Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

What am I, crazy? Why yes, it appears that I am.

I have a 1980 Buick LeSabre Limited with a 4.1 liter V6. My grandfather bought it new. I got it 5 years ago with ~36,000 miles on it. For 4 years it has rotted in my yard because I couldn't afford to insure a toy car. I would look longingly at it, wishing I could take it for a trip because I love driving it. Then I got an idea...the TH350 3 speed automatic means that it could never get practical fuel economy, even with the 2.73 rear end. However, with a 5 speed manual, it has a fighting chance of being hypermiled to some decent numbers. Cheap insurance and cheap parts could partly make up for the low FE, too.

So, I struggled and learned a lot putting in a 5 speed manual from a Chevy S10. Miraculously I made it work. Seriously...it might not be a miracle for someone who knows what he's doing but it is for me. Soon I will replace my 2008 VW with my 1980 Buick for commuting 75 miles per day.

I could post a million pictures but it doesn't matter. This car is ugly. It's going to be ugly for a long time.

Here's some numbers:
3500 lbs curb weight (compare to my VW's 3000)
18 feet long
4.1 liters
125 hp @ 4000RPM (well, when it was new) (VW: 170)
200 ft-lb @ 2000RPM (see, that's not so bad) (VW: 177)
2.73 rear end with 205/75-15 tires

Transmission: Borg Warner T5 1352-145, originally from a 1985 - 86 S10 2.5 L4 or 2.8 V6, although it came in a 1994 S10 2.2 that I bought as a donor vehicle.
1st: 3.76
2nd: 2.18
3rd: 1.42
4th: 1.00 (same as the TH350's 3rd was)
5th: 0.72

This picture is from a few years ago. It looks about the same now, just a little less shiny.
https://lh4.ggpht.com/_oNsRR_T1Qx0/R-...0/IMG_0452.jpg

I haven't remembered to get an interior photo since I got it running. I'll try to remember to get one tonight. So, here's one I took after I finally got the pedals into position.
https://lh4.ggpht.com/_NUF7e4VZj88/TE...0/IMG_5021.JPG

You can see the interior's current condition in this video. It's got a nasty sounding exhaust manifold leak. I know the carburetor isn't working right. Other than that it's functioning pretty well.
[yt]1wxd6KIviRg[/yt]

My first gaslog entry is pretty lame but it's not going to be great immediately...it's going to take some time to get it right.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

great shot of you toes! best wishes in your endeavor...and the car ain't ugly.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

:) Thanks.

It's ugly up close but I won't argue that one too strongly.

The video was mostly for a forum about manual transmissions so I aimed it to get my pedals in frame.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

That's a nice ride!!!

I had one of those a few years ago and they make a great road car. :thumbup:

Killer idea on the manual transmission. Lets us know how it all turns out?

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

Oh I'll definitely be keeping everyone up-to-date. :thumbup:

I'd like to come up with a fair EPA estimate for this car as it was before I modified it. Unfortunately, the EPA doesn't provide the normal data for cars from 1980. Of course I'd like to inflate my ego, but I don't want to be dishonest.

My LeSabre is a 1980 4.1 originally equipped with a 3 speed automatic with a non-locking torque converter.

So, here's some comparisons. Maybe I can derive a fair rating using two different rating systems and comparing the 3.8 which had the 3 speed auto (but by then equipped with a lockup TCC) in 1984 when the good data becomes available.

https://www.fueleconomy.gov/feg/epadata/80guide.txt
- 1980 4.1, 3 speed auto*
Simply says 17MPG. It doesn't specify city or highway. **

- 1980 3.8, 3 speed auto*
Simply says 18MPG. It doesn't specify city or highway. **

https://www.fueleconomy.gov/feg/epadata/84guide.txt
- 1984 4.1, 4 speed auto*
17 city, 20 combined, 26 highway**

- 1984 3.8, 3 speed auto*
19 city, 22 combined, 28 highway**

https://www.fueleconomy.gov/feg/2008c...umn=1&id=27053
1984 4.1 4 speed auto*
New EPA: 14 city, 16 combined, 19 highway

https://www.fueleconomy.gov/feg/2008c...umn=1&id=27052
1984 3.8 3 speed auto*
New EPA: 15 city, 17 combined, 20 highway

*: Lockup or non-lockup torque converter unspecified but I know that 1980 was the last year of non-lockup.
**: Not specified: Whether it's CAFE, old EPA, or new EPA rating.

So...

• In the 1984 data file the city ratings appear similar to the 1980 data file, meaning 1980 data file's ratings may be city.
• In the 1984 data file the 3.8 (now with lockup) gets +1 MPG vs. the 1980 data file 3.8, meaning lockup may be good for 1MPG city.
• In the 1984 New EPA rating the 4.1 gets 3-5MPG less than it does in the 1984 data file.

I can't come up with enough logic to make all the connections, either because I suck or because there's just not enough data. Would it be fair to take the 1984 4.1 New EPA rating and subtract 1mpg city and 3mpg highway for the 4 speed overdrive w/lockup vs. 3 speed non-OD non-lockup?

That would put me at 13 city, 15 combined, 16 highway for guessed New EPA ratings as my car was originally equipped.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

Are you sure its a non-lockup? My 1980 Bonneville had a locking TC in it.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

I would use the EPA's revised numbers from the 1984 model with the 4.1 Subtract 1 MPG city for the T700R4 tranny in place of the TH350 or M200 your car came with new. The highway mileage of all those transmissions was pretty much the same, it was driving at 50 MPH and slower where the different TC's and tranny's made a difference.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

Definitely non-lockup...I took it out and looked at it.

I would think that above 50mph is where that 4th overdrive gear would make the biggest difference. I would also think that lockup doesn't make as much difference until you can use it a lot, when you're cruising in high gear.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

No, because once the TC locks, it does not matter what ratio your high gear is. If you are traveling a steady rate of speed, and the TC is locked your ratio is 1:1. Now, if your speed is not steady, and the TC does not stay locked, then your overdrive may make a little bit of difference, but if that's the case, the transmission is probably going to downshift anyway.

As someone who has converted two vehicles from 3 speed to 4 speed trannys (my Buick and Rusty) the big difference was not in mileage, but in low speed performance. GM's 4 speed automatics of that era had a lower 1st gear ratio as compared to the 3 speed automatics.

Over the years I have tried many transmissions in my vehicles. My Regal was originally equipped with a 3 speed TH350 with lockup. When that died I put a 3 speed M200 with lockup in it from a junked 1980 Century. When that tranny died I put a 4 speed M400 w/ lockup in it.

Rusty originally had a TH350 with lockup, when that died I put a T700R4 with lockup in it.

Mileage only improved marginally with the new upgraded transmissions, but driveability was vastly improved.

Re: Project: 1980 Buick LeSabre, 4.1L V6, 5MT
 

are we talking a full blown project car here or are you gonna keep it looking stock?
either way its a nice toy to mess around with. being an early eighties car id have thought it would get decent mileage as is. id figure 20 combined but i base that on nothing. I know that thing going on a diet would help plenty though.