Turbo Buick

[Blue90]

I saw a car yesterday I was only able to get a quick look at. It was a 2-door Regal T-type; looked like mid-to-late eighties. On the rear was: 3.8 SFI Turbo. Anyone know anything about this powerplant? Reatta compatable?

[2seater]

In the early to mid-80's when the Buick Grand National was being produced, the Regal was also available with the same drivetrain, known as a Turbo T. More accurately, the Grand National was a high end model of the Regal. The engine itself is not compatible with the Reatta. It has a different bellhousing pattern for rear wheel drive cars. The 3800 has the same pattern as the 60* V6 Chevy engine. Even though the engine is a 3.8 Buick, it is a couple of generations older than the 3800, and considerably different internally. The turbo and injectors can be adapted to the 3800, with lots of custom fabrication and tuning, and is a complex DIY project.

[Barney Eaton]

First 3.8 is a clue, Buick changed the engine designation to 3800 in 1988.

Regals as early as 1978 had the turbo option, the last turbo Regals were the 1987 GN. These cars were all rear wheel drive. Attaching the engine to a FWD transmission and turning it 90 degrees causes some problems. Clearance for the accessories would probably be an issue. the exhaust headers would need to be changed and the exhaust pipes reworked.

[Blue90]

Thanks for the info. I knew if it was compatable someone here would have done it by now.

[Guest 84c10]

I'll chime in my 2 cents here, and begin by saying that I'm not entirely sure that it couldn't be made to work easier than is being suggested *if* you got the right parts to do it with. I have a LOT of familiarity with the turbo 3.8 engines.

What many people don't know is there were (depending how far you like to break them down) 7 variations of routing and different sets of headers/turbo/induction parts used over the 1978-1989 lifespan of the motor in production. (Yes, I said 1989 since it appeared in the 1989 Turbo Trans Am Pace Cars in its 86-87 intercooled setup with unique headers and piping.) For reatta purposes lets ignore the 2bbl carb regal/century, 4bbl carb regal/century, and 4bbl carb riviera setups.

This leaves you with three remaining options (also discounting the trans am parts which may actually be a better fit in a reatta since they were redesigned to account for the tighter strut towered f-body engine bay and crossmember...). Basically you had a hotair non-intercooled SFI setup in 1984-85 where in a regal the turbo was mounted up above the intake, but, on a 1984-1985 riviera the turbo was mounted to a unique elbow allowing it to mount *behind* the engine over the transmission - this would be interesting to me for reatta fitment... these turbo rivieras also had unique exhaust manifolds different than the 84-85 regal style of course... and then finally there was the 86-87 regal intercooled setup with the turbo mounted in front and off to the passenger side of the engine which obviously would have issues...

Also note that the fuel injected engines had 8445 casting cylinder heads. Why do I mention this? Well, I have seen references in parts manuals to some early transverse mount 231ci motors also having the 8445 cylinder heads.

In the back of my mind I always contemplated that you could get the early FWD 3.8 longblock with the 8445 heads and chevy 60* bellhousing pattern, assumption being that the intake side would be common to the turbo 3.8 passages and allow bolting on the intake and rearmounted riviera turbo. Along with this you could perhaps use the riviera exhaust manifolds, maybe modify the ones that came on the early FWD long block, or maybe just need to go custom exhaust setup, all depending on how things fit in there. This would discount wiring issues, but, with the number of aftermarket stand alone engine management systems in the turbo buick world these days re-pinning a harness probably isn't necessary and one of those could be used instead.

Not 100% drop in mind you, but, not as impossible of a task as many would lead you to believe. The tough part is that, between 1984 and 1985 combined, under 3000 of the turbo rivieras were built, but then again, I've owned 5 of them, three of which were cannibalized for parts due to extreme rust and rot so at least I have the unique engine parts :cool:

It would also probably be surprising to some how many of the turbo 3.8 parts can come off earlier N/A fwd series cars, including for the 86-87 intercooled style things like the ECM which shares a common part number, just a different chip, or even the coil packs... things which people convert 84-85 motors to run the 8-87 coil pack for example... the early fwd and the late buick SFI 3.8 had far far far more in common than most people give them credit for, its just that the more plentiful older 3.8 n/a motors were carbed and thus clearly different

Edited January 16, 2013 by 84c10 (see edit history)

[Barney Eaton]

84c10.....good input. I am not even close to an expert, with at said, it looks like the Riviera application is the only production FWD to use the 3800 (3.8) with turbo. These are fairly rare and hard to find parts. Also the Riviera had lots of room between the firewall and the engine, so even if the parts are available, there may not be room in the Reatta engine compartment...... end of my observations.

2seater (see his engine photo) has done lots of work over several years building his turbo engine and I always listen to him when this issue comes up.

[Rawja]

It's probably also worth mentioning that the '79-85 Riviera had its engine mounted longitudinally rather than transversely as with the Reatta, so it had a lot more in common with rear-drive applications than you might initially assume..

[2seater]

Ducting the turbo into the existing intake is relatively straightforward. The old style 3.8 intake is different and will not bolt on. The intake port spacing is completely different. The GN exhaust manifolds are sort of compatible, but the round tubular manifolds for the 3800 are better (IMHO). Neither set will work directly without some re-routing of the exhaust to get to the turbine. In my opinion, the only real space for the turbocharger itself is about where the stock air box is. I have seen installations using the stock crossover pipe to feed the turbo and it looks like a natural. It can work pretty effectively if the stock outlet on the rear manifold is deleted and the #6 exhaust stub is turned to face back toward the crossover rather than the stock outlet. Now if you can figure out how to route the exhaust downpipe from the turbine to the existing exhaust the job is almost done. No matter how I tried, I failed to find a good way to get back through the small openings remaining. My first solution was to fabricate a new rear manifold and route the exhaust across the passengers end of the engine and connect to the front manifold, similar to the stock setup, just reversed. That allowed the downpipe to exit through the space where the original crossover was. This first instalation was "hot air" and compressor was ducted directly to the inlet for the MAF. Response was too good and never got the tuning completely ironed out. Second turbo installation uses only the front manifold for feed to the turbine, with a tighter A/R housing and an air-air intercooler was added as well as a divorced wastegate. Boost is lower than desired @ 4psi max, but the operation is seamless. It will just max. out the air flow reading the MAF is capable of. In any case, the O2 sensor must be relocated to after the turbine and probably the EGR tube as well. It should not be in the high pressure exhaust before the turbine. More development to come, as well as resurecting the first installation with an intercooler. When all is said and done, I don't believe the fwd setup is strong enough to handle all the power a GN was capable of unless many other upgrades are done as well. 240-250 hp used with discretion should lead a fairly long life, and that should only require 1/2 bar of boost or so.

[Guest jimmyk]

Would adapting the turbo system from the McLaren Grand Prix turbo be possible? I know that the 3.1L is a completely different engine, but it may be closer to what the Reatta needs since it is FWD transverse powertrain

[D-a-n-i-e-l]

Why would you do all that? You would have to mod the exhaust no matter what so just start with all new parts and do it right. There are several people who have turboed the 3800 with a good amount of success.

[2seater]

Daniel has a point. Used turbochargers are relatively inexpensive and are readily rebuildable for little cost as long as not physically damaged. They work well, but new ones with more modern designs can offer improved performance. A thirty + year old turbo can work just as well today as it did back when it was new, but it won't compete with a ball bearing, ceramic wheel modern version. The original sleeve bearing designs are still available brand new and are more moderately priced. The work I have done is "on the cheap" so to speak, and the old tech. is more than adequate for the modest performance I am seeking. There is generally little to be salvaged from an existing factory turbo offering, except the turbo, wastegate and perhaps some piping. The installation requires a fair amount of fabrication, which I find enjoyable, but it certainly isn't a bolt in. That's the big attraction of transplanting a factory supercharged engine, in part, or the whole thing. It is a proven package that works well, and does bolt in. It is possible to boost almost any engine, it just depends on how it is to be accomplished.