After knowing a friend with a 2m4, I finally decided to get a Fiero of my own. The one I'm looking at is an '88 GT that has 170k on the odometer. My plan is to get a 350 out of a swap I'm doing on a '79 K30 (the motor I'm getting from that originally came out of a 1st or 2nd gen Camaro). Its got a Holley intake manifold, Edelbrock 4-barrel carb, and HEI ignition. After surfing around this forum for a time, I decided I wanted to hook up an F40 to that engine, as it was a six-speed (and a readily available one at that), but then I started looking at the swap kits for both the SBC and the F40 that Archie makes, and I knew I wouldn't be able to afford the entire thing and get it together in one summer. My goal with that setup is to have a good-looking daily driver that I could still take down the strip or the street, and be able to gap a lot of stuff without tearing up the car. However, I don't want to break the bank on a couple of swap kits. Do y'all know any more affordable methods of getting this type of swap done?
In addition to the other thread, I can tell you my F23 swap was very inexpensive. Most of the cost was in labor!
This is from memory, though there is a thread documenting when it was put into my car - however a lot of the pictures are gone. Still good info.: Transmission: $400 (low mileage, and it was one of those yards that pulls the parts for you, so you might find it cheaper) Flywheel: $300-ish? New HTOB: $50 Original Spacer: $25-ish FieroGuru later upgraded the spacer setup... not sure what he would charge to make another one. Cables: California Push-n-Pull has the right cables for this swap 'on the shelf' now, one cable is a standard Getrag cable, the other is from Push-n-Pull, and was about $125 Slave cylinder adapter: ~$125 bucks? Optional - there is a Quaife ATB Helical LSD (gear driven, no clutches or springs!), but that adds about 1000 bucks for the LSD, and around 100 for the Kent tools to put it in.
The transmission takes a beating. And in my 350 on the highway, I was getting around 21mpg. I don't recall my final drive. I think at 70mph I was turning 2800 RPM?
One issue I did have was with axles. Apparently the after-market axles for the Fiero are about 0.25" shorter than OEM (so they can work on more than one application). My F23/350 swap didn't quite leave room for that tolerance. When I broke a tripod at the track, the aftermarket axle kept popping out when driving. FieroGuru kindly supplied me with a factory original.
It sounds like the 350 isn't in the Fiero yet, so other stuff you'll need, in general, to put the 350 into the Fiero. (Again, from memory, not exhaustive, please check out some build threads!) 1" adapter plate from Archie to bolt the engine and transmission together (and create provision for starter), or make your own if you have the machining equipment/skills. Oil filter relocation setup, with the return tube going to one of the other ports on the block (cradle makes it nigh-impossible to use as intended) Electric water pump (optional, but could make your lift with belts much easier) Appropriate fittings to hook up remote electric water pump. Block hugger headers Low rise air filter for the carb (Holley makes a triangle shaped one that works well, though the foam filter in it is prone to melting/damage, especially from any backfires from timing being off or carb not having the right jet sizes... I know from experience!)
Best transmission for a small block? I believe that a beefed up auto is best for the strip but only one small auto trans will fit and it won't take the power unless it is performance built. The TH125H has been modified to work with a V8 by expanding the clutch pack and upping the line pressure via shift kit. The downside is that it limits you to three speeds and in stock shape it just won't cut it. The logical choice is the F40 or F23 5 speed manual trans and there is much info here on how to install it. A few guys here have manual LS3 swaps and you might want to ask them how they are working out.
------------------ " 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 "
In addition to the other thread, I can tell you my F23 swap was very inexpensive. Most of the cost was in labor!
This is from memory, though there is a thread documenting when it was put into my car - however a lot of the pictures are gone. Still good info.: Transmission: $400 (low mileage, and it was one of those yards that pulls the parts for you, so you might find it cheaper) Flywheel: $300-ish? New HTOB: $50 Original Spacer: $25-ish FieroGuru later upgraded the spacer setup... not sure what he would charge to make another one. Cables: California Push-n-Pull has the right cables for this swap 'on the shelf' now, one cable is a standard Getrag cable, the other is from Push-n-Pull, and was about $125 Slave cylinder adapter: ~$125 bucks? Optional - there is a Quaife ATB Helical LSD (gear driven, no clutches or springs!), but that adds about 1000 bucks for the LSD, and around 100 for the Kent tools to put it in.
The transmission takes a beating. And in my 350 on the highway, I was getting around 21mpg. I don't recall my final drive. I think at 70mph I was turning 2800 RPM?
One issue I did have was with axles. Apparently the after-market axles for the Fiero are about 0.25" shorter than OEM (so they can work on more than one application). My F23/350 swap didn't quite leave room for that tolerance. When I broke a tripod at the track, the aftermarket axle kept popping out when driving. FieroGuru kindly supplied me with a factory original.
It sounds like the 350 isn't in the Fiero yet, so other stuff you'll need, in general, to put the 350 into the Fiero. (Again, from memory, not exhaustive, please check out some build threads!) 1" adapter plate from Archie to bolt the engine and transmission together (and create provision for starter), or make your own if you have the machining equipment/skills. Oil filter relocation setup, with the return tube going to one of the other ports on the block (cradle makes it nigh-impossible to use as intended) Electric water pump (optional, but could make your lift with belts much easier) Appropriate fittings to hook up remote electric water pump. Block hugger headers Low rise air filter for the carb (Holley makes a triangle shaped one that works well, though the foam filter in it is prone to melting/damage, especially from any backfires from timing being off or carb not having the right jet sizes... I know from experience!)
Awesome! Thanks for the link and the info. Also, depending on if I can save enough money up, I may or may not be able to buy both of Archie's swap kits for the engine and transmission, but in the event that I don't, are there other options to achieve similar results? Also, what kind of brake rotor/caliper setup and suspension are you running?
Also, between the F23 and F40, which transmission do y'all think is better? In my opinion, I favor the F40 due to its 6 speeds and the fact that it offers more room for a larger power band, but I have heard that 1st gear isn't really that useful, as it is very short, and its obviously a bit pricier that the F23 to put in. Is there a way to get around this problem by changing the ratio on 1st gear, or would you have to change ratios on all six? I am not all that keen on how transmission gear ratios work or which ones are better, so any information that would be helpful as well.
I'm always happy to share what info I can!! Though I openly admit I have always paid people who are much more skilled and knowledgeable to do all the hard stuff.
On the Fiero in question, I was running the stock Fiero rotors/calipers, I had gotten the Brake Booster upgrade (definitely worth it) from a member on this forum, it's a few hundred bucks. In the back, I did an adjustable coil-over setup. I had wanted to do a brake upgrade on that car, but didn't get around to it.
There are a lot of different brake swaps out there. Almost all of them have trade offs, like using old Fiero rotors to make 'hats', or having things machined every time you change your brakes, or having to run after-market wheels to fit, or losing your emergency brake.
This is a thing I would say you need to consider what you are comfortable with, your timeline, and your LONG TERM investment. I have seen a lot of builds die and guys scrap/sell things because they come up with a plan, start to execute, then see "the new hotness swap of the month" and decide to pivot... in the end they throw away a lot of money and burn out.
Please take the time to read, decide what you want, write it down, and revisit it a few times to make sure you are still in agreement with yourself as your knowledge grows. My build(s) have pivoted, though it's all been because I found out something I wanted to do wasn't possible, or I was shown an improvement without changing the core concept. Very important part there at the end.
With bigger projects like this, the adage of "it'll cost twice as much and take three times as long" should be kept in mind so it doesn't demotivate you.
When FieroGuru did a whole bunch of upgrades to my last Fiero (including flipping it over to a EFI and a serpentine belt setup), I think it took him about twice as long as he originally planned. Not from any fault of his own, and not from us changing the plan. Life just gets in the way sometimes, or we'd wait on parts, or the wrong parts show up.
Sorry, it's late, I'll get off my soapbox here.
In short, a brake upgrade, or at least a brake booster upgrade, is well worth it. Please take the time to learn the options and understand the cost/effort for the life of the brake upgrade. You'll be much happier at the end!
My current Fiero isn't a good example here, as we are going full-tilt crazy, swapped in a C5 Vette steering rack and suspension (so Vette brakes and wheels), and grafted C5 suspension to a custom cradle in the back, so Vette gear back there, too. Mike (the guy doing all the hard work) was amazed at how 'easy' it was to put the steering rack in -- but he's an automotive engineer and has decades of auto mechanics and welding under his belt.
Edited to your second post: Most of what I know on the F40 has come from reading FieroGuru's thread. I would suggest starting with his threads, or drop him a PM. He is very knowledgeable, and has always been great about giving me concise, complete information. I think if you are considering doing a lot of highway driving, the F40 has a lot of benefits, and I don't recall too many issues of guys blowing them up!
Take newton ratings from transmissions with a grain of salt. As I was told, the manufacturers strap a transmission to the highest output engine they intend on pairing it with, and beat the snot out of it to see if it holds up. It's a major factor in their rating process. They don't keep throwing more power at it to see when it might blow up. So a transmission rated for 200 newtons, might stand up to a lifetime at 400... while another model rated for 200 might not live for long past 275.
[This message has been edited by Trinten (edited 05-15-2021).]
Make it a manual here is your opportunity to make it as intended.
Manual transmissions have been disappearing for some time and the only remaining vehicles where you can get them is on some select sports cars. The way the Fiero was originally intended was to be offered with the 4 speed manual or the 3 speed auto. The 5 speeds came in 87-88. All transmissions have their advantages and flaws. In the case of the V8 the only ones designed to fit transversely with an auto were the 4.9L and the LS4 engines. The longer SBC doesn't leave enough room for a four speed auto so I would say the F40 is the best choice but by the time you purchase all of the swap parts needed for the SBC swap, the budget may be enough for a more modern engine.
------------------ " 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 "
Also, between the F23 and F40, which transmission do y'all think is better? In my opinion, I favor the F40 due to its 6 speeds and the fact that it offers more room for a larger power band, but I have heard that 1st gear isn't really that useful, as it is very short, and its obviously a bit pricier that the F23 to put in. Is there a way to get around this problem by changing the ratio on 1st gear, or would you have to change ratios on all six? I am not all that keen on how transmission gear ratios work or which ones are better, so any information that would be helpful as well.
Better? There is no answer to that question, it is all about intended use and personal preferences.
Cheaper? - F23 hands down.
Smoother shifting - F23 hands down
Useful 1st gear? - neither is great. 1st gear is 3.77 in the F40 and 3.58 with the F23. The F40 has a 3.55 final drive (13.38 overall launch ratio) vs. the F23's 3.94 (14.1). So stock for stock w/o any gear swapping, the F23 has an overall shorter 1st gear. There are no numerically lower first gears for either transmission... so you are stuck with those. Both the F40 and F23 have a numerically lower final drive that can be swapped. The 3.63 is available for the F23. This lowers the launch ratio to 13.0. The F40 has 3.35 (12.63) as well as 3.091 (11.65) final drives available - but neither are available in the US and will have to be imported from the UK.
I spent a month swapping between my LS4/F40 and Trinten's SBC/F23 on a daily basis. I would drive my car to work, then when I got home would jump in his car for tuning, shakedown runs, and just reliability verification. Both cars were over 400 fwhp, both had similar cam specs, I found myself always looking for another gear or two with the F23. WHen I would normally be in 3rd with the F40, I was in 4th with the F23, which wasn't necessary bad, but when the F40 was in 4th, the F23 would be in 5th and the F40 still had 2 more gears. So for me and my driving style, the F40 gearing was better, while still being less than ideal.
After I did the 3.091 final drive swap, it really changed the feel of the car. 1st gear is good to 44 mph, 2nd takes it to 81 mph, and 3rd is 126 mph, I can run 80 mph on the interstate at less than 2100 rpm, and it can pull down 28-29 mpg with 382 rwhp @ 6800 rpm.
Between my SBC/Getrag and LS4/F40, I have logged close to 100K miles with V8 FIeros, driven them daily 3 seasons each year, used them for 200+ mile daily commutes, and completed many 3000 mile 7 day road trips. So my priorities/expectations from the swap and transmission are a different than most.
Would I have a F23 in one of my personal fieros? Not a chance. Are they a perfectly fine transmission for other people? Absolutely.
[This message has been edited by fieroguru (edited 05-16-2021).]
In addition to the other thread, I can tell you my F23 swap was very inexpensive. Most of the cost was in labor!
This is from memory, though there is a thread documenting when it was put into my car - however a lot of the pictures are gone. Still good info.: Transmission: $400 (low mileage, and it was one of those yards that pulls the parts for you, so you might find it cheaper) Flywheel: $300-ish? New HTOB: $50 Original Spacer: $25-ish FieroGuru later upgraded the spacer setup... not sure what he would charge to make another one. Cables: California Push-n-Pull has the right cables for this swap 'on the shelf' now, one cable is a standard Getrag cable, the other is from Push-n-Pull, and was about $125 Slave cylinder adapter: ~$125 bucks? Optional - there is a Quaife ATB Helical LSD (gear driven, no clutches or springs!), but that adds about 1000 bucks for the LSD, and around 100 for the Kent tools to put it in.
The transmission takes a beating. And in my 350 on the highway, I was getting around 21mpg. I don't recall my final drive. I think at 70mph I was turning 2800 RPM?
One issue I did have was with axles. Apparently the after-market axles for the Fiero are about 0.25" shorter than OEM (so they can work on more than one application). My F23/350 swap didn't quite leave room for that tolerance. When I broke a tripod at the track, the aftermarket axle kept popping out when driving. FieroGuru kindly supplied me with a factory original.
It sounds like the 350 isn't in the Fiero yet, so other stuff you'll need, in general, to put the 350 into the Fiero. (Again, from memory, not exhaustive, please check out some build threads!) 1" adapter plate from Archie to bolt the engine and transmission together (and create provision for starter), or make your own if you have the machining equipment/skills. Oil filter relocation setup, with the return tube going to one of the other ports on the block (cradle makes it nigh-impossible to use as intended) Electric water pump (optional, but could make your lift with belts much easier) Appropriate fittings to hook up remote electric water pump. Block hugger headers Low rise air filter for the carb (Holley makes a triangle shaped one that works well, though the foam filter in it is prone to melting/damage, especially from any backfires from timing being off or carb not having the right jet sizes... I know from experience!)
Say, if I were to put a Quaife LSD in, which model of theirs would be best suited? It seems they made a lot of OEM diffs, but I’m not sure which one would be best for a Fiero axle.
They only make one that works with the F23 (also called the Getrag 287 - probably for use in foreign calls like Vauxhall). The part number is QDF17B.
To my knowledge they do not currently make any others for transmissions going into Fieros. They used to make a few others, but those are discontinued.
My personal opinion is that helical style LSDs are best. Unless they physically break, you never need to maintain them.
There are other companies out there that make the other styles of LSDs (I think you want to avoid Phantom Grip and a few other names they are sold under). Engineered Performance makes some for the Fiero that I've heard good things about, and another company called "Gr8Grip", but I do not have any second-hand knowledge on them, so please do some searches and see if anyone has had issues before buying.
Depending on your power goals, intended use of the car, and driving style, you might not see a benefit. That is a topic that others have debated about. In my opinion, if you want it and can afford it, who cares if you need it. Get it because it will make you happy!!
As Cowspatoot has said to me "No one needs a V8 swapped Fiero!" Though he always does it with a grin, because no one needs a lot of the stuff we do to our cars... him included!
How much tougher than the Factory Getrag are the F40 and F23? How is it measured, torque rating? Does clutch matter to life of the trans, and how?
There is a fundamental problem with the newton rating on transmissions (at least from GM). That is GM does not "test until failure". They design them with what they expect to be the highest output they'll put through them, then the take the alpha and beta and some production units, put them on automated test setups, and run them through cycles (sometimes 24 hours a day, if they are in an area they can get away with the noise pollution). It's not only to make sure they survive the power, but to emulate how much abuse they'll see during the warranty period. The costs that the dealership/manufacturer has to eat for Warranty is calculated and baked into the price.
If the transmissions survive, it get stamped with that number. This is from someone who was an engineer with GM.
So when you see the max torque/newton rating for a transmission, keep in mind that was not a "99% of them survived up to this, 10 more ft/lbs and they blow up!". Which is why people are putting double, triple, or more power through some of these transmissions.
There is one person (JNCOMUTT) who had a twin turbo charged 3800 buckled up to the F23, and was doing clutch dumps and laying out 60' burn outs... and the transmission was fine.
I beat on my F23 as well, transmission lived (CV Joint... not so much).
So if anyone says "It can only handle this much power!" what they mean to say (or should say) is "It was only tested for this much power!"
Originally posted by Trinten: There is a fundamental problem with the newton rating on transmissions (at least from GM). That is GM does not "test until failure". They design them with what they expect to be the highest output they'll put through them, then the take the alpha and beta and some production units, put them on automated test setups, and run them through cycles (sometimes 24 hours a day, if they are in an area they can get away with the noise pollution). It's not only to make sure they survive the power, but to emulate how much abuse they'll see during the warranty period. The costs that the dealership/manufacturer has to eat for Warranty is calculated and baked into the price.
If the transmissions survive, it get stamped with that number. This is from someone who was an engineer with GM.
So when you see the max torque/newton rating for a transmission, keep in mind that was not a "99% of them survived up to this, 10 more ft/lbs and they blow up!". Which is why people are putting double, triple, or more power through some of these transmissions.
There is one person (JNCOMUTT) who had a twin turbo charged 3800 buckled up to the F23, and was doing clutch dumps and laying out 60' burn outs... and the transmission was fine.
I beat on my F23 as well, transmission lived (CV Joint... not so much).
So if anyone says "It can only handle this much power!" what they mean to say (or should say) is "It was only tested for this much power!"
I see, in this case, were the F23 and F40 tested to more power than the Getrag? On paper?
Anecdotally - The GM transmissions are usually numerically designated in newton metres that means F35 is rated at 350 Nm, the F25 at 250 Nm, F40 at 400 Nm, M32 at 320 Nm, and so on.
Originally posted by Trinten: ... Anecdotally - The GM transmissions are usually numerically designated in newton metres that means F35 is rated at 350 Nm, the F25 at 250 Nm, F40 at 400 Nm, M32 at 320 Nm, and so on.
It's kind of interesting that the Cobalt guys break F35s with stunning regularity, with some of the stuff that they're doing. I very seldom (well... never?) hear about a broken F23. Not based on anything scientific. Just what I've gathered from reading forum comments, elsewhere. I personally don't know anyone who has broken an F23. And they seem to get "beat on" a great deal.
Say, I did some looking around, and managed to find another Quaife diff that could potentially work for the f40. The par number is QDF21B. The only thing I’m worried about is if this one is only designed for Euro-style f40 transmissions like the ones Saab or Opel uses. Is this true, or would this diff work across all platforms?
Say, I did some looking around, and managed to find another Quaife diff that could potentially work for the f40. The par number is QDF21B. The only thing I’m worried about is if this one is only designed for Euro-style f40 transmissions like the ones Saab or Opel uses. Is this true, or would this diff work across all platforms?
I would shoot Quaife an email. Their pre-sales support is great (or was when I was investigating this not only for my F23, but other transmissions). I would say just that "I have an MR6/F40 transmission made for a car in the US. Will your part QDF21B work?" They will tell you right away.
My guess is that it will work, as just the bell housings change (to my knowledge!!), but I'm too close to 50/50 to put any money on it.
Say, I did some looking around, and managed to find another Quaife diff that could potentially work for the f40. The par number is QDF21B. The only thing I’m worried about is if this one is only designed for Euro-style f40 transmissions like the ones Saab or Opel uses. Is this true, or would this diff work across all platforms?
Within the F40 production cycle, there are two different differential carriers: AWD and FWD. The AWD version has a splined output sleeve to drive the AWD unit bolted to the transmission differential housing. All the FWD versions share the same differential.
quote
Quaife QDF21B:
Applications:
Fits the following vehicles with GM F40 6-Speed Trans:
