Bigger Injectors
just another Rockwell looser
Joined: Feb 2003
Posts: 4,042
Likes: 0
From: Cocoa, FL
if i put some 19# injectors on my engine that has some upgrades on it( port & polished head, chevy valves, 270 cam, flowmaster exhaust, home made intake and excell whole ignition package) it isn't going to be to much to keep the injectors at the stock fuel pressure.
Posting Guru
Joined: Sep 2004
Posts: 1,556
Likes: 5
Consider this:
Six 19 lbhr injectors at 43 +/- fuel psi can support 192hp comfortably.
The 4.9 has 59 psi, which would cause the 19 lbhr injector to perform like a 25/26 lbhr injector.
Six injectors flowing 26 lbhr (aka six 19 lbhr running with 59 psi fuel pressure), would support 250hp if you think your making near that amount. However, your pushing the injector to perform harder than it normally would. Increasing the fuel psi is nothing new, people have been using FMU's on forced induction applications forever but in your case, you'd be running the injectors harder all the time vs the forced induction application where increased fuel psi only occurs under boost. To remedy this, I'd install 24 lbhr injectors along with an adjustable fuel pressure regulator, bring the fuel pressure down to 43-45 psi and then the injectors would perform "comfortably" and all is well, once you dial in a psi that makes you happy.
Six 19 lbhr injectors at 43 +/- fuel psi can support 192hp comfortably.
The 4.9 has 59 psi, which would cause the 19 lbhr injector to perform like a 25/26 lbhr injector.
Six injectors flowing 26 lbhr (aka six 19 lbhr running with 59 psi fuel pressure), would support 250hp if you think your making near that amount. However, your pushing the injector to perform harder than it normally would. Increasing the fuel psi is nothing new, people have been using FMU's on forced induction applications forever but in your case, you'd be running the injectors harder all the time vs the forced induction application where increased fuel psi only occurs under boost. To remedy this, I'd install 24 lbhr injectors along with an adjustable fuel pressure regulator, bring the fuel pressure down to 43-45 psi and then the injectors would perform "comfortably" and all is well, once you dial in a psi that makes you happy.
Last edited by Motorhead351; Dec 6, 2005 at 06:31 PM.
just another Rockwell looser
Joined: Feb 2003
Posts: 4,042
Likes: 0
From: Cocoa, FL
how would you be running the injectors harder? They are really just a solenoid. They will just have more pressure behind them. From reading your posts it looks like the injectors are different from 5.0 to 4.9. In this case that means a 14lb/hr injector in a 4.9 will only flow 10lb/hr in the 5.0. why would ford do this? just to make it hard on us?
Posting Guru
Joined: Sep 2004
Posts: 1,556
Likes: 5
It would be lower thats for sure, if all injectors are rated at 43 psi, then a 4.9 (14 lb hr) injector, would flow 12 lbhr under 39 psi pressure ( if you use them on a stock 5.0).
Some car 5.0's used 14lbhr.
I probably shouldn't have said harder...but everything has its limitations.
My thinking, if I recall correctly, 70 or so psi is about as high as you wanna take the fuel pressure. With 4.9 having 59 psi stock, in my mind your close to reaching the end of the road. So if you can upgrade to a larger injector, drop the psi somewhat and achieve all your goals, this IMO is ideal, then you have room to grow by simply adjusting the fuel pressure somewhat.
If you factor in what the injector can support, if all injectors are rated at 43.5psi and the stock 4.9 is set at 59psi, this would cause a 14lbhr injector to flow somewhere around 18.9 lbhr. On paper, six 18.9 lbhr injectors, should support around 180hp, which isn't alot.
Some car 5.0's used 14lbhr.
I probably shouldn't have said harder...but everything has its limitations.
My thinking, if I recall correctly, 70 or so psi is about as high as you wanna take the fuel pressure. With 4.9 having 59 psi stock, in my mind your close to reaching the end of the road. So if you can upgrade to a larger injector, drop the psi somewhat and achieve all your goals, this IMO is ideal, then you have room to grow by simply adjusting the fuel pressure somewhat.
If you factor in what the injector can support, if all injectors are rated at 43.5psi and the stock 4.9 is set at 59psi, this would cause a 14lbhr injector to flow somewhere around 18.9 lbhr. On paper, six 18.9 lbhr injectors, should support around 180hp, which isn't alot.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
[QUOTE=Motorhead351I probably shouldn't have said harder...but everything has its limitations.
[/QUOTE]
Harder is a fine word to use. The injectors are just a solenoid, which is a giant resistor. After each cycle they need time to cool. Once you get above about 80% duty cycle the heat gained by being on doesn't dissipate in the 20% down time.
[/QUOTE]
Harder is a fine word to use. The injectors are just a solenoid, which is a giant resistor. After each cycle they need time to cool. Once you get above about 80% duty cycle the heat gained by being on doesn't dissipate in the 20% down time.
just another Rockwell looser
Joined: Feb 2003
Posts: 4,042
Likes: 0
From: Cocoa, FL
Makes sense, how do you determine duty cycle for an injector? i can think of many variables that could affect the injectors duty cycle. Just curious really. How come the fuel wouldn't cool it down. Is there insulation on the 4.9's I am confused. Newly crowned engineer seeking more knoledge.
the reason why i chimed up is because this chistmas is going to be a horsepower one. I am turning my truck full time mudder and removing the head and getting chevy valves put in, new valve train, and electronics. I have 19lb injectors from the 92 f-150 5.0. that has since been upgraded to 24lb because of the engine modifications and nitrous. I guess I need to do it right, and do it once, and pay to get the right injectors an and FPR. To bad i couldn't use my old FPR off my mazda (carbed)
the reason why i chimed up is because this chistmas is going to be a horsepower one. I am turning my truck full time mudder and removing the head and getting chevy valves put in, new valve train, and electronics. I have 19lb injectors from the 92 f-150 5.0. that has since been upgraded to 24lb because of the engine modifications and nitrous. I guess I need to do it right, and do it once, and pay to get the right injectors an and FPR. To bad i couldn't use my old FPR off my mazda (carbed)
Last edited by quadzjr; Dec 8, 2005 at 04:48 PM.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
Duty cycle is just the percentage of time it is open. An injector operating at 50% would be open half the time. The fuel does cool it down, but can only do so much.
I remember when I was a newly crowned engineer. The feeling wore off quickly when the economy went to crap.
I remember when I was a newly crowned engineer. The feeling wore off quickly when the economy went to crap.
just another Rockwell looser
Joined: Feb 2003
Posts: 4,042
Likes: 0
From: Cocoa, FL
yeah I already don't like some of the things that come with being an engineer.
1: higher tax bracket
2: being on salary
3: expected to work more (than 40) hours but still only get paid for 40
But in any case I under stand the theoretical defintion of duty cycle (time on) divided by (total time). But how did you come up with 80% how do you know how long the injector is staying open. That is what i don't understand? dosen't that change with rpm, temp, air flow or density, etc..
1: higher tax bracket
2: being on salary
3: expected to work more (than 40) hours but still only get paid for 40
But in any case I under stand the theoretical defintion of duty cycle (time on) divided by (total time). But how did you come up with 80% how do you know how long the injector is staying open. That is what i don't understand? dosen't that change with rpm, temp, air flow or density, etc..
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
Those things didn't bother me about being an engineer. I knew those things going in and was prepared for them. What I wasn't ready for was that management types typically see engineers as a way to spend money and not a way to make money. It's a cut throat business. You can give a company loyal service for 20 years and they will drop you in a heartbeat to avoid paying your retirement benefits. When the economy takes a dump the engineering department is usually near the top of the chopping block list.
80% is just generally considered the point at which the fuel can no longer keep the injector cool enough. It's a rule of thumb. There are those that say that 80% is either too high or too low. A lot depends on the application. The length of time the injector is on is called pulse width. At idle in most applications it is around 4 milliseconds (ms). You can calculate the duty cycle if you know the rpm and the pulsewidth. The pulsewidth is what the PCM calculates with the sensor inputs.
80% is just generally considered the point at which the fuel can no longer keep the injector cool enough. It's a rule of thumb. There are those that say that 80% is either too high or too low. A lot depends on the application. The length of time the injector is on is called pulse width. At idle in most applications it is around 4 milliseconds (ms). You can calculate the duty cycle if you know the rpm and the pulsewidth. The pulsewidth is what the PCM calculates with the sensor inputs.
just another Rockwell looser
Joined: Feb 2003
Posts: 4,042
Likes: 0
From: Cocoa, FL
Thanks for answering my question. Yeah I am just upset seeing that I got promoted to a professional status with the same company after graduation. Before graduation I was hourly and made good money in overtime. But now I am sallary, work the same hours, have more responsiblity, and make the same money after taxes.
I have noticed one thing to be true atleast down here in florida. Environmental engineering will never die and there is less of a risk of getting the boot. Of course It is a bunch of smoke and mirrors and is boring as hell but it is a job for as long one can take it. I really want to get out into the mechcanical field..but I don't want to relocate and don't want to work on turbine blades..
I have noticed one thing to be true atleast down here in florida. Environmental engineering will never die and there is less of a risk of getting the boot. Of course It is a bunch of smoke and mirrors and is boring as hell but it is a job for as long one can take it. I really want to get out into the mechcanical field..but I don't want to relocate and don't want to work on turbine blades..
Thread Starter
|
Junior User
Joined: Sep 2003
Posts: 66
Likes: 0
Hey, I'm back(internet down). Got the 302 throttle body on as well as the (orange top) 19lb injectors. To answer quadzjr's question, the 302 TB bolts in place of the 300 TB with the following mods: Splice TPS wires(they are the same color), grind the pointless protrusion on the bottom of the TB off to clear the brace, modify/relocate the little ball the throttle cable clips on to(get creative with the welder), and port match the intake plenum itself. I used a die grinder and a 2" hole saw. The hardest part about all of that was cleaning out all the aluminum shavings after port matching.
As far as how it turned out, I am NOT dissatisfied, yet not as impressed as I had hoped. I think that I have a vacuum leak on the vacuum tree(I HOPE) because it doesn't want to idle so well. I have more power, but also a much greater RPM range. Before, when really getting down on the throttle, I would have to shift from 2nd to 3rd at about 35 MAX. Now, I can take second to almost 45. Also, before, when cruising at 55, I couldn't downshift to 3rd from overdrive. The truck would slow down. Now, if I perform said downshift, it takes off up to 65 VERY nicely. I haven't been driving with it long enough to see fuel economy changes
P.S.: I probably should have mentioned this before, but I have an RV cam, I think 285.
As far as how it turned out, I am NOT dissatisfied, yet not as impressed as I had hoped. I think that I have a vacuum leak on the vacuum tree(I HOPE) because it doesn't want to idle so well. I have more power, but also a much greater RPM range. Before, when really getting down on the throttle, I would have to shift from 2nd to 3rd at about 35 MAX. Now, I can take second to almost 45. Also, before, when cruising at 55, I couldn't downshift to 3rd from overdrive. The truck would slow down. Now, if I perform said downshift, it takes off up to 65 VERY nicely. I haven't been driving with it long enough to see fuel economy changes
P.S.: I probably should have mentioned this before, but I have an RV cam, I think 285.
Posting Guru
Joined: Jun 2002
Posts: 1,288
Likes: 1
From: redding U.S.A.
Keep in mind also that the injectors are fairly close to the exhaust manifold on this motor, and also close to the intake manifold which is connected to the exhaust manifold. They get hot.
I've read that the fuel pressure was upped because vapor lock was a common issue on these motors, Ford also added a heat shield between the manifold and injectors.
I don't think an RV cam would be a 285..?
I've read that the fuel pressure was upped because vapor lock was a common issue on these motors, Ford also added a heat shield between the manifold and injectors.
I don't think an RV cam would be a 285..?
Thread Starter
|
Junior User
Joined: Sep 2003
Posts: 66
Likes: 0
The cam was ordered as an "RV cam" and it listed all the lift/duration/whatever specs on a sticker on the box. The actual numbers escape me, but the numbers were between 285 and 295, and the lift was like .47? something.
Posting Guru
Joined: Sep 2004
Posts: 1,556
Likes: 5
I bet it looked like this......listed as a high torque camshaft:
<TABLE cellSpacing=2 cellPadding=0 width=821 border=2><TBODY><TR class=litecell vAlign=top><TD colSpan=13>Ford - Mercury 1965-97 240 - 300 CID L6: 1.6 Rocker Arm Ratio</TD></TR><TR class=default vAlign=top><TD></TD><TD colSpan=2>Advertised
</TD><TD colSpan=2>Duration
</TD><TD colSpan=2>Gross
</TD><TD colSpan=2>Lobe
</TD><TD></TD><TD></TD><TD></TD><TD></TD></TR><TR class=default vAlign=top><TD>Performance
</TD><TD colSpan=2>Duration
</TD><TD colSpan=2>At .050 Lift
</TD><TD colSpan=2>Valve Lift
</TD><TD colSpan=2>Center Line
</TD><TD>RPM
</TD><TD>Part
</TD><TD></TD><TD></TD></TR><TR class=default vAlign=top><TD>Code
</TD><TD>Int.
</TD><TD>Exh.
</TD><TD>Int.
</TD><TD>Exh.
</TD><TD>Int.
</TD><TD>Exh.
</TD><TD>Int.
</TD><TD>Exh.
</TD><TD>Range
</TD><TD>No.
</TD><TD>Price
</TD><TD></TD></TR><TR class=default vAlign=top><TD>2
</TD><TD>280
</TD><TD>289
</TD><TD>204
</TD><TD>214
</TD><TD>.451
</TD><TD>.475
</TD><TD>106
</TD><TD>114
</TD><TD>1200-4700
</TD></TR></TBODY></TABLE>
Performance Code 2- High Torque Performance Code 2 cams offer increased low end torque without sacrificing fuel economy. These cams work well in stock or slightly modified engines. A good choice for light trucks or other heavy vehicles.
...listed as a high torque camshaft:<TABLE cellSpacing=2 cellPadding=0 width=821 border=2><TBODY><TR class=litecell vAlign=top><TD colSpan=13>Ford - Mercury 1965-97 240 - 300 CID L6: 1.6 Rocker Arm Ratio</TD></TR><TR class=default vAlign=top><TD></TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD></TD><TD></TD><TD></TD><TD></TD></TR><TR class=default vAlign=top><TD>
</TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD colSpan=2>
</TD><TD>
</TD><TD>
</TD><TD></TD><TD></TD></TR><TR class=default vAlign=top><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD></TD></TR><TR class=default vAlign=top><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD><TD>
</TD></TR></TBODY></TABLE>
Performance Code 2- High Torque Performance Code 2 cams offer increased low end torque without sacrificing fuel economy. These cams work well in stock or slightly modified engines. A good choice for light trucks or other heavy vehicles.
Last edited by Motorhead351; Dec 11, 2005 at 01:03 PM.