Twin Disc clutch in an F23/Northstar (Page 12/13)
Trinten FEB 27, 11:55 PM
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?
1986 Fiero GT FEB 28, 12:42 PM
Should be back now. Had some DNS errors I needed to clean up.
Trinten FEB 28, 01:08 PM
Yes! Pictures loaded up super fast. Thank you! Going to re-read this thread now.
Dennis LaGrua MAR 07, 02:38 PM
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.

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" 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 "

Will MAR 08, 12:01 PM

quote
Originally posted by Dennis LaGrua:

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).]

Dennis LaGrua MAR 08, 12:32 PM

quote
Originally posted by Will:

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 "

Trinten MAR 08, 02:02 PM
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).]

Will MAR 08, 07:11 PM

quote
Originally posted by Dennis LaGrua:

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?




http://www.fiero.nl/forum/Forum2/HTML/121743.html

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.
Will MAR 08, 07:14 PM

quote
Originally posted by Trinten:

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).]

pmbrunelle MAR 08, 07:20 PM
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)