Should I upgrade to 30lb Injectors?

Brent Francis · Feb 19, 2019

Car came to me with 24lb injectors, Edelbrock Performer RPM intake, 70mm throttle body, aluminum heads, powerdyne supercharger, crower stage 1 cam with 1.7 rockers, BBK headers, Crane ignition box, 5 speed with 373 gears. I want more power so am thinking of upgrading to 30lb injectors. What do you think?

Noobz347 · Feb 19, 2019

I think larger fuel injectors will net you ZERO horsepower.

90sickfox · Feb 19, 2019

With the supercharger you should be running at least 30lb injectors. 42lb would get you in the factory ford lightening range.

If you change the injectors don't forget the mass air flow has to match....or your tune needs adjusting.

If you want more power looks like you'll need a smaller blower pulley to up the boost. No idea where you are ( as far as boost ) now though.

Brent Francis · Feb 19, 2019

Thanks 90sickfox. I agree with you. A smaller pulley, 30 lb injectors and new MAF might be the way to go.

Dan02gt · Feb 19, 2019

So you have a H/C/I set up with a supercharger and 24 lbs injectors? I would think you have those 24s maxed out. There is a chart floating around that gives recommendations for injector size based on HP.

Noobz347 · Feb 19, 2019

I would imagine that there's a Fuel Management Unit in there somewhere perhaps?

Anything that you do with injectors larger than 24s is going to require a tune. You need to factor this in when talking about swapping to larger ones.

Swapping to 30 lb injectors over 24's wouldn't be my first pick either.

If you're going to go through all the hassle, I might pick an injector that's large enough for I plan to do once the blower runs out of steam.

How is the rest of your fuel system? Pump, rails? All stock?

Edit: Oh, and the alternator.

2000xp8 · Feb 19, 2019

If it runs well and reliable you may not want to mess with it.
Powerdynes aren't exactly known to be the highest quality supercharger.
Before i'd add more boost and spin it faster, i'd want it serviced and/or upgraded.

I believe 928 motorsports is the only place to get parts or have one upgraded.

Noobz347 · Feb 19, 2019

2000xp8 said:
If it runs well and reliable you may not want to mess with it.
Powerdynes aren't exactly known to be the highest quality supercharger.
Before i'd add more boost and spin it faster, i'd want it serviced and/or upgraded.

I believe 928 motorsports is the only place to get parts or have one upgraded.

This is what I'm thinking... except for the keeping of the SC.

Unless the plan to add a significant amount of boost through say... an S-Trim or something along those lines, I can't see a reason to go through all the hassle of swapping injectors. I've a suspicion that other components might also need an upgrade to accomodate an injector large enough to make it worth it.

If there is an FMU in the mix, swapping to a larger injector can be a can of worms.

We really do need a complete list of current fuel system components.

VibrantRedGT · Feb 20, 2019

I over inject everything. Went lean on my Vortech supercharged H/C/I/E car and paid the ultimate price. Had to go 347 Stroker and even that had 36lb injectors, Pro-M 80MM MAF. My current 94 project car with just an Edelbrock Performer intake, BBK X-Pipe and Flowmaster 2.5" Cat Back (no other mods) has 24 pound injectors and BBK 76MM MAF.

Oh and I over exhaust everything too. With the Vortech Supercharger it had MAC 1-5/8" Long Tubes, MAC 2.5 Inch Prochamber and MAC 2.5 Inch Cat Back. When I went 347 Stroker it had MAC Ceramic Coated 1-3/4" Long Tubes with 3" Collector, MAC 3" Inch Prochamber and MAC 3 Inch Cat Back.

Wayne Waldrep · Feb 20, 2019

I had a Powerdyne blower on a stock engine long ago. It was stock so no comparison to your set-up but like others have said, that blower is a very basic unit with an FMU. When I first installed mine it was virtually silent. It made decent power but nothing big. I sent it back to Powerdyne and they put the newer upgraded impeller in and man what a difference. The blower was loud and whistling then....I loved it...lol. It put out much better power then. It was a 9psi unit but I never saw over 7.5psi. Back then people would try and put a smaller pulley on but most of them had trouble at that point. It has an internal cog belt instead of gears and just doesn't respond to a lot of extra spinning in my opinion. It a great simple bolt on. I'd say if you decide to go with bigger injectors to ditch the FMU and tune it to run without it. Do lots of research before though since things have changed a lot since my heyday. I built an N/A engine as my last performance build and ran 24# injectors. They were running at 85% duty cycle with a dyno of 321hp at the tires. That's past the comfort level really. That was also 15 years ago.

JimZim · Feb 20, 2019

30 lb. injectors, Quarter Horse (Moates) tuner, adjustable fuel regulator and 190 LPH (min.) pump would be a good way to go. I was able to street tune without bypass tube after some effort learning adjustable parameters and tables. NO warning lights or backfires with Powerdyne 9 lb. , exhaust and intake improvements.

Noobz347 · Feb 20, 2019

JimZim said:
30 lb. injectors, Quarter Horse (Moates) tuner, adjustable fuel regulator and 190 LPH (min.) pump would be a good way to go. I was able to street tune without bypass tube after some effort learning adjustable parameters and tables. NO warning lights or backfires with Powerdyne 9 lb. , exhaust and intake improvements.

I'd be a bit wary of that 190L when using with an FMU. For whatever reason, the 190L Walbro in-tank pumps have a tendency to pop the internal bypass in the pump during elevated fuel pressures. You can imagine what might happen if fuel flow fell on its face while you're in boost.

You have 30's an a tuner but I figured it would be worth mentioning for FMU folks.

Blown88GT · Feb 20, 2019

Brent Francis said:
Car came to me with 24lb injectors, Edelbrock Performer RPM intake, 70mm throttle body, aluminum heads, powerdyne supercharger, crower stage 1 cam with 1.7 rockers, BBK headers, Crane ignition box, 5 speed with 373 gears. I want more power so am thinking of upgrading to 30lb injectors. What do you think?

Powerdyne SC is 6lbs. Total max HP < 300.
You're fine, even though I would love to sell you my FRP 30lb'ers

JimZim · Feb 20, 2019

Walbro has the GPA series pump but I have alway looked for the GSL line for the 190 or 255 liter unit. Is the GPA's the series of pumps that you were referin to with the internal bypass?

Noobz347 · Feb 20, 2019

JimZim said:
Walbro has the GPA series pump but I have alway looked for the GSL line for the 190 or 255 liter unit. Is the GPA's the series of pumps that you were referin to with the internal bypass?

I'm not sure it was specified at the time other than to say it affected units that were not designated "high pressure". Here's a link to the article:
https://www.stangnet.com/mustang-forums/resources/fuel-flow-forensics.55/history

It's a download and the button is in the upper right hand corner

JimZim · Feb 20, 2019

Good reading. Thanks for the link.

Noobz347 · Feb 20, 2019

JimZim said:
Good reading. Thanks for the link.

I still have that issue still laying around somewhere. Years after first reading it (when I couldn't find the magazine to save my life) I found that same article online.

It is very good at breaking the different pumps down into like terms. I've also used it as a good explanation of the difference between pressure and volume in fuel delivery conversations.

General karthief · Feb 20, 2019

Maybe post a copy in the resources?

Brent Francis · Feb 20, 2019

Noobz347 said:
I would imagine that there's a Fuel Management Unit in there somewhere perhaps?

Anything that you do with injectors larger than 24s is going to require a tune. You need to factor this in when talking about swapping to larger ones.

Swapping to 30 lb injectors over 24's wouldn't be my first pick either.

If you're going to go through all the hassle, I might pick an injector that's large enough for I plan to do once the blower runs out of steam.

How is the rest of your fuel system? Pump, rails? All stock?

Edit: Oh, and the alternator.

Brent Francis · Feb 20, 2019

Has a 255 pump, adjustable fuel regulator, rails don't look stock. I bought the car 3 years ago with all the work done.

Should I upgrade to 30lb Injectors?

Brent Francis

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Noobz347

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90sickfox

Wasn't a pretty sight...and I've got big hands

Brent Francis

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Dan02gt

mazing how much gas smell came from that tiny hole

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2000xp8

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VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

Wayne Waldrep

Before I post a pic, do you have one of yours?

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General karthief

wonder how much it would cost to ship you a pair

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Should I upgrade to 30lb Injectors?

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