Also, the Torque app works with the Shelby computer, so logging can work that way fairly easily.
That's good to know. I thought there were issues with the PID list from the Shelby or something. I guess that's why I never even tried it.
On a related topic; I have an external WBO2, but should I have at least one NBO2 connected to the computer? I'm not sure why or how I overlooked that, but I don't have the factory O2s installed. Would I need both if you recommend putting them in? I don't have a cat, though I'm likely to redo my exhaust over the winter. I've been told that upon letting off the throttle after applying large-ish amounts, I spit some pretty gnarly flames. I'd like to see that. Maybe I should rig up the GoPro for some flamethrower shots. Gotta love that disabled DFCO.
Unrelated; I got those Triumph throttle bodies. I think they'll work alright. There's a bunch that I like about them and a few things that I really don't care for.
Things that I like include symmetry.
That is three of the four bodies. They are effectively identical, save for one butterfly shaft boss that is approximately .250" longer than the other two, illustrated below. Fortunately it’ll be on the underside of the intake, so not a deal breaker.
Hopefully, I'm able to shave that back on the lathe and then they can all be identical.
The fourth body is another story. It's got a large, awkward boss cast into it for the TPS, which I don't need. It'll be tough to get rid of, so I'll just get a third set of bodies and use the inner two for the fourth in each set. Me like symmetrical.
So, the bodies will be rotated 90° such that the butterfly shafts are mostly vertical, perpendicular to each other. I'm basically attempting to replicate closely that Kinsler LS setup at this point.
Of course there is some stuff about the bodies that I don't care for.
These are 37-38mm Mikuni bodies. They measure 37mm and change, but there's a '38' stamped on one of the bodies somewhere. So...who knows? Either way that's a bit small, so I'll bore them out to 40mm on the lathe. I've got those 40mm throttle plates from the GSX-R Mikunis, so I'll just steal those I suppose. Less work than making new ones, anyway. The retention bolt holes even line up almost perfectly. Minimal work with a file there, if anything.
The last two photos indicate the lack of diametric clearance for the 40mm plates in the Triumph shafts. This should be easily remedied by a thin file or blade. The slot is, for all intents and purposes, .063" thick - perfect for the GSX-R blades, but I need approximately .033" extra width on each side [total .065"] to clear the larger blades.
Speaking of the butterfly shafts, they're 8mm versus the GSX-R’s 10mm. I don't really mind one way or the other, but 8mm has a smaller profile. A 40mm bore with an 8mm shaft through the center of it will flow more than the same bore with a 10mm shaft.
Right now the shafts ride straight on aluminum bores drilled directly into the bosses cast in the TB, with rubber seals on each end. Instead, I'll counterbore and ream the shaft bosses such that they'll accept 8x12x8 metric roller [Torrington] bearings. I found bearings in a closed flavor which will go on the lower, non-servo horn end of the shaft to enclose it, as well as the standard pass-through type bearing for the top boss. This might help illustrate.
Right now, there's an 8mm bore for the shaft and an 11.3mm counterbore that's 3.3mm deep at the opening of the boss. That counterbore will need to be extended to at least 8mm deep and opened to just shy of 12mm for the bearing fit. Looks like a 12mm-.0005" or .4719" ream should get me where I need to be in the bore. If I can find sealed bearings that would be great, but I may need to add a slight amount more depth to the counterbore for a small seal if not. I might as well incorporate a seal, if I'm going this far.
The new TBs are 2.925" long as opposed to ~3.5". That combined with the 4" head runner length give me a new length of 7". I'll need 7" transition runners between the intake flanges and TBs. Good deal. The only issue there is that means that I don't have any extra length at the openings of the TBs for velocity stacks or trumpets of any kind. We all know how beneficial round transitions in intake tracts are.
There's a nice, meaty lip on these guys. So, what I think I'll do is turn the diameter down until I lose the chamfer on the outside of the TB. Then I'll press on a 6061 ring with sleeve retainer that’ll give me an overall .500" lip width and a ~.250" depth. Basically, it'll allow me to machine a 1/2" half radius directly into the opening of the TB so I can have a trumpet without any additional length. Then again, I may wish to have the butterflies a bit closer to the intake valves for maximum throttle response. According to Jenvey UK, I wouldn't want them any closer than about 200mm (8") to the valve, which brings me back to a short head-TB runner and a short-ish velocity stack. Hah. I'll have to play with it. I'm definitely going to have to draw up and have a flange cut from 3/8” or 1/2” 6061 soon-ish so that I can start to get an idea of how this is going to come together. I bought some large 5/8"-11 bolts to turn down into mock-up studs just for holding the heads on the block. Likely won't get much actual shop time on this much in the next couple weeks. I'm moving to a new house with a large shop next week, so I'll be able to have everything on the same property from now on. Kinda nice.
I got those stepper motors, but I'm not sure that I'll use any of them for this project. Now that I'm using different throttles in a different configuration, I think that I'll just use a single large NEMA23 motor to actuate both banks as they can have ~4Nm of torque direct and are more robust. I'll have to build my own high current MOSFET H-bridge, because those DRV8825s won't handle the current. I can at least work out the firmware with the smaller stepper controller and a NEMA17. I'm thinking about cutting a 1/2"-10 ACME worm gear and then hobbing my own matching 52T worm wheel to make up a 52:1 reduction. That will drive a ~1:4 speed increaser for an overall ~13:1 reduction, allowing for ~50Nm holding torque on the shaft actuating the butterflies. Still waiting on the stepper driver ICs for the Arduino.
I’ve got all of the parts to make the two linkages required to link the banks of throttles together on the bell crank.
I can keep playing with the electronics at work, at least.
[This message has been edited by 1986 Fiero GT (edited 10-02-2021).]
I didn't like the idea of two stepper motors, one per bank, mechanically linked.
Because the motion between both banks will not be perfectly synced, the motors will not remain in phase as they rotate. This can cause them to uselessly apply torque against each other, rather than working together to turn the throttles. Two steppers on separate, but mechanically linked shafts is about as intelligent as paralleling voltage sources.
With the worm drive, the throttle could fail (and remain stuck) at WOT, but if it's just you driving, you should know to kill the ignition.
A homebrew H-bridge for this kind of thing, if not interpolating between positions, should be fairly easy. You just need to schedule a high-impedance dead-time between both pairs of switches being on, to prevent shoot-through. If you don't have enough position resolution (by the no. of steps and gear reduction), then generating intermediate positions means high-frequency PWM. Scheduling sufficient dead-time with PWM is a more complex exercise...
I reccomend dissimilar metals for the worm drive, i.e. steel worm and bronze worm wheel.
What is your feeling regarding the use of a stepper motor blindly? I would not be comfortable without redundant position feedback.
That's a good point about the worm. A standard gear train would at least allow a spring to force throttle reversion in the event of a failure. Something to think about. I wonder if I could source or make a mini ring and pinion setup instead.
My plan was to use two Penny & Giles TPS280DP sensors, one at the pedal and one at the throttle. So, the pedal controls only the throttles and the sensor at the throttles goes to the ECM. Anyway, it's a high resolution microcontroller-based hall sensor with an analog 0.5V - 4.5V output, so I could use that as a motor position sensor for the Arduino as well as a TPS for the ECM. With the 200 motor steps and a 13:1 reduction, I'd be looking at 2600 steps over 360°. That P&G TPS available to me allows 82° range, so that's 592 steps throughout the throttle operation. I think that's enough. I could [and should] add some code to monitor the TPS at the throttles for motor position feedback.
[This message has been edited by 1986 Fiero GT (edited 07-19-2017).]
That's good to know. I thought there were issues with the PID list from the Shelby or something. I guess that's why I never even tried it.
The OBDII codes and standard data work. I was never able to get manufacturer specific codes like misfire detection/counts to work right.
quote
Originally posted by 1986 Fiero GT: On a related topic; I have an external WBO2, but should I have at least one NBO2 connected to the computer? I'm not sure why or how I overlooked that, but I don't have the factory O2s installed. Would I need both if you recommend putting them in? I don't have a cat, though I'm likely to redo my exhaust over the winter. I've been told that upon letting off the throttle after applying large-ish amounts, I spit some pretty gnarly flames. I'd like to see that. Maybe I should rig up the GoPro for some flamethrower shots. Gotta love that disabled DFCO.
You'll need a NBO2 per bank, just like the Shelby car had when it was delivered. That is, unless you had the O2's disabled to make the system open loop all the time. If you did that or had it done you should certainly know it. If you haven't disabled the O2's, and don't have O2's installed, then you should have O2 sensor codes all over the place. Checking and clearing those codes is another good reason to have Torque and an ELM327 interface.
Is your CEL wired up? It should *DEFINITELY* be lit if your O2's aren't connected.
[This message has been edited by Will (edited 07-20-2017).]
You'll need a NBO2 per bank, just like the Shelby car had when it was delivered. That is, unless you had the O2's disabled to make the system open loop all the time. If you did that or had it done you should certainly know it. If you haven't disabled the O2's, and don't have O2's installed, then you should have O2 sensor codes all over the place. Checking and clearing those codes is another good reason to have Torque and an ELM327 interface.
Is your CEL wired up? It should *DEFINITELY* be lit if your O2's aren't connected.
The O2s were tuned out via HPTuners, so I'm in open loop all of the time. I suppose that's what I meant by 'overlooking them'. As in; I decided that they weren't necessary for my setup. I'm not entirely sure why, though. The car does work okay, but certainly could do with some closed loop for efficiency. I'm guessing there really isn't any way for the computer to have a super accurate representation of fuel trims without the O2s. I do know that it's fairly rich. I do not have a check engine light.
Yea, I dunno. I'm guessing I was a bunch dumber when I did some of that stuff. This has been an on and off project for ~10 years. Who knows what I did and when? I mean; it's definitely quick now. I spent several hours last Saturday running around Buffalo with a modified newer GTO. Never had a single problem keeping up with him, even at ~100mph. Still, it's thirsty. I'll add the O2s.
The system works much better the way it was designed. The only reason to go open loop with an OBDII system is that the person doing the tuning is lazy and/or doesn't understand fuel injection.
Yeah, they're fast. I trapped 106 mph with 255 RWHP and 112 mph with 312 RWHP.
IIRC '98-'99 GSXR 750 throttles spaced out for the Northstar bore center at 102 mm. These are/were the largest single throttles with integral port injector bosses used in sets of 4. I'm not sure if there are larger staged throttles now, and there are larger V-twin throttles available as well.
I haven't used them yet because the manifolding and stacks won't fit under an uncut decklid.
EDIT: Is there a maximum length for image tag strings?
[This message has been edited by Will (edited 10-29-2017).]
This project is still alive. It's now got a deadline. Was April 30, now May 31. Anyway, lots of quality stuff here. Borg-Warner S366. Precision Turbo & Engine Boost control (BOV and Wastegate). Stainless CNC-bent fuel lines. FuelLab regulator and dual Bosch 044s supporting a surge tank. Water-to-air-intercooler. Oh my.
Glad to see you're still at it! what's the purpose of the surge tank? Why not just have it dump straight back to the tank?
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Glad to see you're still at it! what's the purpose of the surge tank? Why not just have it dump straight back to the tank?
The theory is that it's pretty much impossible to ever starve the fuel rails. The first 044 is basically a lift pump, circulating fuel up to the surge tank to keep it full. Once it fills to approximately 75% capacity, it begins to overflow into a vertical tube inside the surge tank to return to the main tank. Meanwhile, the pressure pump (which is the one attached to the surge tank) is feeding the rails, then the FuelLab; which returns to the surge tank. It all but guarantees that there's always a 1+ gallon vertical column of fuel on top of the pump feeding the rails. You can see that a little better from the wheel well.
Should eliminate pump cavitation, pressure drop at the rails and AFRs skyrocketing because of it.
This car was also supposed to get a dry sump system as well, but I ran out of time for development there. Just gonna have to put it back together with the wet sump for now. I really like to throw this thing around pretty hard, so I wanted the important fluid systems to be up to par. It was a lot of fun N/A. Can't wait to go to turbotown.
The theory is that it's pretty much impossible to ever starve the fuel rails. The first 044 is basically a lift pump, circulating fuel up to the surge tank to keep it full. Once it fills to approximately 75% capacity, it begins to overflow into a vertical tube inside the surge tank to return to the main tank. Meanwhile, the pressure pump (which is the one attached to the surge tank) is feeding the rails, then the FuelLab; which returns to the surge tank. It all but guarantees that there's always a 1+ gallon vertical column of fuel on top of the pump feeding the rails. You can see that a little better from the wheel well.
Should eliminate pump cavitation, pressure drop at the rails and AFRs skyrocketing because of it.
This car was also supposed to get a dry sump system as well, but I ran out of time for development there. Just gonna have to put it back together with the wet sump for now. I really like to throw this thing around pretty hard, so I wanted the important fluid systems to be up to par. It was a lot of fun N/A. Can't wait to go to turbotown.
I didn't realize the other pump was there, maybe I just can't read... lol!
Are you worried about the pressure pump causing fuel heating recirculating such a small volume or are you relying on the lift pump to cool the recirc? do you have anything in place to help prevent aeration as the tank fills?
On a safety note, I would ditch the gauge glass on the side of the surge tank, to me that looks like a recipe for disaster, if it cracks or somehow gets removed, it could result in a very large fire very quickly, with little to no warning.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by ericjon262: On a safety note, I would ditch the gauge glass on the side of the surge tank, to me that looks like a recipe for disaster, if it cracks or somehow gets removed, it could result in a very large fire very quickly, with little to no warning.
+1
Something as simple as a rock thrown up by the tire could be bad news.
Are you worried about the pressure pump causing fuel heating recirculating such a small volume or are you relying on the lift pump to cool the recirc? do you have anything in place to help prevent aeration as the tank fills?
+1. Since you have the regulator right there, the fuel heating situation isn't as bad as it would be if you had the regulator on the fuel rail, and the fuel went to the engine and came back to the surge tank... OTOH, since it's always returning to the tank maybe that's not an issue.
quote
Originally posted by ericjon262:
On a safety note, I would ditch the gauge glass on the side of the surge tank, to me that looks like a recipe for disaster, if it cracks or somehow gets removed, it could result in a very large fire very quickly, with little to no warning.
quote
Originally posted by pmbrunelle:
+1
Something as simple as a rock thrown up by the tire could be bad news.
+1 more
The sight tube is NOT a good idea.
quote
Originally posted by 1986 Fiero GT:
This car was also supposed to get a dry sump system as well, but I ran out of time for development there. Just gonna have to put it back together with the wet sump for now. I really like to throw this thing around pretty hard, so I wanted the important fluid systems to be up to par. It was a lot of fun N/A. Can't wait to go to turbotown.
The left-most connection is in a completely horrible place for under-pan exhaust routing, so I'd have to go a different way with that one.
quote
Originally posted by Gary at ARE Hi William, We have not made those for several years, but I still have the tooling. I would need to get about $900 + screen fittings to make one now. 4-6 weeks. 50% down. Thanks
[This message has been edited by Will (edited 04-20-2020).]
Got any updates for us? I'd hate to see this stall out, some pretty intense work went into it.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Got any updates for us? I'd hate to see this stall out, some pretty intense work went into it.
Since PTT convinced me I should try their 2x0.105 disk cerametallic clutch, instead of the 2x0.250" organic clutch I had been looking at, meaning I can use PTT's flywheel instead of making my own, this install suddenly becomes more relevant to mine.
Although I'm still using the 282, which has much different fitment challenges than the F23.
Hah. Thanks. I like Tron. Apparently nobody else does, though. You're literally the first person to ever comment on it.
It is indeed 3" OD tubing. The radius looks tighter than it is. Pretty close to 1D, give or take. That's what I was shooting for, but it's a bit of a challenge to hit an intended radius with homemade pie cuts made on a portaband with a fabbed jig.
I built it this way mainly due to cost. From Pegasus racing, 3" donuts are ~$70 and 1.75" are ~$40. If I assumed one donut per primary [which may not be enough] as well as the one I'd need for the wastegate and the two 3" ones, that's $500. I did sanitary process piping fabrication for a few years, so I was able to collect nice chunks of scrap tubing the whole time. Didn't need to buy much after the collector, resonator and v-bands.
I was also concerned with the primaries, not necessarily being positive on how I'd actually be able to shove them all in the engine bay. Using the pie cuts gives me a lot more flexibility with fit up.
I'd love to have an ICEngineworks modeling setup so I could map everything out and know exactly how much I need of what. That would allow me to cut up mandrel bends with their nice bandsaw jig and have a good fit first shot, but that's not very realistic for me right now.
Also, I love welding stainless. Here's a project I spent many months on a few years ago.
I built it this way mainly due to cost. From Pegasus racing, 3" donuts are ~$70 and 1.75" are ~$40. If I assumed one donut per primary [which may not be enough] as well as the one I'd need for the wastegate and the two 3" ones, that's $500. I did sanitary process piping fabrication for a few years, so I was able to collect nice chunks of scrap tubing the whole time. Didn't need to buy much after the collector, resonator and v-bands.
I was also concerned with the primaries, not necessarily being positive on how I'd actually be able to shove them all in the engine bay. Using the pie cuts gives me a lot more flexibility with fit up.
I'd love to have an ICEngineworks modeling setup so I could map everything out and know exactly how much I need of what. That would allow me to cut up mandrel bends with their nice bandsaw jig and have a good fit first shot, but that's not very realistic for me right now.
Also, I love welding stainless. Here's a project I spent many months on a few years ago.
We'd all like an ICEEngineWorks set. Donuts are the cheapest way to get 1D bends, in terms of dollars per degree. However, if you have more minutes than dollars and scraps are free...
[This message has been edited by Will (edited 02-22-2021).]
the thought of welding all of those pie cuts gives me a headache! I'm also not very proficient at welding either... I really need to get in the garage and start welding up my exhaust so that my car isn't ridiculously loud, I have all the stuff, just need to do it...
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I just discovered this thread!! For the last few years I've mostly just hit The Mall and kept up with other threads I had subscribed to. I read everything, but some of the posts on page 2 lost meaning to me with the broken pictures.
From what I can figure, this is pretty awesome. I love your fuel system setup. That is a neat idea. I'm using FueLabs too.
I can tell you and FieroGuru are cut from the same cloth, man. Nice work. Though I have to disagree... A/C is a must for me.
I took down and ditched my image server a few years ago, but last week I found the hard drive from it with all of the files. I started trying to configure MacOS's built-in apache server on my XSERVE last night, but it's a little too Apple-y and weird. I might just set up a virtual machine with Win7 and run standard apache from there. Probably easier. Hah.
Either way, I'm going to try to get it back up and running in the next couple days. The last few pics I posted are hosted on imgur, so I could always move the old ones there, I suppose.
I was about to say that I tried a few different ways of refreshing and couldn't get them to come up. But they seem to be "timing out", like it's trying to fetch them and failing. I think this goes back to what you were saying earlier, some firewall or router configuration issue. Maybe port forwarding?
Must say that this project shows some impressive first class machining and welding work. With a turbo Northstar and an F23 it should work well for street but putting like 400HP into an F23 at the strip raises questions whether it can hold that kind of power. The F23 is designed for 170 ft lbs but it can be modified to hold more. Its not used in any high torque V8 applications.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The F23 is designed for 170 ft lbs but it can be modified to hold more. Its not used in any high torque V8 applications.
Dude, get over it. Everyone who's using one knows that. Nobody cares.
There are people on this forum and build threads in which you have posted using F23's with more power than your car is putting down... so just let it go.
[This message has been edited by Will (edited 03-08-2021).]
Dude, get over it. Everyone who's using one knows that. Nobody cares.
There are people on this forum and build threads in which you have posted using F23's with more power than your car is putting down... so just let it go.
I don't dispute that it may work out short term but there is a such thing as design limits and matching powertrains accordingly. Ask the guys who blew their gear boxes apart if they care! BTW, when are you going to show your face at Carlisle and allow everyone to see your great creation or is this just all talk as I suspect?
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I've been told (notice the emphasis) that GM rates the transmissions by bolting it up to the most powerful engine they designed it for, and then does testing to make sure it meets those requirements. Others might do this too.
I asked a former engineer if they had a special machine or something that would mimic engine input and they would see how much a transmission would stand by continuing to up the input, then write that down. He laughed and said no. They had a testing building with drivetrains in there just running all day long, doing different cycles to make sure everything passed. So while I am sure a lot of transmissions are just barely good enough, some can take way more abuse.
The 4R70W is a great example (yes, I know it's not transverse, this is just about transmissions taking way more than what the label says). Jerry W. (I can't recall how to spell his last name right now) was the guy who designed it, and did so thinking the Tbird it was going into was going to be a sports car. Ford was like "uhh, no. Just a nice looking grocery getter. Make the transmission shift a little smoother." So he did (accumulator springs and valve body), and Ford used a cheaper alloy for the input shaft. But even with those changes, that thing is a beast. You do the "J-Mod" (which Jerry wrote the paper on) and put in a hardened input shaft, there were guys ripping up 700+hp on their track cars.
I beat the hell out of my F23, and it just kept trucking.
unrelated -- which Carlisle events do a lot of Fiero folks attend? I've never been to one. The website says they have events in both PA and FL. I'd like to go! I'm going to miss AutoFair in N.C. this year. Hopefully next year!
[This message has been edited by Trinten (edited 03-08-2021).]
I don't dispute that it may work out short term but there is a such thing as design limits and matching powertrains accordingly. Ask the guys who blew their gear boxes apart if they care! BTW, when are you going to show your face at Carlisle and allow everyone to see your great creation or is this just all talk as I suspect?
He broke his diff carrier, dropped a new one in and kept on trucking. Yeah, it broke. Nobody ever expected it to last as if GM had validated it for that abuse. They (we) know going in and they (we) are ok with that. Use of an F23 is baked into the title of this thread and the title of the thread I linked. You're not adding value to the discussion by always beating that same drum.
The most common failure mode of a 282 is breaking the right diff bearing boss out of the case from axial load on the diff due to the helix angle of the final drive mesh. Spend any time looking at the 282, then compare to an F23 or F40 and the fact that these modern transmissions are tremendously reinforced in this area tells you that the engineers took development seriously. Modern manual transmissions have such stringent standards of NVH and consistent shifting under load that they end up FAR stiffer and stronger than yesteryear's manual transmissions, despite having similar validated ratings.
Personally, I've wrung off the end of GM's tiny inner CV joint in a 282, and then later broke the spider in the CV joint, although that was certainly due to damage that was initiated when I broke the splines. It was both a PITA and interesting to add to my wall of shame, but it was neither surprising nor horrifying... more of a "Hmm... I was wondering when that was going to happen" moment. With spherical bearings in the control arm pivots to tame the wheel hop I was experiencing, I should be able to launch harder with less chance of breaking any more axles.
And sure, if you want to come over to my build thread and post something encouraging, go right ahead!
I'd rather take the care to Summit Point or Watkins Glen than Carlisle, though.
The 4R70W is a great example (yes, I know it's not transverse, this is just about transmissions taking way more than what the label says). Jerry W. (I can't recall how to spell his last name right now) was the guy who designed it, and did so thinking the Tbird it was going into was going to be a sports car. Ford was like "uhh, no. Just a nice looking grocery getter. Make the transmission shift a little smoother." So he did (accumulator springs and valve body), and Ford used a cheaper alloy for the input shaft. But even with those changes, that thing is a beast. You do the "J-Mod" (which Jerry wrote the paper on) and put in a hardened input shaft, there were guys ripping up 700+hp on their track cars.
People put GS6-53BZ transmissions from E90 3 series BMWs behind Cummins diesel engines making 900 ftlbs of torque and they're ok.
The validated rating is really what the manufacturer is ok putting a warranty on. Sales numbers matter... would you rather take warranty claims on 5 million marginal transmissions or 5000 that you sold at a premium anyway due to low production numbers?
[This message has been edited by Will (edited 03-08-2021).]
At work, if we have a warranty return rate of 1000 ppm, we have a really unhappy customer... that's pretty catastrophic. There's even been stuff in the 10 ppm range that people weren't happy about.
Personally, for my modified Fiero, I'm OK with 1:4 odds for the least reliable part. Chances are that I'll be in the lucky 3/4 of cases. (though there shouldn't be too many of those, which would push overall reliability of the entire car down)
