I am looking into buying a 4.9 in a reg cab f-150 i would like to make it as fast as i can within a reasonable price range, does anybody have any suggestions, please anything helps.

 

what year you lookin at? carbed or fi?

 

Define, reasonable price range and what you call fast?

 

Fuel Injected (probly a '93-'95)

I consider anything under $1500 over all to be pretty reasonable for a few ponies. I have owned a '94 4.9 so i know all about how they work, just nothing about souping them up. As I sit here I am thinking that since HP is a # derived from ft lb torque and RPM's maybe finding an efficient way to get the 4.9 to turn faster would be a good start. But by all means gents, the thread is now yours.

 

Luckily there is no voodoo involved with the inline engine. It responds much like any other engine.

The largest single step you could take is to have the stock head ported.

Next determine the compression ratio your after, do you need to replace the pistons or mill the head to achieve this? Both are realistic options, there are v-8 pistons that will work and be cheaper than using custom 4.9 pistons.

Next determine if the stock camshaft is something you wanna work with, maybe higher ratio rockers and an adjustable timing gear set to really dial in the stock camshaft. If the stock cam just doesn't have what your looking for, any popular manufacturer that offers camshafts can help you.

Next step might be headers-exhaust.

Then as a last resort, you may want to install a 5.0/5.8 throttle body and port match the intake to the throttle body.

What is obtainable is up to you.

Just remember, the camshaft ties the longblock together. Which means you should really have an idea of the head work, compression ratio, exhaust, tranny stall speed, axle gear ratios and intended use, before you select a camshaft. Also remember, your intended use or effective desire rpms, will play a role in the port work required.

Now you have the computer to look at, as it controls the timing and fuel delivery to meet the long block demands. You could install larger injectors and an adjustable fuel pressure regulator, along with an O2 sensor in hopes of keeping the air/fuel ratio ideal but chances are you won't have much luck and complain about poor mpg. Ideally, you'd want to work with a chip company and a dyno operator, as to really nail down your computer settings, this way you control when the injectors open and for how long to control fuel delivery vs tweaking the fuel psi with the regulator, in hopes of controlling how much fuel is delievered during stock set parameters. An alternative would be to use something like a mega squirt efi controller, they are cheap and can be reprogrammed up to 10,000 times using your laptop computer. Downside, you tune it and there are many little things you should understand. Your emissions would also become useless.

If your looking for HP levels between 250 and 300, larger valves, port work, 260-270 camshaft, free flowing exhaust and 9.5-10:1 compression should get you there, if you can feed it.

If dyno time is a realistic option for you, you may also wanna consider using a carbed head (if all out flow and mid to upper rpm performance is what your after). The carbed head has a more open combustion chamber vs the efi combustion chamber (which in stock form already shrouds the valves but great for developing low end tq). What these chamber differences translate too and why I mention dyno time, one head likes to use more timing than the other, so this needs to be taken into consideration and adjustments made accordingly.

Sorry I didn't answer your question. Good luck

 

How much improvement is expected out of a 5.0 or 5.8 TB? Could prolly get them cheap at a junk yard. Also do they fit correcty?

I'd get a head of a 240 I6, get it a port and polish job, rockers, and bigger valves, since it would bump up the compression a little bit. Actually, if I were lookin to make some good power out of a I6, I'd get a carbed, just so you dont have to worry about all the computer stuff. I hate computer stuff lol.

 

The 5.0/5.8 TB will work with minor tweaking if you will, nothing major at all. However, the TB bore openings are larger than the 4.9 intake opening, to take full advantage of this addition, you'd wanna port the intake a little. Not really something worth doing on a stock engine.

I once added up the cost to convert from efi to carb vs doing what was required to make the efi work with major modifications, the end out of pocket result was about the same.

I agree though, it would be easier to tune with a carb but then again, not too many know how to tune a carb either.

 

You will need to convert to mass air for major work on this engine. The speed density system will go into la la land with all of those modifications, and you won't see the full potential of your work and $$$. Only '96 models came with mass air, though the 5.0L mustangs had mass air as early as '88 I believe.

 

If you get a chip company or someone to work with you, to reprogram your stock speed density eec, you won't need to switch to mass air.



As a matter of fact, the only thing that would make the speed denisty vehice go bonkers, is if you try and use too big of a cam. If there is anything learnt watching these sites over the years, a big camshaft is not needed to make 250-300hp.



As a matter of fact, last time I checked, I was quoted $200 to have my stock speed density set up for modifications and they would keep changing the tables until it was 100% no extra charge.


Thats why you get the dyno time, one because, who doesn't want to know what kinda HP their vehicle is making and two, you can give this info to your eec man and he can make the appropriate changes.


Honestly, if you have a wide band O2, a company should be able to set up a program to work with your mods without dyno time, unless its using forced induction. Depending on your modifications, a good company should be able to take the mods into account and make changes, without any outside information and get you very close.


If someone is wanting to go mass air, do not use the stock 4.9 mass air found on 96 models (california models pervious years). You would be alot better off using a mustang A9L for a couple reasons, one major reason being most companies offer support for this eec, otherwise, they will need you to send them your eec so they can "crack" the program.

 

Motorhead, I was under the assumption that if you start introducing more air into a speed-density system, that the computer won't be able to adjust the fuel accordingly.

There are parameters in the sysstem that only allow a small change in airflow, since the ecu determines fuel according to the O2 sensor, engine speed, MAP, ect. It doesn't actually measure airflow, it only calculates it based upon certain inputs from various sensors.

Perhaps I am wrong? I'm here to learn

 

Speed density bases everything on vacuum levels and the input from the o2 sensor. Thats why the idles gets screwy when you install a camshaft that doesn't allow the engine to maintain a certain vacuum level, its searching for a predetermined parameter thats not there. Basically, if you have a camshaft that produces the required vacuum, the engine will run smooth, however, SD is stupid, so you have to be sure its delivering enough fuel at any given point or it will run lean to rich and not know any better.


Mass air bases things on airflow.

 

Thank you for clearing that up

 

My 1995 F-150 seems to search for a smooth idle with my new Crane H260. And I get an occasional miss/stumble at idle... once every 10-15 seconds maybe. Kind of like an insantaneous off/on in the ignition. My thoughs are that the computer is having a hard time dealing with it. Vacuume has no apparent leaks

I supose I have the Speed Density system.

Just thought I'd throw that in.

 

Thats interesting...what kinda manifold vacuum are you getting?

 

Didn't measure it. I'm sure I'll be posting a few questions when I get a chance to work on it a little. I'm not currently authorized to play with my truck.