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| Forum name | Turbo/Nitrous Tech |
| Topic subject | i seem to still be running lean |
| Topic URL | https://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=55512 |
55512, i seem to still be running lean Posted by siueclipse, Sep-04-03 10:37 AM
Well, today i finally got on it after my new clutch has been installed....
I floored it in 3rd gear and let it climb.. I reached 1600 degrees at about 5000rpm. I think the fuel pressure was about 80psi. My air/fuel shows very green the entire time.
Im confused. Im running the sfmu with the 2.72 disk, the dark spring, and im running 310cc injectors with a base pressure of 22psi and a 10lb boost fuel pressure of about 80psi.
I don't see how i could be running this hot still. My engine compartment is usually very hot. Im wondering if i have done something wrong which is keeping my egt temps high.
Something else thats going on with the car... My car wont idle correctly. It will stay at 1200rpm at idle, the boost pressure shows -18, right where it should be, but then sometimes when im sitting still at a light, the rpms will drop down to 850 or like and the boost pressure shows -15.
Im wondering if that might be causing me to run hotter than normal as well.. I dont think ive ever felt and engine compartment that is as hot as mine.
Also, my egt might be wrong. Where do most people have their probe on their manifold? Mine is actually closer to the #1 cylinder than more centrally located.
Im about to put in some 440cc injectors so i can up the boost, but I don't think that simply adding fuel to cool it down is going to fix this problem.
Does anyone have any suggestions?
Thanx James
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55515, RE: i seem to still be running lean Posted by DarkOne, Sep-04-03 11:08 AM
best two suggestions i can make would be a wideband on the dyno and a datalogger.. if its not pulling timing and your AF ratio isn't way outta whack, then you're probably okay.
I'd try tweaking your bleed valve to get a little more fuel pressure under boost as well. it'll probably help.
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55518, RE: i seem to still be running lean Posted by Avenger, Sep-04-03 11:52 AM
I'm thinking that the 2.72" disk is too small to be running 310cc injectors. I know that is the disk that most people use when running 440cc but I'm not so sure about it using 310s. How about going up a disk size? Also, don't look at a blinky light a/f gauge. It's not good for very much and doesn't show you crap. Get one that show o2 voltage but still a wideband is even better.
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55523, RE: i seem to still be running lean Posted by grain, Sep-04-03 12:28 PM
try upping the static pressure. i have the sfmu 2.72 disk, biggest ring, dark spring. idle is around 23 - statis is around 45ish. i go wot at 7# it stays around 1400.egt
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55562, RE: i seem to still be running lean Posted by soldier101, Sep-05-03 04:59 AM
he said his a/f setup was still way green? either he has it hooked up wrong, or hes running really rich and has afterburn right?
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55563, RE: i seem to still be running lean Posted by Kirby, Sep-05-03 05:17 AM
Wait a min, wasn't DEANO D running an 8:1 disc or something like that with his 310's at 10 psi? I know he was not using the 2.? disc. But he was using the standerd FMU not the SFMU I think your running really lean regardless of what your A/F says. I don't see how a rise rate that low pared with 310 injects could supply enough fuel. Those injectors are not that much bigger than stock. However your fuel pressure under boost sounds about right.... What are we missing here? Check this thread it may answer a few things, or not.
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=39551&mesg_id=39551&listing_type=search#39666
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55565, RE: i seem to still be running lean Posted by siueclipse, Sep-05-03 06:37 AM
i should have the 8:1 disc in there right now. its the second to largest ring, (the one that the disc doesn't fit tight in the ring).
I know my air/fuel is hooked up correctly.
Could it be the generic ngk plugs i have installed? they aren't iridiums.
James
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55568, RE: i seem to still be running lean Posted by siueclipse, Sep-05-03 06:44 AM
from reading that thread.. it sounds like i need to take the idle pressure from 21psi up to 25psi. maybe that would give me just the slightest bit more fuel that i need.
who knows.. i might just say screw it and wait for the 440s.. no sense in trying to tune injectors when they will be replaced next week.
James
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55619, RE: i seem to still be running lean Posted by siueclipse, Sep-06-03 04:37 PM
well, i decided to change out my fuel filter, which was damn near clogged. things are cooling down but i haven't been able to run a realy good test.
James
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