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View Full Version : 1978 Buick LeSabre Sport Coupe - EFI turbo conversion Q's


Daytona_83
04-21-2013, 11:38 AM
Hey guys, my dad has a 1978 Buick LeSabre Sport Coupe that he bought from a guy in Minneapolis that converted the original carb'd turbo to an EFI turbo from an '84-85 hot-air car. The block/internals are the original 1978 engine, but the heads and up are from the '84-85 setup. It needs a little bit of work to get everything going right (wipers don't work, cruise doesn't work, etc), but it runs and drives pretty good. It has Poston hot-air headers and needs gaskets (I was told that OEM replacements work perfectly with the Poston headers).
What I'm wondering is, if he gets the car to where it's really a nice driver and works out all the bugs out of it, is there a way to take the converted '84-85 setup and upgrade it to the '86-87 setup? Or would I have to source out an entire '86-87 engine? Is the '78 block ok to run with the '84-85 EFI setup or would it be best to try and locate a correct 84-85 block?
Also, if I kept the "hot air" setup, how hard is it to add an intercooler to it?

The reason I'm asking these questions, is that my dad said he'd sell me the car and I'd love to get back into another turbo Buick (had an '87 GN years back), but the car is big and I'd like it to move. Any help would be greatly appreciated. Thank you!

Shawn N
04-21-2013, 01:06 PM
You would have to swap engines/harness to move up to the 86/87 and adding a intercooler would cost anywhere from 1000 to 2000 bucks depending on which model is used.

Daytona_83
04-21-2013, 05:31 PM
So buying a universal intercooler and fabbing up your own piping wouldnt work?

Shawn N
04-21-2013, 09:20 PM
Well you could make your own just using a generic intercooler and custom pipes. That's a lot of work to do though and the results may not be what is desired. Spearco has a intercooler/piping for 84/85 hot airs but it lessons spool up with the pipes being so long. The best bet and hp gains is going to be the 86/87 swap.

Keller
04-21-2013, 09:33 PM
You would have to swap engines/harness to move up to the 86/87 and adding a intercooler would cost anywhere from 1000 to 2000 bucks depending on which model is used.
Have you read the 84/85 ECM swap article on the site? I have a feeling the harnesses are not all that different. By changing a few wires, and using the adapter Casper's electronics make for the 86/87 ignition on an 84/85 car, I think it might be fairly easy.

I would not recommend trying to turn a pre-84 motor into a 86/87 setup. There are enough block differences that might make it a motor with a pretty limited lifespan. My suggestions for a block are (1) get an 84/85 block, because people often unload them pretty cheap, and they are perfectly fine for moderate power or (2) get a normally aspirated 86/87 block. Our chat and metallurgic testing has shown that the block is the same, and only lacks a turbo drain hole, which can be drilled and tapped, as the boss is cast in for it. Note that the crank, rods, pistons, are NOT the same. That is where the additional cost will be felt.

As far as an intercooler costing $1000 to $2000, I have no idea what sort of unit you are thinking about. Anything from a stock location 86/87 unit to a budget front mount is not quite that high. The car mentioned here has a lot of front end room. Plus a large grille. The car would be a natural fit for a front mount. Something like a big rig unit modified or cut to fit, or a Ford Powerstroke truck intercooler might be a great option. And used, they won't be that expensive. Nowhere near $1000 - $2000.

Keller
04-21-2013, 09:43 PM
And these B/C bodies of that area can hook well. Witness my friend ElectraJim's '77 Electra. Pretty sure he is running Addco sway bars front and rear, plus has the bracing tubes from a Cadillac of similar vintage that fit between the frame ends on both sides where the bumper(s) mount.

Its not a V6, however. Big block Buick 455.

Shawn N
04-22-2013, 01:14 AM
Ok Keller heres your $1100 84/85 spearco kit. The Kenny Bell Big Boy I had was $1200 with the plumbing and adapters!

http://www.forcedinductions.com/product4.htm

Shawn N
04-22-2013, 01:35 AM
Daytona have you thought of using a alky kit instead of trying to intercool it? They work really well on the hot air 84/85's since it lowers intake temps!

Keller
04-22-2013, 05:49 AM
Ok Keller heres your $1100 84/85 spearco kit. The Kenny Bell Big Boy I had was $1200 with the plumbing and adapters!
Just because it exists (or existed) doesn't mean it was worth it. There are better solutions out there.

Daytona_83
05-01-2013, 07:25 AM
Well I guess first I gotta see how much my dad would sell the car to me for. I might just save a few more bucks and be able to buy a good running/driving 86-87 T-Type that needs paint and interior work for around $5-6k. I just really like the LeSabre because its so different and theres really not a whole lot of em around...thd car's got tons of character! Its just slow...lol