You can skip the next paragraph and go straight to my question if you dont wanna read alot of my reasoning haha.

So driving around town alot has really got me wondering about how restrictive the heads are, I have a VW bug with some mildly worked heads, and an open header. You can be cruising at about 25-30% throttle, and sink it down to about 50, and the engine noise jumps (its sucking more air) and the car starts to accelerate. Well you can floor it (100% throttle) and the exhaust note gets considerable louder, because its got more air going in, well on my truck, it gets loud when you give it about 50% throttle, and then you can floor it, and it barely gets the least bit louder, are the heads such a restriction that the motor is only getting a slight increase in air between 50/60% throttle, and 100% throttle? My intake is not the restriction( dual cone filters, you guys think 1 is cool, try have the only "dual cold air intake" as the ricers wanna call it), and I doubt its my exhaust either, but it might be (cat back flowmaster 40 with 3 inch piping) because the cats could be messed up, butttt.....

So Im thinking about taking my head (off a 93 f150 4x4) and taking it to our local race shop and haveing it ported and polished out the @$$. Im planning on a turbo down the road( as you all have probably gathered from my other posts) so Im staying with EFI, real question is can the stock EFI system take the headwork if I increase the injector size by 10-15 lbs an hour (say from the stock 17-19 to a more resonable 25-35, or will it leave me grossly underpowered and a strange feeling that 400-500$ was wasted.

 

stock injectors are 14#s so you know. If i were you i'd put 24# injectors in afterwards. You could still keep the 24#ers after the turbo upgrade and be fine. If it weren't for the fact that you plan on turboing it i'd say get 19#s which you will find in most of the fords smaller v8s.

With a 1993 fuel injected motor you have a speed density computer which won't take kindly to your motor mods of any kind. Most people say they are only good for 10% over or underbuild.

If i were you i'd take it and have it dyno'd afterwards and have a custom reflashing of the cpu. If that isn't an option talk to some chip manufacturers about making you a custom chip to make your mods work.

Btw most people say a mild porting and polish will serve you just as well as a full hogging out of the head.

 

Thanks for the info.
Whats best, I mean if you cant tell the truck is a constantly being modified, so a single chip may not be the best best bet. I dont wanna go standalone, I mean, if nothing else shouldnt the computer go into open loop all the time, kill my mileage but handle the mods if the injectors can take it?

 

You also have fuel maps etc to consider...

check into megasquirt...its relatively cheap and it would make life easier for someone wanting to mod the efi six...re read the information a few hundred times...it becomes less intimidating after a while, actually kinda simple.

Good luck

 

Yah it would probably just cause bad gas milage if you left it alone. Which would hinder performance. I'd check in to the megasquirt unit myself if i were you. Go to megasquirt.com. It's completely tuneable by labtop and most say it's fairly easy to use. I've read the article once and it sounded like way to much for me but, i was in a hurry and didn't reread it or take any of it in realy.

 

Oh its a great system, Ive used it before on my friends car, but ive never done it from scratch. Ive always gotten baselines from other people. The only thing that you need to realize with megasquirt is its NOTHING but equations. Other than that, its just time. Your looking at about 14 wires, thats it. And a little under 400$ for an assembled box and a harness (dont get the relay board, trust me on that 1). Check ebay, thats where I got the last 1.

 

There is a fella over on fordsix.com that used the MS on his 4.9, maybe you could convince him to give you a "baseline" to get you into the ballpark.

I believe someone is selling them a little cheaper and is known on the MS forums...maybe...I think it takes a while though to actually get it...

 

19# Injectors will work fine, stock pump has 50 psi, and the 19# injectors need around 35 psi. I went to summit racing and got a Holley 10-55 psi adjustable fuel pressure regulator with a pressure gauge port (so I could mount my guage to it), mounted it inline on the fire wall under the hood, that way I can fine tune the pressure instead of using this kind www.bigblocksix.com/eddie/injectorswap.

With the 19# injectors running on the stock 50 psi of fue,l It floods the motor out, But with the adjustable regulator you can cut it back to around 35 psi where it needs to be, then then you can adjust it as you add mods to it. Same goes with 22#+ injectors.

I have contacted a guy that Clifford Performance referred me to that builds ECU's, He was going to build a fully programmable one for me (not a MS) but it was going to cost around $1,100 so I decided that I would rather install a V8 instead of spending that kind of money. If you would like his name and number just let me know.

 

Tweaking the fuel psi is more of a bandaid than fix...your mpg will "usually" suffer...


I would still look into the MS if your serious, then you can run a larger cam and set your fuel maps accordingly.


Nice truck johnsonswamp

 

Ditto to all that especially the nice truck part.