Got a question for the L guys.

[chrisheltra]

Have any of you ever heard of needing 60# injectors for my mods? (I think most of you know what Im running)

I took my truck up to AVT to let Arthur tune it on Friday. He strapped it on the dyno and made a few pulls. On all the pulls at about 4K rpm the AFR would start to go lean and wouldnt stop going lean it would usually peak at 12.8 or so. It never changed no matter how much he fattened it up in that range. He suspected the fuel filter at first and swapped it out and no change. Then he put a fuel pressure gauge on it and he said the motor had enough fuel pressure from the pumps. So that lead him to believe I needed new injectors based on all that info and the injector duty cycles he was seeing. He will get the injectors on monday that I ordered and see if that fixes it. If it does that might be the reason Ive been running less than expected at the track lately. Also if that does fix it kudos to him b/c no other tuner saw or found a/the problem.

[Mike]

Never would of thought you needed 60's, but Arthur knows a heck of a lot more than me.

Another possibility could be something was wrong with your stock injectors, and if that was the case, I don't see any reason why you shouldn't just upgrade to 60s

[chrisheltra]

Never would of thought you needed 60's, but Arthur knows a heck of a lot more than me.

Another possibility could be something was wrong with your stock injectors, and if that was the case, I don't see any reason why you shouldn't just upgrade to 60s

I also thought about a problem with the stockers but I dont know of anyway to prove that. So I figured might aswell get some 60's and see what happens. Im going to need them eventually anyways.

[slow04]

At what RPM range did he check the fuel pressure? It could still be a bad pump or the sock clogged on the end of the pump, you wouldn't think that you'd need 60# injectors....weird

[1998ta__1991rs]

12.8 is rich, not lean

[DolSVT00]

12.8 is rich, not lean

Not for a blower mod motor.............. 12.8= BOOM.......Normaly with good gas we run 11.8-12.1 at the most for 93. Any leaner and well I'll let Mike and Bill tell you what happens

[Whaler]

I had 60's in my motor when it was a stock block. That's when it made ~450 RWHP on 14* timing and pump gas.

[chrisheltra]

At what RPM range did he check the fuel pressure? It could still be a bad pump or the sock clogged on the end of the pump, you wouldn't think that you'd need 60# injectors....weird

He said the fuel pressure was good all the way through the pull to redline

I had 60's in my motor when it was a stock block. That's when it made ~450 RWHP on 14* timing and pump gas.

I hope thats what I have too look forward too although he does have a dynojet and they do read higher.

[Mike]

I hope thats what I have too look forward too although he does have a dynojet and they do read higher.

I doubt they read higher than Amazon's MD.

[chrisheltra]

12.8 is rich, not lean

Compared to stoich (14.7) yes it is rich.
Compared to what the motor wants/needs its lean. (11.7)


I doubt they read higher than Amazon's MD.

True:bigthumb:

But to be honest I dont really give a damn at this point about dyno numbers.

[1998ta__1991rs]

Not for a blower mod motor.............. 12.8= BOOM.......Normaly with good gas we run 11.8-12.1 at the most for 93. Any leaner and well I'll let Mike and Bill tell you what happens

learn somthing new every day

[chrisheltra]

Well I talked to Arthur today and it was infact the injectors causing the tuning problems.

After he did some talking with some people, research on the SCT forums and so on he came to the conclusion that 420-430 RWHP was about the limit for the stockers. He was able to make me a street tune and a race tune. Tomorrow hes going to take it out for the street test drive and Ill be picking it up at ~5pm. Cant wait to take it to the track and see the results.

[DolSVT00]

Well I talked to Arthur today and it was infact the injectors causing the tuning problems.

After he did some talking with some people, research on the SCT forums and so on he came to the conclusion that 420-430 RWHP was about the limit for the stockers. He was able to make me a street tune and a race tune. Tomorrow hes going to take it out for the street test drive and Ill be picking it up at ~5pm. Cant wait to take it to the track and see the results.

Cough Cough Cough Uhhhh my truck must have a special "in my best Days of Thunder voice" matched injectors capable of 1.21 jiggawatts. I think you just had a clogged or bad injector or two, if the outside of your motor is any testament to the inside well............ anything is possible.

[chrisheltra]

Cough Cough Cough Uhhhh my truck must have a special "in my best Days of Thunder voice" matched injectors capable of 1.21 jiggawatts. I think you just had a clogged or bad injector or two, if the outside of your motor is any testament to the inside well............ anything is possible.

LOL who knows he did say the duty cycle on the injectors was pretty high though. At any rate Ill need the 60's eventually anyways.:twisted:

Maybe 60's should be or will be in your near future aswell who knows. He did say that the info he got about the power levels and injectors actually came from Sal.

[DolSVT00]

Brake specific fuel consumption (BSFC) is the amount (in pounds) of fuel that an engine requires to make one horsepower for one hour. An estimate for NA engines is .45-.50. An estimate for engines with forced induction or nitrous is .50-.60. Estimate on the high side of those figures unless you know exactly what the engine's BSFC is.

Injector duty cycle is the amount of time (as a percentage) that the injector will remain engerized (delivering fuel). Fuel injectors should never be run at 100% duty cycle. A "safe" maximum is 90%. Ford fuel injectors are rated at a specific pressure (42 PSI) and at 100% duty cycle.


Here is the low side of the HP rating for 42# injectors.

42 x 8 x .9 / .6 = 504hp (supercharged)

[chrisheltra]

Damn randy I didnt know you were a mathematician LOL.

[DolSVT00]

Damn randy I didnt know you were a mathematician LOL.

Im not, I'm probably pushing the limits of my 42# injectors. and will probably need a set of 60's myself. You probably needed them quicker because they were not performing as they should have been.

But, I will know the limits of the equiptment that I am working with and I will do the research to find out when I actually need to upgrade them. I absolutely refuse to read forums and get opinions on "what worked for me " and what opinions that I may get from someones incidental experience.

I by far, am not a gifted mechanic and am at most a back yard experiment type of guy. But I do heavy research on what I attempt to do before I do it. And I do not have the funds to throw my check book at a problem to make it go away.

With that said, I strongly disagree with people who say "buy this part and put it there" or "I saw this in a magazine so it must work" or "If I bolt all this on I'll be a good mechanic and you will go fast" If all you do is bolt shit on you are not a mechanic nor a good one for that fact. You are a parts installer and thats all.

But if you take Chicken Shit and make Chicken Soup, you graduate from a water boiler and become soui chef.

[chrisheltra]

Well i guess I suck then

[DolSVT00]

Well i guess I suck then

Speaking of you sucking, where'd you get to shiney flashy 10hp clear corners with the bulbs from. I have someone asking me because they want some.

[slowgreen99]

But if you take Chicken Shit and make Chicken Soup, you graduate from a water boiler and become soui chef.

Whats this process consist of? I might go buy some more chickens if its easy.