Fuel pump

**123pugsy** · 03-10-2011, 06:27 AM

I'm building an injected 496 stroker which should be running about 650 ft/lb and 520 HP.

This will be run with the 0411 ECM.
I'll be using the Edelbrock Pro Flo XT.

I believe injectors required will be about 44 LBS. Is there such a size?
Any recommendations?

Is an OEM fuel pump up to handle the job?

I'm about to fab my new fuel cell so I need to pick out a sending unit/pump set up.

Pugsy

**Smittro** · 03-10-2011, 07:05 AM

Injectors come in many different lbs per hr.

Many folks as well as myself (TT project) go "bigger" so it leaves room for modding/power adding later down the road..

Don't know about your OEM pump being able to keep up tho..

I'm not building a huge cubed engine but definetly had to change out my OEM pump it would never be able to keep up with my setup..

Just my .02.

Goodluck and Welcome to LS1.com!

**blackSS01** · 03-10-2011, 08:47 AM

I know F.A.S.T makes 46lb and 50lb fuel injectors. Not sure about a company that makes 44lb. 46lb should be fine

As far as fuel pumps, I would contact one of our sponsors or visit one of their sites. They can point you in the right direction for both injectors/pump.

**0rion** · 03-10-2011, 08:51 AM

they make injectors much much larger than 44 lb/hr. Your stock pump won't get the job done though.....you'll definitely need to upgrade that and probably run a boost a pump too.

**importhater81** · 03-10-2011, 09:02 AM

Originally Posted by 123pugsy

I'm building an injected 496 stroker which should be running about 650 ft/lb and 520 HP.

This will be run with the 0411 ECM.
I'll be using the Edelbrock Pro Flo XT.

I believe injectors required will be about 44 LBS. Is there such a size?
Any recommendations?

Is an OEM fuel pump up to handle the job?

I'm about to fab my new fuel cell so I need to pick out a sending unit/pump set up.

Pugsy

IMHO,I think 44lb injectors is not going to be enough for a engine the size you're building. I run 42 lb injectors in my stock displacement Ls1.

**35th-ANV-SS** · 03-10-2011, 09:09 AM

There is a way to calculate what size injectors you need

Also, if you get the hot wire kit using a Racetronix pump, you probably do not need a BAP.

**blackSS01** · 03-10-2011, 09:13 AM

Originally Posted by 35th-ANV-SS

There is a way to calculate what size injectors you need

Also, if you get the hot wire kit using a Racetronix pump, you probably do not need a BAP.

Did not know there is a way to calculate

**35th-ANV-SS** · 03-10-2011, 09:32 AM

Injector sizing:

Flow Rate = (HP x BSFC) / (# of Injectors x Max Cycle)

BSFC is "Brake Specific Fuel Consumption and on a F.I. application is generally said to be 0.55. For N.A. the standard figure is 0.45. Max duty cycle on injectors should be no more than 80%, or 0.80.

So your formula would be:

Flow Rate = (520 x 0.45) / (8 x .080)

Flow Rate = 234 / 6.4

Flow Rate = 36.6 lb/hr injectors

**123pugsy** · 03-11-2011, 02:04 AM

Thanks guys.

I was checking one of my dyno simulations and it showed 640 HP. I don't think it will be that high but I want to make sure I use big enough injectors and pump.
I'm building more of a high torque, good off the line, good for highway cruising engine.

Using the formula I came up with 45 LBS.
Would it be safe to go with 60 LB injectors? If the injectors are too large, will there be problems at idle or low RPM cruising?
I read somewhere that bigger is not always better.

**0rion** · 03-11-2011, 03:27 AM

just remember that injectors are rated at 43.5 psi and will flow more at 58psi

**123pugsy** · 03-12-2011, 04:01 PM

Originally Posted by 0rion

just remember that injectors are rated at 43.5 psi and will flow more at 58psi

OK, I guess??

I'm gonna get real confused here.
So a higher pressure pump can flow more from a smaller injector?
Of coarse a fuel pressure regulator is required. I guess it can be set to a higher pressure if the pump is big enough?

I just went to FAST's site and was looking at injectors.
I came across LOW and HIGH impedence injectors. What's the difference with these?

**Cutlass** · 03-12-2011, 05:28 PM

Fuel injectors are rated by flow. Most people say 44 lbs or 60 lbs injectors. But its actually 44 lbs/hour at say 43.5 psi.
Our LS1s run 58 to 60 psi fuel pressure. More pressure increases the lbs/hour flow. Thats all 0rion was saying. Its just another thing to think about.

**0rion** · 03-12-2011, 06:15 PM

Originally Posted by Cutlass

Fuel injectors are rated by flow. Most people say 44 lbs or 60 lbs injectors. But its actually 44 lbs/hour at say 43.5 psi.
Our LS1s run 58 to 60 psi fuel pressure. More pressure increases the lbs/hour flow. Thats all 0rion was saying. Its just another thing to think about.

this....I have an injector flow spreadsheet somewhere on a thumb drive. I'll see if I can find it.