Down grade to 24lbs injectors??

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deepsea1969

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Nov 14, 2004

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Sep 30, 2005

#1

• Sep 30, 2005

• #1

Would I benifit dropping to 24lb injectors instead of 30's with my combo in my sig?? Thanks for your opinion.

 

S_Charged306LX

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Sep 30, 2005

#2

• Sep 30, 2005

• #2

i am running 19lb injectors on almost exactly the same combo except for that i have TF heads. on the dyno my car did not look like it was going lean any time
soon, maybe you are overkilling it a bit switch down might not be a bad idea cause i thought of puting 24lb ers on mine.

 

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deepsea1969

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Sep 30, 2005

#3

• Sep 30, 2005

• #3

Ok, I still have the 19's, I may put them back in with a new sample tube. What fuel pressure did you go with??

 

S_Charged306LX

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#4

• Sep 30, 2005

• #4

fuel press

fuel press is around 38-40. is your mustang running bad?

 

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deepsea1969

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#5

• Sep 30, 2005

• #5

well, it seemed to run like it wasn't getting enough fuel, so I pulled the spark plugs and they were white. Indicating a lean condition. Checked fuel pressure it was at 39. Plus my gas mileage was around 11mpg and I didn't drive it hard. That was city. Increased fuel pressure and seemed to fix the prob. a bit. So I was thinking maybe the computer was having a hard time and thus causing it to be lean.

 

gt40_2003wes

I did sound a wee bit gay there.

Aug 14, 2005

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ky

Oct 1, 2005

#6

• Oct 1, 2005

• #6

i would go with the 24s and see wht that does for it.

 

Michael Yount

Mustang Master

Apr 10, 2002

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Oct 1, 2005

#7

• Oct 1, 2005

• #7

I run 19's as well with a mild h/c/i combo. You can't rely on plug reads to tell you much meaningful on the newer efi cars. The computer is DESIGNED to run them as lean as it can get away with to save fuel. The egr system allows the computer to pull fuel (lean) and add timing - to save fuel and improve emissions. An efi engine in perfect working order will almost always show bone-white plugs. I did a guilt plug change on my wife's Bimmer at about 65K miles -- except for grime in the threads, I could barely tell the 7 year old/65k plug from the new one.

If you're wondering about a/f ratio - get some dyno runs with a wide band. That'll tell you much more about your a/f ratio than plug reads will. Plug reads are fine for leaded racing fuel and carbs -- but even many of those guys use a/f meters to tune with.

30's are way more than you'd ever need with your combo. 24's are plenty; 19's are probably just fine.

 

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deepsea1969

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Oct 1, 2005

#8

• Oct 1, 2005

• #8

Ok, thanks micheal, that makes me feel a bit better...the plugs where bone white.

 

Michael Yount

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Oct 1, 2005

#9

• Oct 1, 2005

• #9

You and I are running an almost identical combo - you have stock cam, I have a mild custom. I run a ProM 73 mm maf set up for 19's. Mine actually ran a bit rich on the dyno - we had to use the chip to take out a bit of fuel. 24's are plenty; 30's are big time overkill; 19's will likely be fine. Your biggest challenge is getting an accurate maf signal with that C&L maf. Keep your fuel pressure stock.

 

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deepsea1969

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Oct 1, 2005

#10

• Oct 1, 2005

• #10

so, should I get the 19 sample tube or go ahead and get 24lb......if you know anyone that want's to trade 30's for 24's let me know...they have been on only 6mos.

 

Michael Yount

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Apr 10, 2002

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#11

• Oct 1, 2005

• #11

If you're gonna keep modding, put the 24's in. By the way, if it's running ok, and the a/f is ok, why not just stick with the 30's since they're already in there?

 

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deepsea1969

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#12

• Oct 1, 2005

• #12

I've got it running alright with the 30's...my fuel pressure is at 39. No idle issues at all. I haven't put it on a dyno though. My gas milage sucked though around 11mpg. city. I'll keep them in for now. I was just curious if anyone thought the overkill was hurting me right now.

 

5spd GT

"the 5.0 owns all"

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#13

• Oct 1, 2005

• #13

I wish I would have went with 24's instead of listening to the bigger is better crowd. I have 30's on a more "steppedup" setup than you and they run rich but I get good gas mileage. It causes hot start problems due to too much cranking fuel. Also a nice rich idle...

One guy actually swapped from 30's to 24lb injectors (swapped sample tubes I believe) and gained some at the track. It was a small amount...that could have been changed from anything but the overall leaner condition could help that. My car would run happier with 24's. I know that.

 

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stang619

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Sep 6, 2004

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Oct 2, 2005

#14

• Oct 2, 2005

• #14

Not to hijack the thread but i have a similar combo and the guys on the ford racing techline recommended 30 lb. inj. ..although most evryone else said 24's... Any thoughts guys?

 

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87GT 306

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Oct 11, 2004

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Oct 2, 2005

#15

• Oct 2, 2005

• #15

what about me? Do u think Im running to big with the 30's? keep in mind Ill be running a 150 shot next year too. But Im curious.

 

Michael Yount

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#16

• Oct 2, 2005

• #16

87 - if it's a dry shot, I'd run the 30's.

Stang619 - I think a lot of it has to do with how the car is gonna be used. If it's a street car - 95% of your run time is spent with the injectors barely being tasked at all. I'd go with 24's in that case on a combo like yours. If it's a dedicated racer where almost all time is spent at w.o.t. between 4000-6500 rpm, then I'd probably put the 30's in it so the injectors aren't working so close to their max limit.

 

5spd GT

"the 5.0 owns all"

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#17

• Oct 2, 2005

• #17

Michael Yount said:

87 - if it's a dry shot, I'd run the 30's.

Stang619 - I think a lot of it has to do with how the car is gonna be used. If it's a street car - 95% of your run time is spent with the injectors barely being tasked at all. I'd go with 24's in that case on a combo like yours. If it's a dedicated racer where almost all time is spent at w.o.t. between 4000-6500 rpm, then I'd probably put the 30's in it so the injectors aren't working so close to their max limit.

Click to expand...

Yep Yep...looks good to me

 

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stang619

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#18

• Oct 2, 2005

• #18

thanks guys