#30 injectors

[black945.0]

i am going to buy a set of 30's i dont want to be adding to much fuel tho my current set up is e303 i would get the c&l 76mm mass air and 70mm t/b and i all ready have complete mac exhaust does any one a similar set up and if so did u up grade the ignition

 

[final5-0]

The 30's most likely will cause you probs with too much fuel at small pulse conditions.

What are your goals with your car?

If a mild combo at say 250 to 275rwhp and no custom tune then I'd go with 24's and elevated fuel pressures.

For a more serious combo at say around the 300rwhp range then I'd go to the 30's with custom tune which is way more accurate than the afpr thing.

Later
Grady

 

[BlackVert]

30s should be fine, but if you are going blower, then 42s at least.

 

[94GTLaserRC]

30's are too much!
RC

 

[broken_joke]

minus the cam i ran almost an identical setup with stock injectors and the car ran great. but you could find a dyno shop and make a couple of runs to see exactly what your air fuel ratio is so you could make a better decision after that reading

 

[greenlantern]

I ran 30's for a couple of months but I ended up stepping down to 24's. Car ran rich and crackeld a lot on the decel. Ran much better with the 24's.

 

[DarkMesa8]

Also consider that the higher you go with injectors/calibrated MAF the further off your MAF curve will be adjusting the EEC.

My 293rwhp combo had 30's on it for the dry shot, naturally aspirated the EEC was running it 16:1 lean! Had to TwEEC the curve in order to get it safe.

 

[final5-0]

I would like to point out that a custom tune needs no raised fuel pressures so the size of the inj will act smaller at the stock pressure than what most peeps are used to who have been using elevated fuel pressures to tune with.

I don't doubt it a bit that those who tried to run 30's or larger had some probs with small pulse width issues. The afpr does not have the range of adjustment to dial back enough fuel at those very small pw's.

Later
Grady

 

[BlackVert]

i am going to buy a set of 30's i dont want to be adding to much fuel tho my current set up is e303 i would get the c&l 76mm mass air and 70mm t/b and i all ready have complete mac exhaust does any one a similar set up and if so did u up grade the ignition

do you have stock heads and intake?

 

[DarkMesa8]

I would like to point out that a custom tune needs no raised fuel pressures so the size of the inj will act smaller at the stock pressure than what most peeps are used to who have been using elevated fuel pressures to tune with.

I don't doubt it a bit that those who tried to run 30's or larger had some probs with small pulse width issues. The afpr does not have the range of adjustment to dial back enough fuel at those very small pw's.

Later
Grady

I completely agree, my TwEECer made my AFPR rather useless. One thing that AFPR's can be useful for, though, is daignosing rich/lean problems. You can jack the pressure up or down 10psi and it will take time for the EEC to compensate, thus you can see if your problem is fuel related. For tuning, though, the EEC will adjust pulsewidth over time to compensate for the changing fuel pressure.

My 255lph BBK intak pump, non high pressure, was unable to keep up with my 150 dry shot. I had to richen the mixture up really really fat through pulsewidth to get it to the proper A/F ratio. I'm bringing this up showing how much of an effect that pulsewidth has as opposed to fuel pressure.

 

[final5-0]

I completely agree, my TwEECer made my AFPR rather useless. One thing that AFPR's can be useful for, though, is daignosing rich/lean problems. You can jack the pressure up or down 10psi and it will take time for the EEC to compensate, thus you can see if your problem is fuel related. For tuning, though, the EEC will adjust pulsewidth over time to compensate for the changing fuel pressure.

My 255lph BBK intak pump, non high pressure, was unable to keep up with my 150 dry shot. I had to richen the mixture up really really fat through pulsewidth to get it to the proper A/F ratio. I'm bringing this up showing how much of an effect that pulsewidth has as opposed to fuel pressure.

Jason

I know absolutely nothing about nitrous as that stuff scares me cause of all the carnage I've seen it do at the track but I do find it suprising to see that big pump was inadequate for your needs.

Very interesting to say the least.

Later
Grady

 

[DarkMesa8]

Jason

I know absolutely nothing about nitrous as that stuff scares me cause of all the carnage I've seen it do at the track but I do find it suprising to see that big pump was inadequate for your needs.

Very interesting to say the least.

Later
Grady

No, the pump flowed all the fuel I could need, but dry nitrous kits require a very high amount of fuel pressure to compensate for the shot. This is unlike wet kits, which inject the fuel along with the nitrous to compensate.

With the dry 150 shot, I was making approximately 495 bhp (293rwhp = approx 345bhp+150 shot). In a dry kit that was gonna require a helluva lot of fuel pressure ontop of the 30's, and the standard 255lph didn't give me that pressure. When I TwEEC'd the pulsewidths of my injectors, I accidently ran it 9:1 rich during the 150 shot, so I knew that the 255lph could handle flowing the appropriate fuel, just couldn't get the pressure high enough. After testing and tuning, I got it at 11.5:1 just where I wanted it.

Now if I had an inline T Rex pump, or the 255lph high pressure pump, all this dickin around wouldn't have been necessary. Or I could've gotten a wet kit and been done with it.

(PS: for those of you wondering, I am using an NOS 5115 kit and did install the washer)

 

[final5-0]

Jason

Very good info and thanks for sharing.

I too have the 255 high volume NOT high pressure pump. I went with that one cause I saw some of the power adder boys complain they could not get their pressure below the low 40 range.

At that time I had plans to Tune with the Tweecer so the stock fuel pressure value was important.

Last thing is I knew I would not move up to a pa combo anyway...... now I'm not so sure about that original thought, lol.

btw ...... I see your hangin out more on this site and its good to have you here.

Later
Grady

 

[5spd GT]

I have 30lbers on my daily driver (no tune) at 39psi (vacuum line off)...and get 21mpg so my tune isn't bad off...

I do have a rich idle. It causes a slow start and sometimes a no start. I have to push the pedal to the floor to Clear the Keep alive memory (KAM) to get it to start (cuts off the fuel momentarily)...

I think I could probably get a bit better track times with 24's...who knows...

 

[94gtslow]

I run 30# injectors also. I am going to run a 125-150 dry shot.

MY car idles fine and I have no drivability problems fp at 38 timing at 10.



Then later on upgrading to a 347 hopefully,and juice it, but that is a long time away.

 

[black945.0]

thanks for all the good info i guess its up to me now ill let u know what i do

 

[final5-0]

I have 30lbers on my daily driver (no tune) at 39psi (vacuum line off)...and get 21mpg so my tune isn't bad off...

I do have a rich idle. It causes a slow start and sometimes a no start. I have to push the pedal to the floor to Clear the Keep alive memory (KAM) to get it to start (cuts off the fuel momentarily)...

I think I could probably get a bit better track times with 24's...who knows...

The rich idle is IMHO aggravated by a couple of things

1 The small pluse width at idle and the size of the inj. The pcm's adaptive strategy can help by trimming some of the fuel away but it does have its limits.

2 the last reason for the rich idle is ...... well ...... its got a thing or two to do with Ed's magic making its presence made known due to one of the cam specs that I'll just not talk about but seems to be common in his street cams. I assure you I'm all too well familiar with it cause I spent a good bit of time in slaying that idle dragon, lol. An afpr will be of no help with this as adjustments need to be made to several pcm values to regain stock like idle conditions, cam lope not included, lol.

Later
Grady

 

[black945.0]

so having the 30's will make a lopey idle

 

[final5-0]

I run 30# injectors also. I am going to run a 125-150 dry shot.

MY car idles fine and I have no drivability problems fp at 38 timing at 10.



Then later on upgrading to a 347 hopefully,and juice it, but that is a long time away.

I'm glad those 30's are working good for you

Your spark level at 10* is lower than what a lot of peeps run and that helps a bit for a more stable idle btw.

When peeps ask me about running 30's with no help form a custom tune I do try to emphasize the phrase ...... you might have probs at small pulse width conditions.

These combos are really strange and even though most of em have similar stuff they can act very differently after it is all said and done with the install of the various parts

The adaptive strategy of the pcm is pretty good at smoothing some things out a bit like idle but it can only do so much.

Sometimes tiny things changed like the idle speed increased by 50 rpm can make all the difference in a stable idle but ...... you gotta wait to see how the pcm will or will not react to the change

That little silver box has bested me on more than one occasion .............

However



Over time I will make it reveal ALL its secrets to me

Later
Grady

 

[94gtslow]

Yea I guess I am one of the lucky ones, ive heard storys of people that can't get thier car to idle right etc...


Oh and by the way I had my car dynoed and it made the best power set at 10* we tried everything fomr 10-18*

I guess I get the best of both worlds, more power, and run it on 87 octane gas.