LeSabre Grand National - LG3 3.8SFI engine - speed density and turbo conversion...

[turbokinetic]

Hi guys! Today I started on a really good project. A friend has tasked me with giving his LeSabre Grand National (LGN) a real, worthy-of-name, boosted engine. I'm sharing this thread on a couple other forums so if it looks familiar that's why!

The car is awesome looking. It is black, it is 2-door, and it has all the shiney stuff GM puts on the Grand Nationals. GM built about 117 of these to qualify the LeSabre Coupe for NASCAR. The back end and rear windows are modified for aerodynamics. Otherwise it's just a base LeSabre Coupe.

This is a "low cost" build. The owner wants a daily driver, not a race car. He has a Regal GN, and a Turbo Trans Am both of which are very compenent race cars. His LGN is to be a daily driver. So, the car needs to keep all its features.

-ECM swap and 3-bar Code59 tune.
-Turbo / intercooler build.
-Full gauges cluster swap.

The LG3 has a very low-tech ECM and unreliable MAF meter. This has to go. First, I am converting the engine control system to a 1227730 ECM. This is the same one the later 2.8 and 3.1 engines have. It has many more functions, including boost control and MAP based (speed density) fuel control. No more MAF with all its drivability issues.

Today I installed the new ECM and re-pinned the harness. Hope to get the baseline N/A starter tune done tomorrow. Then it's time to start on the turbo system build.

Modification pictures forthcoming!
David

 

[Pronto]

Clean looking car. That will be a ball turbo'd. Sneak up on unsuspecting riceboys and ruin their day.
Why not run the TB ecm and run a TT SD chip? No MAF involved.

 

[turbokinetic]

Thanks! The owner has done a lot of work to it. He bought it non-running and replaced the fuel tank and pump, paint job, all brake lines and brake parts, multiple other repairs.

As far as the ECM swap? The main reason is, I have plenty of speed-density tuning experience with Code59 on another 3.8 enigne. Made over 400 HP at flywheel.

Another good point is the high speed datalink on the ALDL. The 7730 ECM will send nearly a 10 complete parameter sets per second. It's about real-time on the laptop display. The original ECM sends a parameter set about every 1.5 seconds. :-(

It's all inexpensive stuff. I got junkyard ECM etc. and bought no "performance" parts. I guess you could say I love to use what I have and can get. The performance is there if you know where to look. My Century with same engine and same ECM has been a blast to drive and has been very reliable.

I just got it running with the Code59 ECM. The idle is very good. Tomorrow I will put the WB on it and do some VE tuning.

The Code59 has a really handy road-speed Vs. boost function. It lets me limit boost in lower gears to protect this car's most vulnerable area - the transmission. This is what has allowed my other FWD car to live. Boost minimized until 3rd gear, then ramp it up as car acellerates.

Sincerely,
David

 

[Street Lethal]

Code $59 is an expanded $58 code albeit with kludged VE tables, and other than some added features it is essentially the same code with less resolution. If this project above won't be exceeding 15-psi then your better off running a reworked $58 with the '730 and through relocateable table switch from 16k to 32k. If the engine will be seeing above 15-psi then all the more reason to run Eric's SD chip, as he did all of the hard work for everybody...

 

[turbokinetic]

Well - I have my reasons for choosing this route, knowing there are other options for SD. I am sure Eric's program is very good and tailored perfectly to the LC2 engine characteristics.

My engine is an LG3, which has a factory roller cam. LC2 factory flat-tappet cam. Buick changed the N/A 3.8 motor to from flat-tappet to roller, and netted 15 or 20 HP. Where I am going with this is - the VE of my engine is surely radically different than an LC2. Therefore any LC2 SD program would need tuning anyway. What I am using can be easily tuned with wideband and auto-tune. I already have the equipment and software to do this.

I don't know what level of boost it will have. The transmission is a limiting factor. Whatever it can take before it slips. I have a feeling it will take 15 in tird gear. Time will tell. Eventually the car will get a "fully built" transmission. Then I know it will see 15+ PSI. My other LG3 Code59 build runs 20 PSI or more. It has a fully built 4T65EHD transmission.

It's a fairly tame engine. Resolution on the tables is not a problem. Even with no turbo, and the 3-bar MAP, the engine runs very very well. I can see how a really cammy engine could have some problems with low MAP VE resolution but thankfully this one is not that way.

Sincerely,
David

 

[RUDE DOG]

Nice car I saw one of these at the junkyard a few weeks ago. It was really clean, makes you wonder why it was there at all, anyways your build will be sweet and im looking forward to seing this thing in a finished state to kick some ricer ass. SUBSCRIBED!!

 

[turbokinetic]

Nice car I saw one of these at the junkyard a few weeks ago. It was really clean, makes you wonder why it was there at all, anyways your build will be sweet and im looking forward to seing this thing in a finished state to kick some ricer ass. SUBSCRIBED!!

Thanks!

It's sad to see one at the JY. Was it in TN? I know my friend bought a parts car and had to scrap one. His was stripped clean and the interior was badly deteriorated. Was there any of the special parts on it? (the window covers, spoilers etc.)

Unfortunately I got called out to go overseas today. Sitting at airport. Hope to be able to resume this project next week. I did have time to get all the remaining parts ordered (intercooler etc.) so it will hopefully come together quickly.

When I was test-driving the new ECM, everywhere I went, people complimented the car. It is a looker for sure. Fun!

Sincerely,
David

 

[RUDE DOG]

It was in Indiana

 

[turbobob924]

sweet

 

[turbokinetic]

Hi guys! Got a little progress to report today!
I spent most of the morning driving around town in my CieraXC Turbo, collecting parts for the LGN build I was able to get most of the items neded, except for the Parker hydraulic fittings for the oil pressure line.
But I got the exhaust components and started on the exhaust system fabrication.
The turbo position in this car is a little better than in the A cars, because the full-size H car has more room under the hood. I don't have to tuck the turbo in close to the engine like on the Century. This will make for easier fabrication.
Here is a picture of the turbo tack-welded into position:

Got the crossover / turbo mount completed, with support bracket and insulation wrap:

Got the turbo mounted on the crossover, still working on building the downpipe. Found out I don;t have an exygen sensor bung fitting, nor do I have the flange to connect the rest of the exhaust system. So this is how it sits tonight.
Hope to have much progress on the fabrication this weekend! May get all the exhaust and charge air pipework done, but don't have the oul supply fittings so running the engine won't happen this weekend.
Sincerely,
David

 

[charlief1]

Looking foward to how this goes. I'm suprised more haven't looked at it yet.

 

[Pronto]

I've wanted to do this to a Buick Regatta or an Olds Trofeo. What air filter are you going to use, looks kind of tight there.

 

[turbokinetic]

I've wanted to do this to a Buick Regatta or an Olds Trofeo. What air filter are you going to use, looks kind of tight there.

Pronto, Go for it on the Reatta or Trofeo! Those are very beautiful and rare cars and would be a blast to drive with a turbo engine. One thing to watch out for, the newer ones have a special factory ECM tune that communicates with the car's electronic dash. Nobody seems to have a tuning definition for this one. It may be hard to get a turbo tune done for it!

On the LGN, I'm going to use the original airbox housing with a K&N filter in there. It is very tight in the picture with the complete air filter installed. But, after that picture was taken, I removed the tack welds and moved the turbo aft about 2 inches. Also, the current radiator is not going to stay. I have one from a 1990-up LeSabre, with the transmission oil cooler hoses on the other end. This will free up room for the air intake hose. With these 2 modifications; there's room to have an intake tube made of Duravent hose. It is a high-temp corrugated hose that looks almost identical to the factory's plastic corrugated hose the LG3 came with. I used it on my Century and it has lasted 50,000 miles. Still soft, too.

I always get asked why not install a cone filter? I just don't like the way they look. I want this to look as "factory" as possible. It will never be a race car (transmission limitation) so I am going for a refined look and great drivability instead.

Thanks for the replies!
David

 

[turbokinetic]

Looking foward to how this goes. I'm suprised more haven't looked at it yet.

Thanks. I think it will get more attention as more pictures get added to the thread! I should be able to work on it and make lots of progress soon. The only thing, I have to replace the engine mounts and work on the transmission during the build. It's an old car and many small problems to fix.

 

[Rafs-T-Type]

My girlfriend had an interesting question. How many were made to be sold, and how many were made for nascar? I wonder if that's why there is a question about the production numbers. Maybe the 112 was for sale to public and the other 5 went to nascar.

 

[tta983]

Heres a pic of a LGN in Tennessee. Looking thru the window of a GN it is in front of the TTA and there is also a white Typhoon to the side you can't see.

 

[turbokinetic]

My girlfriend had an interesting question. How many were made to be sold, and how many were made for nascar? I wonder if that's why there is a question about the production numbers. Maybe the 112 was for sale to public and the other 5 went to nascar.

That could be the case! I'm not a historian, just a technician!

 

[turbokinetic]

Heres a pic of a LGN in Tennessee. Looking thru the window of a GN it is in front of the TTA and there is also a white Typhoon to the side you can't see. View attachment 170473

I see. This one lives in Tennessee, near Memphis. The owner has a TTA and a Regal GN. The seats in this one are not near as nice as what you're showing there. I don't know the story on the seats in this car. They are the correct color, but it has split-bench seats.

Thanks!
David

 

[turbokinetic]

OK! Got a little more done today. Not as much as I would have liked to - but you know how that goes!
The downpipe and rear manifold are done.
Downpipe all fabricated and insulated. It has to have a flexible joint in it, because I didn't want to reduce it down to the original exhaust size just to keep the factory ball-and-socket connection. The downpipe is 2.5" from inlet ot outlet. There is an oxygen sensor port, as well as mounting brackets on it. The insulation is very important. This is something I learned on earlier turbo builds. If the turbo system is not insulated, damage will come to other parts of the car which are near the exhaust system. The heat will bake and melt things. The more it is insulated, the better. The non-insulated end is under the car connecting to the catalytic converter where there is already a factory heat-sheild.

Rear maifold, before and after insulation:

Also, here is an interesting picture. Ever wonder what is wrong with a catalytic converter that is rattling and restricted? Here is a cut-away view. Originally there was a fiberglass sleeve around the catalyst, that had it held securely in the housing. After so many years, this disintegrated and then the catalyst rattled around and broke up. You can see how if a piece of it got sideways at the outlet port, it could cause a blockage!

 

[tta983]

I see. This one lives in Tennessee, near Memphis. The owner has a TTA and a Regal GN. The seats in this one are not near as nice as what you're showing there. I don't know the story on the seats in this car. They are the correct color, but it has split-bench seats.

Thanks!
David

This one was in Pigeon Forge Tennessee. The LGN was sold I don't know where it is now. I got the TTA. And the GN was sold also as well as the Typhoon.

The LGN was in pretty good shape, it needed a window regulator and a new battery, just minor stuff.