Mission Possible: A Boxy 1984 Caprice Classic

[jcp123]

Headers, maybe. My Mustang shifts at 11-1300rpm bust still gets 15-16mpg. Lacks o/d though.

A 6.2 diesel swap would be intriguing. I'd put my vote in for a 4-53t Detroit Diesel 2-stroke though

[101Volts]

The more I work on the car the more I find I didn't know about it; I was trying to remove screws from the trim around the wheel wells and some of them were frozen on. I asked my neighbor about it and he showed me a way to get them out which includes hitting the screws on the sides.

And I know I can get more MPGs already if I put the tire pressure from 35 to 45. I'll drive it at 35 for a while though.

Originally Posted by spacemanspif

I'm going to stand by my statement that headers MAY help MPG due to the fact that those old exhaust manifolds don't flow well at all and are definitely a choke point in the system. The Y-pipe before the CAT isn't the best either, nor the CAT itself.

I did read about CATs not being very efficient when they were first introduced in 1974. Duly noted, and the car is rather stinky upon first start-up of the day compared to my Dad's 2000 Caravan which I saw the CAT light flashing on twice when I was passing semi trucks although I haven't seen it show up since then. The Caprice is getting close to 111k miles, do you think it needs the air-cleaning equipment replaced just going by description here? I'm thinking that when it does come time I'll have the air-cleaning equipment replaced with something more efficient.

Originally Posted by spacemanspif

You're running an electronic QuadraJet which has a love/hate relationship with car people as some swear by them and other swear they are only good for paper weights. Either way, they are basically the half step between carburetors and TBI because they are still carbs but can adjust fuel mixture like EFI. The carb isn't tunable quite like an old mechanical one but are still tune-able, just a little more complicated. A good book on Rochester carbs will show you where to tweak. One of the first steps is to make sure the giant secondaries aren't opening too soon and adjust your driving style to stay in the zone where only the small primaries are in use. Also turn the key to the run position and listen for the clicking of the mixture control solenoid it should click for about 5 seconds (Kinda like the fuel pump on new cars).

It does do that clicking. My Dad has been talking about getting a book about maintenance for this car, I may end up getting it and a book about carburetor tuning too.

Originally Posted by spacemanspif

FWIW the carb on my Monte was never tweaked when I bought it with 140K and I didn't touch it either before I pulled the engine at 195k. But I also only got about 15mpg the entire time I drove it except for 1 summer where I ran it with a 2.29 rear on the highway getting 25mpg.

If you are set up like my 305 was there is a secondary air pump that pumps air down to the CAT. Located low on the passenger side if the engine. It should have it's own belt. If you want to fiddle with taking off ALL the other belts to remove that one, go for it, but I just cut mine out and never had any issues, removed all the equipment eventually but ran with no belt for quite a while. Those cars have a ton of vacuum lines too, a good check to make sure they are all in good shape and not leaking is one of those preventative things that keep the engine running well and might net a gain in MPG. The vinyl tubing that controls the HVAC ducts can get brittle and crack if you look at it wrong. Also check that the EGR valve is holding vacuum. If you don't have a vacuum pump, unhook the hose, reach under and push the diaphragm up, while holding it up put a finger over the vacuum port and let go of the diaphragm, hold for a minute or 2 and release; if you hear air hiss chances are the EGR is good. You can also keep a finger under the EGR to feel if the diaphragm is moving while keeping the finger over the port.

Sorry for the novel but basic maintenance is the key to a good running, efficient engine.

Yeah, Maintaining cars is a great place to start. Even though we've had work done to this car I think I should check the hoses and whatnot in the engine. I know one of the hoses is broken (If lifted off its place; It holds together, otherwise.) but I think that's only going to the Air Conditioner which doesn't work (Which is not due to the hose.)

Also, Did anyone here read that post on the Station Wagon Forum that I posted on Page 6? It's about Aerodynamics on a car very similar to this sedan and the owner said he noticed a difference.

[cRiPpLe_rOoStEr]

Originally Posted by mechman600

I would be disabling half of the V8. Remove the pan, unhook the rods on one bank and secure them all at TDC, put clamps (nut & spring kind instead of gear) on the empty rod journal oil holes to stop the oil spray. Disable the valve train on the same bank. Voila, a 2.5 four banger.

Replacing it with a real 4-cyl would be more worthwhile because there would be less dead weight to still haul around. BTW there were some Caprices from the 80s fitted with a version of the Iron Duke enlarged to 2.8L, mostly intended to be used as taxi. This engine is currently available for stationary/industrial and marine applications.

[Sven7]

http://www2.warwick.ac.uk/fac/sci/wm...tion120221.pdf

Once you get into simple aero mods, check this out. You might be able to throw a carefully trimmed piece of plexi onto the rear of the trunk lid so it sticks up and encapsulates some of the turbulence behind the rear window. Bring it up to the level of the Aero Template and see how it works! See page 6 in the PDF.

Since boat tails and kammbacks on sedans are notoriously difficult to pull off while maintaining trunk operation, this might be a middle ground good for one or two percent gain. Maybe you could figure out a flexible fabric or plastic kammback covering from there?

[LeanBurn]

I am not sure if you have mentioned this or not, but what are you willing spend on this project?

Engine swaps, modifications etc can add up in a big hurry and you aren't starting off with something that has enormous potential. This site is about making what you have better for fuel economy sake, but if you are spending more than the car is worth, well that is only something you can decide if it's worthwhile.

Once you get the engine running as ecomodder as you can for the least expense, aero is
your nemesis as you know, there are a lot of good hints, but choose those with the biggest points & least expense/effort for the greatest returns. Driver skill will have the biggest impact overall of course.

Get rid of the mudflaps too.

[spacemanspif]

Originally Posted by LeanBurn

Get rid of the mudflaps too.

Dunno why this jogged my memory but it just came to mind that car is running a mechanical fan. Depending on budget, an E-fan upgrade could be in the works. Can go all aftermarket with a controller and fan or get a controller and pick up a Taurus/Mark8 fan out of a JY. They are one of the most popular fans to swap into everything because pretty much universal size and the fact that they pull more air than almost anything else out there.

Don't cheap out on a controller kit that uses those damn radiator probesthat wedge between the fins; get one with a real temperature sensor and adjustable on/off switch...might want to get a temp gauge now too lol.

If I keep this up, that car is a going to be one hell of a pro-street eco-mobile.

Yes read that post in the link. Rear diffuser looks interesting but would take some work to build one and test for actual better MPG.

[101Volts]

I'm surprised how much an electronic fan can help. As it is now, the mechanical fan is on all the time while the car is on. Thanks for that.

Also, I'm buying a locking fuel cap some time soon which is also an aid in fuel efficiency if the old cap was leaking fumes.

[cRiPpLe_rOoStEr]

Originally Posted by 101Volts

As it is now, the mechanical fan is on all the time while the car is on.

Since an electric fan is activated only on-demand, it leads to a quicker warm-up to the correct operational temperature, thus shortening the "cold phase" which is when the fuel consumption at idle is at its peak and the emissions control devices are still not operating at their best.

[101Volts]

I now have a book about the Rochester Quadrajet (Among other carburetors) to read among a number of other automotive books. One of the books is specifically on the cover for Buicks, Oldsmobiles and Pontiacs of similar car models (Station Wagons included) but for some reason not the Chevrolets.

As for mods on the car? Nothing yet really. Can an alternator that needs replaced or repaired negate fuel efficiency? Numerous times the car took longer to start than usual. Was I just not pumping enough fuel to the carburetor before cranking the starter motor? Regardless, if we get the opportunity we're looking at the alternator.

[cRiPpLe_rOoStEr]

Originally Posted by 101Volts

Can an alternator that needs replaced or repaired negate fuel efficiency?

If its bearings are damaged, one can easily guess it would lead to a decreasement on fuel-efficiency, altough it may be deemed negligible.