How much can a getrag really take? I dont want to over build my SBC and grenade a trans. Reliabilty is key here.

Archie allways says that any of the Manual transmissions in fieros can handle upto 500 HP with proper clutches. My friend has a 86GT with a semi built 2.8 on it with nitrous, and the trans has about 280k miles on it. We did replace the final drive or whatever that piece that holds the CV's is, with a lower mile one out of a caviler trans, however we only did this because we had the trans out of the car (TO bearing melted = damage to the input shaft)

On other note, I did ALOT of research on the TDC 3.4 awhile back, and I found out that they had to detune that engine massivly because they designed it around the current getrag/muncie transmissions that were popular with GM at the time, and the auto transmissions couldnt handle the power of the TDC.

O and one last thing. DONT EVER BUY A CENTERFORCE CLUTCH. As my friend did with the 86GT, it destroyed itself in 3 months, on a 170hp/160trq engine.

spec 3 clutches are the best by far, and I think that archie has a special clutch for the SBC guys too.

wasnt going to say anything till the centerforce comment.

I ran one behind a 220hp 3.4 for 2 summers and no issues. Just pulled it last week and it looks next to new. Centerforce makes a stock replacement clutch and the better Dual Friction clutch. The stock replacement clutch will let go. The DF wont. its a good clutch.

Spec clutches are good units also.

And your point about "doing alot of research on the TDC" is bullshit. The ONE site that says the engine was detuned because of the trannies has been proven over and over that the whole site is false information.

[This message has been edited by DOHC_SWAPPER (edited 01-18-2006).]

oops, well maybe I didnt look into the TDC too much yet, but I thought that was an interesting article.

Thanks for clearing that one up for me.

I'm glad someone asked I was a little worried about my future L67 swap. I hope it can take around 400 torq. I got an 88 GT 5 spd

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1988 Fiero GT

The dual friction is just as problematic as the rest of CF products. I got a new flywheel and CF DF clutch setup. Cleaned and prepped the flywheel and PP before install. I dont slip my clutches, but after less than 4000 miles it was trashed. The Kevlar side was down to the rivets, the pressure plate side was like new. The flywheel was good clean and shiny smooth, except for the grooves the rivets put in it.
talking to various people complaning about it and asking advice I discovered im far from the only person with this kind of problem. I switched to a Spec stage 2.5 and had to replace the flywheel again, so we'll see. Im liking the way it grips already.

Me and my friend installed his centerforce on a newly rebuild 4speed with a mild v6 build, broke in the clutch for about 600 miles, hooked up his 55 shot, and lit it up on my DIRT road only to have the clutch slip HORRENDOUSLY. He ordered the clutch from a local speedshop, and had it rush delivered for about $380, lets just say it was a very huge waste of time, and an even bigger waste of money, as everyone here knows that changing clutches in fieros is not a 4 hour job........

BTW he still has it in there, it just sucks.

quote Originally posted by darkhorizon: Archie allways says that any of the Manual transmissions in fieros can handle upto 500 HP with proper clutches.

Trannsmissions aren't rated by horsepower, they are rated by torque. A 500hp 3.4 DOHC is going to do a lot less damage to a trannsmission than a 500hp small block. I guarantee you a 500hp Duramax will laugh at a Getrag as it makes meatball spagetti of the internals.

As for the clutch issue, we ran a CenterForce Dual Friction in our 68 Camaro (Mild 350 4-speed), our 1994 Z28 (stock 5.7 M6), and my friend's Firebird (Built 383 T5). None gave us any problems at all, I actually really liked the CF in the two Camaros. But these are in typical SBC setups, and that is CF's claim to fame. I will be using a Spec III on my 3.4 DOHC Fiero. And after feeling one in my friend's Cavilier, I think I'm going to like it.

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"all pushrod motor are better than the dohc because it has less rotational mass"
-rick17, MyMonte member, owner of a 3100 Monte Carlo LS

Transaxles are rated for torque handling, not horsepower.

The maximum torque a particular Getrag can handle varies with the individual transaxle. Depending on how accurately the parts were machined, how much wear it has on it, what alloy batch the gears and bearings were made from, etc - it's hard to put a number on it and say "no more than this".

However, GM rated the 282 transaxle for 250 ft/lbs of torque. At this rating, any Getrag should last 100,000 miles. They'd warranty it at that level, but it can handle more. As you increase the load on the transaxle you'll shorten its life expectancy.

There is a limit, though - if you try to run 500 ft/lbs of torque through a Getrag 282 it'll self-destruct in a matter of minutes.

It also depends on how you drive. If you shift agressively even a healthy 3.4 can brake one over time. I did. A 350lbs+TQ SBC will do it much quicker. If you baby the shifts then even a 450lbs+TQ engine will live with it longer. Bottom line if you plan on big TQ then plan on having spare trannies around.

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Palm Beach Fieros
http://pbfieros.tripod.com

I've watched as a Gehtrag grenaded with only a little over 200 hp. ( I think this one was spider gear failure)

The issue in my book is the age of the parts. Metal fatigue is a reality for 20 year old parts.

If I was doing 400+ hp, I'd be putting in lots of new gear parts and maybe even cryogenic stuff

Arn

quote Originally posted by darkhorizon: Archie allways says that any of the Manual transmissions in fieros can handle upto 500 HP with proper clutches.

His website doesn't agree with you.

quote From http://www.v8archie.com/faq.htm 1) With the 4-speed trans. (‘84 4 cylinder & ‘85-’86 V-6 4 speeds) I have used 300+ H.P. engines repeatedly with no problems. 2) With the ‘85 thru ‘88 4 cylinder 5 speed transmissions I have used 300+ H.P. engines repeatedly with no problems. 3) With the ‘86 thru ‘88 6 cylinder 5 speed transmissions, I have used engines rated at 460+ H.P. (One even had an additional 200 H.P. dual quad carb. NOS system on top of a 460 H.P. 383" Chevy stroker engine) With no failures yet. One final note on this subject: It is my opinion that: "even though we have had no failures, that any motor vehicle can fail if subjected to severe and constant abuse."

quote Originally posted by Formula88: 1) With the 4-speed trans. (‘84 4 cylinder & ‘85-’86 V-6 4 speeds) I have used 300+ H.P. engines repeatedly with no problems.

I have an issue with this statement and the 84 transmission case is severely weaker than the 85+ v6 transmission case.. the ONLY failures of the 4speeds i've been able to track down were the 84 cases, and then the spyder gears in the differential.. to date i have not tracked down a single person who has broken any of the drive gears in the 4speed or broken a 85+ tranny case.. with a stronger differential I feel that the 4speed will be the strongest one available.. and i think GM would agree since thats the tranny they chose to use for their racing fieros (with a nice limited slip differential)

The 4 spd IS the strongest...

I think the attraction to the 5 spd is the extra gear. It is not stronger than the 85 4 spd.

Funny thing though...all these folks on this board who drag race and use a 5 spd...lol...they would pick up 1/2 a sec with a 4 spd tranny... but its a 5 spd!!!111oneone!!

quote Originally posted by DOHC_SWAPPER: The 4 spd IS the strongest... I think the attraction to the 5 spd is the extra gear. It is not stronger than the 85 4 spd. Funny thing though...all these folks on this board who drag race and use a 5 spd...lol...they would pick up 1/2 a sec with a 4 spd tranny... but its a 5 spd!!!111oneone!!

I wouldn't mind having an extra gear for the highway..

quote Originally posted by Kohburn: I wouldn't mind having an extra gear for the highway..

why? at 2300 rpm in 4th gear on my 3.65 im doing 60mph.

quote Originally posted by DOHC_SWAPPER: why? at 2300 rpm in 4th gear on my 3.65 im doing 60mph.

i'd rather be doing 1780rpm like i would be with a g6 tranny - milage is the only reason..
but thats why i run the 4speed, reliability is more important to me than the extra gear

I had a old fiero in arizona with a 4 speed muncie, I beat the Sh!t out of that transmission.... It laughed at me and kept going, finally the clutch went bye bye.

If I was doing a L 67 swap and had to run a stickshift, It would be either a 4speed muncie or a getrag out of a cavalier or something, And with the getrag I would still worry about breaking it.

Of course Im running a Izusu behind a 4.9 and it's still running fine..... But everytime I hit second gear I sh!t bricks.

quote Originally posted by DOHC_SWAPPER: why? at 2300 rpm in 4th gear on my 3.65 im doing 60mph.

Where I live 80mph is the standard hwy speed. Wouldn't mind living in the country side.

well thanks for the input I am now scared to death. I think I am going to take my trans apart and have everything nitrided and triple shot peened. Before you tell me about not doing this I am an engineer at a spring company and we do all kinds of stuff to get springs to live when there is no-way they should www.racingsprings.com. We will see if 400 foot pounds is too much

Want to increase your parts strength (100 to 400%) at very a affordable price !!! ?

http://www.300below.com/site/home.html

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Car History: https://www.fiero.nl/forum/Forum1/HTML/025670.html

[This message has been edited by California Kid (edited 01-19-2006).]

Sounds good but I would be more enthusiastic about it if I could see some test data in place of the testimonials, they should be very easy to conduct with a tensile test of a treated peace of metal next to an untreated peace, but 100% plus increase in metal strength is just too much of a stretch for my imagination without test data. Reminds me of cryogenics and the money paid in advance by people wishing to have their bodies fronzen in hopes of technology developing to bring them back to life, despite the fact that the freezing process destroys the cells in the body that they will need to stay alive were such a thing possible, due to crystals forming and puncturing them.

[This message has been edited by Joseph Upson (edited 01-19-2006).]

quote Originally posted by Whuffo: There is a limit, though - if you try to run 500 ft/lbs of torque through a Getrag 282 it'll self-destruct in a matter of minutes.

Never mind

[This message has been edited by Tina (edited 01-19-2006).]

I don't understand the reasoning for nitriding something such as gear steel which is darned hard to begin with. The gears are most likely 8620 that's already been heat treated. They should already have a high rockwell hardness. Nitridiing has it's place however. As an example, the cast transmission slip yokes for front engine rear drive cars. I had problems with the one on the Corvette wearing where it contacts the tailhousing bushing. I had it nitrided rather than get a billet one from Mark Williams. I've suggested in a post that a good extreme pressure lube from Redline will dampen a little of that shock between the gears that causes some of the problems. It won't help if the case flex though. Try to avoid the grabby clutches (it's mostly in disc design) that impress your friends with tire chirps. By the way, the GM training/service manual 17004.04-1 copyright 1987 states; "rated torque input capacity of 170 ft. lbs. (future capacity of 200 ft.lbs.). Maybe a small change for the "88 and later ones.

From pics I've seen posted here, the problem is often case flex. A lot of times people destroy the case, which of course lets all the fluid out, which is a 3 second recipe for disaster if you're running it hard enough to break the case. Also, once the case is split, it can flex a lot more and things start moving around inside, and then you're going to start shearing teath and messing up internals. The gears a pretty tough normally, but if things start getting out of alignment with 300+ ft-lbs going through them, bad things are going to happen. I'd be willing to wager that a lot more transmission reliability under high power could be had if a way to strengthen/reinforce the transmission casing could be found.

quote Originally posted by darkhorizon: Archie allways says that any of the Manual transmissions in fieros can handle upto 500 HP with proper clutches.

I wish people would quit mis-quoting me. You say I ALWAYS say that & I've NEVER said that to ANYONE.

A few weeks ago, someone said that I had said that I claim every TPI car I've built is >400 HP. And I've never claimed that even once, let alone EVERYTIME.

I know there are some people who will swear that I said that, they would just love find another thing to try to bash me with. But I never have made claims like that. Anyone who says I have, should be required to post a link to proof that I've said what they claim.

Geeze....... if you're gonna quote me then quote me correctly.

Archie

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[This message has been edited by Archie (edited 01-19-2006).]

Put everything you wish to be NOT misquoted on your website, particularly about the getrag. It's the price of being a celebrity!

Lol, yea kinda reminds me of what archie said a few weeks ago, about how no one ever misquotes him

I wouldnt be afraid of using the Getrag on anything. Hell, they're all pretty much the same, no particular tranny has failed more often than any other on here. Tina is running mid 11's with a 383 on a getrag, as well as many others on the top of the 1/4 mile list. Tranny failure has more to do with random luck (in selecting that one tranny that has that little extra slop). So in my opinion you're better off selecting based on gear ratios than strength.

And my 5spd 86GT would beat my buddys 4spd 86GT every day, and with the 3.4DOHC, well my AC compressor was unknowingly stuck on, but, I was quicker than the 4spd in the low end, though around 70-100 he had a little on me, I dont know how much power an AC compressor draws at 7000 RPM but needless to say it destroyed the compressor and seeing as the gear ratios are lower, and we were running in between shift points, im postive it was causing my loss. The insanely low 1st gear and overally lower gear ratio's make up for the extra 1/8 second it takes to throw that one more gear. Heck when im running my turbo, my BOV barely even blirps during shifting.

Plus its not really a sports car if you dont get to row through the gears, kinda like why they're not as much fun with autos. Its great always having just the right gear. Conversly to that, sometimes (well, not often) it can get tiring loping around town having to shift so much. Really it depends on what you are builing, a high revin 327 would be better for the 5spd as you would have the gearing advantage, where as a torquey 383 that doesnt give a crap would just plow right through with the 4spd.

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Boost is like Venerial Disease, one night of passion can result in weeks of pain (and work.)
http:\\www.myspace.com\keeptherubbersidedown

The reason you nitride is 2 fold one is to help with wear another the most important for me is you get a pretty decent amount of residual compressive stress from the nitriding as well as you can get a higher residual compressive stress at the surface on a notrided part VS a non nitrided part.

quote Originally posted by 86GT3.4DOHC: And my 5spd 86GT would beat my buddys 4spd 86GT every day, and with the 3.4DOHC, well my AC compressor was unknowingly stuck on, but, I was quicker than the 4spd in the low end, though around 70-100 he had a little on me, I dont know how much power an AC compressor draws at 7000 RPM but needless to say it destroyed the compressor and seeing as the gear ratios are lower, and we were running in between shift points, im postive it was causing my loss. The insanely low 1st gear and overally lower gear ratio's make up for the extra 1/8 second it takes to throw that one more gear. Heck when im running my turbo, my BOV barely even blirps during shifting.

that comparison really doesn't mean anything because my old 2.8 auto was faster than my buds very clean cared for getrag -- 20 year old engines vary a LOT

besides the gearing for 1-3 are almost the same for the 3.65 4speed and the getrag -

[This message has been edited by Kohburn (edited 01-23-2006).]

We both had fresh rebuilds, mine stock, he had a cam and mild stuff. I think mine was like 3000 miles older than his at the time. Final gear ratios between the two are around .50 lower in the getrag in all 3 gears, its a small number but a big diffrence side by side.

quote Originally posted by 86GT3.4DOHC: We both had fresh rebuilds, mine stock, he had a cam and mild stuff. I think mine was like 3000 miles older than his at the time. Final gear ratios between the two are around .50 lower in the getrag in all 3 gears, its a small number but a big diffrence side by side.

um the getrag final drive is 3.61 VS the obvious FD of 3.65 of the 4spd we are talking about. 0.04 is the difference. Nothing you would notice.

Also last gear in a getrag and last gear in a 3.65 is 2.96 VS 2.60 (for the getrag) ... so thats a difference of .33 in gearing.

Final gear RATIOS not drive ratio,

Ive run 2.8s side by side, and 3.4DOHCs side by side 4spd vs 5spd, both times getrag pulled ahead.

Edit:
And in the above post I meant to say all 4 gears. Trannys are a simple function of mathmatics, lower gear ratios= better acceleration. The 5 spd will always be faster than the 4 spd with stock ratios. Theres a reason everyone is looking for a 6spd tranny and no one is looking for a 3 spd. more gears = more speed either top speed or acceleration depending on configuration.

[This message has been edited by 86GT3.4DOHC (edited 01-23-2006).]

quote Originally posted by 86GT3.4DOHC: Final gear RATIOS not drive ratio, Ive run 2.8s side by side, and 3.4DOHCs side by side 4spd vs 5spd, both times getrag pulled ahead. Edit: And in the above post I meant to say all 4 gears. Trannys are a simple function of mathmatics, lower gear ratios= better acceleration. The 5 spd will always be faster than the 4 spd with stock ratios. Theres a reason everyone is looking for a 6spd tranny and no one is looking for a 3 spd. more gears = more speed either top speed or acceleration depending on configuration.

Geez wrong again.

please, do explain........

*makes popcorn*

Perhaps we should unearth Einstiens notes and see where he is wrong, because apparently DOHC is going to show us how 10 is less than 5 as well as defy many other laws of physics

[This message has been edited by 86GT3.4DOHC (edited 01-23-2006).]

quote Originally posted by 86GT3.4DOHC: please, do explain........ *makes popcorn* Perhaps we should unearth Einstiens notes and see where he is wrong, because apparently DOHC is going to show us how 10 is less than 5 as well as defy many other laws of physics

Stop ****ing guessing. Numbers DONT lie. For instance, the gearing in a 3.65 4spd is better for acceleration VS the getrag. Would it kill you to know SOMETHING about what you talk about? I know you know **** all about turbos, dohcs and tuning.

[This message has been edited by DOHC_SWAPPER (edited 01-23-2006).]

the tranny that may be geared better for one powerband may be completely wrong for another engine's powerband.. but either way people will use the tranny they like..

if you want to do roughly equal comparisons that don't add up my 3.4 ohv isuzu 5speed 87GT vs my friends 3.4ohv getrag 87gt and i killed him..

drive what you like -- my primary reason for the 4speed is strength since i've shattered most other trannies but the 4speeds keep on ticking (even after wearing out the synchros and just starting to short shift without using the clutch)

quote Originally posted by DOHC_SWAPPER: Stop ****ing guessing. Numbers DONT lie. For instance, the gearing in a 3.65 4spd is better for acceleration VS the getrag. Would it kill you to know SOMETHING about what you talk about? I know you know **** all about turbos, dohcs and tuning.

Im still waiting on that explanation as to how a final gear ratio of 12.08 is going to outperform a 12.64.
Actualy, Ive said repeatedly that when It comes to turbos I have no idea what im talking about, since then, Ive learned a lot for instance the diffrence between flow and pressure, but still lack some information, which is why I make threads asking questions. You have yet to make one post Ive seen to indicate that you know the first thing about anything, lol

That being said, Im not going to defame my user name by arguing petty crap like this with you anymore, Ive made my point, posted the supporting information, if you can find counter information, do post it, but please dont dirty up this thread with your yelling and personal attacks just because you cant prove your point. Ive seen enough people come through here with the same attitude, some hang on, some dont. All I have to say is, say hi to Shawn when you meet up with him.

Seabird296, sorry for messing up your thread, im done.

I said before, its all based on what you want it for, IE 327 screamer or 383 grunty, former for the getrag, the latter would work better on the 4spd.

Thr reason the fiero clutches tend to slip is because they can only be so wide. If you could make the clutch bigger than the problems many have mentioned would be nonexistent.

quote Originally posted by 86GT3.4DOHC: Im still waiting on that explanation as to how a final gear ratio of 12.08 is going to outperform a 12.64.

Easy. Have the power to weight ratio to render those gears useful. For example, there is a reason an R1 rides 1st gear out to 65mph and 2nd out to almost 100. It is because the bike makes so much power (183 IIRC), and weighs so little, that gears any taller would make the bike slower. Guys regear their bikes all the time, and while it makes them easier to ride, it does very little for performance in an all out race bike (The new supersports ARE race bikes). In fact, if they were better at riding the bike, they'd drop their 1/4mi more than they ever would with gears. Same goes for cars. There is a reason the Z06 rides the gears out to like 55, 90, and so on. It has so much power, that gears and taller would slow it down becuase it'd take more time to shift than to get through the gear.

And this could also be true in another way, let's use the 685hp/9000tq SL65 AMG for example (Tuned by Renntech). Having driven one for a few months, I can say gearing would do nothing but slow it down--AND IT'S AN AUTOMATIC. It already can't stop barking the tires until 90mph, and you below 90 you don't get full boost anyways. Taller gears and the thing would just spin the tires more. What good is that? Besides, and take my word on this, when you have a limited 900 ft/lbs, it doesn't matter what gear you are in or at what RPM. I never even looked at the tach. It was useless. If the boost gauge was above 0, it was hauling a$$. It didn't matter how fast I was going, or what gear I was in, just lay on the throttle, and it just covers ground like no car I've ever been in before.

quote Actualy, Ive said repeatedly that when It comes to turbos I have no idea what im talking about, since then, Ive learned a lot for instance the diffrence between flow and pressure, but still lack some information, which is why I make threads asking questions. You have yet to make one post Ive seen to indicate that you know the first thing about anything, lol

Oh trust me, this isn't a mystery, anyone would knwo by reading one of your ignorant posts. He called you a f*cking idiot, that's enough for me to see he knows a little about what he speaks, cause he surely isn't lying.

quote that being said, Im not going to defame my user name by arguing petty crap like this with you anymore, Ive made my point, posted the supporting information, if you can find counter information, do post it, but please dont dirty up this thread with your yelling and personal attacks just because you cant prove your point. Ive seen enough people come through here with the same attitude, some hang on, some dont. All I have to say is, say hi to Shawn when you meet up with him.

Oh if only kindness mattered at the drag strip.

quote Seabird296, sorry for messing up your thread, im done.

Oh damn, this couldn't have come soon enough.

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"all pushrod motor are better than the dohc because it has less rotational mass"
-rick17, MyMonte member, owner of a 3100 Monte Carlo LS