24lb SVO Pressure Settings
#1
Junior Member
Thread Starter
Join Date: May 2004
Location: Littleton, Colorado
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 K15 Blazer
Engine: 383 with TPI, Edelbrock Intake & Runners, 24lb svo injectors, 730, $8d
Transmission: 700r4
24lb SVO Pressure Settings
Just want to see what pressure setting that people are using with there 24lb svo inectors. (Without Vacume)
#2
Supreme Member
iTrader: (2)
Join Date: Jul 2003
Location: Dallas, TX area
Posts: 3,205
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Formula WS6 (Black, T-Tops)
Engine: 383 MiniRam (529 HP, 519 TQ - DD2K)
Transmission: Built '97 T56, Pro 5.0, CF-DF
Axle/Gears: 4.11 posi Ford 9"
Standard GM pressure is 43 with the vacuum line disconnected and plugged, which should net 39-40 at idle, I beleive. They are actually rated at 43.5 PSI.
#3
Supreme Member
iTrader: (15)
Originally posted by vernw
Standard GM pressure is 43 with the vacuum line disconnected and plugged, which should net 39-40 at idle, I beleive. They are actually rated at 43.5 PSI.
Standard GM pressure is 43 with the vacuum line disconnected and plugged, which should net 39-40 at idle, I beleive. They are actually rated at 43.5 PSI.
#5
Supreme Member
iTrader: (2)
Join Date: Feb 2002
Location: Nashville TN
Posts: 1,141
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1989 Trans Am
Engine: 355 HSR
Transmission: Pro-Built 700r4 w/ 3400 converter
Axle/Gears: 10 bolt w/ 3.42 gears
SVO injectors aren't rated at the same pressure as GM pieces. GM injectors are rated at 43.5 and SVO injectors are either 38 or 39 IIRC. I know its in the 30s though...
#6
Supreme Member
Join Date: Jul 1999
Location: Mims, Florida
Posts: 2,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
52 psi with my mods.
Actually, the fuel pressure setting for you could be alot different. You should set the fuel pressure at whatever pressure makes the engine happiest at WOT. Dial in the fuel pressure that yields 12.8:1 AFR (or there abouts), while in PE mode. While not in PE mode, the ECM will learn and get you the desired 14.7:1 AFR at part throotle.
BTW: Our GM fuel injectors are rated at 43.5psi and the Ford injectors are flow rated at 39.5psi. However, there is a person on this board who had his SVO 24#/hr injectors flow rated at Cruizin Performance and they flowed 24#/hr @ 43psi. Go figure!!!
Actually, the fuel pressure setting for you could be alot different. You should set the fuel pressure at whatever pressure makes the engine happiest at WOT. Dial in the fuel pressure that yields 12.8:1 AFR (or there abouts), while in PE mode. While not in PE mode, the ECM will learn and get you the desired 14.7:1 AFR at part throotle.
BTW: Our GM fuel injectors are rated at 43.5psi and the Ford injectors are flow rated at 39.5psi. However, there is a person on this board who had his SVO 24#/hr injectors flow rated at Cruizin Performance and they flowed 24#/hr @ 43psi. Go figure!!!
#7
Supreme Member
iTrader: (15)
Originally posted by doc
52 psi with my mods.
Actually, the fuel pressure setting for you could be alot different. You should set the fuel pressure at whatever pressure makes the engine happiest at WOT. Dial in the fuel pressure that yields 12.8:1 AFR (or there abouts), while in PE mode. While not in PE mode, the ECM will learn and get you the desired 14.7:1 AFR at part throotle.
52 psi with my mods.
Actually, the fuel pressure setting for you could be alot different. You should set the fuel pressure at whatever pressure makes the engine happiest at WOT. Dial in the fuel pressure that yields 12.8:1 AFR (or there abouts), while in PE mode. While not in PE mode, the ECM will learn and get you the desired 14.7:1 AFR at part throotle.
Yes the ECM can in a sense "learn" a desired blm but if it goes +/- 0.10 from the VE table than it will set a code. Allowing the ecm to correct itself is not an approach for longetivity, rather tuning is. Too small a pulse width at idle can be unstabble and, bad.
Trending Topics
#8
Supreme Member
Join Date: Jul 1999
Location: Mims, Florida
Posts: 2,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
11.5:1 to way rich even for best power. In all the threads I have checked and all of my tuning manuals state that best power is typically gotten at 12.6. But this can vary with the specific mods to the engine.
I stated 12.8 because its a good compromise between best power and best torque AFRs.
In the above starter post, we are talking about an injector which is close to the stock GM injector as far as flow is concerned. A chip change would be good but is not necessary. But the cost of an AFPR is well founded to dial in whats good for the motor at WOT. The part throotle stuff will take care of itself. I stand by my words on this matter.
BTW: The way BLMs work, you should not have a problem with setting an error code until you are about 16% off. That covers a pretty good range.
I stated 12.8 because its a good compromise between best power and best torque AFRs.
In the above starter post, we are talking about an injector which is close to the stock GM injector as far as flow is concerned. A chip change would be good but is not necessary. But the cost of an AFPR is well founded to dial in whats good for the motor at WOT. The part throotle stuff will take care of itself. I stand by my words on this matter.
BTW: The way BLMs work, you should not have a problem with setting an error code until you are about 16% off. That covers a pretty good range.
#9
Supreme Member
iTrader: (2)
Join Date: Feb 2002
Location: Nashville TN
Posts: 1,141
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1989 Trans Am
Engine: 355 HSR
Transmission: Pro-Built 700r4 w/ 3400 converter
Axle/Gears: 10 bolt w/ 3.42 gears
12.8 is best torque, and 13.3 is best power. Straight from several dyno shops I know of.
As for the pressure. Set it where you need it. I would leave it at the factory 43.5 and then tune w/ the chip from there.
As for the pressure. Set it where you need it. I would leave it at the factory 43.5 and then tune w/ the chip from there.
#10
Junior Member
Join Date: Feb 2003
Location: Calgary AB, Canada
Posts: 55
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88' Iroc
Engine: 383
Transmission: T56
Just had my 24lb SVO flow tested and they averaged 25lbs per hour at 42psi, part number crosses to ford truck 360 injector rated at 26lbs per hour.
#11
Member
iTrader: (4)
Join Date: Jun 2004
Location: Cleveland, OH
Posts: 192
Received 0 Likes
on
0 Posts
Car: '70 Chevelle, '63 Corvette
Engine: 383, 327
Transmission: B&M 700r4, Muncie M-21
Changing the fuel pressure effectively changes the flow rating of the injector.
http://www.rceng.com/technical.htm
(Squareroot(new pressure/old pressure) ) * old_flow_rate = new_flow_rate.
As an example, I have a set of SVO 30 lb/hr injectors (red top). If they are rated by Ford at 39.5 psi and I up my fuel pressure to 50 psi, my new flow rate is:
Squareroot(50/39.5) * 30 = 33.75 lbs/hr.
Or, as an extreme, if I up my fuel pressure to 60 psi: (does anyone go this high?)
Squareroot(60/39.5) * 30 = 36.97 lbs/hr
The one thing I don't know is, how different would an engine run if it has 30 lb/hr injectors running at 60 psi, versus 36 lb/hr injectors running at 39.5 psi.
-Dave
http://www.rceng.com/technical.htm
(Squareroot(new pressure/old pressure) ) * old_flow_rate = new_flow_rate.
As an example, I have a set of SVO 30 lb/hr injectors (red top). If they are rated by Ford at 39.5 psi and I up my fuel pressure to 50 psi, my new flow rate is:
Squareroot(50/39.5) * 30 = 33.75 lbs/hr.
Or, as an extreme, if I up my fuel pressure to 60 psi: (does anyone go this high?)
Squareroot(60/39.5) * 30 = 36.97 lbs/hr
The one thing I don't know is, how different would an engine run if it has 30 lb/hr injectors running at 60 psi, versus 36 lb/hr injectors running at 39.5 psi.
-Dave
#12
Moderator
Join Date: Feb 2000
Location: Schererville , IN
Posts: 7,015
Likes: 0
Received 1 Like
on
1 Post
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
this was debated and argued. Ive run 2 sets in two vastly different cars.
Stock: Set the Constant at 24# with stock fuel pressure(43.5) and leave it alone :-) works perfect. Datalogged it watched it changed it, leave it at 24
Modified, start at 24 and change from there accordongly to pressure and your combo etc. Less lying you do the easier it makes your life on the VE table and thus the AE stuff
later
Jeremy
Stock: Set the Constant at 24# with stock fuel pressure(43.5) and leave it alone :-) works perfect. Datalogged it watched it changed it, leave it at 24
Modified, start at 24 and change from there accordongly to pressure and your combo etc. Less lying you do the easier it makes your life on the VE table and thus the AE stuff
later
Jeremy
#13
Member
Join Date: Jul 2003
Location: Colorado
Posts: 144
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1989 IROC-Z Camaro
Engine: 5.8L 355
Transmission: T-5 5-speed
I don't have all this stuff figured out. One guy told me to set it at 49 some say 47, some say 43....how do i know what one to run. Have vette ported heads, XE268 cam. I do have the pump to push the high pressure too. I noticed I'm running alittle rich to right now. I just don't know where to set it at
#14
Supreme Member
Join Date: Jul 1999
Location: Mims, Florida
Posts: 2,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
snow,
Every car is different, you have ported Vette heads and a big cam, and you are in Colorado. Your car might like anything from 43 to 50psi.
You need to get on a chassis dyno with a wide band O2 sensor and tune-in the best fuel pressure to maximize your RWHP. OR go to a dragstrip and let the trap speeds (not ET) dictate whats best for your engine.
Every car is different, you have ported Vette heads and a big cam, and you are in Colorado. Your car might like anything from 43 to 50psi.
You need to get on a chassis dyno with a wide band O2 sensor and tune-in the best fuel pressure to maximize your RWHP. OR go to a dragstrip and let the trap speeds (not ET) dictate whats best for your engine.
#15
Supreme Member
Join Date: Jul 1999
Location: Mims, Florida
Posts: 2,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
BTW:
From the varying flow rates given above for 24#/hr SVO injectors,
just points out the importance to have your injectors flow matched. There is alot of variation in a set of injectors. Send them to Cruzin Performance, Rich is great to work with and he knows his stuff.
From the varying flow rates given above for 24#/hr SVO injectors,
just points out the importance to have your injectors flow matched. There is alot of variation in a set of injectors. Send them to Cruzin Performance, Rich is great to work with and he knows his stuff.
Thread
Thread Starter
Forum
Replies
Last Post
ambainb
Camaros for Sale
11
04-25-2016 09:21 PM
Firechicken86
Engine/Drivetrain/Suspension Parts for Sale
0
08-12-2015 10:07 PM