My Dyno Sheet (requested)

[TurboGt]

Do you want to keep it an auto? The manuals in the fiero have been proven to hold the power you are putting down. I have a 4 speed sitting at my house doing nothing that would love to see that kind of power (rebuild to make sure every thing is sound and then you could put a lsd in while you were at it). Also you could go with the 4t80e with a aftermarket controler. One of the guys on real fiero tech is runnign one behind his north* with paddle shifts.

http://www.realfierotech.com/phpBB/viewtopic.php?t=2526&highlight=dyno+north+star

Either way cool engine and good luck with whatever you swap it into.

[TurboZ24]

The car is a manual right now, using the same Getrag/Muncie that was in the Fieros. The diff has exploded once, broken mounting bosses off the case, as well as syncro issues with shifting at high rpm. I would also still end up with axle failures.

A lot of people think the Fiero guys with V8's and manuals have no issues, but that's because they never run slicks. I talked too several fiero shops and they all say run sticky tires and the trannies blow.

As for autos, the 4T80E is massive (350-400 lbs) and seeing that I don't have a stock ECM, I'd then also have too buy a 700 dollar electronic tranny controller, so once again, makes it cost too much when other choices are less expensive.

[Will'sFiero]

The HM 282 might be a bit stronger than you think. Have you ever tried a freshly overhauled one?
Most of the people I've heard from who have destroyed 282's were using high mileage units. This is ill-advised because of the way the diff carrier bearings wear. The transmission can take a lot more than most people think when it's overhauled properly.

"Tina" on www.fieroforum.com is running mid or low 11's with a 383 Fiero. She went through Isuzu transmissions like there was no tomorrow, then had the internals of a 282 cryogenically treated and hasn't broken it yet (to my knowledge). She's running a 7.25" twin disk clutch, so it's a pretty serious setup.

As for axles, breaking GM axles is exceedingly rare. Almost everyone I've ever heard of in the Fiero community who was breaking axles was using reman units. When they switched to factory GM axles, no matter the mileage on the axles, the breakage problem went away.

4T80E's only weigh 300#.

[Will'sFiero]

Why the F#%$ doesn't posting in this topic subscribe me to it?

[Nightingale]

Didn't happen to have taken any video of the dyno runs did you? Just love to see cars all out on the dyno.

[v6h.o.]

The HM 282 might be a bit stronger than you think. Have you ever tried a freshly overhauled one?
Most of the people I've heard from who have destroyed 282's were using high mileage units. This is ill-advised because of the way the diff carrier bearings wear. The transmission can take a lot more than most people think when it's overhauled properly.

"Tina" on www.fieroforum.com is running mid or low 11's with a 383 Fiero. She went through Isuzu transmissions like there was no tomorrow, then had the internals of a 282 cryogenically treated and hasn't broken it yet (to my knowledge). She's running a 7.25" twin disk clutch, so it's a pretty serious setup.

As for axles, breaking GM axles is exceedingly rare. Almost everyone I've ever heard of in the Fiero community who was breaking axles was using reman units. When they switched to factory GM axles, no matter the mileage on the axles, the breakage problem went away.

4T80E's only weigh 300#.

I've been with Curtis the few times that he has blown shit up. I was partly responsible for one of the axle breakages, The last blow up he sheared the inner CV joint at the half shaft spline into the diff,
I've been very fortunate to have personally driven Curtis' car on a number of occasions. At 7200+ RPM (It wants to shift around 7400-7500) the internals are spinning so fast in the trans that it does not want to shift 2nd gear at all. This has been with 2 or 3 different transmissions in there all the same issue. The centrifical forces are starting to cause issues with the power his engine puts down.

What you are proposing can be done yes. But again I know from many a conversation with Curtis that yes it can be done but whats the point, The trans is still going to blow up and then you've sunk how much into it for Cryo and a true LSD and all other parts to have something take out a good chunk of the trans and have to start all over again.
He's wanting RWD (tradtional rear axle) setup to keep from breaking parts and I don't blame him. The car never runs because it keeps breaking things and is so unstreetable as it is now.

[TurboGt]

Why the F#%$ doesn't posting in this topic subscribe me to it?

Will I dont get subscribed to this thread or anyother one I post over here, it dosent even remember me when I come to the sight, I have to log in every time.


As for the 4t80e trans weighing 300lb, this sound like a good thing to me, and even megasquirt is or is going to be coming out with a trans controller so that would only be ~$250 to control the tranny.

What ever you do I like to the engine and would like to see where it ends up runnign at it full boost on the dyno. Good luck.

[tejohnson]

Dumb question... Why would you spin the input up to 7000+ RPM? With all the work I'm doin, ~6500 will certainly be my cutoff...

Looking at the dyno sheet, optimal shift would be ~5800 - 6000 RPM

[TurboZ24]

The dyno sheet is actually incomplete. The only reason it craps out at 5800-6000 rpm is because that's where spark crapped out. The plugs were fouled badly from the previous day of street tuning and the coils were worn, which has since been fixed. It should achieve maximum HP at higher rpm (6800 or so). It still needs more tuning, but not sure I want too spend the cash too retune it just too have too tune it again with new exhaust when I swap chassis.

You also can't forget that that dyno sheet is only at 7 psi, we launched at 16 psi on the last drivetrain failure which even with the spark issues should end up at around 430 wheel HP.

The 4T80E I was weighing was the same as the engine (4.6), and the motor was around 400, so..... Not saying that scale was acurate, but the 4T80E is massive. It dwarfs the 3.1.

As colin mentioned, it's also about cost. Sure, I can spend 2000 bucks on a 4T60 (damn tight fit) or a HM-125, get it too handle it (Still an open diff, though). Or I send a 282 too Colin, sink 500 into a 282 rebuild kit, custom redo the syncros too shift correctly, and sink another 1000-1400 into the gear LSD, but for what that would cost, I can get a T-56 or a TKO, a rear end with a full LSD, and maybe even have some left over for a replacement chassis.

Both trannies I used were both under 60K miles. I have never had differential bearing issues, I blew apart part of the diff cage along with the pin on the first tranny. Also sheared off the mounting tabs where the motor mount bracket attaches. The 2nd tranny is still working, but as colin said it shifts like crap and the case sections seem too be shifting, because it always ends up leaking between the housings.

The axles I run are 700/pair, custom axles from Driveshaft Shop. They blame the launch technique (rev too 3500-3800 and pop the clutch) and I'm sure the solid motor mounts don't help, but there really isn't another way too launch the car on slicks and it goes no where on street tires. An auto would be easier on the axles, since you can preload the tranny, but I really don't like the idea of driving a street car with a 3500 stall.

[tejohnson]

I feel your pain, unfortunately there are some tradeoffs Hope you can find a good solution. I assume you could set up a pretty stout 60e, not quite such a high stall tho. I have always been curious about putting on slicks, but with 345 torque to the pavement, it has me curious with this 45e...

I wanna see another dyno run with a fresh set of plugs Even autolite 605's would do ya for a few pulls....

[RidgeRunner]

Still, pretty danged impressive numbers for a Cavalier.

Looking into an MG GT

Those 3 we were eyeballing up in Oregon or wherever it was ended at $405 IIRC... be nice if there was a similar deal somewhere in the southeast.

[TurboGTU]

I remeber seeing a MG at Pick-n-pull here in San Antonio. It was compleate with a possom nest under the hood . It looked compleate minus some body damage on a rear quater panel and a peeling primer paint ,but otherwise good for a project.

I would have thought you would go with a Chevett. Just needs a ford 8.8 axle and some f150 leaf springs. Hod Rod mag did a write up on it where they stuffed a Caddi 500ci into one. Just tryhing to keep it GM...

Rx-7 are easy too since you already know that.
But have you considered late 70s toyota Celicas?

Eather way...Impressive numbers with a crappy tune. You can see the misfireing by the irratic lines.

EDIT: the MG I saw was a convertible...maybe not a GT? Looks like this one but convertible..

http://www.yesterdays-cars.com/car922/car922.php4

[TurboZ24]

Um. Chevette is pretty ugly and I sat it one, my head hits the roof.

I thought about a pre-73 vega too. I've also considered a 70's Celica GT Fastback, yeah. They seem harder to find than the MG's, though.

[Will'sFiero]

Both trannies I used were both under 60K miles. I have never had differential bearing issues, I blew apart part of the diff cage along with the pin on the first tranny. Also sheared off the mounting tabs where the motor mount bracket attaches. The 2nd tranny is still working, but as colin said it shifts like crap and the case sections seem too be shifting, because it always ends up leaking between the housings.

The axles I run are 700/pair, custom axles from Driveshaft Shop. They blame the launch technique (rev too 3500-3800 and pop the clutch) and I'm sure the solid motor mounts don't help, but there really isn't another way too launch the car on slicks and it goes no where on street tires. An auto would be easier on the axles, since you can preload the tranny, but I really don't like the idea of driving a street car with a 3500 stall.

The later transmissions (maybe after '90... not exactly sure) had beefier spiders and diff hardware.

Nobody makes a helical limited slip for the 282, but there are a couple of friction or clutch based units around, like Phantom Grip, GR8 Grip, and EP (if anyone's ever actually received an EP...).

The only helical ever made for the 282 was the crossed axis Torsen for the Achievas, and that would not last in dragstrip duty.

I didn't realize you had solid mounts... that will lay a hurting on any driveline... you NEED something in the drivetrain to cushion the shockload of dumping the clutch. If there's no cushion, something will give... THAT is why you're snapping axles and having trans issues.

Better cluch technique (feed, not pop), might be in order as well.

[TurboZ24]

The later transmissions (maybe after '90... not exactly sure) had beefier spiders and diff hardware.

Both trannies I've used were 91's.

there are a couple of friction or clutch based units around, like Phantom Grip

Got one and it sucks.

If there's no cushion, something will give... THAT is why you're snapping axles and having trans issues. Better cluch technique (feed, not pop), might be in order as well.

Unfortunately when I had stock mounts and poly ones, it tore both, so that's out. The only way I could really slip the clutch would be to rev to 5000-6000 and smoke the crap out of it, and I'd rather stop racing or blow CV's than blow a 500 dollar clutch. The clutch I currently have really doesnt like to slip. It's almost an off/on clutch.

I really was contemplating getting an automatic (HM-125C or 4T60) and spending the money to get it built up. It would solve at least the drivetrain shock issues on launch, but I still don't see the point in spending that kind of cash on a FWD tranny, when the real issue is always going to be the fact it's FWD.