I'm pretty sure I need to up my injectors, what do you think?

[Magnus]

If we had an Advance technical section, this would be a good post to put in there....

Well.. I don't have the atap logs with me, they are at home.. but I believe I am seing 20ms pulse widths at 5800 or so RPM's.. kinda high right?

And when I do Heads/Cam.. I'm going to be breathing even more..

So what are the exact specs on our injectors and at what PSI? ANyone know?

Also, James, I know you have the accel 24 lb'ers.. your don't like them huh? What are some issues you are noticing?

I would like to go the very next step up.. Nothing to big. I am thinking the PCM is going to have a hard time with them. I already run rich at idle and WOT from my custom MAF and ported TB. :(

[v6maro]

I may actually have a set of 6 30#'ers that i can sell ya, i will let you know asap, asking only what i paid since they have not been used by me, for $90 + shipping
lemme make sure i wont be using them
-Steve

[Magnus]

30 is way too much.

[Magnus]

RPM, Pulse Width, O2, O2

4214,22.23,0.910,0.910
4255,22.35,0.910,0.910
4326,22.74,0.910,0.905
4354,22.13,0.915,0.905
4398,21.65,0.910,0.910
4473,21.88,0.915,0.910
4551,22.02,0.920,0.910
4648,21.74,0.910,0.910
4698,21.99,0.910,0.910
4784,21.04,0.910,0.905
4872,21.77,0.910,0.910
4927,21.85,0.910,0.910
5002,21.73,0.910,0.910
5080,21.91,0.910,0.915
5160,21.38,0.915,0.910
5243,20.84,0.915,0.910
5285,21.50,0.915,0.910
5372,20.39,0.915,0.915
5416,21.36,0.910,0.910

What do you think?

[ October 30, 2001: Message edited by: Magnus ]</p>

[v6maro]

sorry for trying to help man...

[Magnus]

Don't be sorry. I am looking for help. [img]smile.gif[/img]

But because of the fact that I cannot get the PCM reprogrammed, I would like to go the smallest possible step up that I can.

24 lb/hr sounds nice.. but I would like to poll the masses about this.

[Bird_Of_Prey]

Keith, i know there is some way to convert pulsewidth to duty cycle. Find out what your injector duty cycle percentage is and go from there. Anything over 85% on the stock injectors risks locking the injector. On the typhoon, that thing sees about 110% duty cycles with 50# injectors [img]redface.gif[/img]

Tom

[Magnus]

We are going to have to do something here.. With all the peeps wanting to do heads/cam.. were going to need more fuel.

I was doing some calculations.

lb/hr = (HP * .5) / (num. injectors * .8)

Stock:
(200 * .5) / (6 * .8) = 20.83 lb/hr

Heads/Cam and 250 Crank HP
(250 * .5) / (6 * .8) = 26.04 lb/hr

We have 21.4 or 22 lb/hr injectors.

Now I know both Mike and Royce go WOT with their cams and I bet they are dumping lots of fuel so I'm wondering if they too are very close to the edge if not already over it.

*sigh*

[Magnus]

Heres the max pulse with table:

RPM
1600 75
2400 50
3200 37.5
4000 30
4400 27.25
4800 25
5200 23
5600 21.4
6000 20
6400 18.75

I'm REALY close.

[Pro Stock John]

I'm pretty sure you will need to upsize your injectors. 21-22 is like the max that is safe from my understanding.

I would look into getting a set of used 24 lb injectors and I would try to calibrate them the same way LS1 folks do... Either running a ported MAF and also a MAF T.

If you current MAF is not giving you reliable reading since you did all that porting you may need to get another one.

Going from 19's to 24's will absolutely require that you take some fuel out of the BASE. Otherwise the plugs will get wet and you could even wash down the cylinders with fuel.

I think someone on the www.mfba.org has 24's for $100.

Reason that some folks have not blown up is that they are either seeing max pulsewidth at WOT, and you would not see any damage until you tried to go WOT for like a few miles... Car would run lean... At the track it's not as big of a deal but you might not see the gain from heads/cam if you don't have enuff injector.

I run 40 lbs @ 58 psi in my car. They are good for up to 525 rwhp. I was at 440 rwhp last time.

John
11.1 LS1

[DEE97GTP]

<blockquote>quote:</font><hr>Originally posted by Magnus:
Heres the max pulse with table:

RPM
1600 75
2400 50
3200 37.5
4000 30
4400 27.25
4800 25
5200 23
5600 21.4
6000 20
6400 18.75

I'm REALY close.<hr></blockquote>


I worked it out by hand that is what I got. Isn't .91 pretty rich for a N/A car? I agree with H&C you might need more injector. I think GTP injectors flow 32lbs at 52psi. They are good for 400+HP at stock fuel pressure.

BTW, you can't have over 100% duty cycle(constantly on), unless you are redefining what duty cycle means.

Since you already have a MAFT+, you shouldn't have a problem in tuning them.

DEE

[Pro Stock John]

GTP injectors would be too big and too big to calibrate with a MAF T.

I have GTP Bosch white top injectors in my car.