30# injectors
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
30# injectors
Ok, I found this calculator ... http://www.rceng.com/technical.htm .
According to it I need 31# injectors. The ford SVO's I have are rated at a higher psi (not sure exactly, but somewhere around 50psi i think).
So my question. R94 LT1 says that 30# injectors aren't needed for a 383 and that even LPE doesn't replace the injectors when they do a 383. So do I really need to stick these 30#'ers in there .. or should I stick with the 24#? (btw, i thought my 24's were leaking before, but my builder checked them while he had it apart and they are fine).
[Modified by Glock'94, 8:39 PM 1/26/2002]
According to it I need 31# injectors. The ford SVO's I have are rated at a higher psi (not sure exactly, but somewhere around 50psi i think).
So my question. R94 LT1 says that 30# injectors aren't needed for a 383 and that even LPE doesn't replace the injectors when they do a 383. So do I really need to stick these 30#'ers in there .. or should I stick with the 24#? (btw, i thought my 24's were leaking before, but my builder checked them while he had it apart and they are fine).
[Modified by Glock'94, 8:39 PM 1/26/2002]
Drifting
Joined: Nov 1999
Posts: 1,502
Likes: 12
From: Yorktown Heights NY
Re: 30# injectors (Glock'94)
Dear Glock,
I have the 30# Fords and they work just fine!!!
What you have to do is reprogram the ECM so that it knows what the heck is at the end of the injector wires.
I have mine set as 32#, since Fords are rated at 30#/hr at a fuel pressure of 36 psi. As you know, the Vette has an avg. fuel pressure of 42psi, therefore 42/36x30#/hr=Approx 32#/hr Capish?? :crazy:
If you don't reprogram the ECM it will never really work right.
Hope this helps you.
Al
I have the 30# Fords and they work just fine!!!
What you have to do is reprogram the ECM so that it knows what the heck is at the end of the injector wires.
I have mine set as 32#, since Fords are rated at 30#/hr at a fuel pressure of 36 psi. As you know, the Vette has an avg. fuel pressure of 42psi, therefore 42/36x30#/hr=Approx 32#/hr Capish?? :crazy:
If you don't reprogram the ECM it will never really work right.
Hope this helps you.
Al
Melting Slicks
Joined: Apr 2000
Posts: 2,793
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From: Elizabeth City, NC
Re: 30# injectors (Glock'94)
With the 24's you will have to run way too high a duty cycle to get all the fuel that you need. You don't want to run higher than 85% at WOT. Use the 30's and you will be right where you need to be with a bit to spare. Set the FP at 48-50 PSI with the line off just to get a good spray pattern.
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: 30# injectors (95BLKVette)
Yup, that is what I was going to do ... make them 32# injectors. I'm just wondering if I need to use them over the 24#'s or not.
I know that the 24# would have a lot higher duty cycle than the 30# (which would last longer because of it)
I know that the 24# would have a lot higher duty cycle than the 30# (which would last longer because of it)
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: 30# injectors (LPDesRoche)
With the 24's you will have to run way too high a duty cycle to get all the fuel that you need. You don't want to run higher than 85% at WOT. Use the 30's and you will be right where you need to be with a bit to spare. Set the FP at 48-50 PSI with the line off just to get a good spray pattern.
Melting Slicks
Joined: Apr 2000
Posts: 2,793
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From: Elizabeth City, NC
Re: 30# injectors (Glock'94)
You should upgrade to the 255lph intank pump. It is less than $100. Well worth the extra insurance. Even with the stock injectors you may need it. The stock pump can only keep up with the stock injectors when they are at the "stock" duty cycle. You can get by without a AFPR it's not necessary. But you NEED a larger pump.
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: 30# injectors (LPDesRoche)
You should upgrade to the 255lph intank pump. It is less than $100. Well worth the extra insurance. Even with the stock injectors you may need it. The stock pump can only keep up with the stock injectors when they are at the "stock" duty cycle. You can get by without a AFPR it's not necessary. But you NEED a larger pump.
Le Mans Master
Joined: Oct 2001
Posts: 5,302
Likes: 2
From: Atlanta GA
Re: 30# injectors (Glock'94)
Glock, are you only planning on making 400 hp w/ your stroker? Comeon man, you know you can easily put out 450 on that motor. Most strokers I see use at least 30 lb, and usually 36lb. You might want to rethink this, as you can always turn down the fuel pressure a hair and make life easier on your injectors rather than having to run them at a 90% + duty cycle. :cheers:
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Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: 30# injectors (dtorc4)
Glock, are you only planning on making 400 hp w/ your stroker? Comeon man, you know you can easily put out 450 on that motor. Most strokers I see use at least 30 lb, and usually 36lb. You might want to rethink this, as you can always turn down the fuel pressure a hair and make life easier on your injectors rather than having to run them at a 90% + duty cycle. :cheers:
[Modified by Glock'94, 8:38 PM 1/26/2002]
Pro
Joined: Jun 2001
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From: College Station Tx
Re: 30# injectors (Glock'94)
I would go ahead and do an in tank pump as suggested above.
At stock fuel pressures realistically you are going to get 375 or so rwhp out of the stock fuel injectors at decent duty cycles. A stroker will turn a little less rpm - and the less rpm you pull the greater the hp you can support with a given injector. If you upped the fuel pressure you can get around 400rwhp with stock injectors.
Since you have the 30's I would just stick with those though - at stock pressure they will be fine up to 450 or so rwhp, and you can up the pressure easily on them (you just need a better pump). I wouldn't bother with 36's - for a couple of reasons (1) You don't need them (2) They don't make them anymore (3) They cost 150+ more than the 30's generally, if you can find them.
At stock fuel pressures realistically you are going to get 375 or so rwhp out of the stock fuel injectors at decent duty cycles. A stroker will turn a little less rpm - and the less rpm you pull the greater the hp you can support with a given injector. If you upped the fuel pressure you can get around 400rwhp with stock injectors.
Since you have the 30's I would just stick with those though - at stock pressure they will be fine up to 450 or so rwhp, and you can up the pressure easily on them (you just need a better pump). I wouldn't bother with 36's - for a couple of reasons (1) You don't need them (2) They don't make them anymore (3) They cost 150+ more than the 30's generally, if you can find them.
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: 30# injectors (ChrisB)
Thanks Chris :seeya :seeya I will see how low my psi drops when giving it a lot of throttle with the 30's and decide if I need a new pump. What kind of psi do you think I should see at say 5k with those 30#'ers? (in neutral .. not drive .. i don't have a sweet digital guage like scorp :cool: )
Team Owner
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
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Re: 30# injectors (Glock'94)
I needed 30#ers for my set-up.
They work fine with the stock pump as long as i keep enough gas in the tank.
They work fine with the stock pump as long as i keep enough gas in the tank.
Burning Brakes
Joined: Jun 2001
Posts: 838
Likes: 2
From: Out by the bridge again, TampaBay
Re: 30# injectors (Glock'94)
Ok, I found this calculator ... http://www.rceng.com/technical.htm .
According to it I need 31# injectors. The ford SVO's I have are rated at a higher psi (not sure exactly, but somewhere around 50psi i think).
According to it I need 31# injectors. The ford SVO's I have are rated at a higher psi (not sure exactly, but somewhere around 50psi i think).
I think SVO injectors are rated at ~38 psi ? They should work fine for your motor. A better fuel pump would be a good idea and custom programming for sure. :D
[Modified by Half Fast, 1:56 AM 1/27/2002]
Safety Car
Joined: Mar 2000
Posts: 3,620
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From: Hillsboro OR
Re: 30# injectors (Glock'94)
That injector formula is conservative. You can probably use 24#s and get close to 400 rwhp and run at 75% duty cycle for a while but if the injector flow rate drops by 10% because of clogging, dirty filter, or weak fuel pump you'll pass the 80% recommended limit. That could toast the injectors or the engine could go lean. Thirty pounds seem to work well for most people.
Its always a good idea to have some safety margin of error built in to what you are doing if you can. GM went conservative on their injector sizing because they wanted to be sure the motor stays in emissions compliance for 100K miles under all condtions.
Its always a good idea to have some safety margin of error built in to what you are doing if you can. GM went conservative on their injector sizing because they wanted to be sure the motor stays in emissions compliance for 100K miles under all condtions.