Max Boost on 44lbs injectors
09-19-2007, 07:46 PM
#12
TECH Veteran
Originally Posted by 365ZUM
Strange... I have 44lb injectors in my 06' LQ9 and run ~9lbs or so full time. Besides an MSD Boost-a-Pump, my fuel system is stock. No pinging whatsoever, and my A/F (though I can't recall the exact number) is actually too rich, even at high RPMs. Meth is installed, but not injected.
As long as you have a good, safe tune IMO you'll be fine with the 44's.
As long as you have a good, safe tune IMO you'll be fine with the 44's.
9psi on an LQ9 should be way out of fuel for 44's. That's either running meth or you aren't making the power you should. If you run meth, that's a fuel. Meth is also a band-aid for too small of injector.
09-19-2007, 08:10 PM
#13
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Originally Posted by zippy
9psi on an LQ9 should be way out of fuel for 44's. That's either running meth or you aren't making the power you should. If you run meth, that's a fuel. Meth is also a band-aid for too small of injector.
I have a few things being done to the truck in two weeks. I might just throw in a set of larger injectors to see what difference they might make- that should shed some light on the subject.
09-19-2007, 08:20 PM
#14
just because the afr is good doesn't mean the injectors aren't maxed. That dyno pull in your sig 365ZUM, what gear? to what RPM? I was doing just fine as well, afr wise, my IDC was approx 110%, but what does it matter after 100%. Everything was okay until I decided to shift at 6200 instead of 5800. I didn't get ping, just my lovely afr of 11.7 went to 12.7.
09-19-2007, 08:35 PM
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365zum what kind of track time are u seeing? i have the same set up and my 44# are doing just fine at 8psi, all i have is a set of f.a.s.t 44s and a walbro 255, and im a 60% on them. but my meth is not hook up yet and im not runing as much timeing as i well be with the meth.
09-19-2007, 10:30 PM
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Originally Posted by dewmanshu
just because the afr is good doesn't mean the injectors aren't maxed. That dyno pull in your sig 365ZUM, what gear? to what RPM? I was doing just fine as well, afr wise, my IDC was approx 110%, but what does it matter after 100%. Everything was okay until I decided to shift at 6200 instead of 5800. I didn't get ping, just my lovely afr of 11.7 went to 12.7.
Dew- Don't have the graph in front of me (out of town), but if I remember correctly, it was a 3rd gear pull up to 6200RPM. I may be a few tenths off, but I believe the A/F ratio was no less than 11.5:1 throughout the entire pull.
I hope to have Allen Nelson himself tuning this truck in two weeks.
We've worked out a deal to have him do an in-house tune after the new transmission, converter, exhaust, methanol, and now, looks like 60lb. injectors. 
I'll be sure to do a more recent dyno run before the new equipment is installed so the air/fuel info from the 44lb. injectors can be compared to that of the 60lb'ers.
09-19-2007, 10:44 PM
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Originally Posted by 05crew
365zum what kind of track time are u seeing? i have the same set up and my 44# are doing just fine at 8psi, all i have is a set of f.a.s.t 44s and a walbro 255, and im a 60% on them. but my meth is not hook up yet and im not runing as much timeing as i well be with the meth.
No track time yet- haven't found the time quite frankly! Here in San Diego, the nearest 1/4 mile track (the only track that matters, IMO) is Fontana (over 2 hours away). I plan on taking her to the track once the new tranny, tuning, etc. is complete- I'll feel a hell of a lot more comfortable going with a built tranny!
09-20-2007, 07:25 AM
#18
TECH Veteran
Originally Posted by 365ZUM
Zippy- All I can tell you is that 44lb injectors work just fine...look at my dyno numbers below (meth was not used for the run because it simply wasn't needed with Allen's safe, rich tune)...fairly respectable numbers considering I have no other modifications. As I said, I'm running rich, not lean, so the flow rate must be sufficient out of the 44's.
I have a few things being done to the truck in two weeks. I might just throw in a set of larger injectors to see what difference they might make- that should shed some light on the subject.
I have a few things being done to the truck in two weeks. I might just throw in a set of larger injectors to see what difference they might make- that should shed some light on the subject.
Aren't you putting down about the same dyno number as Grippy did with his LQ4 and Radix at 7psi? That's with the parasitic drag of a blower as well as a 4L80E and 10.5" rear diff. An LQ9 with 9psi should make alot more power than what you're getting, this is why you aren't lean on injector.
09-20-2007, 03:53 PM
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When I had my radix on at 7-7.5psi the 44# injectors that come with the kit actually killed my engine(flooded and stalled) when the tune got messed up. The last AFR I remember seeing on the wideband was 10:1 and I think that might even be the max rich reading on it. Whatever it was it was rich enough to stall the engine out. 
In the REALLY cold weather I would see 9psi+ sometimes. I checked the AFR after the first time boost jumped up like that and it was completely fine(below 12:1 if I remember right).
I was also using the stock shift points in the maggie tune so the low rpm could be why I never had any troubles.
The fuel system consisted of the Magnuson in tank pump and the 44# injectors. That was it.
In the REALLY cold weather I would see 9psi+ sometimes. I checked the AFR after the first time boost jumped up like that and it was completely fine(below 12:1 if I remember right).
I was also using the stock shift points in the maggie tune so the low rpm could be why I never had any troubles.
The fuel system consisted of the Magnuson in tank pump and the 44# injectors. That was it.
09-20-2007, 07:52 PM
#20
Originally Posted by XLR8NSS
When I had my radix on at 7-7.5psi the 44# injectors that come with the kit actually killed my engine(flooded and stalled) when the tune got messed up. The last AFR I remember seeing on the wideband was 10:1 and I think that might even be the max rich reading on it. Whatever it was it was rich enough to stall the engine out.
In the REALLY cold weather I would see 9psi+ sometimes. I checked the AFR after the first time boost jumped up like that and it was completely fine(below 12:1 if I remember right).
I was also using the stock shift points in the maggie tune so the low rpm could be why I never had any troubles.
The fuel system consisted of the Magnuson in tank pump and the 44# injectors. That was it.
In the REALLY cold weather I would see 9psi+ sometimes. I checked the AFR after the first time boost jumped up like that and it was completely fine(below 12:1 if I remember right).
I was also using the stock shift points in the maggie tune so the low rpm could be why I never had any troubles.
The fuel system consisted of the Magnuson in tank pump and the 44# injectors. That was it.
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