24lb SVOs installed - shoulda went with 30lbers...
#1
Supreme Member
Thread Starter
Join Date: Jul 1999
Location: Maryland
Posts: 2,844
Likes: 0
Received 3 Likes
on
2 Posts
Car: 2005 Subaru STI
Engine: 153ci of Turbo Power!
Transmission: 6-Speed
24lb SVOs installed - shoulda went with 30lbers...
I finally received my 24lb SVO injectors on thursday. I took off work on Friday and installed them. Easy install with the MiniRam. Took me maybe a 1/2 hr and I was taking my time. Straight forward swap with no problems encountered. 100% bolt-on. I spent the rest of the day programming new EPROMs to narrow down my tuning. Good news and not so good news.
Short story:
1) If I had to do it all over again I would not order 24lb SVOs ... I would order the 30lb SVOs. I have no doubts. 30lbers would have been the better decision. However, even though I would rather have the 30lbers, I can say that the car is running much stronger.
2) Be careful if you deal with Muscle Motors. Why? It should NEVER take 1-1/2 months to receive a used set of injectors, send them back because you want new ones, and then receive a new set of injectors. That is just way too long.
Long Story:
I was previously running stock 22lb injectors that had been cleaned and flowed by LPE (1990 IROC, MiniRam'd, 218/224 cam, AFR heads, 2800 stall, 3.73s). The diacom readings with these injectors showed that the O2 sensor looked great: 880mv across the board ... even at 6500RPMs. But, the Injector Duty cycles were 100+%. I decided on 24lb SVOs to be safe. Everybody runs them and the 30lbers seemed too big ... ESPECIALLY since the Ford 24lbers are really like GM 26lbers (since Ford rates them at 37psi(?) and GM at 43psi). Well, I burned a new PROM for 25lb injectors (just to be safe) and made several adjustments to the fuel curve. However, WOT runs showed that my injector duty cycles were crawling up to 97%. I pumped up the fuel pressure (50psi) and burned a new chip for 28lb/hr injectors. WOT runs now show 89% duty cycle at 6300rpms. Although I have dropped my duty cycles substantially, I would much rather have the 30lb injectors and run less fuel in the rail (45psi) and just use a higher injector flow constant in the PROM. The first thing that some of you will say is that more pressure is better because the fuel atomizes more (big TPIS statement). Although this is True they forget to tell you that your fuel pump is set to flow a certain amount of fuel at a certain pressure in the fuel rails. Running 50+ psi taxes your fuel pump more than if you were running in the mid 40's.
Anyone who can calibrate their own ECMs (or PCMs) and has a healthy setup on a 350 should consider 30lb injectors.
On a good note - the car is definitely stronger using the 'ol Butt-O-Meter. I regained a substantial amount of lowend torque and a substantial amount of upper HP. Hopefully track times will agree with the SOTP interpretation.
THOSE OF YOU WITH NA 350 HEALTHY SETUPS:
WHAT ARE YOUR INJECTOR FLOW RATES AT 6000+ RPMS ACCORDING TO DIACOM?
Tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
Short story:
1) If I had to do it all over again I would not order 24lb SVOs ... I would order the 30lb SVOs. I have no doubts. 30lbers would have been the better decision. However, even though I would rather have the 30lbers, I can say that the car is running much stronger.
2) Be careful if you deal with Muscle Motors. Why? It should NEVER take 1-1/2 months to receive a used set of injectors, send them back because you want new ones, and then receive a new set of injectors. That is just way too long.
Long Story:
I was previously running stock 22lb injectors that had been cleaned and flowed by LPE (1990 IROC, MiniRam'd, 218/224 cam, AFR heads, 2800 stall, 3.73s). The diacom readings with these injectors showed that the O2 sensor looked great: 880mv across the board ... even at 6500RPMs. But, the Injector Duty cycles were 100+%. I decided on 24lb SVOs to be safe. Everybody runs them and the 30lbers seemed too big ... ESPECIALLY since the Ford 24lbers are really like GM 26lbers (since Ford rates them at 37psi(?) and GM at 43psi). Well, I burned a new PROM for 25lb injectors (just to be safe) and made several adjustments to the fuel curve. However, WOT runs showed that my injector duty cycles were crawling up to 97%. I pumped up the fuel pressure (50psi) and burned a new chip for 28lb/hr injectors. WOT runs now show 89% duty cycle at 6300rpms. Although I have dropped my duty cycles substantially, I would much rather have the 30lb injectors and run less fuel in the rail (45psi) and just use a higher injector flow constant in the PROM. The first thing that some of you will say is that more pressure is better because the fuel atomizes more (big TPIS statement). Although this is True they forget to tell you that your fuel pump is set to flow a certain amount of fuel at a certain pressure in the fuel rails. Running 50+ psi taxes your fuel pump more than if you were running in the mid 40's.
Anyone who can calibrate their own ECMs (or PCMs) and has a healthy setup on a 350 should consider 30lb injectors.
On a good note - the car is definitely stronger using the 'ol Butt-O-Meter. I regained a substantial amount of lowend torque and a substantial amount of upper HP. Hopefully track times will agree with the SOTP interpretation.
THOSE OF YOU WITH NA 350 HEALTHY SETUPS:
WHAT ARE YOUR INJECTOR FLOW RATES AT 6000+ RPMS ACCORDING TO DIACOM?
Tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
#2
Nice post Tim.
It doesn't surprise me that problem showed up. Healthy volumetric efficiency and therefore horsepower at relatively elevated rpms start to tax injectors. Especially if they're pulsing twice per engine function and are saturation type (high impedance) instead of peak and hold, (low impedance).
I'm curious to hear your idle figures. RPM, pulsewidth, duty cycle, and air fuel ratio.
I heard some mention that these Ford injectors don't repond as well to higher fuel pressure as do the external pintle types. I'm assuming your 24s have a four hole metering orofice. The best that I can tell, they have an internal pintle and are not the disc type. I have heard the four hole type provide a more desireable spray.
I have the four hole 24s and also had to return a batch of used ones (external pintle type) that were represented as "brand new" in an ad on this site. I paid $160 and sent them back to receive new four hole types for the same price. Whole process took 3-4 weeks but was from a different supplier.
Sorry can't help you with your specific question, as this engine is not as "healthy" and isn't running anyway.
Have your SCs and Mufflex hooked up?
Curious to hear some track results and or dyno figures.
It doesn't surprise me that problem showed up. Healthy volumetric efficiency and therefore horsepower at relatively elevated rpms start to tax injectors. Especially if they're pulsing twice per engine function and are saturation type (high impedance) instead of peak and hold, (low impedance).
I'm curious to hear your idle figures. RPM, pulsewidth, duty cycle, and air fuel ratio.
I heard some mention that these Ford injectors don't repond as well to higher fuel pressure as do the external pintle types. I'm assuming your 24s have a four hole metering orofice. The best that I can tell, they have an internal pintle and are not the disc type. I have heard the four hole type provide a more desireable spray.
I have the four hole 24s and also had to return a batch of used ones (external pintle type) that were represented as "brand new" in an ad on this site. I paid $160 and sent them back to receive new four hole types for the same price. Whole process took 3-4 weeks but was from a different supplier.
Sorry can't help you with your specific question, as this engine is not as "healthy" and isn't running anyway.
Have your SCs and Mufflex hooked up?
Curious to hear some track results and or dyno figures.
#3
Junior Member
Join Date: Nov 1999
Location: Wichita, KS USA
Posts: 60
Likes: 0
Received 0 Likes
on
0 Posts
Okay guys... yeah go ahead and make everyone else here feel like they are 3 inches tall...
You guys definitely know your sh**...
------------------
1992 Red RS with 305 TBI
You guys definitely know your sh**...
------------------
1992 Red RS with 305 TBI
#4
Supreme Member
Thread Starter
Join Date: Jul 1999
Location: Maryland
Posts: 2,844
Likes: 0
Received 3 Likes
on
2 Posts
Car: 2005 Subaru STI
Engine: 153ci of Turbo Power!
Transmission: 6-Speed
Christobal,
>I'm curious to hear your idle figures. RPM,
>pulsewidth, duty cycle, and air fuel ratio.
My car idles at 750-800RPMs. The injector pulse width at some of the higher RPMs along with the duty cycles are listed below:
4000, 9.6ms, 64%
4500, 9.2ms, 69%
5000, 8.7ms, 72%
5500, 8.4ms, 77%
6000, 8.3ms, 83%
6500, 8.3ms, 90%
My O2 voltages run anywhere from 850->930mV. I'm in the process of nailing down the fuel curve even more. Problem is ... I need to add fuel at RPMs > 5000. That means that my pulse widths and therefore the duty cycle will be going up even more.
BTW - I am running new SVOs that have the 4-hole design as you mentioned. Funny thing is ... I heard that the SVOs are better at higher pressures than the GM injectors. Wierd. I'll probably sell my new 24lbers and purchase a set of 30lbers. There goes another $100 down the drain :-(
>Have your SCs and Mufflex hooked up?
Nope. This is going to be one expensive exhaust. The headers cost $400, the HPC coating is $300, the Mufflex 3-1/2" catback is $450, the Mufflex Y is $250, a catted mufflex Y is another $450, and then you have the money for Mufflex labor. That is an insanely expensive exhaust. But - it'll be done by the experts and it will support some serious horsepower. I'm still saving up.
tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
>I'm curious to hear your idle figures. RPM,
>pulsewidth, duty cycle, and air fuel ratio.
My car idles at 750-800RPMs. The injector pulse width at some of the higher RPMs along with the duty cycles are listed below:
4000, 9.6ms, 64%
4500, 9.2ms, 69%
5000, 8.7ms, 72%
5500, 8.4ms, 77%
6000, 8.3ms, 83%
6500, 8.3ms, 90%
My O2 voltages run anywhere from 850->930mV. I'm in the process of nailing down the fuel curve even more. Problem is ... I need to add fuel at RPMs > 5000. That means that my pulse widths and therefore the duty cycle will be going up even more.
BTW - I am running new SVOs that have the 4-hole design as you mentioned. Funny thing is ... I heard that the SVOs are better at higher pressures than the GM injectors. Wierd. I'll probably sell my new 24lbers and purchase a set of 30lbers. There goes another $100 down the drain :-(
>Have your SCs and Mufflex hooked up?
Nope. This is going to be one expensive exhaust. The headers cost $400, the HPC coating is $300, the Mufflex 3-1/2" catback is $450, the Mufflex Y is $250, a catted mufflex Y is another $450, and then you have the money for Mufflex labor. That is an insanely expensive exhaust. But - it'll be done by the experts and it will support some serious horsepower. I'm still saving up.
tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
#5
Member
Join Date: Jul 1999
Location: Oklahoma City, USA
Posts: 223
Likes: 0
Received 0 Likes
on
0 Posts
Car: 89 IROC
Engine: Yes
Transmission: That, too.
Tim:
The word I've heard is that the Rochester brand injectors are the ones which can't take the high pressures. I ran my Rochesters (stock 19 lb size) up to over 60 psi once to try and cure a lean problem, but I reached a point where an increase in pressure actually resulted in a decrease in fuel flow.
I'm running Bosch 24 lb injectors now, and doing fine at around 43 psi with my current (extremely lame) motor setup. I'm currently planning on leaving my injectors alone when I do the cam/head change (yeah, yeah... any day now...), and I'll wait and see how it runs. I figure to be putting out just a tiny bit less power than you have on your setup, so maybe the 24 lb size will be able to handle it.
Ever hear of Linder Technical Services? It's actually a training academy for mechanics, but they do injector balancing, reconditioning, etc. When I brought my weak 19 lb injectors in to have them looked at, they told me that they were way too small for my motor. They took them in on trade for a full set of wonderfully flow matched 24 lb Bosch injectors, and charged me $200 for the whole deal.
Linder Technical Services
4-D Gasoline Alley
Indianapolis, IN 46222
(317) 487-9460
or e-mail at LINDERTECH@JUNO.COM
The word I've heard is that the Rochester brand injectors are the ones which can't take the high pressures. I ran my Rochesters (stock 19 lb size) up to over 60 psi once to try and cure a lean problem, but I reached a point where an increase in pressure actually resulted in a decrease in fuel flow.
I'm running Bosch 24 lb injectors now, and doing fine at around 43 psi with my current (extremely lame) motor setup. I'm currently planning on leaving my injectors alone when I do the cam/head change (yeah, yeah... any day now...), and I'll wait and see how it runs. I figure to be putting out just a tiny bit less power than you have on your setup, so maybe the 24 lb size will be able to handle it.
Ever hear of Linder Technical Services? It's actually a training academy for mechanics, but they do injector balancing, reconditioning, etc. When I brought my weak 19 lb injectors in to have them looked at, they told me that they were way too small for my motor. They took them in on trade for a full set of wonderfully flow matched 24 lb Bosch injectors, and charged me $200 for the whole deal.
Linder Technical Services
4-D Gasoline Alley
Indianapolis, IN 46222
(317) 487-9460
or e-mail at LINDERTECH@JUNO.COM
#6
Supreme Member
Thread Starter
Join Date: Jul 1999
Location: Maryland
Posts: 2,844
Likes: 0
Received 3 Likes
on
2 Posts
Car: 2005 Subaru STI
Engine: 153ci of Turbo Power!
Transmission: 6-Speed
D-
>I'm currently planning on leaving my
>injectors alone when I do the cam/head
>change (yeah, yeah... any day now...), and
>I'll wait and see how it runs. I figure to
>be putting out just a tiny bit less power
>than you have on your setup, so maybe the
>24 lb size will be able to handle it.
That's what most of us do. In fact, you saw my times ... I was running 12.5s with the stock 22lb injectors. Diacom readings looked great. Problem is - slowly but surely you are asking for trouble by running really high IDCs. You will definitely be fine with your 24lb injectors as long as you don't go MiniRam :-) My fuel flow needs at 6000+ RPMs are what's killing me. With a long runner setup the 24lb injectors work great because you are shifting at 5500rpms. No big deal.
>Ever hear of Linder Technical Services?
Nope - can't say that I have. But, for $250 you can't beat a set of brand new 30lb SVO injectors. In fact, I already pulled my SVO 24lbers out of the car and already have a buyer. I'll be ordering the 30lbers in about a week and a half.
Take it easy,
tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
>I'm currently planning on leaving my
>injectors alone when I do the cam/head
>change (yeah, yeah... any day now...), and
>I'll wait and see how it runs. I figure to
>be putting out just a tiny bit less power
>than you have on your setup, so maybe the
>24 lb size will be able to handle it.
That's what most of us do. In fact, you saw my times ... I was running 12.5s with the stock 22lb injectors. Diacom readings looked great. Problem is - slowly but surely you are asking for trouble by running really high IDCs. You will definitely be fine with your 24lb injectors as long as you don't go MiniRam :-) My fuel flow needs at 6000+ RPMs are what's killing me. With a long runner setup the 24lb injectors work great because you are shifting at 5500rpms. No big deal.
>Ever hear of Linder Technical Services?
Nope - can't say that I have. But, for $250 you can't beat a set of brand new 30lb SVO injectors. In fact, I already pulled my SVO 24lbers out of the car and already have a buyer. I'll be ordering the 30lbers in about a week and a half.
Take it easy,
tim
------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr)
All Natural. No Force. No Drugs. Stock Bottom End.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
Thread
Thread Starter
Forum
Replies
Last Post
gixxer92
Engine/Drivetrain/Suspension Parts for Sale
5
09-01-2015 04:32 PM
Firechicken86
Engine/Drivetrain/Suspension Parts for Sale
0
08-12-2015 10:07 PM