injector size

mustangmaniac247 · 04-17-2001, 06:28 PM

I will be installing a Vortech supercharger in the very near future and was wondering if my 24#injectors will be enough or do I need to get larger ones.

04-17-2001, 07:47 PM

A "rule of thumb" that I've learned.....take your HP and divide it in 1/2. Then, divide that @ by the # of cylinders. The # you get is the minimal injector size your car will need. I would recommend going with a 30# injector. What psi are you planning on running? Which Vortech?

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside sub-connectors; K&N cone filter charger; Hurst shifter; fiberglass cowl hood; A/C-less; rear seat-less; cat-less; Flomasters; Corbeau racing seats (fronts);
30# injectors; 190 lb fp FPR; TFS Twisted Wedge Intake 12.513 @ 108 mph (Pre-inj/fuelpump/FPR/ intake)

mustangmaniac247 · 04-17-2001, 08:48 PM

It's an s-trim.Im gonna run about 6-8p.s.i.
Can you have a fuel pump thats to big?190lph or 255lph.Will a 255lph work on a stock motor?

Greasy Carl · 04-17-2001, 09:51 PM

In , my experience 24 lb injectors are good until about 430 horsepower. That is with 80 psi of fuel pressure. You don't really want to go too much higher on fuel pressure because the injectors become unpredictable at pressures above 90 psi...I have used pressures as high as 120 psi but i was gritting my teeth while doing it and it was definitely pushing the envelope. 30s can get you to the low 500 horsepower levels at the wheels if treated accordingly.

If you have a choice, go with a T-rex pump instead of an in-tank. The in-tank pumps are not really good at sustaining the high pressures required for the very high fuel pressures caused by the FMU in blower setups. A T-rex with a stock intank can support a good amount of power 400 or so at the wheels usually, depends on what kind of shape the pump is in....just go with the T-rex first and replace the in-tank later when you get ready to make more power....hope this helps, good luck guys!

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91 coupe, SVO block 380 windsor, Brodix Neal heads, Super victor spyder intake, 90mm Accufab, 160 lb. Bosch injectors, D2-R procharger, Dynamic powerglide, 4500 stall, 9" rear, Speed Pro injection. 1047 hp at the wheels on Dynojet dyno with 23 lbs. of boost.

04-18-2001, 01:28 PM

255 lph fuel pump would just be overkill. 190 would be sufficient!

04-17-2001, 06:28 PM	#1
mustangmaniac247 Registered Member Join Date: Jan 2001 Location: Bakersville,N.C. USA Posts: 10	injector size I will be installing a Vortech supercharger in the very near future and was wondering if my 24#injectors will be enough or do I need to get larger ones.

04-17-2001, 07:47 PM	#2
1mintlx Guest Posts: n/a	A "rule of thumb" that I've learned.....take your HP and divide it in 1/2. Then, divide that @ by the # of cylinders. The # you get is the minimal injector size your car will need. I would recommend going with a 30# injector. What psi are you planning on running? Which Vortech? ------------------ '90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside sub-connectors; K&N cone filter charger; Hurst shifter; fiberglass cowl hood; A/C-less; rear seat-less; cat-less; Flomasters; Corbeau racing seats (fronts); 30# injectors; 190 lb fp FPR; TFS Twisted Wedge Intake 12.513 @ 108 mph (Pre-inj/fuelpump/FPR/ intake)

04-17-2001, 08:48 PM	#3
mustangmaniac247 Registered Member Join Date: Jan 2001 Location: Bakersville,N.C. USA Posts: 10	It's an s-trim.Im gonna run about 6-8p.s.i. Can you have a fuel pump thats to big?190lph or 255lph.Will a 255lph work on a stock motor?

04-17-2001, 09:51 PM	#4
Greasy Carl Registered Member Join Date: Apr 2001 Posts: 13	In , my experience 24 lb injectors are good until about 430 horsepower. That is with 80 psi of fuel pressure. You don't really want to go too much higher on fuel pressure because the injectors become unpredictable at pressures above 90 psi...I have used pressures as high as 120 psi but i was gritting my teeth while doing it and it was definitely pushing the envelope. 30s can get you to the low 500 horsepower levels at the wheels if treated accordingly. If you have a choice, go with a T-rex pump instead of an in-tank. The in-tank pumps are not really good at sustaining the high pressures required for the very high fuel pressures caused by the FMU in blower setups. A T-rex with a stock intank can support a good amount of power 400 or so at the wheels usually, depends on what kind of shape the pump is in....just go with the T-rex first and replace the in-tank later when you get ready to make more power....hope this helps, good luck guys! ------------------ 91 coupe, SVO block 380 windsor, Brodix Neal heads, Super victor spyder intake, 90mm Accufab, 160 lb. Bosch injectors, D2-R procharger, Dynamic powerglide, 4500 stall, 9" rear, Speed Pro injection. 1047 hp at the wheels on Dynojet dyno with 23 lbs. of boost.

04-18-2001, 01:28 PM	#5
bada$$lx Guest Posts: n/a	255 lph fuel pump would just be overkill. 190 would be sufficient!