 02:46
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Nuevo posted:I enjoy that it doesn't even get to 7th gear Isn't that a car that doesn't actually reach top speed in 7th, though? I think it's just a super tall overdrive for cruise purposes, too tall to reach top speed with the amount of drag it has. It's not like that's a recent concept, LT1 fourthgens were the same way. 300hp can't pull a 0.5:1 OD in sixth.
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Mar 28, 2019 07:05
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Applebees Appetizer posted:Right or wrong thread? I don't get it, why did you post a bone stock Chevy SSR getting some paint work done?
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Mar 28, 2019 16:34
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IOwnCalculus posted:Isn't that a car that doesn't actually reach top speed in 7th, though? I think it's just a super tall overdrive for cruise purposes, too tall to reach top speed with the amount of drag it has. I read a short review of the new Porsche 911. 8 gear transmission, one more than the previous model. Top speed reached on 6th gear.
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Mar 28, 2019 23:56
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The higher gears are usually just to get the revs down for highway cruising. The corvette's 7 speed has 3 overdrives. 0.74, 0.50, and 0.42. If you're driving it spiritedly, you'll likely only ever use the first 4 gears. That lets it get 25mpg highway through.
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Mar 29, 2019 00:07
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I wish my RS had a seventh gear. It sits at 3 grand on the highway and it gets real annoying.
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Mar 29, 2019 00:26
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Yeah, I think the only "normal" cars I have where you really can rev out in top are Panda 4x4s with 5.4 diff ratios. Most stuff with 5+ gears has overdrive top gear(s). You need some serious power to run out of gears in most cases, they're deliberately over geared for economy/refinement. Though in fairness more gears also lets you do that while af the same time tightening up ratio steps
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Mar 29, 2019 00:31
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KillHour posted:I wish my RS had a seventh gear. It sits at 3 grand on the highway and it gets real annoying. Cut away some fender and stick taller tires on. like 33x10.5s The taller tires have the same effect as lower gearing. The taller tires on my pickup take me down to 1100RPM at 70kph/45mph.
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Mar 29, 2019 00:33
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Sure, I'll just take a sawzall to the sheet metal. I'm sure that will be great for resale.
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Mar 29, 2019 00:34
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3k at highway speeds sounds OK to me? Just how it is with small revvy petrol engines.
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Mar 29, 2019 00:36
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KillHour posted:Sure, I'll just take a sawzall to the sheet metal. I'm sure that will be great for resale. Sure would. 
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Mar 29, 2019 00:36
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i would buy that in a heartbeat 
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Mar 29, 2019 00:38
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Powershift posted:Sure would. There's really well done even though it breaks my heart a little.
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Mar 29, 2019 00:38
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That is very much a render. A gorgeous render, but a render none the less.
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Mar 29, 2019 00:40
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davebo posted:I don't get it, why did you post a bone stock Chevy SSR getting some paint work done? That kit is far better proportioned than an SSR.
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Mar 29, 2019 00:44
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Powershift posted:Sure would.  Elmnt80 posted:That is very much a render. A gorgeous render, but a render none the less. 
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Mar 29, 2019 01:26
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Elmnt80 posted:That is very much a render. A gorgeous render, but a render none the less. Not pretty enough. WHITE LETTERS
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Mar 29, 2019 02:50
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I'd like you to know that while there aren't a ton of people piling up RSs yet I've seen a couple salvage title STs around for $4-6k, and a good used cordless sawzall runs about $60
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Mar 29, 2019 03:05
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KakerMix posted:Not pretty enough. WHITE LETTERS This man speaks true.
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Mar 29, 2019 03:36
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InitialDave posted:3k at highway speeds sounds OK to me? Just how it is with small revvy petrol engines. How it was with 1960s V8s, too.
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Mar 29, 2019 03:45
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Godholio posted:How it was with 1960s V8s, too. Still is, too. E: oh yeah you're the guy with the 327 vette, you know this
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Mar 29, 2019 09:29
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| # ? May 31, 2024 01:49 |
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Lol I'll be happy with 3k. yes it's a Miata
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Mar 29, 2019 15:27
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