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injector size question

  • Thread starter Thread starter Project 77
  • Start date Start date Nov 27, 2007

Project 77

Founding Member
Jun 30, 2002
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16
Bernville PA
Nov 27, 2007
#1
  • Nov 27, 2007
  • #1
I picked up a 93 Cobra that at one point had a Paxton Novi2000, with 42 pound injectors. The blower is no longer on the car, but the 42's and C&L meter are still on the car. I know the car runs rich, I got a sample tube to put in the meter for 24's and i'm waiting on my 24's to come via the mail. My question is would running that rich cause the car to overheat? It has a griffin alum rad., but if i sit for more than a few minutes the heat slowly creeps up until I turn the electric fan on.
 

Wallzy

New Member
Aug 20, 2006
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Orlando, FL
Nov 27, 2007
#2
  • Nov 27, 2007
  • #2
"My question is would running that rich cause the car to overheat?"

No.

- If you sit without your fan on you are probably going to overheat, unless it is pretty cool out that day.

Walz
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
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gainesville
Nov 27, 2007
#3
  • Nov 27, 2007
  • #3
I dont think that would cause the car to overheat, but I am sure that your plugs are well on their way to being fouled. I would change those out and run some seafoam through the car.
 

5spd GT

"the 5.0 owns all"
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Aug 7, 2002
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Arkansas
Nov 27, 2007
#4
  • Nov 27, 2007
  • #4
If you have no airflow over the radiator, whether it be by you cruising at 25+ mph or by a fan, it is going to overheat.

The injectors are not the problem, and swapping to 24 lb injectors is good, and those are the factory injectors on the '93 Cobra.
 

Project 77

Founding Member
Jun 30, 2002
370
2
16
Bernville PA
Nov 27, 2007
#5
  • Nov 27, 2007
  • #5
I always wondered if that seafoam stuff worked...can I run 10 PSI of boost with 24's through a stock Cobra motor??
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
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99
Arkansas
Nov 27, 2007
#6
  • Nov 27, 2007
  • #6
The 42 pound injectors would be much safer for 10 lbs of boost.

Seafoam really does not do much at all. A buddy and I tried it on his 00 GT. It did not doing anything noticeable.
 
C

chevyfan1

New Member
Jan 22, 2008
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0
Jan 23, 2008
#7
  • Jan 23, 2008
  • #7
how can i tell what lbs my injectors are by looking at them
 

PUNISHER RACING

Active Member
Aug 27, 2007
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36
FORD CITY, PA.
Jan 23, 2008
#8
  • Jan 23, 2008
  • #8
orange 19, blue 24, red 30, dark blue 36, green 42
 

5spd GT

"the 5.0 owns all"
Founding Member
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99
Arkansas
Jan 23, 2008
#9
  • Jan 23, 2008
  • #9
Fuel Injector Selection:

Injector HP Ratings: divide flow rating by .5 and multiply the result by the number of injectors. The following examples use a 100% duty cycle. These ratings are for N/A engines at the flywheel.

Example:

19 lb injectors/.5 = 38 - 38 x 8 = 304 HP
24 lb injectors/.5 = 48 - 48 x 8 = 384 HP
30 lb injectors/.5 = 60 - 60 x 8 = 480 HP
36 lb injectors/.5 = 72 - 72 x 8 = 576 HP
42 lb injectors/.5 = 84 - 84 x 8 = 672 HP

The preferred duty cycle is about 85% maximum, so for a safety factor multiply the final figure times .85.

304 HP x .85 = 258 HP for 19lb injectors
385 HP x .85 = 326 HP for 24lb injectors
480 HP x .85 = 408 HP for 30lb injectors
576 HP x .85 = 490 HP for 36lb injectors
672 HP x .85 = 571 HP for 42lb injectors

Remember that the above ratings are at 39 PSI. Increasing the pressure will effectively increase the flow rating. Example: a 19 lb injector will flow 24 lbs at 63 PSI, and a 24 lb injector will flow 30 lbs at 63 PSI.

See http://users.erols.com/srweiss/ to get the calculators used in these examples.

The above information is courtesy of jrichker!
 
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