Fuel Injector Tech Thread

JeremyH

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Pick up some low mile takeoff injectors from the classifieds, would be cheap and easy way to freshen them up.
 

JeremyH

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Most places reccommned having fuel injectors cleaned or serviced every 25-30k miles. There are lots of factors that play into that though.
 

Schwettmann06

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K this is slightly off subject but is a injector question. My injectors make a very loud ticking. I've read others with the same thing and they say the injector is fine. I'm wondering why they are loud and what I can do about it. Oh they are frpp but I can't remember size, I want to say 47lb and being run with a whipple.
 

JeremyH

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While that doesn't hurt, unfortunately no. lol

To clean properly you need to remove and clean the filter screens and pulse the injector while using fuel injector cleaner or an ultrasonic sink. Most shops also will flow test them afterwards as well and look for differences.
 

JeremyH

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It depends, if it s a wet shot, you can get away with smaller injectors. Most guys run a 100 shot with stock injectors.
 

CammedS197

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If I'm crusing on the highway and drop to 3rd my car will hiccup really bad then go. I'm running 340rwhp so roughly 380-400 crank and still got a few more mods coming long tubes and more. Did the math and calls for 27-30lb and has my 24lbs running at max. 2006 3v. Will be upgrading fuel pump to a walbro 405lph. Stick with stock 24's or go bigger?
 

weather man

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If I'm crusing on the highway and drop to 3rd my car will hiccup really bad then go. I'm running 340rwhp so roughly 380-400 crank and still got a few more mods coming long tubes and more. Did the math and calls for 27-30lb and has my 24lbs running at max. 2006 3v. Will be upgrading fuel pump to a walbro 405lph. Stick with stock 24's or go bigger?

Contact LITO on here. Cheap insurance to have him look over a pull. Heck, he has done so many combo's, might know off the top of his head.
 

BruceH

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If I'm crusing on the highway and drop to 3rd my car will hiccup really bad then go. I'm running 340rwhp so roughly 380-400 crank and still got a few more mods coming long tubes and more. Did the math and calls for 27-30lb and has my 24lbs running at max. 2006 3v. Will be upgrading fuel pump to a walbro 405lph. Stick with stock 24's or go bigger?

What delta did you calculate at? The stock tune will command up to 70 psi with higher airflow. This makes the injectors able to support a whole lot more power than the standard 3 bar psi used by most calculators.

The 5.0 takeoff injectors work well and are well priced. The old 39lb blue cobra injectors work well for a budget price too.

 

CammedS197

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What delta did you calculate at? The stock tune will command up to 70 psi with higher airflow. This makes the injectors able to support a whole lot more power than the standard 3 bar psi used by most calculators.

The 5.0 takeoff injectors work well and are well priced. The old 39lb blue cobra injectors work well for a budget price too.


Delta? What size are 5.0 injectors? Im cammed exhaust and a CAI and brenspeed tune. I do believe the stock fuel pump has a good play in whats happening but its so often and will be that hesitation and a hiccup when I drop it like that. I'll have to datalog it but already going to a walbro pump from S&H. And thanks guys
 

Wes06

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Stock fuel pump causes that hiccup on the highway. Swap it for something else and good to go
 

BruceH

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Delta? What size are 5.0 injectors? Im cammed exhaust and a CAI and brenspeed tune. I do believe the stock fuel pump has a good play in whats happening but its so often and will be that hesitation and a hiccup when I drop it like that. I'll have to datalog it but already going to a walbro pump from S&H. And thanks guys

Delta is the fuel pressure you used for your injector calculation. Most online calculators don't take into account a variable delta that is possible with a returnless fuel system.

The 5.0 injectors are 32lb at 39.15 or 43.5psi, I can't remember which but they flow about 33% more than the stock 24lb injectors that come with a 3v.

A slight hesitation can be caused by many things, I really doubt it's your fuel pump. I say this because the only hicupp I've experienced was tune related.

In any case good luck.
 

lito

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Delta? What size are 5.0 injectors? Im cammed exhaust and a CAI and brenspeed tune. I do believe the stock fuel pump has a good play in whats happening but its so often and will be that hesitation and a hiccup when I drop it like that. I'll have to datalog it but already going to a walbro pump from S&H. And thanks guys

Quite sure your problem will still be there with the new pump.
 

CammedS197

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Quite sure your problem will still be there with the new pump.

Oh ok. I believe it was the stock delta. Never messed with it at all. Lito would you want to look at a datalog just to look at it as I go? Also do you recommend I go to the 5.0 injectors since I will be going to long tubes and a couple more mods and will likely be well over the 400 crank hp mark? Especially when the math adds up to the stock 24lbs being at almost 100%?
 

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