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| Choosing the right Transmission (Page 2/3) |
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cvxjet
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AUG 21, 08:19 PM
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I bought my 85 SE V-6 new...My father, who had been into British sports cars (Look up Jowett Jupiter) before I came along and ruined his life, drove a Corvair for my first 4 years....He warned me about the DTO...Told me to just "get back on the throttle a bit"....
I was hot dogging getting on the freeway but had to cut the throttle in mid-turn and the tail came around- Remembered what he had said and gave it some throttle....Survived....
Years later, I was working at NAS Alameda and living in San Leandro- every day I would drive home on I880 and get off at Marina blvd...The offramp had a bit of a kink in it- Instead of turning the wheel, I would chop the throttle which would kick the tail out slightly....Basically, I was practicing dealing with the DTO every day.
Once, as I was entering that turn, a BMW 3 series started tail-gating me...So I dropped a gear and "Went for it"...when I cut the throttle it really came around, and as I got back on it, it drifted thru the turn at quite an angle....And the BMW disappeared...at the next intersection I stopped and was adjusting the stereo and finally here comes Mr. BMW....I looked over at him- WHITE as a SHEET!
You should always learn how each of your vehicle reacts to situations- experiment a bit so you know what it will do.[This message has been edited by cvxjet (edited 08-21-2023).]
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NotYourDadsPontiac
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AUG 21, 09:32 PM
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Um, well to start with, I'm not here to step on anyone's toes, but lets get back down to earth, shall we. Everyone talks about wanting 800 hp, but the truth is that 99.99% of EVERYONE on this planet couldn't handle a mid-engine car with more than 400 hp without traction control (that will automatically cut engine output when the wheels spin) and anti-lock brakes. The Fiero has neither. Even if you did get to 400hp, that squirrely car would kill you before your 19th birthday.
A mid-engine car has more weight in the rear than in the front. I bought my first Fiero when I was 26 and quickly spun it twice on wet roads with just that same wimpy 98hp iron duke that's in your car. Even higher torque will help the rear tires break loose that much easier and you'll wake up either in a ditch or in the morgue. So realize that you are not a real race car driver and probably never will be. None of us will be. Modify your car with that fact in mind.
You mentioned the "wimpy" Olds and Cadillac engines of the early '60s. Hmmm, where are you getting your data? The TH-425 transmission was installed from 1966-1978 only in the 4000 lbs Olds Toronado, Cadillac Eldorado, and the 12,000 lbs GMC motorhome. The smallest engine used in any of these vehicles was the Olds 407. The Cadillac 500 put out 550 lbs-ft torque all day long. Not so whimpy after all. But, it's still a horrible choice for a Fiero simply because of its very high weight and the extensive mods necessary to get it to work. If you were an experienced welder, machinist, and fabricator (all at the same time) you might be able to pull that off, but at 16 you couldn't possibly be one of those professionals, let alone all three. It's also only a 3-speed automatic with no overdrive gear. Not a great choice. Did I mention it's very heavy? It's not a great idea to add more weight to the rear of a mid-engine car that already has a rear weight bias unless you enjoy looking like a fool when you lose control of you car (again).
The Cadillac 4t80 is a great transverse automatic transmission that is now dirt cheap and made to handle the high torque of a 300hp Northstar V8, but it is also quite heavy and still needs plenty of modifications to work with an ls4 in a Fiero. It may be a 4-speed with overdrive, but it's still not a good choice for a Fiero.
If you ask the owner of any 2005-2008 Impala SS, Monte Carlo SS, or Grand Prix GTP what the weakest link is in their cars, they will gladly tell you its the 4T65-HD transmission. It doesn't so much break as it wears out much quicker than anticipated behind the stock 303hp ls4 V8. Please, go to their forum and just ask.
Having said that, it's by far the best automatic transmission for our Fieros because of its cost, weight, adaptability, torque capability, upgradability, and cost. Yes, I listed cost twice. As a broke 16 year old, your cost should be everything to you. Speaking of which, the amount of fabrication work (and cost) just to get an LS4 (even with this matched tranny) to work in a Fiero is rather exorbitant. It's not necessarily the cost of the engine and/or tyranny that breaks the bank. It's the cost of all those pieces and parts you'll need to pull it off.
As for standard transmissiins, the F40 is a great choice, but it is quite rare an expensive to aquire. Then there is a whole list of modifications necessary to just mount it into a Fiero and even more to adapt it to an ls4.
A much, much, much better choice for a stick is the 1985-86 Fiero 4-speed stick that came with V6 Fieros before the Getrag 5-speed became available. My understanding is that the 4-speed used with the V6 can handle more torque than the Getrag 5-speed.
Don't even look at any 4- or 5-soeed standard transmission mated to any 4 cylinder iron duke. These were very low torque Isuzu transmissions that will break behind the torque of a V8.
There is a great alternative that you should consider. Buying a running front-wheel-drive car with a supercharged Series II 3.8 V6 engine is not only doable, but it's cheap and relatively easy to swap into a Fiero along with its matching transmission. These vehicles are around 20 years old now and therefore very cheap for one that is still running and driving. Yes it's less than 250 hp, but it will retain your front/rear weight ballance, will be affordable, yet still give you tons of fun.
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Patrick
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AUG 21, 10:25 PM
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| quote | Originally posted by BruhMans06:
I also won't be driving it hard with the LS until I fully trust my ability to drive the car. I'll probably baby the car for about a year or until I've passed the break in period.
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Don't kid yourself. You may not put the pedal to the metal the first few times out, but I guarantee there's no way you or anyone else is going to curb their "enthusiasm" for a full year. At some point, you'll be wanting to see what she does.
I was no different 50 years ago. I was fortunate to not have wrapped my big block Chevy(s) around a pole... and I consider myself a good driver. Horsepower and speed are as intoxicating as any drug... and potentially just as deadly.
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Patrick
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AUG 21, 10:40 PM
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| quote | Originally posted by cvxjet:
Also, when you are jacking the FIERO up and working underneath you need to be very careful- We lost a very nice guy who'd just started working on his Fiero- Wife came home and found him crushed under the car...
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That was truly heartbreaking. Probably the saddest turn of events I've ever experienced in the 24 years I've been a member here. 
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BruhMans06
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AUG 22, 08:38 PM
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Yeah I bit over my head here, but I'll keep trying my best. I know how to weld (not the greatest obviously) and I just want a car to spend my time on as I've had many cars I've worked on come and go in the blink of an eye. So I want a car I can work on for years without running out of things to improve. That's the main reason I bought this car. I'll build the v8 up over time. I won't go all out at once, ill probably just start out with a cammed v8 that probably put out less than 400 (which i now realize is a lot for a little car like this, thanks to all of yalls input) I'll try my best not to be an idiot when driving this car and I now realize that all of this stuff is not something to mess around with when I'm out on the road. I always make sure to keep the rims I remove under the car so if the jacks do fail the car will land on the rims and I won't immediately be crushed to death.
Thank yall very much for all of your input. I'm going to continue this project as I originally planned but I'm going to make this a very long term project. Immediately going to start off by putting a "new" iron duke in back in the car and drive that around until I can find the right trans and engine for me.
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82-T/A [At Work]
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AUG 23, 09:40 AM
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| quote | Originally posted by NotYourDadsPontiac:
You mentioned the "wimpy" Olds and Cadillac engines of the early '60s. Hmmm, where are you getting your data? The TH-425 transmission was installed from 1966-1978 only in the 4000 lbs Olds Toronado, Cadillac Eldorado, and the 12,000 lbs GMC motorhome. The smallest engine used in any of these vehicles was the Olds 407. The Cadillac 500 put out 550 lbs-ft torque all day long. Not so whimpy after all. But, it's still a horrible choice for a Fiero simply because of its very high weight and the extensive mods necessary to get it to work. If you were an experienced welder, machinist, and fabricator (all at the same time) you might be able to pull that off, but at 16 you couldn't possibly be one of those professionals, let alone all three. It's also only a 3-speed automatic with no overdrive gear. Not a great choice. Did I mention it's very heavy? It's not a great idea to add more weight to the rear of a mid-engine car that already has a rear weight bias unless you enjoy looking like a fool when you lose control of you car (again). |
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I immediately take offense to the term "wimpy" and Oldsmobile in the same sentence! Hahaha...
I looked, and I don't think I saw where anyone said this, but I wanted to take this opportunity to mention how fantastic the Oldsmobile motors are. This is a 1969 Olds 455 Big Block that I bought for $250 bucks, in trade for a running LD9 TwinCam.
I brought it home looking like this ... dirty and nasty:
And it looks like this:
- 1969 Oldsmobile 455 Big Block (69 "F" Block, F1 [High Nickle Content])
- 1969 Oldsmobile 455 "C" Large-Port Heads (2.07:1 Intake / 1.72:1 Exhaust Valves, Stainless Steel)
- 1970 Oldsmobile 455 HO Toronado "K" Intake
- TRW Forged Pistons .030 Overbore (w/ Chrome Moly rings)
- 1969 Hardened Crank / Forged Rods (Shot peened / polished)
- Joe Mondello JM-20-22 Camshaft (1400-5800 RPM Range, 0.496 In. Lift / 0.512 Exh. Lift)
- Crane 1.6:1 Roller Rockers
- Cloyes Tru-Roller Roller Timing Chain
- 1972 Rochester QuadraJet (Tuned for a 72 Olds 455)
- GM Performance Parts Hi-Volume Oil Pump
- Light bowling / port and polish
I love this engine so much that it's literally been sitting in a central Florida storage unit for the past 13 years, wrapped in a Moroso engine back with some dessicant packed in, and the cyl bores filled with oil. Who knows if it's still good... I don't even have a car to put it in anymore. Haha...
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fierosound
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AUG 23, 10:44 AM
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82-T/A [At Work]
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AUG 23, 10:58 AM
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| quote | Originally posted by fierosound:
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Wow, that is actually really cool looking. It has Porsche 944 vibes going. I assume that's a 3rd-Gen F-body hatch lid that they've fabricated on. Really, really cool. I wonder how it drives. Is it getting the oxygen for the engine from the passenger compartment? I wonder what that must sound like back there...
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Patrick
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AUG 23, 05:25 PM
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| quote | Originally posted by 82-T/A [At Work]:
Wow, that is actually really cool looking.
I assume... I wonder how... Is it... I wonder what...
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If you weren't wasting so much of your time here arguing pointless politics over the years, you could've been following this build since 2003.  [This message has been edited by Patrick (edited 08-23-2023).]
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fierosound
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AUG 23, 08:47 PM
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| quote | Originally posted by 82-T/A [At Work]:
Wow, that is actually really cool looking. It has Porsche 944 vibes going. I assume that's a 3rd-Gen F-body hatch lid that they've fabricated on. Really, really cool. I wonder how it drives. Is it getting the oxygen for the engine from the passenger compartment? I wonder what that must sound like back there... |
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Firewall, rear window etc. is all still intact like on any Fiero....
 [This message has been edited by fierosound (edited 08-23-2023).]
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