Which size injectors should I get for cam ls1? 48?

**allbaugh_04** · 04-21-2010, 01:44 PM

I have stock injectors and I have them ready to ship to a company that can make them up to 48lb by changing the discharge plate.

Some say with the right tuner, you can use just about any size and they will make them work? Is this true? Should I just make them 48lb?

I have full bolt-ons and a cam. So 36lb or so should be enough, but I might use nitrous in the future...should I just make them 48lb and let the tuner do his job?

**JRENIGAR** · 04-21-2010, 01:51 PM

03 cobras have 39's, mine made 500rwhp and still had some inj duty left.

**allbaugh_04** · 04-21-2010, 01:52 PM

The main thing I need to know is if the right tuner can make em work...Then I'll just get 48lb so i can be ready for the future.

Anyone know?

**JRENIGAR** · 04-21-2010, 01:57 PM

I have hp tuners and it will change em if ya know how. its just simple math and then using a multiplier in the injector table.

**allbaugh_04** · 04-21-2010, 01:57 PM

Originally Posted by JRENIGAR

I have hp tuners and it will change em if ya know how. its just simple math and then using a multiplier in the injector table.

OK thanks, I'm sure my tuner knows what he's doin then.

Thanks for your help.

**JRENIGAR** · 04-22-2010, 12:20 PM

I havent checked what the max injecto size it will adjust for is but surely it will go that high or higher.

**KP1** · 04-23-2010, 03:15 AM

If you're having a reputable service like FIC resize your oem injectors, and check for flow balance it is a simple matter to change the injector flow rate and the other parameters such as voltage offset remain stock.

One thing to remember is that Ford injectors are rated at 42 PSI (3 bar) and GM are rated at 58 PSI (4 Bar), so you have to make sure you compare sizes at the same PSI.

I think I had my oem gm injectors resized to 38 lb/hr at 3 bar and I have right at 500 hp at the wheels.

**bills98ta** · 04-23-2010, 03:33 AM

If you plan on a dry shot, I'd go with the 48's !!!

**allbaugh_04** · 04-23-2010, 08:45 AM

Originally Posted by KP1

If you're having a reputable service like FIC resize your oem injectors, and check for flow balance it is a simple matter to change the injector flow rate and the other parameters such as voltage offset remain stock.

One thing to remember is that Ford injectors are rated at 42 PSI (2 bar) and GM are rated at 58 PSI (3 Bar), so you have to make sure you compare sizes at the same PSI.

I think I had my oem gm injectors resized to 38 lb/hr at 2 bar and I have right at 500 hp at the wheels.

Yep, I'm having FIC do em.

Originally Posted by bills98ta

If you plan on a dry shot, I'd go with the 48's !!!

I did go with 48

**SOMbitch** · 04-26-2010, 07:06 AM

Originally Posted by KP1

If you're having a reputable service like FIC resize your oem injectors, and check for flow balance it is a simple matter to change the injector flow rate and the other parameters such as voltage offset remain stock.

One thing to remember is that Ford injectors are rated at 42 PSI (2 bar) and GM are rated at 58 PSI (3 Bar), so you have to make sure you compare sizes at the same PSI.

I think I had my oem gm injectors resized to 38 lb/hr at 2 bar and I have right at 500 hp at the wheels.

It is actually 3 bar and 4 bar...... I have 42lb Bosch design III's that flow 48lb's at 4 bar FWIW......

**dude2000_22222** · 04-27-2010, 08:00 AM

I mean is it sad to say that I have a head and cam ls402 and still using the stock 98' injectors

**35th-ANV-SS** · 04-27-2010, 09:34 AM

Originally Posted by SOMbitch

It is actually 3 bar and 4 bar...... I have 42lb Bosch design III's that flow 48lb's at 4 bar FWIW......

Thanks for clarifying that. I thought it was 3 and 4 also.

**shady milkman** · 04-27-2010, 12:38 PM

Originally Posted by dude2000_22222

I mean is it sad to say that I have a head and cam ls402 and still using the stock 98' injectors

yes

**dude2000_22222** · 04-27-2010, 06:27 PM

I mean what would be the reason to upgrade I don't think you would see any performance increase?

**Hi-Po** · 04-27-2010, 06:44 PM

Originally Posted by dude2000_22222

I mean is it sad to say that I have a head and cam ls402 and still using the stock 98' injectors

Originally Posted by dude2000_22222

I mean what would be the reason to upgrade I don't think you would see any performance increase?

I would love to see your injector duty cycle from ~4500ish RPM and up. Do you know what it is?

**allbaugh_04** · 04-27-2010, 08:21 PM

Originally Posted by dude2000_22222

I mean what would be the reason to upgrade I don't think you would see any performance increase?

The cam is bringing in more air so i need injectors that can keep up. That's all.

**KP1** · 04-28-2010, 03:42 AM

Originally Posted by SOMbitch

It is actually 3 bar and 4 bar...... I have 42lb Bosch design III's that flow 48lb's at 4 bar FWIW......

You're right. Corrected.

**dude2000_22222** · 04-28-2010, 04:58 AM

To be honest I didn't even think to ask the tuner about it. But to come to think of it the car's hp curve dies around 5200 rpms and he could not figure out why. He just assumed I needed better heads but could it be the injectors?

**allbaugh_04** · 04-28-2010, 05:04 AM

Originally Posted by dude2000_22222

To be honest I didn't even think to ask the tuner about it. But to come to think of it the car's hp curve dies around 5200 rpms and he could not figure out why. He just assumed I needed better heads but could it be the injectors?

What year is your LS1? What are your mods?

**dude2000_22222** · 04-28-2010, 05:49 AM

Its a slp 402 with a 236/236 cam, headers, 98' heads heavily worked, bigger valves, ls6 intake. The car makes around 445rwhp and 460trq. But the power curve dies at 5200 or 5400. He believes its the heads but unless my flow charts are lying I think they flow fairly well. He says it should be around 500 at the wheels easy.