i am about to get into chip tuning, i have ford svo 24's and an adjustable fpr, and some heads cam intake, would it be ok to set the injector constant rate at 26lbs an hr and set fuel pressure to 50psi that way i get better fuel atomization??

or lower fuel pressure with 24inj constant rate

 

Best IC I found for stock pressure 43.5 and SVO 24# is using an IC of 23.8 on a stock engine and tune.

Which ever route you decide to go, always try and size the IC in accordance with the FP as you described in your original post.

There is some merit to running a higher pressure and some benefits that I have found, such as hot restarts and hot days. TPI cars like to royally boil the fuel in the rails, return system or not, I have alleviated this problem running roulghy 48psi vs stock 43.5

Every car is different. Also, almost all new OEM setups are running a higher FP than our cars had back in the day and also have returnless fuel systems.

Just remember, if u up the pressure, u may have to do some AE rework and do some additional tweaking.

U did mention u are a beginner so I would personally suggest running the stock FP and setting the IC accordingly.

later
Jeremy

 

Start with the actual inj size, and rated PSI.

You need to start with as few changes as possible. *IF* you have issues, then you MIGHT want to change.

Fuel pumps can only do so much work, when you raise the pressure you lower the volume they can supply. And the older the pump the worse it gets. So while you might get a lil better atomization down low, you might have a volume problem at WOT.

 

well i dont think thats a problem ive been running 48psi for the longest time on a stock motor,

a little more detail about my engine

stock bottom, trick flow alum heads 23degree 195cfm, lt4 hot cam 525, 224duration 112lsa, accel super ram runners and plenium, edelbrock ported tpi base, ford svo's , comp cams 1.6 full roller magnums, and edelbrock headers shorties.

so i think ill finally get around to replacing my sending unit and ill throw in a walbro 255lph.

thanks guys for letting me know my idea will work.

 

I won't tell you how many people I've heard say, I didn't think it was a problem, only to later hear them say they tore the corners of the piston domes off, or galled the compression ring. Don't forget, as hotrod the motor, you will definetly be needing more fuel. What got you by on a stocker, might have little to do with what you need for a modified engine.

255?, how about at least a 307?.

 

A Walbro 307 does flow 255 LPH so does the Walbro 340. The 307 will actually outflow the 340 at 43.5 PSI but the 340 will outflow the 307 at 80 PSI. So for our cars the 307 is better, for a newer Corvette with 60 PSI fuel pressure, the 340 may be better.

I just stuck a Walbro 307 in my car in replacement of my Buick GN fuel pump. It raised the fuel pressure from 43.5 to 50 pounds, so keep an eye on that if you change out the fuel pump....

 

U can also shim the spring in a 307 to make it equal and surpass the 340 :-)

Gut one of each and u will notice the spring is the only difference.

Ask me how I know lol

later
Jeremy

 

have any pics of this spring???

im a newb to gutting fuel pumps

 

Dont waste your time touching it if your running under 70psi...

My friend used to make all the ocnversion "improved" 307's for a well known vendor. Also tested them as well

Equal in flow till around 70 psi where the 340 took a lead in overall volume. So 340 and up for extremely high FP or boost.

Shimming the 307 made it every bit the equal of and depending on how far u went better than the 340

later
Jeremy