Has anyone had any luck getting a few more HP out of their 2.5 engines? I know there is probably not alot to be had without major modifications, but was wondering if anyone had done exhaust, intake, or computer mods to get a bit more. I truly don't want to sacrifice the reliability, so I'm not willing to do anything "radical" to it. Probably not even a turbo. Like I said, just looking for a couple more solid hp. Mine is a 99 automatic.

Thanks!
Al

 

i had a 2.5 ranger a few years ago and i went pretty extensive is my search for reliable power without going internal or with boost, with accel coil packs a gibson cat back and a "cold air" intake, modified tb, i also ditched the AC. i spent big money on a sct tune and some dyno time and i was a sad boy. if i remember correctly it made 92hp and 117torque which maybe more than stock but i dunno. mine was also a 5 speed. i no longer have the truck but i know the guy i sold it too and he still drives it everyday and his only complaint was he didnt like the drone of the catback.

 

Here is the problem. The truck already comes with a good sized CAI, Accel coil packs are a downgrade, the exhaust is already adequately sized, the TB is already large enough, the stock tune is good. The engine is already well designed to produce as much power as it can safely.

To get more power you must modify the internals. Larger valves, different cam profiles, port work, changes to compression ratio can boost a few HP, but this costs money, and will give you little gain for the money.

By far, the best bang for the buck of HP versus money is turbocharging. You can use the internal parts from a 2.3L turbo motor from an 80's Ford Mustang, Thunderbird, Mercury, or Merkur to convert your motor into a turbo ready motor. To keep heat and AC, the turbo exhaust manifold must be flipped. There is a kit made for that. The main parts you are gonna need is the turbo pistons, rods, and possibly the crank, which will also convert your 2.5L into a 2.3L. You will next need either the turbo valves (which won't fit the 2.5L head without modification), or stainless steel replacement valves specific to your head. You can stick with stock sized or you can oversize them. You need need larger injectors, (the ones of a turbo motor will work), and a larger MAF (the one for an F150 lightning will do) and a way to retune the computer. You will also need a larger fuel pump and to convert your system to a return style fuel rail. Some type of intercooler is also a really good idea.

Cost for the engine parts will be fairly low if you can find a good used 2.3L turbo motor, that should get you the pistons, rods, crank, exhaust manifold, turbo, and injectors, and possibly some other odds and ends. Its a lot of the supporting changes you have to make that are costly. It can be big bucks, but instead of netting you a meager 10-15 hp that you will barely feel, you will get in the ballpark of 70-150 hp over stock, depending on which turbo you use, and which supporting mods you do. Instead of around 100 hp at the crank, a stock 2.3L turbo motor is able to put out 190 hp ('87-'88 Thunderbird Turbocoupe with manual trans ran 190 hp stock), and all the motors are able to produce at least that. Mine is producing around 250 hp to the wheels (around 269 at the crank), but mine is a T-bird, not a Ranger so I already had the right vehicle with the right equipment. I just had to upgrade various parts to support the increased power.

 

Hmmm...that is exactly what I thought. I always felt they are reasonably well built/designed, and it does run good, run clean, and run quite. Thank you Zombie for sharing your experience, that was exactly what I feared. I will probably just leave it alone. Keep it in good tune, and run good gas. For what it is, it's pretty nice. It's quite, economical, and kinda fun to drive, so I'm not sure I want to mess with that for five or even ten horsepower. The idea of a turbo, and twice the hp sounds fun, maybe after we get the boss a new car. But thank you Khan for the info...it's interesting for sure.

 

I have a 2.5-99-I took out the stock paper air filter(restrictive to this engine) and replaced with a K+N, and modified the air box: I used some sheet metal to cover the waffled bottom of the box and brought it up to the top in the back of the lower part-screwed it down with small screws. The air coming in moves across the metal easier than the plastic waffles, and goes right up to the filter. I turned the air horn around the other way, also made another hole in the front of the air box using a hole saw-2"), and another on the fender side. I got rid of the rubber intake tube(didn't like the "bellows" part of the tube,makes the air "ripple"), and made one out PVC pipe(2"), for much smoother air flow. You can buy cheapo air intake tubes, but the PVC costs less than $20. Also used some sheet metal to block hot air from engine at the air box, with small screws. For better throttle response, see how much cable slack you have at gas pedal-pull up on the pedal, and look to see how much cable is hanging out at top of the pedal-used zip ties to take up slack, just leave a little slack for idle speed. Also, make sure you have DOUBLE PLATINUM spark plugs(I use Autolite)as this engine REQUIRES them for optimum efficiency and performance.