1988 LeSabre T-Type Turbo: Input needed!!

[Guest 2fit661ca]

With the help of some of my instructors from school, I am going to follow in SteveX's foot steps and begin to work on turbocharging my BLT. Now I know I am an ameture shade tree mechanic, but I have a basic understanding of how a turbo charging system works beyond the theory of compressed air. The turbo Grand Nationals is what initially had me interested in Buicks, and the SFI LeSabre is what got me hooked. Now that I have a LeSabre worth building, I feel it has come time for me to make my dream come true by bring two great things together into one great car.

My plan is to use my 59K LeSabre motor out of my 91, but before I go blowing up my best motor, I am going to invest some time and money into a "trial" vehicle; another 4-door LeSabre or like Olds or Pontiac.

My plan is to reroute the exhaust manifolds to exit through the crossover pipe into the exhaust side of the turbo with either a vacuum, electronic, or manual waste gate. From there, where the exhaust meets back up, I will have the O2 sensor, then run it down to the cat and out the back. The intake side will enter through a true cold air intake placed somewhere in the inner fender, then feed through a MAF donated by a supercharged 3800 into the turbo, down infront of the radiator into an intercooler, then back up to the throttle body. The throttle body and intake will be from a Series I Tuned Port for better flow. I have yet to determine where I will get oil pressure for the turbo from.

On the fuel control side, I will be using injectors from a Series I Supercharged, as well as the fuel pressure regulator, and potentially the fuel pump. The fuel rail will be from a Series I TP.

I have actually located a running 93 Park Avenue Ultra for one of the donor cars. From this, I will use the transmission, the coil pack, the ECM, and all of the fore-mentioned supercharged parts.

Now, I know this sounds like a crazy idea and alot of this had been just thrown together, and that I'm in way over my head, but I am determined to creat a masterpiece here. The SFI 3800 is my all time favorite engine and the idea of building one of Buick's legacies gives me thrills and chills beyond belief.

I would like to say that I am educated in the automotive electronics world and I have a good understanding resistance, voltage, amperage, etc. But that is not to say that I don't have alot to learn before this project will ever hit the streets. That is why I am here. If there is any input that anyone can give me for any aspect of this project, I will be most greatful to hear it. That is providing the input is constructive in some way, and not from some "troll" who wants to bash my ideas and dreams. Even my ideas allready posted need help, for example, I am unsure if the SC injectors even allow more volume than the SFI injectors. Failure is not a concern of mine. As is shown in my signiture, SFI Buicks are not at all hard for me to come by, so I am not affraid to blow up five of them before I decide to tear one down and rebuild it fresh with all new parts so that it may take the pressure I am going to give it. Every mistake made will be nothing more than a trial and error learning experience.

I am not attached to my entire plan stated above, providing my final project has some street manors and sports a turbocharged 3800, so please, any input you may have will be accepted.

Thank you to everyone who has been so helpful in the past, and thank you for your time here as well.

-Chris

[60FlatTop]

Chris,

Here is the place for you: The Buick Lesabre T-type Page

Lots of turbocharged and supercharged write ups there.

Bernie

[Guest 2fit661ca]

I am a member of that page, but I rarely go there because it always seems as though everyone else rarely goes there. There are so many more active Buick users here that I'd rather just go to you guys.

[Guest Redwind89]

Chris

I'm on both sites. I wish I could offer you advice on this but I don't have clue one. To me the T-types were/are fine the way they came and I plan on keeping mine stock. But different people different strokes. I don't hold it against anyone and I love seeing what people do to their cars, just not my cup of tea. I think I have SteveX's email address some where. I'll look, he can help you out a lot more then any one else as he's the only one I know who has done a turbo charge change in the T-types, everyone else goes for the Series II swap. Good luck cant wait to see it.

[60FlatTop]

Well 2Fit & Redwind, check out the T-Type site today. I put some pictures of my '85 PA convert.

I know the T-Type forum is not real active so I put in when I can. I have used their search a lot.

I posted today's pics on this forum as well.

[JohnD1956]

I remember my 95 Riv having an 8.0-1 compression ratio and still requiring 93 octane gas. The 91 will have 8.5-1 compression ratio. You said you would not be too concerned with failure but I would think this will lead to detonation which would then automatically retard the timing and result in lack of power comensurate with the beefed up fuel mix supply.

You said the 93 was running, I would consider using that block.

[Guest 2fit661ca]

I remember my 95 Riv having an 8.0-1 compression ratio and still requiring 93 octane gas. The 91 will have 8.5-1 compression ratio. You said you would not be too concerned with failure but I would think this will lead to detonation which would then automatically retard the timing and result in lack of power comensurate with the beefed up fuel mix supply.

You said the 93 was running, I would consider using that block.

That is actually something I considered, and I know that octane booster will be a frequent purchase from Arnold's. I am keeping the 93 Block, and if it's not too badly worn, I might rebuild it, or just use the heads on my block. My only concern is that I think the intake bolt patterns are different, but don't quote me on that. This car is not my daily driver, so paying more in fuel would be something I could sleep with.

THANKS FOR THE INPUT! It's exactly what I'm looking for.

[Guest 2fit661ca]

Chris

I'm on both sites. I wish I could offer you advice on this but I don't have clue one. To me the T-types were/are fine the way they came and I plan on keeping mine stock. But different people different strokes. I don't hold it against anyone and I love seeing what people do to their cars, just not my cup of tea. I think I have SteveX's email address some where. I'll look, he can help you out a lot more then any one else as he's the only one I know who has done a turbo charge change in the T-types, everyone else goes for the Series II swap. Good luck cant wait to see it.

I can't tell you how awesome that would be, but if you don't have it, that's still fine. He didn't have anyone to ask when he built his, so...

[BUICK RACER]

RegalGS is another place you might want to check out!

[NTX5467]

RegalGS is another place you might want to check out!

RegalGS plus 3800Performance, too. There are many links on the 3800 Performance website to lots of aftermarket vendors which have internal and external engine parts you might desire. PLUS a good explanation of how the GM detonation limiter works! Many of the performance posts will usually reference Pontiac Grand Prix vehicles, but most should also work on Buicks or other vehicles with the Buick V-6.

To me, turbos can be very problematic, but can also produce more ultimate power. You must also remember that the later-model factory transaxle for the last-gen Grand Prix GTP V-8s was the most HD of all of the 4T65E-HD transmission (which are stronger than ANY of the transaxles you have at your disposal) and the engine was "computer-limited" for warranty durability purposes. There are some links on the 3800 Perf website, as I recall, to vendors who have parts to internally upgrade the 4T65E-HD unit for increased power input.

For an idea as to how to configure the turbo plumbing, you can study the original Buick turbos which came as factory options on earlier fwd Grand Prix and Monte Carlos. From experience, these engines clattered on ANY kind of acceleration, especially from low speeds. These earlier years were not GM's best shining hour for turbos! When the turbo oil seal would deteriorate, they'd basically vacuum the crankcase of motor oil, which usually ended in major engine damage. Things became much better in later years.

Another potential look-see could be the later Pontiac TransAM Turbo cars, which used a special version of the Buick V-6 in them. A Buick 3800 with 3300 cylinder heads (to clear the Firebird's inner fenders, compared to the wider heads on the 3800s) and a turbocharger. Yet these cars were rear wheel drive as opposed to the earlier cars mentioned, which were front wheel drive.

Several years ago, there was a company which had turn-key supercharger kits for the Buick 3800 V-6, marketed to the Grand Prix owners. To me, this would be a better option . . . and possibly more likely to fit under the existing stock hood. That way, you could use the many supercharger upgrades (i.e., under-drive pulleys) for more power.

As to the compression ratio and octane requirement. The lower compression ratio is there to decrease detonation tendencies. But it now appears that detonation tendencies can be more related to piston/combustion chamber design and interfaces. In any event, the 93 pump octane is needed to keep the detonation limiter at bay when the supercharger pumps up the cylinder pressure with "boost". The 93 pump octane fuel can equate to the older 97 Research Octane fuel rating. Using octane booster with fuel which is already high octane can, as many articles stated in the 1980s, marginal at best in the increase in fuel octane, even for the more effective brands of that era. Some brands of octane booster are simply adding more alcohol to the fuel to increase octane whereas others add other chemicals at greater cost. There is no really cost effective way to increase fuel octane, other than run unleaded race gas, but that's more costly too.

There's a reason that Buick used superchargers on the more "mass market" vehicles. One reason is "throttle response", rather than having to wait for the turbo to spool-up before it can build boost, whereas the supercharger is already there. Under cruise conditions, there are ways to bleed off supercharger boost, as minor as it might be, to decrease power consumption of the s/c unit, resulting in no cruise fuel economy loss.

Also, you might need to investigate the fact that factory s/c cars had a 3.29 axle ratio rather than the more normal 2.86 or 3.08 (approx) ratio. The 2.86 ratio means that it'll take about 84mph for the engine to be at 2000rpm on the highway. The more relaxed cruise rpms will also mean a longer spool-up time for the turbo when the throttle is suddenly openned, even in "kick-down" mode.

The OTHER thing to also consider is how you're going to plumb the exhaust system under the car, whether for the t/c or s/c motor upgrades! Things can be pretty tight under the hood already, much less with the addition of t/c piping . . . piping which will need some decent-sized radius bends in a very tight area . . . with about 2.5"+ pipes. Once you get the engine bay configured, then once the pipes get under the floor, just using larger pipes and such can be operative . . . relying upon many of the Grand Prix-oriented parts and configurations, I suspect.

With the powertrain items "under control", you'd probably better consider upgrades to the chassis and braking systems. Upgraded brakes, for one. Upgraded chassis calibrations (springs, shocks, tires) for another.

You've got a very ambitious plan laid out. The ultimate amount of power which can be used will be determined by what's on the output side of the engine's flywheel, NOT what's in front of it. The factory s/c engines, the later ones, were rated at about 260-280 horsepower, with the 5.3L V-8s being about 303 horsepower, yet the earlier s/c engines were well below what the later ones produced. Yet the last 3800 s/c engines had more torque than the 5.3L V-8 did, as I recall. Still, though, going to great pains to build more than 300 horsepower can be both over-kill for what the transaxle can tolerate or what the tires can effectively put to the ground--one reason the Grand Prix V-8s had "competition grade" Bridgestones which were wider on the front than on the ones on the rear were.

Perhaps a more viable project might be to find a later-model Grand Prix GT Supercharged car (which will have many brake and suspension upgrades on it, too, which might be able to be transferred to your existing Buicks) and use that as the donor car for your T-Type? This would also generate the necessary computer hardware and such, to run everything, too.

Regards,

NTX5467

[Guest 2fit661ca]

That is an amazing amount of information!! Is it something you pulled from another site, or?

I did buy that supercharged park avenue (turns out it's a 92 only 205 horse motor). I did some research, and the only electrical component that my 88 SFI and that 92 S/C don't share is the Mass Air Flow. I had that supercharger checked out, and it is good to go, so when I pull the engine for the transmission swap, I'm going to throw the supercharger on my exhisting motor and run that for a little while. I am making a slightly smaller pulley for it at school (I tweaked the old one accidentally) so that with the slightly higher compression heads should build a little more power. If I do run into pre detonation problems, I will shoot from there.

thanks for the input, NTX!!

[NTX5467]

Interesting that the earlier s/c engines had very similar horsepower as the later 1990s regular 3800s had, but NOT similar torque output.

Enjoy!

NTX5467