So I have an extra low mileage 3.1L motor that was going into my 87 GT but I sold the car and its just sitting on a stand. When walking my local Pick n Pull I noticed a couple Chevy Sonic's w/ the turbo 1.4L motors and got to thinking about using two of them, one on each bank, and building a twin turbo motor. I already have a line on some steel tube headers that have a center dump so I'm sure I could get them made up w/ the turbo bracket or V clamp so the mechanical side should be easy. My questions are more on the tuning side, how easy/difficult is it to tune twin turbos on any motor? I'm sure one larger turbo is better but I just want to ask about the twin's first. Thanks in advance for any help
There are a lot of posts on this if you search for 'twin turbo' in entire forum + archives. Many negative opinions, most complaints about the difficulty of tuning. But here is a picture from GM on their twin turbo engine that sports a tantalizingly elegant set up ...
If both compressors are in parallel, with both compressor discharges feeding into the same throttle body, it wouldn't add any complexity controls-wise. The only aspect that would be twinned would be the turbos and piping. The two small turbos could work together as one larger turbo.
On the other hand, if you had a dual-plenum intake, with two MAP sensors (and potentially different manifold pressures for each bank), and cross-connected turbos, that may be outside the realm of typical ECU hardware.
Also if you wanted to to sequential turbos, you might need more specialized ECU hardware to do it.
quote
Originally posted by Notorio:
There are a lot of posts on this if you search for 'twin turbo' in entire forum + archives. Many negative opinions, most complaints about the difficulty of tuning. But here is a picture from GM on their twin turbo engine that sports a tantalizingly elegant set up ...
That turbo is located smack in the middle of the Fiero transmission shift linkages... so you might need to get creative if you wanted to implement that.
Also note that a rear-pointing turbine exhaust is not ideal if you want to package a catalyst, a muffler, and a full trunk.
[This message has been edited by pmbrunelle (edited 12-05-2021).]
Installing a turbo can be a bolt on/plumbing job but there is more to it than that. For low boost 5-7 lbs you can achieve a successful install but if you go to higher boost levels you will need forged pistons and ideally a turbo camshaft. The tuning can be tricky on these as your ECM will need to be reprogrammed to operate with a 2 BAR MAP sensor with a timing table in the program for vacuum and boost.
------------------ " 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 "
I would agree with Dennis here. Before you get too far I would speak to a tuner who has turbo experience and show him what you want to do.
It is easy to bolt the parts on but to get them to run correctly and live is another. To get power you need decent boost but then in the 60 degree engine the head gaskets start to go, then the pistons and rods or even a crank. Get the fuel mixture wrong you will burn a piston. On top of that you need to get the turbo oiling right or you lose a turbo.
Now you are up to the tuning where that has problems all its own.
I ran a 2.0Turbo for 10 years, I saw first hand what all GM did to make the engine survive and make power. They nearly re engineered the engine. They reduced the size to 2.0 from 2.5, they made a special head and block. They created special oil cooling for the pistons and more. My engine made 300 HP and 23 PSI of boost but it was not something I could have done on my own as this was a complete engineered and mfg package from GM.
Then you need to deal with under hood heat.
Based on those from the past I have seen you will lose the head gaskets first and then the pistons if you make any kind of boost.
Back in the old days they made a bolt on kit for a Trans Am 400 CID. Our customer bolted it on. It worked for a while then the crank broke. It had horrible lag as it was a large single unit.
Don't want to be negative here but I have seen too many here end up with a car they can't drive or hate to drive due to a turbo install project. Few get it right so just do your homework before you start.
Regarding re-engineering the engine, I don't really think that's necessary (or economically feasible in most cases) for a garage build.
OEMs need to be thorough in what they do, because even 1/100 engines blowing up is pretty catastrophic money-wise and reputation-wise. If you have that kind of reliability for a garage build, you'll probably be part of the lucky 99 without problems...
As for underhood heat, you plan the exhaust pipe routing accordingly and make heat shields in consequence.
Nowadays, there's a plethora of information available on the internet to the DIYer, which makes these turbocharging easier than it was even just 20 years ago. Tuning is easier now, with people modifying the tunes of ECUs, rather than using RRFPR and SAFC patches. Wideband oxygen sensors are affordable.
The main issue here is this engine was not made for high compression or higher pressures of turbocharging.
There was a guy in the 90’s from PA that did a lot with the 60 degree engine and learned a lot. He went through a number of engines to learn the failure points.
The durability even with low boost was not great. Head gaskets failures broken pistons were all seen at moderate boost levels.
My friends with a Shelby GLHS. He built a 11 second car but could never keep the engine to where it lived long.
By studying what the OE engines are doing it will teach you much of what they learned the hard way. The Buick GN is a classic today but the Buick Turbo T types prior to the GN with a water cooled housing all failed. That is why you never see them today. Same for the Monte Carlo Turbo. Most died by 30,000 miles.
Engines like the Chevy V 8 are forgiving as most were over built so mods make it easier to modify than other engines. 5 head bolts around a cylinder add strength as do some other features.
I agree with some of the points that Hyperv6 has made but Turbo 60* V6 engines have been built, ran well and survived. The point that he makes is that the engines must be built to take boost and the crank strength and head could be an issue. Years back a drag racer by the name of Ron Meyers from Western PA ran 12's in the 1/4 mile with a built turbocharged 3.1L engine and a small shot of Nitrous. The engine had a stock crank ran high boost and held together. His engine control was an aftermarket Haltech ECM. He used a Getrag but clutch life was short. His car was a Burgundy red 1987 Fiero GT. After a couple of years of racing Ron packed up moved to the West coast and sold the car. Its probably still out there but not being raced.
------------------ " 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 "
I’d do a single over twins. It’s just way easier from a plumbing and real estate perspective.
That being said, don’t let the old guys scare you off because they couldn’t make it work. My 2.8 is almost completely stock, including headgaskets, and it has seen as much as 16psi. I imagine a 3.1 wouldn’t be terribly different.
[This message has been edited by Honest Don (edited 12-09-2021).]
I agree with some of the points that Hyperv6 has made but Turbo 60* V6 engines have been built, ran well and survived. The point that he makes is that the engines must be built to take boost and the crank strength and head could be an issue. Years back a drag racer by the name of Ron Meyers from Western PA ran 12's in the 1/4 mile with a built turbocharged 3.1L engine and a small shot of Nitrous. The engine had a stock crank ran high boost and held together. His engine control was an aftermarket Haltech ECM. He used a Getrag but clutch life was short. His car was a Burgundy red 1987 Fiero GT. After a couple of years of racing Ron packed up moved to the West coast and sold the car. Its probably still out there but not being raced.
The key point Dennis is built. You are not just going to bolt on turbo chargers to end engine with cast pistons and no o rings and get good results.
It takes Rod,pistons, crank and o rings on the heads. Even intakes can be an issue if you produce any boost that makes a difference.
Then you need to get the fuel matched to the boost and that is where it takes a good tuner.
Finally it take a good measure of heat management . You will kill the electronics fast with out it and could do other damage.
I never said it could not be done but to bolt on a turbo from a junkyard and get good results is just not a simple thing to do.
Like I have said I have seen over the years a hood number of Fiero’s get Turbos and it takes a good bit of money to get it right. Even then without good knowledge many never see the road again.
There is a guy out there with a TT LS V8 turbo in a Fiero. He really knew what he was doing and did a very good job. It was not cheap or easy but I believe he was making around 700 HP.
There is a guy out there with a TT LS V8 turbo in a Fiero. He really knew what he was doing and did a very good job. It was not cheap or easy but I believe he was making around 700 HP.
There is a guy out there with a TT LS V8 turbo in a Fiero. He really knew what he was doing and did a very good job. It was not cheap or easy but I believe he was making around 700 HP.
Sorry this one dynoed ay 850 hp. Note too the rest of the car was built to take advantage of the power. Making power is one thing but putting it to the ground is a whole other issue. Most fail to follow through.
Cheap is a clue that you should walk away. Maserati of this you are better off just burning the money in a money pit. At least it will keep you warm.
The Alfa Turbo cars had a burst panel on the hood as they were known for intakes blowing. They could hav3 fixed the engine but the blow panel was cheaper. They explained it on Grand Tour. Clark son had one of these cars and I guess he had one let go.
If you want more power, affordable power and trouble free power just drop in a LS v8 or a 3800 SC. Both are easy to find, buy parts for and have few issues.
I know it is cool to have something different but if it will be something that becomes more grief then best to keep away.
Yes we old guys think this way but remember some of us have made this mistake or we have seen others make this mistake. There are a number of Fiero’s out in garages unable to run due to poor project choices as they got in over their heads in experience or money.
If you want something special be the first to put in a new flat crank Z06 engine. They will be showing up in junk yards in the coming years. I expect a create engine too.
Most Italian cars are affordable to buy used but most people can’t afford the up keep.
[This message has been edited by hyperv6 (edited 12-11-2021).]
By studying what the OE engines are doing it will teach you much of what they learned the hard way. The Buick GN is a classic today but the Buick Turbo T types prior to the GN with a water cooled housing all failed. That is why you never see them today. Same for the Monte Carlo Turbo. Most died by 30,000 miles.
T-types and GNs were built at the same time; they were option packages. I think you're confusing that with the progression from carb to efi. Even today, getting good driveability out of a carb/turbo setup is a tall ask. I didn't know that the monte existed, but 40-year-old-low-production cars aren't a common sight in general.
quote
Originally posted by hyperv6:
The key point Dennis is built. You are not just going to bolt on turbo chargers to end engine with cast pistons and no o rings and get good results.
It takes Rod,pistons, crank and o rings on the heads. Even intakes can be an issue if you produce any boost that makes a difference.
Then you need to get the fuel matched to the boost and that is where it takes a good tuner.
Finally it take a good measure of heat management . You will kill the electronics fast with out it and could do other damage.
I never said it could not be done but to bolt on a turbo from a junkyard and get good results is just not a simple thing to do.
Like I have said I have seen over the years a hood number of Fiero’s get Turbos and it takes a good bit of money to get it right. Even then without good knowledge many never see the road again.
Turbocharging is not for the novice.
LOL @ o-rings. Maybe for a four cylinder making 4-digit power?
Aftermarket engine management is a must. I'm using an MS2 which is relatively inexpensive, easy to tune, and has a large and helpful following. Getting a fuel pump and injectors goes without saying. More power is going to require more fuel. Stock L44 regulator is good for ??? (more than what I got)
Killing electronics? Ok, I did have to relocate my ICM to the trunk firewall along with a heat sink.
I suppose "good results" and "simple" are relative terms, but roughly doubling output without even pulling the heads or timing cover is good enough for me. Our local internet-sensation gave me the best advice with "You can have a lot of things not 'right' with a turbo and still make good power."
A failed/forgotten project on jackstands is not a turbo-exclusive situation. What's a good bit of money?
We all gotta start somewhere. I'd much rather burn up an engine that would be getting pulled anyway and learn something vs. hurting a "built right" engine because of inexperience or a missed detail.
quote
Originally posted by hyperv6:
There is a guy out there with a TT LS V8 turbo in a Fiero. He really knew what he was doing and did a very good job. It was not cheap or easy but I believe he was making around 700 HP.
His entire trunk was an intercooler.
Admittedly mine isn't 800hp or a swap, but it does have an intercooler and full(empty?) trunk. It was nice out last Thursday so I took it to buy groceries. The milk was still cold when I got home.
[This message has been edited by Honest Don (edited 12-11-2021).]
A Twin-Turbo V6 Fiero, an interesting concept never attempted on Fiero.nl, though imagined by starry eyed ambitious dreamers, desiring more power from their pathetically anemic '84's. Out of the box, the Maserati Biturbo pumps 180hp, lighter than the Iron Duke or 2.8 iron V6, because it's aluminum. The interface is simple, the '80s blowthrough design is basic, and with a decent intercooler, with more blow-off spring pressure, digital dial-a-boost, more and more. An adapter plate for the transaxle will have to be measured and fabricated, as usual, whether auto or manual, exhaust downpipes to cats and mufflers the ho hum drudge, stainless and titanium mo' better, lol. A few things should be done to insure long reliable life for the bottom end before applying fuel and spark. Head bolts, gasket sealing, bearing clearances, oil pressure, rod bolts, piston sqirters, ping detectors, methanol-water injection, spark control, oil scavenging and cooling, a thorough cleaning and inspection of the red headed six. Twin turbocharging your 3.1 is possible, with time and money to develop strength and durability, new rods, pistons, valves, springs, cams, chains, oil pumps, pans, exhaust piping, turbos, the systems custom and off the shelf, experimentally assembled to function while testing. A fun way to meld junkyard parts into a fire breathing dragon, a Fiero sports performer, all done before by engineers with huge budgets. Keeping it up for the years to get it all sussed out, to a turnkey install, without abandoning the quest or languishing under a pile of fiberglass doodads, gimcracks, flares and wings. So, yeah, the twin turbo ' crate ' engine is an alternative for the Fiero transplant candidate, all systems go. Now, it may be possible to get another 1500 rpm out of the smallblock Maserati, a good thing, screaming. lol. ' V6 Turbo GaleBanks Alfa-Romeo V6 'Busso' Engine The V6 Violin: Alfa Romeo Flame Out MASERATI GT M139 4.2L '04-12 ~3K$ AMG V8 5.5 BiTurbo ~12.5K$ ' TwinTurbo V6 ' Busso ' Throwing money at the problem is one solution, but buying a Maserati, Lancia, Fiat, AlfaRomeo, Lamborghini, or Ferrari engine for your Fiero would be a compassionate act of love, a gift into it's waiting mounts, exciting. lol.
The Maserati Bi-Turbo had an extremely bad reputation for reliability. That engine went into a vehicle that was designed to sell at an affordable price. It became known as the peoples Maserati due to the low price. The engine made 180 HP with 2.5L and twin turbos without an intercooler. Even if it were possible to do a Fiero engine swap with this engine I would stay away. Replacement parts would also be hard to find.
------------------ " 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 "
Originally posted by Honest Don: Admittedly mine isn't 800hp or a swap, but it does have an intercooler and full(empty?) trunk. It was nice out last Thursday so I took it to buy groceries. The milk was still cold when I got home.
Don the TTypes we’re available back to 1977. The early cars lacked the later water cooled housings and most died at 30k miles. It was big business taking these cars and replacing the Turbo with a 4 barrel intake. The EFI car were where the new engine package with the better turbo units were added along with better oils and an intercooler.
No matter the car Monte Lesabre etc these early engines were not very well done. It was 1984 before they started to get them right.
Even the Miller Woods unit was estimated to only live 80,000 miles at best by Miller Woods for the Fiero.
As for O rings it Varys from engine yo engine and what boost you run. A small block Ford V8 will lose a head gasket with moderate boost. But my 2.0 turbo had 5 head bolts per cylinder and reduction in size to have a thicker block. Now I ran 23 psi for ten years with no failures.
The real trouble is the 60 degree blocks and heads were not made for boost of any significance. The internals need upgraded.
You look like you have a nice set up but you don’t list what all you did and you don’t give boost or power levels. If conservative the engine may live.
But on the other hand many people really have no clue when they get into this stuff and most fail and often end up with a car that is a thing they stack stuff on.
I in no way am saying never Turbo. Hey I owned one myself along with a series of supercharged cars. I am just saying don’t get in over your head. Ask for help, educate yourself and even pay for help if needed to get it right. Also consider the other options as an engine swap to a modern engine often is the most gain per dollar spent and often more reliable.
I work in the performance industry and I see failure all the time. I also see success but often those are the people who either know what they are doing or take the time to plan this out. Just taking a turbo from a junk yard and bolting it on is not a sure formula for success.
Too often people watch this crap on Motor Trend TV and often don’t see the dark side or the amount of money the TV guys spend.
A Twin-Turbo V6 Fiero, an interesting concept never attempted on Fiero.nl, though imagined by starry eyed ambitious dreamers, desiring more power from their pathetically anemic '84's. Out of the box, the Maserati Biturbo pumps 180hp, lighter than the Iron Duke or 2.8 iron V6, because it's aluminum. The interface is simple, the '80s blowthrough design is basic, and with a decent intercooler, with more blow-off spring pressure, digital dial-a-boost, more and more. An adapter plate for the transaxle will have to be measured and fabricated, as usual, whether auto or manual, exhaust downpipes to cats and mufflers the ho hum drudge, stainless and titanium mo' better, lol. A few things should be done to insure long reliable life for the bottom end before applying fuel and spark. Head bolts, gasket sealing, bearing clearances, oil pressure, rod bolts, piston sqirters, ping detectors, methanol-water injection, spark control, oil scavenging and cooling, a thorough cleaning and inspection of the red headed six. Twin turbocharging your 3.1 is possible, with time and money to develop strength and durability, new rods, pistons, valves, springs, cams, chains, oil pumps, pans, exhaust piping, turbos, the systems custom and off the shelf, experimentally assembled to function while testing. A fun way to meld junkyard parts into a fire breathing dragon, a Fiero sports performer, all done before by engineers with huge budgets. Keeping it up for the years to get it all sussed out, to a turnkey install, without abandoning the quest or languishing under a pile of fiberglass doodads, gimcracks, flares and wings. So, yeah, the twin turbo ' crate ' engine is an alternative for the Fiero transplant candidate, all systems go. Now, it may be possible to get another 1500 rpm out of the smallblock Maserati, a good thing, screaming. lol. ' V6 Turbo GaleBanks Alfa-Romeo V6 'Busso' Engine The V6 Violin: Alfa Romeo Flame Out MASERATI GT M139 4.2L '04-12 ~3K$ AMG V8 5.5 BiTurbo ~12.5K$ ' TwinTurbo V6 ' Busso ' Throwing money at the problem is one solution, but buying a Maserati, Lancia, Fiat, AlfaRomeo, Lamborghini, or Ferrari engine for your Fiero would be a compassionate act of love, a gift into it's waiting mounts, exciting. lol.
I know of one TT attempted here and it ended poorly.
The best swaps are to find a combo someone has got to work. Ask them for help and copy. Or even builds in magazines can be a recipe for success.
There are just some folks able to sort these things out but there are many that just need help as there is a lot to this and mistakes cost money many can’t afford to waste.
I built mine in the 90's, and I'm still driving it every summer. The turbos are parallel. They are t3's from Saabs of the day (plentiful and cheap used then). Two were a close match for the displacement(3.5L V8). At the time, the most hacked tuning stuff was a 7730 ecm for TPI F bodies. I tuned for a 2 bar MAP and other params for my engine. The pics are from a couple of years ago when I dropped the powertrain to clean up 20 years of grime and replace the old insulation with Dynamat.
OldsFiero - I am envious of your really slick drivetrain creeper! That is a super clever idea and gives a lot more control than my "drop the cradle on it" design. I might have to look into making something similar, that's inspiring!
I'm also envious of your very professional heat shield install. Your template was spot-on. I hope when I redo my bulkhead insulation I can it close to looking as good.
I wouldn’t want to have twin turbos just due to complexity. There is twice as many parts to fail, vacuum lines, oil lines, coolant lines, exhaust flanges can leak, and it is heavier. There’s also many nice examples of well done V6 turbo setups on this forum, the Fiero engine bay gives lots of options for turbo placement that makes a big single no problem with a nice short exhaust.
I could see a benefit to twin turbos being that there are many factory turbos viable as options, so tons of cheap oem jukyard parts available. But I personally wouldn’t do it when a good single turbo setup will be just as powerful and much cleaner.
[This message has been edited by zkhennings (edited 02-19-2023).]
Bugatti EB 110 Ferdinand Piëch did it a different way, used four. Drawing the proposal on the back of an envelope. ' Four ? ' ' Yes ' ' Ok ' I am certain that no more than eight cylinders have been swapped into a Fiero, so far. He.. he.. he.. Not like the concept and practice is something new, since 1988. More than a third of a century.
[This message has been edited by Valkrie9 (edited 02-22-2023).]
It is interesting that today some vehicles use twin turbo as a stock engine. The Ford Expedition is one of them. They replaced the NA V* with a twin turbo V6. The HP rating is almost the same and the turbo engine is 3-4 mpg more efficient than the NA vehicle.
Bugatti EB 110 Ferdinand Piëch did it a different way, used four. Drawing the proposal on the back of an envelope. ' Four ? ' ' Yes ' ' Ok ' I am certain that no more than eight cylinders have been swapped into a Fiero, so far. He.. he.. he.. Not like the concept and practice is something new, since 1988. More than a third of a century.
May I interest you in a 12 cylinder twin turbo BMW motor in a Fiero?
[This message has been edited by IMSA GT (edited 02-22-2023).]
xxx wrong photo ! Front Side xxx wrong photo ! Rear Side
Sure. Entirely possible to adapt these manifolds to a 2.8 - 3.1 cylinder head. Probably simple enough to cut and shut all the exhaust port flanges to the 2.8 - 3.1's pattern. Cut and prep the four factory manifolds on strategic lines, weld, re-assemble. Make room on the front and rear sides of the engine, route exhaust, cats, mufflers, resonance chambers, tips. Definitely will be needing some welding rod. Having a professional welder do the job is a sound plan. ARC Magazine TV This is a huge job, not as simple as it may seem. The benefits of a glowing pair of turbo hot sections will be borne out in the dyno and track testiing. The engine's internals modified to maximum durability, in anticipation of tripled power. Snapping transaxle parts at will ! G6 ! 6T70 !
[This message has been edited by Valkrie9 (edited 02-28-2023).]
I think the easiest way, well maybe not easy due to rarity, but the simplest way to get a 3.1 turbo set up would be from the factory. In 1989 and 1990, Pontiac made a Grand Prix Turbo and GP STE Turbo.
They came with a single turbo, intercooled 3.1 running 11 pounds of boost, (if I remember correctly. It was in '92 when I had mine) and made 205 hp. I believe it used a Mitsubishi turbo. You can occasionally find a set of the manifolds for sale on fleabay or C-list. If you had a donor car, I bet the computer swap and wiring harness mods would not be too difficult and may even have some common circuits being from the same basic generation at Pontiac. This would get you factory spec engine management and an already beefed-up engine built for boost. You would only need tuning if you wanted to turn it up even more. I'm not sure, but you may be able to get an e-prom chip burned for these without much trouble.
quote
Originally posted by hyperv6:
Don the TTypes we’re available back to 1977. The early cars lacked the later water cooled housings and most died at 30k miles. It was big business taking these cars and replacing the Turbo with a 4 barrel intake. The EFI car were where the new engine package with the better turbo units were added along with better oils and an intercooler.
No matter the car Monte Lesabre etc these early engines were not very well done. It was 1984 before they started to get them right.
Just to provide a little information about GM's turbo G-bodies.
The T-Type name didn't come out on the Regal until 1983. Prior to that they were called Sport Coupes. The Regal Sport Coupe and it's turbocharged 3.8, 231 ci engine, debuted as a 1978 model, and it was produced until 1982. The Monte Carlo Turbo was a two-year only production in 1980 and 1981 with the same Buick engine as the SC. The Grand National began as a 1982 model but was not black, it was a two-tone gray. There were about 215 produced with just a few of them turbocharged. Most had a n/a 4.1. The GN went away in 1983, leaving the T-Type as the only boosted Regal. You are correct that it was in 1984 when they started to get them right. In 1984 the, black and bad GN came out, but it was the jump to fuel injection (SFI) and distributorless ignition that made the turbo Regals come alive. In 1986, an intercooler was added that allowed more boost and defeated heat soak problems and the legends were born.
In 1987, the T-Type nameplate went away and the non-GN cars got a simple T emblem and were called a Regal Turbo. The "T" does not stand for turbo like most people think. It actually stood for the touring suspension package that was required on all turbo cars. The same suspension could be had on V-8 Regals which is why you have non-turbo, "T" cars powered by an Oldsmobile 5.0/307 ci engine. In 1987, the GN finally became its own model and was coded into the vin. Prior to that, GN was just an appearance package added to a T-Type car. The only differences were a GN had a fully blacked out exterior, specific chrome wheels, a two-tone interior, and a spoiler as part of the package. With the exception of the 547 GNX's which received special treatment from ASC/McLaren, all GNs and TRs are, front to back, mechanically identical. There were a few other special models such as the Limited and the WE4 but those were strictly appearance and trim packages.
The Buick's turbo 3.8 came back to life at Pontiac with a few changes in 1989. There were 1555, 20th Anniversary, Trans-Am Turbo editions produced. These cars made a lot of Pontiac purists mad when they came out because it was the fastest Trans-Am produced, but it wasn't Poncho powered. Many people think the GMC Syclone and Typhoon use the same engine as the GN but it does not. They Sy/Ty's use a 4.3 Chevrolet engine.
Buick SFI engines used Garrett AiResearch turbos and were air/oil cooled. They did not have water cooled turbos. I can't say for sure about the carbed cars, they may have been water cooled, but I don't think they were. A lot of the early turbo deaths were due to heat soak and lack of proper maintenance and cool down procedures plus Buick's oiling system does leave something to be desired in the blow thru set-up's location. Fuel hitting the compressor blades didn't help, causing increase strain and wear on the turbos. Fuel injection cured some of these problems and allowed some layout changes for the engine that made a world of difference in their ruggedness.
[This message has been edited by Corsair231 (edited 02-28-2023).]
Sure, it will fit.
Used BiTurbo.
