I know a pretty similar question was asked here about a 1996 4.0L engine, but the 3.0L is not the same. If you were going to get your engine rebuilt, as I am, what would you ask the shop to do to increase high end bhp while still satisfy environmental limitations.

Philippe.

 

put in a 4L

 

make the intake ports 65% of their original size, use a smaller diameter intake (2 1/2 the entire length, with a smoother curve toward the intake), roughen the intake ports, use 1 3/4" pipe for a new Y-pipe, and 2" pipe into the cat, after the cat, the rest is up to you, but don't oversize it. If you did all of these thing, gains would be pretty good (I could see 165 hp, but torque would be the real gain here) You would possible get 24 mpg highway consistently as well. It would still not be as powerful as a 4.0, but it would be a mean 3.0. You could also make the cylinders slighty larger. Maybe bore it out to a 3.4L . Don't go too much more than that, otherwise you may assume the 4.0L only real weakness. The 4.0 is not tollerant of even minor overheating.

 

Thanks Khantyranitar, you have often been a good help here.
I may do what you suggest. Could you elaborate a little bit so that I will understand: How reducing by 1/3 the size of the intake ports and pipes would generate more power? I thought that the idea was to make the engine "breathe"??? Just curious.
Philippe.

 

It is a very complex thing, but this is where the increased power is comeing from in todays newer engines. The smaller size will start to restrict as RPMs increase, but at lower speeds, the air in these smaller ports is moveing at greater speeds, produceing an extremely efficient jet like effect. The air will actually force itself into the engine. You have t realize the intake port opens before the cylinder reaches TDC, and closes after the cylinder has begun its compression stroke. IF the ports are too large, the air moveing through them will not have the velocity needed to keep air from flowing backwards as th compression stroke begins. Most intakes on most vehicles are too large to properly accomodate this. If the size is just right, the air will continue flowing through the port and into the chamber as the mixture starts compressing, and you will have an increase in volumetric efficiency. Increased volumetric efficeincy = increased power. The size of the ports will decide the power curve, the smaller the port is, the lower in the powerband this occurs. Stock ports will produce most power in the mid to high rpm range. Smaller ports result in broader powerbands with low end power. If you wanted to try this more moderately, you could make the ports 80% of their original size, and the powerband would be somewhat closer to stock.

A smooth surface slows down air near it a lot. Turbulent surfaces create tiny ball bearing made of air. The surface should be rough, to accomodate this. In a smooth intake, the fuel in the mixture will condense on the metal surfaces, and run into the engine instead of being properly mixed with the gases. You can observe this by looking at your windsheild during a rainstorm, notice the water droplets move rapidly as they fall fromt he sky, but once they hit your smooth windshield they slowly move across the glass, even though the air rushing around your car may be moveing at 60 mph. Notice the droplets often get wisked away from rougher areas, like the trim, because that creates a disruption. The rough intake port probably creates more benefit for a properly tuned vehicle that any other singular aspect of fuel/air mixture tuning. If you deside to increase the engines displacement, be more moderate on reduceing the intake ports size. But whatever you do, do not make them larger unless you want to be revving the moter at 6000 rpm. Only enlarge the intakes if you want a narrow high rpm powerband.

 

I think the 93 Aero 3l engine has sequential fuel injection that is timed with the valve opening event. So it should not have the problem of fuel droplets not mixing well with the incoming air. In this case, you want the the air flow to be smooth. Laminar flow is more dense and takes less energy to move than turbulent flow of the same velocity. The turbulence that will mix the air and fuel will startat the port when the flow has to bend around the valve, and again in the combustion chamber, if it has been so designed. In any case, velocity definitely helps.

A 4l v6 may have more power and torque that a 3l, but its biggest problem is that it has nothing left above 4500 rpm. It may have the type of tuning that Khanty is talking about.

Some of the newer (and not so new) cars use variable induction to broaden the torque and power bands. The SHO Taurus was the first American car (or maybe the ZR1 Corvette) to use this. But like so many other engine combinations, that 3 liter v6 won't fit in the Aero's engine compartment either.

 

a 4000 lb XLT van with all seats in needs torque not horsepower to get up to freeway speed.....most of our driving is 0 to 60 acceleration...not 140 mph runs on straight test track
go out and take on one of these new 6L Ford F350 with the duallys and big meats on the back rims in 4wdr and a Bully Dog Stage 5 putting out 1200 lb ft of torque with your new 06 'Vette....The Ford TPS winds every time 0 to 60..... and it's 1 1/2 tons heavier....

Torque is the champion from the red light
get a real on ramp engine....a 4L

 

Thanks Kanty, XLT and 90 4WDR for your points about i how to improving the Vulcan's bhp output. I would like to ask a supplementary question which I think applies to your comments: what should we think of electric motor driven axial intake air compressors that the market offers. Some of them seem to be affordable ($300.00). To a layman such I myself a device that increases pressure on demand when the intake valve opens should improve the bhp and torque output...or am I wrong? The manufacturer in question claims a guaranteed 4% bhp increase...is this snake oil?

Philippe

 

LOL! Don't waste your time or lessen your wallet with one of these "hair dryers". The manufacturers of these should be tarred and feathered. Like you suspected, pure snake oil.

 

At least they're honest about the power increase, but 4% is barely perceptible.

Significant power gains require significant increases in air and fuel input. Because gasoline is such a dense source of energy, delivering large amounts of it is usually not the problem for most cars. Getting enough air into the engine is the problem. You can do this by fancy induction systems, or an air compressor of some sort, like a supercharger or turbocharger. Either one will take power to drive; usually more power than a small electric motor will provide.

For example, the Thunderbird Supercoupe used a twisted lobe Roots type compressor that was more efficient than the original straight-lobe Roots blower. It added about 60hp and 100 lb-ft of torque to the 3.8l v6. Ford claimed that it used no more than 20hp at its maximum output. You would probably need a 25hp electric motor to deliver 20hp to a compressor, and that would be a pretty big and heavy motor. It's not a very efficient way to try to make more power. This is the same reason that those "Ramair" kits consisting of a large funnel and dryer duct won't do anything but suck up road debris.

 

I have read that in year 2000 the Taurus 3.0 OHV was offered with a 155 hp stock engine...... a 10 hp increase from previous years with seemingly the same design. Does any one know what Ford did to achieve this?

Philippe.

 

It's not even changes in air flow input, but rather in boost, since turbos and superchargers don't help the engine flow more air, they force it to, and anywhere between 5 to 25 psi above atmospheric pressure. Those lame electric superchargers don't even turn over as much CFM as the engine normally aspirates. There are some good electric ones, but they bolt directly to the intake ports, and can only be run about 20 or 30 seconds and require major upgrades to the electrical system. They also require 24 volt power.

 

the idea of a supercharger on an Aero V6 especially the 3L is intriguing....superchargers produce extra power right from idle on acceleration....the Thunderbird SC is an oustanding Ford example of a good low priced supercharger implementation...315 lb ft of torque at only 2400 rpm with an Eaton sc and 8 lbs of boost....0>60 of less than 15.8....4 wheel ABS brakes...4 wheel electronic suspension control w full independent rear suspension

owned one in the mid 90s....a real screamer right front the line...undersize the sc pulley and get 250+ hp out of 3.8L....easily outperformed the Volvo 850 Turbo the wife had and weighted half a ton more...
i could see easily 30 hp increase on a 3L with enough boost

there is a reason that only super chargers and no turbos are used on fuel dragsters and funny cars.....hole shot torque

 

You can do it easily, The trick is fabricateing the supercharger such that in mounts on top of the engine. Would require some fabrication skills, but it would not be difficult to make it put out over 200 hp. Remember, the 3.0 is an overbuilt engine (bigger block than the 4.0), so if used properly, it can handle the heat and pressures from a supercharger better.

 

http://www.whipplesuperchargers.com/...pr11_25_03.asp