Dynoed my 84 tonight.
05-19-2009, 03:00 PM
#16
Rennlist Member
that wont do it. Just because you have vacuum or pressure on the vacuum port of the fuel regulator, doesnt mean you get a rise of fuel pressure proportionally. normally, there is about 17psi pulling the fuel regs open to let more fuel back to the return lines. removing that line, produces about a 4-5psi net fuel pressure change. adding pressure fights against the diaphram that the 100psi fuel pump is already trying to fight against to give equalibrium of about 50psi. 10psi on the damper wont do much and probably would be half of what idle vacuum does at 17psi (i.e. 4psi net fuel pressure changes). think about it, you are using 10psi to close the return line fuel return, it has nothing related to fuel line pressure, and everything about the spring tension of the regulator, which has kind of proved itself of how much fuel it allows back to the return line based on vacuum.
bottomline, you are slightly lean. get one regulator and install it on the the passenger side and clamp down the driver regulator. you will end up at 12.5:1 no problem, without any fuss.
BTW, im going to try and put 10-20psi on my regulator vacuum input and see what the fuel pressure rises to and get back to you . good idea for a temporary test, maybe you need 20 or 30psi to simulate what we see with the RRFR and clamped driver side regulator return line.
mk
bottomline, you are slightly lean. get one regulator and install it on the the passenger side and clamp down the driver regulator. you will end up at 12.5:1 no problem, without any fuss.
BTW, im going to try and put 10-20psi on my regulator vacuum input and see what the fuel pressure rises to and get back to you . good idea for a temporary test, maybe you need 20 or 30psi to simulate what we see with the RRFR and clamped driver side regulator return line.
mk
Last edited by mark kibort; 05-19-2009 at 03:30 PM.
05-19-2009, 04:34 PM
#17
Drifting
Thread Starter
Mark, it does work. It's based on the Bernoulli Equation.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
05-19-2009, 05:31 PM
#18
Race Director
226 wheel hp @ 4600
277 wheel ft-lb @ 3600"
John
You need LOTS more fuel....your torque peak is quite good, but the max power is FAR too low, due to lack of fuel most likely
using 14.1 AFR for the above numbers and 2.5 bar fuel pressure (36.75psi) I came up with this
AFR now Fuel pressure now AFR you want Fuel pressure you need (psi)
14.10 36.75 12.50 46.76
With the numbers you quoted....making 226hp at 4600rpm equals 258ftlbs so your curve is falling, but not that bad.....with proper fuel you could extend the torque out and maybe make 250whp higher in the rpms...say 5500....
277 wheel ft-lb @ 3600"
John
You need LOTS more fuel....your torque peak is quite good, but the max power is FAR too low, due to lack of fuel most likely
using 14.1 AFR for the above numbers and 2.5 bar fuel pressure (36.75psi) I came up with this
AFR now Fuel pressure now AFR you want Fuel pressure you need (psi)
14.10 36.75 12.50 46.76
With the numbers you quoted....making 226hp at 4600rpm equals 258ftlbs so your curve is falling, but not that bad.....with proper fuel you could extend the torque out and maybe make 250whp higher in the rpms...say 5500....
05-19-2009, 06:39 PM
#19
Rennlist Member
Thats not the system you are working with. If you had a MAP system, yes. Those regulators can vary pressure with manifold vacuum. the less vacuum, the closer that valve inside the regulator is to being shut. at idle, max vacuum, the least amount of fuel is present. I dont know how boost systems run, but under pressure, they might have a linear relationship . those are not the regulators we have, I dont believe.
Do you have the map system or stock? If stock, we are not talking bernoulli here. We are talking how much pressure goes up in the line based on the distance the valve is open in the fuel regulator. If the spring is weak, there would be more reduction in pressure for a given vacuum. under pressure, you are trying to move the diaphram to close off the little hole. It has flow characteristics as well. meaning if it wide open, it doesnt nessarily mean you will get no fuel pressure in the line, it will be a function of the hole in the regulators return line.
In otherwords, what you have done is not going to reflect the change you need to make to fuel pressure. adding 10psion the diaphram side of the regulator, doesnt correlate to a 10psi change in fuel pressure, just as when the vacuum is applied, it doesnt reflect a 17psi change to pressure. (more like 3-4psi)
you need about 52psi of fuel pressure to make it about 12.5:1 based on what we have seen.
anyway, Ive done this with very accuratly predicted results going all the way to 293rwhp on the stock Ljet system and stock injectors and no changes to the system except fuel regulators and the mod I listed. If you do as I have done, you will get plenty of fuel and be, at worst, 13:1.
mk
Do you have the map system or stock? If stock, we are not talking bernoulli here. We are talking how much pressure goes up in the line based on the distance the valve is open in the fuel regulator. If the spring is weak, there would be more reduction in pressure for a given vacuum. under pressure, you are trying to move the diaphram to close off the little hole. It has flow characteristics as well. meaning if it wide open, it doesnt nessarily mean you will get no fuel pressure in the line, it will be a function of the hole in the regulators return line.
In otherwords, what you have done is not going to reflect the change you need to make to fuel pressure. adding 10psion the diaphram side of the regulator, doesnt correlate to a 10psi change in fuel pressure, just as when the vacuum is applied, it doesnt reflect a 17psi change to pressure. (more like 3-4psi)
you need about 52psi of fuel pressure to make it about 12.5:1 based on what we have seen.
anyway, Ive done this with very accuratly predicted results going all the way to 293rwhp on the stock Ljet system and stock injectors and no changes to the system except fuel regulators and the mod I listed. If you do as I have done, you will get plenty of fuel and be, at worst, 13:1.
mk
Mark, it does work. It's based on the Bernoulli Equation.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
05-19-2009, 06:42 PM
#20
Rennlist Member
Nah, thats the most any 2 valve stock 84US has ever made. 220 is on the high side and 200 on the low, with headers and straigth through exhaust. with no other changes but intake and cams, it goes to 243rwhp on that same 200rwhp engien at 12.5:1 fuel ratios and the stock system, probably 250 to 255ish with a car that starts out near 220rwhp as his did .
here is a dyno with the fuel almost a straight line from beginning to end at 12.5:1. We played with fuel and lost 5hp at 12:1 and 13:1. I dont have i on this graph, but take my word for it as i could dig it up if you would like to see the fuel curve.
Headers,exhaust and euro stuff
mk
here is a dyno with the fuel almost a straight line from beginning to end at 12.5:1. We played with fuel and lost 5hp at 12:1 and 13:1. I dont have i on this graph, but take my word for it as i could dig it up if you would like to see the fuel curve.
Headers,exhaust and euro stuff
mk
226 wheel hp @ 4600
277 wheel ft-lb @ 3600"
John
You need LOTS more fuel....your torque peak is quite good, but the max power is FAR too low, due to lack of fuel most likely
using 14.1 AFR for the above numbers and 2.5 bar fuel pressure (36.75psi) I came up with this
AFR now Fuel pressure now AFR you want Fuel pressure you need (psi)
14.10 36.75 12.50 46.76
With the numbers you quoted....making 226hp at 4600rpm equals 258ftlbs so your curve is falling, but not that bad.....with proper fuel you could extend the torque out and maybe make 250whp higher in the rpms...say 5500....
277 wheel ft-lb @ 3600"
John
You need LOTS more fuel....your torque peak is quite good, but the max power is FAR too low, due to lack of fuel most likely
using 14.1 AFR for the above numbers and 2.5 bar fuel pressure (36.75psi) I came up with this
AFR now Fuel pressure now AFR you want Fuel pressure you need (psi)
14.10 36.75 12.50 46.76
With the numbers you quoted....making 226hp at 4600rpm equals 258ftlbs so your curve is falling, but not that bad.....with proper fuel you could extend the torque out and maybe make 250whp higher in the rpms...say 5500....
05-19-2009, 07:30 PM
#21
Drifting
Thread Starter
I know it needs quite a bit more fuel. I bought some 86 rails and injectors from Mason earlier today. I figure that with the Aeromotive adjustable regulator I have should get me in the ball park, at least under power. I'll have to live with running rich everywhere else until I get the other controller on it.
Mark, my car still uses the complete stock injection system, so no MAP just yet.
Thanks for the info guys.
05-19-2009, 07:37 PM
#22
Rennlist Member
I just noticed Brian's response. He showed something like 46psi?pretty close. I was at 52psi. Dont mess with the 86 injectors or fuel lines, just use the stock stuff as I have described and you will be just fine. remember, clamp off the driver side fuel regulator and use an S4 regulator on the passenger side, or a common adjustable regulator.
The beautiful thing about the Ljet, is that under part throttle, the fuel will be controled well, so you wont run rich, even with high fuel pressure. (closed loop mode)
as I said, we did this with Scot and his worked perfect.
you start messing with larger injectors, or other mods and you dont know what you will end up with. (until your non-Ljet system is installed)
Remember, with our systems, the vacuum lines on the fuel regulator is for idle fuel pull back, and thats it. at WOT, there is no vacuum and the system pressure is self regulating via the internal spring to the diaprham and return line and fuel pump pressure.
mk
The beautiful thing about the Ljet, is that under part throttle, the fuel will be controled well, so you wont run rich, even with high fuel pressure. (closed loop mode)
as I said, we did this with Scot and his worked perfect.
you start messing with larger injectors, or other mods and you dont know what you will end up with. (until your non-Ljet system is installed)
Remember, with our systems, the vacuum lines on the fuel regulator is for idle fuel pull back, and thats it. at WOT, there is no vacuum and the system pressure is self regulating via the internal spring to the diaprham and return line and fuel pump pressure.
mk
I was happy with the torque it made. Started at 260 ft-lbs at 2000 rpm. It was flat basically out to the peak and then rolled off pretty sharp.
I know it needs quite a bit more fuel. I bought some 86 rails and injectors from Mason earlier today. I figure that with the Aeromotive adjustable regulator I have should get me in the ball park, at least under power. I'll have to live with running rich everywhere else until I get the other controller on it.
Mark, my car still uses the complete stock injection system, so no MAP just yet.
Thanks for the info guys.
I know it needs quite a bit more fuel. I bought some 86 rails and injectors from Mason earlier today. I figure that with the Aeromotive adjustable regulator I have should get me in the ball park, at least under power. I'll have to live with running rich everywhere else until I get the other controller on it.
Mark, my car still uses the complete stock injection system, so no MAP just yet.
Thanks for the info guys.
05-19-2009, 07:45 PM
#23
Rennlist Member
Did you get a fuel pressure value from the rail? if not, its probably not as high as you think by just adding 10psi to the intended "vacuum" line .
46psi was fine for us at 230 to 250rwhp. we bumped a little higher to 50psi to handle the 290rwhp with the same exact system. it was closer to 12:1 with scot, but safe.
. My 84 euro 5 liter ended up at 12.5:1 and 285rwhp
mk
46psi was fine for us at 230 to 250rwhp. we bumped a little higher to 50psi to handle the 290rwhp with the same exact system. it was closer to 12:1 with scot, but safe.
. My 84 euro 5 liter ended up at 12.5:1 and 285rwhpmk
Mark, it does work. It's based on the Bernoulli Equation.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
new flow rate = old flow rate * square root (new pressure/old pressure)
= 19 lb/hr * sqrt (3.19 bar/2.5 bar)
= 21.4 lb/hr
That increase in fuel flow matches up with the change in A/F ratio we measured.
As intake pressure rises, fuel pressure rises directly with it. That way the injector is always working against a constant pressure. Fuel mass that gets delivered that way can be constantly approximated by pulse width. Now if you have a rising rate fuel pressure regulator, fuel pressure rises faster than intake pressure. Thus, the name.
05-19-2009, 07:56 PM
#24
Drifting
Thread Starter
I did not actually measure the rail pressure, but just saw the drop in A/F ratio from 15.2:1 to 14:1 on the last two pulls after we put pressure on the regulator.
05-19-2009, 08:09 PM
#25
Rennlist Member
Again, if you look how our regulators are constructed, you can see the problem with just adding pressure to the idle vacuum pull back chamber. when 17psi vacuum is applied, what does the pressure change to at idle? about 3-4psi off?
Now, if you were adding pressure directly to the line pressure with fuel, you would see the change you are looking to see. The raising pressure is a function of how much fuel is allowed to return on the return lines, not the pressure differential at the diaphram. (which still determines overall line pressure, but due to the size of the hole the fuel can return through. )
you can also test this by putting a vise grip on the return line or lines and see the AFR's change. thats how we determined that one regulator was needed and that with one regulator closed off at the return, and an S4 regulator exchanged, we could get almost perfect ratios at 250rwhp.
Now, if you were adding pressure directly to the line pressure with fuel, you would see the change you are looking to see. The raising pressure is a function of how much fuel is allowed to return on the return lines, not the pressure differential at the diaphram. (which still determines overall line pressure, but due to the size of the hole the fuel can return through. )
you can also test this by putting a vise grip on the return line or lines and see the AFR's change. thats how we determined that one regulator was needed and that with one regulator closed off at the return, and an S4 regulator exchanged, we could get almost perfect ratios at 250rwhp.
06-03-2009, 07:32 PM
#26
Drifting
Thread Starter
Got the new parts all put together and redynoed the car tonight. Now it has modified 86 fuel rails and injectors, an Aeromotive adjustable regulator (set at 42 psi idle), Euro heads, Euro cams. Torque stayed the same but power went from 226whp @ 4600 to 270whp @ 5250. Initial pull the A/F was 12:1 and it made 255. We took a little fuel out and got it to 13:1 and it made the 270whp. I'm very happy with it.
dyno pull
dyno pull
06-03-2009, 08:43 PM
#27
Rennlist Member
Thats what scots made at near 12:1. 250rwhp. (euro heads, cams, intake, throttle body on a 4.7 euro bottom end but with Ljet US 82 and a fuel regulator)
Wow, 270rwhp?? thats crazy!! 15hp from going to 13:1 from 12:1? That doesnt sound right, but heck, 270 is huge for a 4.7 and the Ljet system.
What did you do with the second fuel regulator? (pinchoff the return line?)
Ljet is pretty amazing, besides the small little opening for air.
So wait a minute!! no euro intake? You did 270rwhp with a 2.5" diamter throttle body (i.e. US stock '84 Ljet)???? thats like a 50% restrictor vs the euro!!
I had a bunch of pulls with my 5liter part euro that were in the 270s, but with a tuned peak of 293. most of my later pulls never got beyond 285rwhp. (and I had 5 liter bottome end AND the euro intake)
amazing!
mk
Wow, 270rwhp?? thats crazy!! 15hp from going to 13:1 from 12:1? That doesnt sound right, but heck, 270 is huge for a 4.7 and the Ljet system.
What did you do with the second fuel regulator? (pinchoff the return line?)
Ljet is pretty amazing, besides the small little opening for air.
So wait a minute!! no euro intake? You did 270rwhp with a 2.5" diamter throttle body (i.e. US stock '84 Ljet)???? thats like a 50% restrictor vs the euro!!
I had a bunch of pulls with my 5liter part euro that were in the 270s, but with a tuned peak of 293. most of my later pulls never got beyond 285rwhp. (and I had 5 liter bottome end AND the euro intake)
amazing!
mk
Got the new parts all put together and redynoed the car tonight. Now it has modified 86 fuel rails and injectors, an Aeromotive adjustable regulator (set at 42 psi idle), Euro heads, Euro cams. Torque stayed the same but power went from 226whp @ 4600 to 270whp @ 5250. Initial pull the A/F was 12:1 and it made 255. We took a little fuel out and got it to 13:1 and it made the 270whp. I'm very happy with it.
dyno pull
dyno pull
06-04-2009, 12:04 AM
#29
Drifting
Thread Starter
Wow, 270rwhp?? thats crazy!! 15hp from going to 13:1 from 12:1? That doesnt sound right, but heck, 270 is huge for a 4.7 and the Ljet system.
What did you do with the second fuel regulator? (pinchoff the return line?)
Ljet is pretty amazing, besides the small little opening for air.
So wait a minute!! no euro intake? You did 270rwhp with a 2.5" diamter throttle body (i.e. US stock '84 Ljet)???? thats like a 50% restrictor vs the euro!!
What did you do with the second fuel regulator? (pinchoff the return line?)
Ljet is pretty amazing, besides the small little opening for air.
So wait a minute!! no euro intake? You did 270rwhp with a 2.5" diamter throttle body (i.e. US stock '84 Ljet)???? thats like a 50% restrictor vs the euro!!
I ditched the entire stock fuel system. I put a brass T where the old pressure damper went and the outlets of the rails T back together and into an adjustable regulator. It also has 24lb injectors now. We played with the fuel pressure to get the ratio we wanted at WOT. The stock system still compensated back to 14.3:1 everywhere else.
I also did some tweaking on the throttle side. Originally I had some slack in my throttle cable and the throttle wasn't opening all the way. Also, the WOT switch was mis-adjusted and it would disengage itself again once you went beyond about 90% throttle. It drops lambda about 0.15 when you hit the switch.
It's faster for sure. It's a little strange though. It's all top end power so you don't notice it unless you spin it past 4k. Now it just doesn't fall on it's face. It will haze the 285s at the top of first now. It does have MSDS headers and a complete 3" exhaust too.
06-04-2009, 10:39 AM
#30
Rennlist Member
this is about as amazing as dennis' results. Plus, out of a US intake.
I dont understand the need for the fuel system and dont think that is the reason as we have been getting up near 300rwhp (290 and 293rwhp) with the stock system and a fuel regualtor at adjustability up to 12:1 if needed.
anyone as amazed as me? what is different with this 4.7 liter? How is it pulling 270rwhp with the Ljet and restrictive 2.5" diameter throttle body vs the 3.3" diameter throttle body. remember, JL got near 275rwhp out of his euro, but it was CIS.
very cool
I dont understand the need for the fuel system and dont think that is the reason as we have been getting up near 300rwhp (290 and 293rwhp) with the stock system and a fuel regualtor at adjustability up to 12:1 if needed.
anyone as amazed as me? what is different with this 4.7 liter? How is it pulling 270rwhp with the Ljet and restrictive 2.5" diameter throttle body vs the 3.3" diameter throttle body. remember, JL got near 275rwhp out of his euro, but it was CIS.
very cool