Can '80s 'muscle' be ecomodded?
 

Going to try to improve on the improbable.
1987 Oldsmobile Cutlass one of the last of RWD body on frame midsize V8 coupes.
140 odd horsepower of smogged to death goodness pushing ~3500lbs
It may be a hopeless challenge but someones got to try :p

The good.
Fairly sleek body design, can easily reach triple digit speeds.
The bad.
Whoever thought an electronic carbuerator was a good idea needs their head examined.
The ugly.
Can you believe GM stuck 2.14:1 final drives in these cars. 0-60 with a sun dial, but cruising with traffic and the tach staying well below 2Krpm always gives me a fuzzy feeling.

Original EPA was 17/23, revised is 15/21. Is 18/25 too far off, maybe 20/27.
Lets trim some weight off this piggy and see what she can do.

Trimming weight will help most in stop-and-go city driving. Cutting aerodynamic drag will help most for highway cruising. Maxxing-out the tire inflation will help both.

Why bother? Sell the thing (or give it away) and get a small FE frindly car. Both cheaper and better for the environment!

Yes......sell it! (jezzzz........)

You sell it to a boy from the hood.
He wants 'dubs'
He gets finasncing at the local rim shop and pays $3000 for 22" rims and tires. (ps europe....waste of material!!!!.........'sell it'..........)
he also gets teribble mileage.
The the car is repo'd because he cant make payments on the rims......
(should I go on...........)
you buy another car.........more waste.

welcome MAD MIKE!

What about a desiel replacement at some point?
love the rear ratio!

My 66 mustang had a straight six 200 ci and a 2.89 rear ration......loved freeway driving!

My opinion is swap in an obd2 engine and ecu if possible, the advanced computer controls will make a big difference.

Lax swap!!! For economy I vote for a junkyard 4.8 or 5.3 backed by a 6 speed and decent rear gear. Maybe 3.08 or 3.20's? Eliminate all smog stuff you can and have it tuned for economy at cruise and power when you need it.

Or is reusing the original engine eliminate all the smog stuff and add a better flowing intake/carb with better flowing exhaust. Manual trans conversion.

It's simple, it's heavy and not aero dynamic... so you might be able to do better with some mods but even if you swap a diesel or even electric drive you're still using double the energy a cheap small car will use

First off welcome to the forum. Second don't sell it... Especially if there isn't anything wrong with it! The first thing you should do is make sure your vehicle is tuned up and happy. Air filter, plugs, wires, dizzy cap, rotor, carb adjustments, etc...

If you haven't already started doing so start keeping detailed records of your fill ups and mileage. You can calculate MPG and get a ballpark average. The first mod you should think about is to do a "driver mod". See the 100+ hypermiling tips we have here..100+ Hypermiling tips

Since you have a carb try a vacuum gauge and note what readings you get around town, on hills, cruising and on the expressway. A vacuum gauge isn't perfect but it will get you an idea of how hard the engine is working. You want to balance RPM, gear and engine load to get the best efficiency.

The physical mods should wait until you get some baseline numbers. It isn't good to start going nuts and not really know if what you did made an improvement or maybe made your fuel economy worse.

+1 to what Razor02097 said.

Your car is lighter than my truck and has less frontal area. You have a less efficient engine and (I'm guessing) an automatic transmission, but that just gives you more opportunity for improvement.

Good records + persistence is the key.

I'd vote for an engine swap or at least fuel injection.
It seems like it might be a decent vehicle to try to fit a diesel engine from a frieghtliner van, those are pretty small 2.2L turbo diesels if I remember right and have plenty of power to push a big van around while getting over 25mpg.

Well - he could also swop it with a small FE car - what ever....
Point beeing - that by doing so - he would save a lot of $ right away.

Over at the Jeep forums some people would ask how to improve fuel economy... I always hated when there was a reply to sell it and buy an econobox.

I'm sure the OP knows that by selling it and buying a different vehicle one can get better fuel economy but that isn't what the OP asked.

"Original EPA was 17/23, revised is 15/21. Is 18/25 too far off, maybe 20/27.
Lets trim some weight off this piggy and see what she can do."

That to me says the OP wants to experiment with ways to achieve better fuel economy than the EPA says. Isn't that what we all want to do here? This forum would be very boring if every answer to the question "how do I improve my gas mileage?" was "buy a more fuel efficient car"...

Yes Razor - improving any cars FE, or try to do so, is much better than doing noting. I agree. But depending om the miles covered per year, it might be better to sell the gas guzzler and by a small car - economically that is.... Also CO2 wise....

Almost any car can be improved - as shown many times here at ECOmodder, point beeing that car manufactors could do a lot better, but don't dues to beeing afraid that cars might not sell well if they look to odd.....

Ecomodder is about many things, saving fuel and money, doing someting for the environment etc. People motives vary.

Personally I like the econoboxes - so does my wallet....

That isn't my point. If you asked someone "hey I want to make my old house more efficient" how would you feel if they said "tear it down and build another"...?

Sure you can have a more efficient house by replacing it but there are massive improvements you can do to make the house that is bought and paid for more efficient... Just like you can make a bought and paid for car more efficient.

@mad mike I also have a g body it is an 84 cutllass. it has has a built 403 olds in it with the 2.41 gears in it, on the highway it does great 22 mpg, in town about 10. with the right motor combination 20/25 mpg should not be a problem.

1. Get some lightweight aftermarket wheels. You have the most common bolt pattern for any older car, 5x4.75 inches. A used set of Weld or Centerline wheels will save you probably at least 10 pounds of rotational mass per wheel.

2. Electric fan. Lose the factory clutch fan. Electric fuel pump will help too.

3. Lower it. All G-Bodys look better lowered a bit anyway lol.

4. If you want to spend more money, then an aluminum driveshaft, aluminum radiator, and aluminum intake manifold.

5. Pull the carpet, and take out all the sound deadener, then replace the carpet. That stuff is heavy, especially is the inside of the car has ever gotten wet, it soaks up water and holds it.

6. If the vehicle was not going to be used on a public road *cough cough*, I will say that the hydraulic struts that the bumpers attach to are really heavy, they compress in an accident. I have heard that people remove them and replace them with a simple piece of aluminum or steel. Said people have also been know to cut the steel crash bars out from behind the bumpers (which are already steel), and some even the impact beams out of the doors. They are 20 or so pounds a piece. Apparently. But such actions are obviously irresponsible!! :snail:

The tone in this thread reflects badly on this forum. I'm going to edit/delete some posts now, on both sides. (Benevolent dictator, that's me.)

We can disagree without being insulting or getting political.

Some of these suggestions could be considered a bit "extreme" by some (swap in a diesel engine & manual trans, for example). I looked back and saw MADMIKE, the OP, only posted the once and didn't give any indication of "how far" he was willing to go.

However, it looked like his MPG goals weren't "crazy", just a couple more than EPA. As we all know, beating EPA shouldn't be too terribly tough without going "crazy".

Already have started on the weight savings, some early variants came with aluminum hood, and bumpers. These have already been installed with about a weight savings of ~60#s if not more. The hood alone was ~55lbs and the replacement is only 21lbs, according to the trusty bathroom scale. Bumpers were harder to balance on the scale due to shape. The significant change was apparent on the backroads, less plowing, more carving.

Says the guy who is only getting ~37MPG in a Yaris. I thought those things were rated 32/38. :p
*snicker*
I think I'll be looking up your posts for mods of a fellow 3000+lb V8 powered brick;)
As for diesel, meh. It would be nice to avoid the bi-annual smog inspection, and these cars did have the notorious diesel V8s which would be a drop in, but it would need massive amounts of modification of the original induction and fuel system to make it work like a proper diesel.
Engine conversion is tempting with the LSx series. I always did enjoy being in the later 4th gen F bods with a 6 gear. Cruising at 80MPH with the engine burbling along at 1700 rpm with 3.42s was always neat.
Smog components must be maintained, '76-present vehicles still have a bi-annual test.
Compared to other, even newer RWD coupes, it's not that heavy. As for aerodynamics, it is actually a fairly sleek body. 1987 Cutlass profile*link disabled*, and the nose on the 87-88 is more rounded than the earlier brick face 81-86s *link disabled*
I will most likely be looking into cleaning up the undertray of the car, although my main concern is not causing heat issues with the catalyst.
Thanks fellas.
Have gone over the 100tips, however some of the tricks are not applicable to the car due to the emissions control/auto transmission. A manual conversion would be the ticket.
Installed a Vac gauge for diagnostic/engine health reasons, but more recently has become a MPG device.
I already go shoeless, but that was more for brake feel/modulation. And the car came with a block heater.

As for aero, I have a few ideas. It is fairly easy to get this car into the triple digits without even realizing. A highway cruiser for sure.
Thanks razor02097 my feelings exactly.
Heh, yeah I have a few Rockets lying around. The nasty idea of using the swirl port 307 heads on the 403, backed by a Th2004R and keeping the 2.14s has been dancing in my head. I take I5 to L.A. from the Bay Area from time to time. Cruising at a svelte 80MPH while farting along at 1500rpm has me intrigued.:D
I did have a '79 Calais with the 260 TH200 and 2.56:1 rear. 29MPG was not that hard to attain on the freeway. It had Al bits all over.
I actually have been looking but surprisingly the size and offset I would desire are not readily available, heavier than anticipated, or are cost prohibitive. The 'pro touring' trend has killed any normal size wheels.
I thought I could find some AL donut spares and have them modified for a wider hoop/tread. I know Fords came with AL spares but I have yet to stumble upon a GM 5 x 4.75" variant.

The delco clutch fan when off freewheels very easily. I cannot justify replacing that just yet. Now the fuel pump would offer a few advantages, including security.

Already 1" lower ;)

I have been looking into a driveshaft. The Camaros of this era used AL rads that do bolt in, however If I can, I avoid plastic tank rads like the plague. Intake is AL from the factory.

Replaced the carpet a while ago, the old one was about 20lbs heavier with no visibile reason except it probably has accumilated that much grime over the years.

Actually, these cars need a bit of added bracing to keep them from being so sloppy. Removes the vagueness of the car. I will need to maintain the bumper shocks as there are plenty of klutzs on the road. Most folks think they can play bumper car while parking due to the metal bumpers :rolleyes:
Well I'm not going to gut the interior that is for sure. It does have the awful 'Brougham' pillow seats stuck in permanent recline. Which would be nice to get rid of and replace with factory buckets or maybe some ProCar units.

This ain't no Anal Probe!

Currently the goal is modesty, although aero modifications to the nose are going to be the first visible improvements. I have gathered a few air dams to mess with and a few sheets of plywood(can't think of the technical name) for splitter/undertray work. Along with fender vents borrowed from the GNX crowd, luckily the body lines of the Regal/Cutlass are similar in some aspects.

mad mike personally id go for the 350 olds heads 68-72 they would bump the measly 8:1 compression of the 403 to 9-9.5:1 depending on head work and gasket combo. thats what i am going with as soon as i can find a set of heads. also tire rolling distance is a huge factor with older cars checkout 1010tire.com their tire size calculator lets u compare 3 different tire sizes at once


olds motors are known for their low end power and are perfect for cruising down the highway at 1500 RPM in a 3700 lb car

also regal doors are the exact same door as a cutlass and if you really wanted to mess with people take the bumper fenders hood frontclip from the regal and put it in front of the cutlass body

Don't be so afraid of a Diesel swap :D

But instead of the problematic Olds 350 Diesel I'd tell you to get a Cummins 4BT or an Isuzu 4BD1-T.

I'm also not so favorable for such a high rear-end, maybe getting a lower one and either bolting an aftermarket overdrive unit (such as a Gear Vendors) or getting another transmission with a higher ratio for the final drive would help you to improve the inner-city mileage without harming the highway cruising :thumbup:

Factory aluminum intake manifold? I did not know that, that's pretty neat. As for the wheels, there was a time when I remembered the backspacing that worked best with a 15x7 wheel on the back of a G-body, but it isn't ringing a bell anymore. I try to tell myself that I am not that old and that everyone still runs 15 inch wheels so I tend to repress memories of pro-touring nightmare sized wheels lol. My buddy just sold a set of 15x7 & 15x3.5 Convo Pro Centerlines from one of his Grand Nationals for $400. Maybe that stuff is more common up here, but it is still out there, don't lose hope. And yes Ford did have aluminum spare wheels. The two common ones I can think of are from later model Town Cars or Thunderbird Supercoupes. But they are 16 inch, so good luck finding a 16 inch tire that will fit onto a 3.5 inch wide rim. The other aluminum spare was from fox body 5.0 Mustangs, but only the convertibles had the aluminum ones. 15 inch, so you can at least find tires skinny enough to fit them, but they are a 4 bolt pattern so unless you have a 5 bolt pattern redrilled in them, they won't work for you. That's if you can find one. I used to have a pair that I had scrounged, but I lost one. I to this day have no idea what happened to it lol, how do you lose a big chunk of solid aluminum with a tire on it?? But as far as I know, GM never offered an aluminum spare wheel in 5x4.75. I would think that if they ever did it would have been in a Corvette back before they went to run flats and got rid of spare tires altogether, but my plastic pig has a steel, run of the mill space saver.

I have heard that there is a great deal of energy lost in the overdrive units.

Those energy losses are everywhere. So, how many gears does it have? If it's just a 3-speed automatic it might worth consider to replace it with a 4-speed, or even a 6-speed if you can get the engine and transmission out of a wrecked truck with the harness.

Should be easy to do. Start with all the easy, free stuff first. Document changes and FE reading per change. Slightly narrower, taller tires with high pressures work wonders. Good tune up and timing the engine for economy, if possible. A carb rebuild (and re-jet if possible), or a smaller carb, or a Holley aftermarket TBI setup that's programmable. better flowing intake, and exhaust.
Even with the clutch fan, there still is a parasitic drag from it.

Lower rolling resistance, less frontal area, and less RPM will be the ticket... always. Good luck! I'm anxious to see the results. I am highly considering buying a 77 GranPrix again.. (after all these years)...Just to see what we can milk out of it FE speaking.

The 64cc heads would help, but if I go wiht the swirl ports I still only have 67cc heads, along with the smaller intake ports to promote velocity at a low rpm. This car came with the stainless tubular 'headers' that only fit the weeny port 307 7A heads. Don't want to bother changing those two parts out just yet if I switch to the 403 shortblock.
Ewww, Regals. I'm cool. The 87/88 front end messes with people enough. Only the cholos and lowrider crowd seems to know what it is.
I think the Olds diesel just was misunderstood by the engineers and owners. Replace a few things add a proper water separator/filter system would take care of a few basic issues. It would also keep ancillary components attachment simple.
The TH2004R I mentioned is an OD unit. Only change would be to use a different trans crossmember, everything else stays the same.
GV units are neat and splitting gears is neat, however the unit is big, expensive and requires some fab work. Plus the current transmission(TH200C) uses a one piece case. No where to bolt the GV unit on, and a TH350C unit would net me a loss in first gear from 2.74 to 2.5*.
Just easier to use the TH2004R unit.
I was hoping to find a 17" AL space saver. The 98-02 F bods did have them in steel, but the offset is all wrong. Thoughts of the various lightweight drag wheels have come to mind, but again the backspacing/offset is all wrong. 7" width with 40mm/6" back spacing. A bolt on spacer could be used, but then it would just start adding unsprung parts/weight to the car. This car came with one of those 16" steel rims too, not much of a space saver and weighs nearly as much as the factory 205/70 R14 and Super Stock, typical GM goofiness.
Meh, adding a harness, and one of those jantastic 6L80E would be a project in itself. A T56 would be far easier to bolt in.
Heh, with that front end I dunno. Now a later model with the 2+2 nose would be the ticket.

For now I'll focus on cutting through the air, maybe filling up the panel gaps and adjusting the panels for a snugger/sleeker fit. Tuft testing is probably what needs to be done after getting a base line down.

Indeed. But I still like direct-injection engines more than the IDI Oldsmobile Diesels, that's why I suggested the Cummins and the Isuzu :thumbup:

the 350 diesel is a junk diesel motor thats why every converts them to gas

It's actually not the worst engine ever, it suffered mainly from unskilled mechanics and the absence of a water separator filter.