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A Supra Good Year [car thread]

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    EinzelEinzel Registered User regular
    Juggernut wrote: »
    I've found it. I've found my car.

    https://youtu.be/zifW8n9O088

    Its a 1948 Dodge Custom, 3 speed manual transmission, inline 6 engine and rear suicide doors.

    She's sitting down in Tampa, Florida for $10,500 and I am in lust.

    That thing is far too interesting for Tampa.

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    JuggernutJuggernut Registered User regular
    That is why I must get it and bring it back to here, Upstate South Carolina which... is... ok its actually even less interesting but still

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    stormbringerstormbringer Registered User regular
    edited September 2020
    Finished up the mechanical and paint on the 550 spyder. Been home from work a lot due to Covid. Still need to do ~70% of the electrical then we can bug hunt for issues. Still missing my aluminum brake covers and a few very small detail pieces. Did get the OG style handbrake and shifter though which looks really good.

    SYBvngk.jpg

    stormbringer on
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    Bendery It Like BeckhamBendery It Like Beckham Hopeless Registered User regular
    my 04 WRX is a patchwork of spliced hoses due to lots of shortcuts and limited access fixes I've put in place over the years. I'm coming up on 200k and have been putting off a TON of maintenance.
    I also just finished paying off all my debt and thought maybe it would be a good time to reignite my car enthusiasm. Researching some of my build options I came to the realization that at this stage in Subaru ownership dropping money on a crate engine is the most economical thing to do. The EJ205 engine in the 04wrx is just not the best thing to build on and has a high failure rate.

    But then I see shit like this and remember I'm actually a child who shouldn't be allowed to have things; https://www.iagperformance.com/IAG-900-Closed-Deck-Long-Block-Subaru-WRX-STI-p/iag-eng-4025.htm
    The one I'm seriously considering is this one ; https://www.iagperformance.com/IAG-Performance-600-Long-Block-Subaru-WRX-STI-p/iag-eng-4010.htm but it sure is hard to not drop the extra $2,000 for zoom zoom numbers when you have financial access to do the things you've wanted to do since you were a stupid teen.

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    Grey GhostGrey Ghost Registered User regular
    Battery died outside the liquor store late last night. got a jump and got it home, had it checked this morning. surprising nobody, the 8-year old original battery in this car was finally toast.

    you are awaited in Valhalla, little guy

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    pimentopimento she/they/pim Registered User regular
    my 04 WRX is a patchwork of spliced hoses due to lots of shortcuts and limited access fixes I've put in place over the years. I'm coming up on 200k and have been putting off a TON of maintenance.
    I also just finished paying off all my debt and thought maybe it would be a good time to reignite my car enthusiasm. Researching some of my build options I came to the realization that at this stage in Subaru ownership dropping money on a crate engine is the most economical thing to do. The EJ205 engine in the 04wrx is just not the best thing to build on and has a high failure rate.

    But then I see shit like this and remember I'm actually a child who shouldn't be allowed to have things; https://www.iagperformance.com/IAG-900-Closed-Deck-Long-Block-Subaru-WRX-STI-p/iag-eng-4025.htm
    The one I'm seriously considering is this one ; https://www.iagperformance.com/IAG-Performance-600-Long-Block-Subaru-WRX-STI-p/iag-eng-4010.htm but it sure is hard to not drop the extra $2,000 for zoom zoom numbers when you have financial access to do the things you've wanted to do since you were a stupid teen.

    I mean, a closed deck engine is definitely going to be more reliable in the long run, and more desirable in the event that you need to sell the vehicle, and also other good reasons that I could make up if you want.

    It's very low on my list of things to do, but it'd be fun to have a built EZ30 for my LGT. Might just have to get on with blowing up the engine that's in there..

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    EinzelEinzel Registered User regular
    but it sure is hard to not drop the extra $2,000 for zoom zoom numbers when you have financial access to do the things you've wanted to do since you were a stupid teen.

    This has been me the past few days when I found out people are making 280ish HP on n/a K24 engines. Then I see they're doing full builds to get there. That's like... lots.

    So I look up supercharger/turbos amd womp womp, those aren't really made anymore.

    I really miss my 323 GT during times like this.

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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    my 04 WRX is a patchwork of spliced hoses due to lots of shortcuts and limited access fixes I've put in place over the years. I'm coming up on 200k and have been putting off a TON of maintenance.
    I also just finished paying off all my debt and thought maybe it would be a good time to reignite my car enthusiasm. Researching some of my build options I came to the realization that at this stage in Subaru ownership dropping money on a crate engine is the most economical thing to do. The EJ205 engine in the 04wrx is just not the best thing to build on and has a high failure rate.

    But then I see shit like this and remember I'm actually a child who shouldn't be allowed to have things; https://www.iagperformance.com/IAG-900-Closed-Deck-Long-Block-Subaru-WRX-STI-p/iag-eng-4025.htm
    The one I'm seriously considering is this one ; https://www.iagperformance.com/IAG-Performance-600-Long-Block-Subaru-WRX-STI-p/iag-eng-4010.htm but it sure is hard to not drop the extra $2,000 for zoom zoom numbers when you have financial access to do the things you've wanted to do since you were a stupid teen.

    If you're really going to get a built engine so you can pump some decent boost into it, get a late model 2.5 litre with the variable valve timing - with a turbo sized to make the same kind of horsepower you would be aiming for from a 2 litre (450-500 wheel horsepower), you'd get much better boost response and far fatter torque curve in the lower rev range. In short, it'll be a much nicer engine to daily.

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    davidsdurionsdavidsdurions Your Trusty Meatshield Panhandle NebraskaRegistered User regular
    Look what I stumbled upon locally here:
    vDCZc2a.jpg

    I had to drive back around the block to snap this picture. I’m definitely jealous of whoever had done this.

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    TefTef Registered User regular
    Hello friends! I would really appreciate some advice.

    My wife and I are looking to buy a new car. She really wants an SUV, I'll take an SUV but would prefer a station wagon. We are in New Zealand, so Japanese imports are the probably the best option for us, as I understand it.

    We love Subarus. I would like an outback station wagon, the missus is looking at a Forester SUV.

    Only real parameters for us:
    $35k NZD max
    4WD/AWD with decent towing capacity (say 2.5t)
    Diesel preferable but not mandatory

    I think honestly I would get a Toyota, probably a Prado but lol good luck with my budget

    help a fellow forumer meet their mental health care needs because USA healthcare sucks!

    Ever tried. Ever failed. No matter. Try again. Fail again. Fail better

    bit.ly/2XQM1ke
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    honoverehonovere Registered User regular
    Look what I stumbled upon locally here:
    vDCZc2a.jpg

    I had to drive back around the block to snap this picture. I’m definitely jealous of whoever had done this.
    Look what I stumbled upon locally here:
    vDCZc2a.jpg

    I had to drive back around the block to snap this picture. I’m definitely jealous of whoever had done this.

    Must be an amazing ride with that movement range for the front suspension

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    pimentopimento she/they/pim Registered User regular
    edited September 2020
    Tef wrote: »
    Hello friends! I would really appreciate some advice.

    My wife and I are looking to buy a new car. She really wants an SUV, I'll take an SUV but would prefer a station wagon. We are in New Zealand, so Japanese imports are the probably the best option for us, as I understand it.

    We love Subarus. I would like an outback station wagon, the missus is looking at a Forester SUV.

    Only real parameters for us:
    $35k NZD max
    4WD/AWD with decent towing capacity (say 2.5t)
    Diesel preferable but not mandatory

    I think honestly I would get a Toyota, probably a Prado but lol good luck with my budget

    Last I heard the diesel Subarus weren't worth bothering with, but that was a while ago. If you're looking at Toyotas, how about a second hand Fortuner (no not a fourunner)? I assume they have those there?

    pimento on
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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    Tef wrote: »
    Hello friends! I would really appreciate some advice.

    My wife and I are looking to buy a new car. She really wants an SUV, I'll take an SUV but would prefer a station wagon. We are in New Zealand, so Japanese imports are the probably the best option for us, as I understand it.

    We love Subarus. I would like an outback station wagon, the missus is looking at a Forester SUV.

    Only real parameters for us:
    $35k NZD max
    4WD/AWD with decent towing capacity (say 2.5t)
    Diesel preferable but not mandatory

    I think honestly I would get a Toyota, probably a Prado but lol good luck with my budget

    Imports, huh?

    ST246 model Caldina GT-Four? You won't be able to tow much with it but otherwise it's a small wagon with ST205 model Celica GT4 Group A Rallye running gear in it.

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    TefTef Registered User regular
    Not many fortuners on the market here second hand that I can find anyway. Numbers, the Caldina might struggle a bit pulling the boat. We have some steep as fuck Hills over here!

    I got sent this one today: https://www.bayswatervehicles.co.nz/stock/details/597922/2019-subaru-xv-used

    How does XV stack up against the Forrester?

    help a fellow forumer meet their mental health care needs because USA healthcare sucks!

    Ever tried. Ever failed. No matter. Try again. Fail again. Fail better

    bit.ly/2XQM1ke
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    pimentopimento she/they/pim Registered User regular
    The XV is a bit smaller but they're real similar mechanically. They're both less powerful than the Caldina though, no turbos available on XVs or current model Forresters.

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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    edited September 2020
    Yeah the Caldina would be a fun daily you can fit a doggo into for trips to the beach, or take for a WRC-inspired thrash down some gravel roads. If you wanna tow a big boat, the best advice I can give you is get in contact with your nearest Isuzu dealer. Even a Landcruiser isn't really suitable for towing 3.0-3.5 tonnes when you get right down to brass tacks. You're going to want an actual truck.

    EDIT: to be perfectly honest, I really don't have much faith in manufacturers towing limits these days. When manufacturers are out there saying dual cab utes weighing two tonnes with rear drum brakes are fine to tow 3.5 tonnes of loaded trailer, I get very fucking suspicious. It only takes the very smallest of compounding environmental factors (light drizzle and moderate winds) and suddenly you're in a "tail wagging the dog" situation where you, your car, all the people in it, and your trailer are all sliding towards the nearest cliff at 100 km/h with no say in what happens next.

    You've just gotta hope the dice roll in your favour and nobody ends up dead.

    Donovan Puppyfucker on
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    jgeisjgeis Registered User regular
    edited September 2020


    Here's a cool one on BaT: a 1 of 1 1980 Mercury Capri widebody with a 1.6L Cosworth-built DOHC I4. It also has some neat little details like heated Recaro seats, functional brake and hood ducts, BBS wheels, and a 9" locking rear diff. These Capris are on the Fox platform, they're essentially just Mustangs with a different body.

    jgeis on
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    mRahmanimRahmani DetroitRegistered User regular
    edited September 2020
    Yeah the Caldina would be a fun daily you can fit a doggo into for trips to the beach, or take for a WRC-inspired thrash down some gravel roads. If you wanna tow a big boat, the best advice I can give you is get in contact with your nearest Isuzu dealer. Even a Landcruiser isn't really suitable for towing 3.0-3.5 tonnes when you get right down to brass tacks. You're going to want an actual truck.

    EDIT: to be perfectly honest, I really don't have much faith in manufacturers towing limits these days. When manufacturers are out there saying dual cab utes weighing two tonnes with rear drum brakes are fine to tow 3.5 tonnes of loaded trailer, I get very fucking suspicious. It only takes the very smallest of compounding environmental factors (light drizzle and moderate winds) and suddenly you're in a "tail wagging the dog" situation where you, your car, all the people in it, and your trailer are all sliding towards the nearest cliff at 100 km/h with no say in what happens next.

    You've just gotta hope the dice roll in your favour and nobody ends up dead.

    It depends pretty heavily on the trailer being properly loaded, a weight distributing hitch, and so on and so forth. That said, under proper circumstances, long-wheelbase pickups can tow pretty impressive loads safely. My Tahoe is rated to 8,000 lbs, and with my dad's 23' boat behind it (~6,000 with the trailer) it drives great. His diesel Silverado is rated for 12,000 I think and is definitely up to the task.

    EDIT: Which manufacturer is still shipping trucks with drum brakes? As far as I know they all went disc around the mid-00s. That said, drum brakes are actually quite capable for towing duty; they offer more friction bite initially, with the downsides of more difficult maintenance and limited cooling. You wouldn't want to ride them down a mountain, but you should be using engine braking to limit speed on downhill grades anyway, not riding the brakes.

    mRahmani on
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    webguy20webguy20 I spend too much time on the Internet Registered User regular
    Yea Im far more worried at the skill of the driver. Its boggling that we have folks hauling around 35’ camping trailers without any additional licensing.

    Steam ID: Webguy20
    Origin ID: Discgolfer27
    Untappd ID: Discgolfer1981
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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    mRahmani wrote: »
    Yeah the Caldina would be a fun daily you can fit a doggo into for trips to the beach, or take for a WRC-inspired thrash down some gravel roads. If you wanna tow a big boat, the best advice I can give you is get in contact with your nearest Isuzu dealer. Even a Landcruiser isn't really suitable for towing 3.0-3.5 tonnes when you get right down to brass tacks. You're going to want an actual truck.

    EDIT: to be perfectly honest, I really don't have much faith in manufacturers towing limits these days. When manufacturers are out there saying dual cab utes weighing two tonnes with rear drum brakes are fine to tow 3.5 tonnes of loaded trailer, I get very fucking suspicious. It only takes the very smallest of compounding environmental factors (light drizzle and moderate winds) and suddenly you're in a "tail wagging the dog" situation where you, your car, all the people in it, and your trailer are all sliding towards the nearest cliff at 100 km/h with no say in what happens next.

    You've just gotta hope the dice roll in your favour and nobody ends up dead.

    It depends pretty heavily on the trailer being properly loaded, a weight distributing hitch, and so on and so forth. That said, under proper circumstances, long-wheelbase pickups can tow pretty impressive loads safely. My Tahoe is rated to 8,000 lbs, and with my dad's 23' boat behind it (~6,000 with the trailer) it drives great. His diesel Silverado is rated for 12,000 I think and is definitely up to the task.

    EDIT: Which manufacturer is still shipping trucks with drum brakes? As far as I know they all went disc around the mid-00s. That said, drum brakes are actually quite capable for towing duty; they offer more friction bite initially, with the downsides of more difficult maintenance and limited cooling. You wouldn't want to ride them down a mountain, but you should be using engine braking to limit speed on downhill grades anyway, not riding the brakes.

    Tef and I are in the Southern hemisphere.

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    SporkAndrewSporkAndrew Registered User, ClubPA regular
    So 3 of my shocks are weeping oil meaning this is the first car I've had that's failed an MOT in 20 years of driving. And I've owned some wrecks

    I'm waiting on an Eibach Pro replacement kit to come in so the garage has given me a 2020 Corolla to putz about in for the next week. It's definitely a car all right. 4 wheels. Goes when you press one pedal, stops when you press another. Certainly the most car car I've driven. Just the epitome of car as an appliance.

    The one about the fucking space hairdresser and the cowboy. He's got a tinfoil pal and a pedal bin
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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    Sounds like a typical Toyota. Camrys and Corollas are extremely good automotive whitegoods. You can drive them places, and as long as you keep them serviced they will last for decades.

    I can't remember the exact year or the exact demographic spread, but I do remember that some time ago the average age of a Corolla driver in Australia was pretty damn close to retirement age. Hence the extremely hard push with new styling and marketing trying desperately to get people under the age of 45 to buy Corollas for the last decade or so.

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    SporkAndrewSporkAndrew Registered User, ClubPA regular
    I can't remember the exact year or the exact demographic spread, but I do remember that some time ago the average age of a Corolla driver in Australia was pretty damn close to retirement age. Hence the extremely hard push with new styling and marketing trying desperately to get people under the age of 45 to buy Corollas for the last decade or so.

    Sounds about right. They're pushing the Corolla hybrids and made them all squinty and mean at the front but at the end of the day it's just automotive creamcheese. It's there, you enjoy it, but it's not exactly memorable

    The one about the fucking space hairdresser and the cowboy. He's got a tinfoil pal and a pedal bin
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    L Ron HowardL Ron Howard The duck MinnesotaRegistered User regular
    To be absolutely honest, I kinda like the new Corolla XSE hatchback. I'd get one with the hyperblue color. And do all kinds of things to it, like lower it and give it a better suspension, turbocharge it, etc.

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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    To be absolutely honest, I kinda like the new Corolla XSE hatchback. I'd get one with the hyperblue color. And do all kinds of things to it, like lower it and give it a better suspension, turbocharge it, etc.

    You could also just buy an 86?

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    L Ron HowardL Ron Howard The duck MinnesotaRegistered User regular
    To be absolutely honest, I kinda like the new Corolla XSE hatchback. I'd get one with the hyperblue color. And do all kinds of things to it, like lower it and give it a better suspension, turbocharge it, etc.

    You could also just buy an 86?

    I know. But part of the point is that the Corolla would be more unexpected to scoot a little fast.

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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    To be absolutely honest, I kinda like the new Corolla XSE hatchback. I'd get one with the hyperblue color. And do all kinds of things to it, like lower it and give it a better suspension, turbocharge it, etc.

    You could also just buy an 86?

    I know. But part of the point is that the Corolla would be more unexpected to scoot a little fast.

    Here in Australia they actually released a turbocharged Corolla "Sportivo" a while back.

    It was like a Corolla, but with a low-boost turbo kit, slightly better coilovers, and stickier tyres.

    And it was at least $15k more expensive than a regular Corolla.

    They sold very few of them.

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    pimentopimento she/they/pim Registered User regular
    Also you can get a Corolla with a proper manual, which is nice.

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    IronKnuckle's GhostIronKnuckle's Ghost Registered User regular
    Corolla sends power to the wrong wheels, though...

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    TallahasseerielTallahasseeriel Registered User regular
    I'm supposed to get my forte into the dealership tomorrow afternoon to get some routine work done

    Except I've been so sick lately. I literally feel asleep sitting up in a chair in a lit room yesterday for an hour. Which is super unlike me. I'm kinda scared to even drive to the dealership.

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    EinzelEinzel Registered User regular
    edited September 2020
    The most tragic of modern Toyotas to me is the C-HR. It actually looks *good. But then it drives like an unenthusiastic golf cart.

    * by Toyota standards that for the past decade have been "bad Japanese tuner bodykit"

    Einzel on
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    mRahmanimRahmani DetroitRegistered User regular
    mRahmani wrote: »
    Another fun work story for you guys:
    If you’ve done any programming, you’re familiar with edge cases. Division, for example: you can punch any two numbers in to a division calculation, but if the second number is 0 it’s going to break. This applies just as much to brake control software as it does to any other kind of software.

    I’m working on traction control for a certain large 4WD vehicle. During the summer, we simulate ice and snow with wet ceramic or basalt tiles. Figure a stretch of ceramic tiles two lanes wide, two lanes of concrete, and two lanes of basalt tiles. Each lane has a row of sprinklers that allow us to simulate polished ice, packed snow, wet asphalt, or dry asphalt.

    A major part of our testing is dealing with the aforementioned edge cases. Tonight I was collecting data on split surface 4WD launches (2 wheels on ice, 2 wheels on concrete.) Pull onto the tiles, stop, begin recording data, and do a WOT launch down the tiles. We have certain acceleration and wheel slip targets the vehicle has to hit for production.

    Accel needed some adjustment but generally worked. Kept the throttle floored most of the way down the strip and then hit the brakes.

    Nothing happened.

    If you’ve driven a lot in the winter, or maybe aggressively on track, you might have heard the term “ice mode.” It’s a condition where the brake system detects such low amounts of grip that it virtually freezes the brake pedal to prevent too much pressure being applied, in an attempt to keep the wheels from locking up. You can stomp the pedal as hard as you want, but it won’t budge until the brake system determines there’s enough grip to allow more brake pressure.

    So anyway, I yeeted our million dollar prototype truck off the end of the track and into the weeds today.

    Truck is fine, I’m fine... my pants are not!

    So the solution to this problem ended up being trivial, but the root cause was pretty interesting. Spoilers for long engineering talk.
    The only information we really have on a vehicle’s velocity is based on wheel speed sensors and g sensors. Which is to say, we can really only guess how fast a car is moving at any time. Seems obvious, but isn’t something you think about very often. We have what’s called a “reference velocity” which is our current estimate of the actual vehicle speed, and we have “wheel speed” which is how fast the wheels are spinning.

    For four wheel drive vehicles, speed estimation is very tricky. If you launch a 4WD on ice, all four wheels start spinning, so wheel speeds are useless. You can fall back to the g sensor to roughly guess your speed, but if you have any steering inputs that can get thrown off pretty easily. Fortunately, 4-wheel-spin conditions rarely last long, and with a bunch of complicated logic you can usually regain an accurate estimate quickly once one or two of the wheels stops spinning.

    Two wheel drive vehicles, on the other hand, are very simple: whatever speeds the non-driven wheels are moving are usually a good indicator of your actual speed. If you have a 1,000 hp RWD car doing a huge burnout, the car is still only moving as fast as the front wheels are spinning.

    In the case of this test, I was running in 4WD with the left side tires on simulated ice. There were no locking diffs or LSDs, so the left side wheels spun up really fast while the right side kind of meandered along.

    The bug: Vehicle incorrectly identified drive state. The chassis was in 4WD, but the BCM thought it was still in 2WD.

    The result is that the truck used the two wheel drive logic to estimate speed. It saw a sustained high speed on one of the front wheels, determined that the only way to attain that speed was for the vehicle to actually travel that fast, and set that as the reference velocity. When I released the throttle, the two left wheels stopped spinning and dropped to match the speed of the right wheels... but the reference velocity takes longer to drop, so it stayed high.

    When I applied the brake, the software registered a high reference velocity but low wheel speeds - something that under normal operation means the wheels are locked and sliding. It blocked off hydraulic pressure to the brakes to try and release the “locked wheels” until the reference velocity finally matched up with wheel speed again.

    Complicated cause; simple solution.

  • Options
    QuantumTurkQuantumTurk Registered User regular
    Einzel wrote: »
    Juggernut wrote: »
    I've found it. I've found my car.

    https://youtu.be/zifW8n9O088

    Its a 1948 Dodge Custom, 3 speed manual transmission, inline 6 engine and rear suicide doors.

    She's sitting down in Tampa, Florida for $10,500 and I am in lust.

    That thing is far too interesting for Tampa.

    That is SO much cheaper than I'd have guessed. I assume you couldn't really daily it.

  • Options
    L Ron HowardL Ron Howard The duck MinnesotaRegistered User regular
    mRahmani wrote: »
    mRahmani wrote: »
    Another fun work story for you guys:
    If you’ve done any programming, you’re familiar with edge cases. Division, for example: you can punch any two numbers in to a division calculation, but if the second number is 0 it’s going to break. This applies just as much to brake control software as it does to any other kind of software.

    I’m working on traction control for a certain large 4WD vehicle. During the summer, we simulate ice and snow with wet ceramic or basalt tiles. Figure a stretch of ceramic tiles two lanes wide, two lanes of concrete, and two lanes of basalt tiles. Each lane has a row of sprinklers that allow us to simulate polished ice, packed snow, wet asphalt, or dry asphalt.

    A major part of our testing is dealing with the aforementioned edge cases. Tonight I was collecting data on split surface 4WD launches (2 wheels on ice, 2 wheels on concrete.) Pull onto the tiles, stop, begin recording data, and do a WOT launch down the tiles. We have certain acceleration and wheel slip targets the vehicle has to hit for production.

    Accel needed some adjustment but generally worked. Kept the throttle floored most of the way down the strip and then hit the brakes.

    Nothing happened.

    If you’ve driven a lot in the winter, or maybe aggressively on track, you might have heard the term “ice mode.” It’s a condition where the brake system detects such low amounts of grip that it virtually freezes the brake pedal to prevent too much pressure being applied, in an attempt to keep the wheels from locking up. You can stomp the pedal as hard as you want, but it won’t budge until the brake system determines there’s enough grip to allow more brake pressure.

    So anyway, I yeeted our million dollar prototype truck off the end of the track and into the weeds today.

    Truck is fine, I’m fine... my pants are not!

    So the solution to this problem ended up being trivial, but the root cause was pretty interesting. Spoilers for long engineering talk.
    The only information we really have on a vehicle’s velocity is based on wheel speed sensors and g sensors. Which is to say, we can really only guess how fast a car is moving at any time. Seems obvious, but isn’t something you think about very often. We have what’s called a “reference velocity” which is our current estimate of the actual vehicle speed, and we have “wheel speed” which is how fast the wheels are spinning.

    For four wheel drive vehicles, speed estimation is very tricky. If you launch a 4WD on ice, all four wheels start spinning, so wheel speeds are useless. You can fall back to the g sensor to roughly guess your speed, but if you have any steering inputs that can get thrown off pretty easily. Fortunately, 4-wheel-spin conditions rarely last long, and with a bunch of complicated logic you can usually regain an accurate estimate quickly once one or two of the wheels stops spinning.

    Two wheel drive vehicles, on the other hand, are very simple: whatever speeds the non-driven wheels are moving are usually a good indicator of your actual speed. If you have a 1,000 hp RWD car doing a huge burnout, the car is still only moving as fast as the front wheels are spinning.

    In the case of this test, I was running in 4WD with the left side tires on simulated ice. There were no locking diffs or LSDs, so the left side wheels spun up really fast while the right side kind of meandered along.

    The bug: Vehicle incorrectly identified drive state. The chassis was in 4WD, but the BCM thought it was still in 2WD.

    The result is that the truck used the two wheel drive logic to estimate speed. It saw a sustained high speed on one of the front wheels, determined that the only way to attain that speed was for the vehicle to actually travel that fast, and set that as the reference velocity. When I released the throttle, the two left wheels stopped spinning and dropped to match the speed of the right wheels... but the reference velocity takes longer to drop, so it stayed high.

    When I applied the brake, the software registered a high reference velocity but low wheel speeds - something that under normal operation means the wheels are locked and sliding. It blocked off hydraulic pressure to the brakes to try and release the “locked wheels” until the reference velocity finally matched up with wheel speed again.

    Complicated cause; simple solution.

    May I ask why not have a backup of GPS for speed calculation? I mean, every second or two could help reinforce the G meter?

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    mRahmanimRahmani DetroitRegistered User regular
    Vehicles may have onboard GPS for navigation, but I’m not aware of any that are using it for speed calculation as well. You would need to convince the OEM that the cost of the GPS is worth the performance benefit, and the only time reference velocity is generally an issue is low speed on slippery surfaces, and only on 4WD vehicles. If the software had correctly recognized that the truck was operating in 4WD, it would have correctly estimated the reference velocity based on the right side wheels, and there wouldn’t have been an issue.

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    Donovan PuppyfuckerDonovan Puppyfucker A dagger in the dark is worth a thousand swords in the morningRegistered User regular
    So what is the actual solution? Referencing wheel acceleration rates? Two 6-axis accelerometers so you can account for vehicle movement better?

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    mRahmanimRahmani DetroitRegistered User regular
    edited September 2020
    We already measure wheel acceleration and have access to the SRS accelerometer data, it’s just a matter of interpreting it correctly. The actual solution is to fix the missing CAN message to tell the BCM we were in 4WD. Once that’s in place, the correct speed estimation method gets used.

    That’s something that ultimately needs to be resolved by the OEM powertrain team, but I can work around it for now by manually setting the 4WD flag.

    mRahmani on
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    Bendery It Like BeckhamBendery It Like Beckham Hopeless Registered User regular
    my 04 WRX is a patchwork of spliced hoses due to lots of shortcuts and limited access fixes I've put in place over the years. I'm coming up on 200k and have been putting off a TON of maintenance.
    I also just finished paying off all my debt and thought maybe it would be a good time to reignite my car enthusiasm. Researching some of my build options I came to the realization that at this stage in Subaru ownership dropping money on a crate engine is the most economical thing to do. The EJ205 engine in the 04wrx is just not the best thing to build on and has a high failure rate.

    But then I see shit like this and remember I'm actually a child who shouldn't be allowed to have things; https://www.iagperformance.com/IAG-900-Closed-Deck-Long-Block-Subaru-WRX-STI-p/iag-eng-4025.htm
    The one I'm seriously considering is this one ; https://www.iagperformance.com/IAG-Performance-600-Long-Block-Subaru-WRX-STI-p/iag-eng-4010.htm but it sure is hard to not drop the extra $2,000 for zoom zoom numbers when you have financial access to do the things you've wanted to do since you were a stupid teen.

    If you're really going to get a built engine so you can pump some decent boost into it, get a late model 2.5 litre with the variable valve timing - with a turbo sized to make the same kind of horsepower you would be aiming for from a 2 litre (450-500 wheel horsepower), you'd get much better boost response and far fatter torque curve in the lower rev range. In short, it'll be a much nicer engine to daily.

    I also had this thought, there is sentimental value in the car so i originally wanted to build it up, but as I look at myself in the mirror the kid who's fine fixing his car every weekend doesn't have time for that shit.

    the '22 STI is rumored to be based on the FA24 platform, I can wait.

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    TefTef Registered User regular
    Found a decent price on a 2016 Toyota Rav4 GXL. It’s my current front runner, I haven’t been able to find a Subaru Outback or XV that doesn’t cost $Texas

    help a fellow forumer meet their mental health care needs because USA healthcare sucks!

    Ever tried. Ever failed. No matter. Try again. Fail again. Fail better

    bit.ly/2XQM1ke
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    m!ttensm!ttens he/himRegistered User regular
    The thread title reminded me that I saw my first Supra in the wild today. It was matte/satin finish grey with some glossy red accent pieces (brakes for sure, maybe a pinstripe or spoiler?) and it looked real nice cruising down the freeway.

    The last few days I've seen some interesting vehicles/paintjobs. Considering I live in the midwest, exotic cars are pretty damn rare, but I saw a Bentley Continental convertible, the Supra listed above, not one but two color shift painted Mustangs (one was Orange/Purple and the other one was Purple/Black), and finally my favorite ridiculous paint job: a white BMW X3 with (painted/decaled/wrapped) the Louis Vuitton monogram pattern all over it, so delightfully tacky :biggrin:

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