EPS 234/246 112LSA Idle Vid
07-24-2011, 09:45 PM
#1
EPS 234/246 112LSA Idle Vid I was going to put this in the multimedia section but I know that this cam has not been used much at all from all the research I did on this site and youtube. I know a lot of members were asking questions about it so I feel this section would be better, especially since I will be posting results ina week or so regarding dyno numbers and how it runs. If a mod feels its better suited in the multimedia please feel free to move it.
I just finished my LS1 Fox swap and pulled it out of the garage after the almost 6 month build The exhaust is just tack welded in and has some bad leaks. I will be lining it all up and welding it fully in the next day or two and will post another video.
Any questions feel free to ask, I have not driven it yet more then a mile so I cant comment on driveability at the moment.
BTW the car has a base tune in it from my tuner but Im sure it can still use some work since it's throwing a MAP code 0106, but based ont he scanner it appears to be functioning properly.
http://www.youtube.com/watch?v=jx1DG2Je6Yg
I just finished my LS1 Fox swap and pulled it out of the garage after the almost 6 month build The exhaust is just tack welded in and has some bad leaks. I will be lining it all up and welding it fully in the next day or two and will post another video.
Any questions feel free to ask, I have not driven it yet more then a mile so I cant comment on driveability at the moment.
BTW the car has a base tune in it from my tuner but Im sure it can still use some work since it's throwing a MAP code 0106, but based ont he scanner it appears to be functioning properly.
http://www.youtube.com/watch?v=jx1DG2Je6Yg
07-24-2011, 10:04 PM
#4
Thanks, mod list is
Stock 241s, LS6 intake, SLP 25% underdrive, Kook 1 3/4 long tubes, Magnaflow muffler with built in Tru-X, Mcleod Street Twin, 4.10s, custom 4" CAI, Stock TB and maf for now gonan port the TB when I get the tune.
Stock 241s, LS6 intake, SLP 25% underdrive, Kook 1 3/4 long tubes, Magnaflow muffler with built in Tru-X, Mcleod Street Twin, 4.10s, custom 4" CAI, Stock TB and maf for now gonan port the TB when I get the tune.
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07-31-2011, 02:50 AM
#10
Staging Lane
Join Date: Jan 2011
Location: South London UK
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I'd guess it's the cam throwing the MAP code, you could try remote mounting the sensor via a bit of damping (like a small in-line fuel filter ir even an adjustable clamp across the feed pipe. If you can look at MAP live you will see it jumping around all over the place.
I quote from here:http://www.megamanual.com/v22manual/mtune.htm about 3/4 of the way down.....
It worked for me when I was tuning a single cyclinder engine where the pulses are a long way apart.
Love the GM Ford too, I'm working on a similar project here in the UK
Tuning Issues
If you have a very long duration cam in your motor, and it idles poorly, you might be able to get it to idle better through careful tuning with MegaSquirt. Often a rough idle may be caused by lean air/fuel ratios. This is really is more of a cam issue than a fueling issue. The exhaust valve is held open later into the intake stroke and the intake opens earlier near the end of the exhaust stroke. At low speeds and relatively high intake vacuum you get more exhaust contamination of the fresh air/fuel charge. As you get more contamination of the air/fuel charge you typically need a richer mixture to get it to ignite and burn properly.
This means you probably cannot run a stoichiometric [chemically correct] mixture of 14.7:1 with your long duration cam. You need to run richer. So you tune your idle by ear rather than with a narrow band EGO [oxygen] sensor. And make sure you are not allowing EGO correction at idle if you have a rowdy cam! It will be trying to “correct” your mixture back to a lousy idle. If your engine will not idle well at stoichiometric mixtures, set the EGO Active Above RPM to a few hundred RPM above your idle speed. This will ensure that MegaSquirt® does not try to lean the mixture back to stoichiometric to compensate for your adjustments.
Another tip you can try if you have a large overlap cam is to pinch off the MAP hose slightly while the engine is idling, and see if the idle quality improves. If so, then try a restriction in the MAP vacuum line. This has the effect of damping the vacuum pulses that the MAP sensor sees. Start with a ~0.040" (1.0mm) restriction in the line. You may have to experiment with restrictor sizes to see what works best for your system.
I quote from here:http://www.megamanual.com/v22manual/mtune.htm about 3/4 of the way down.....
It worked for me when I was tuning a single cyclinder engine where the pulses are a long way apart.
Love the GM Ford too, I'm working on a similar project here in the UK
Tuning Issues
If you have a very long duration cam in your motor, and it idles poorly, you might be able to get it to idle better through careful tuning with MegaSquirt. Often a rough idle may be caused by lean air/fuel ratios. This is really is more of a cam issue than a fueling issue. The exhaust valve is held open later into the intake stroke and the intake opens earlier near the end of the exhaust stroke. At low speeds and relatively high intake vacuum you get more exhaust contamination of the fresh air/fuel charge. As you get more contamination of the air/fuel charge you typically need a richer mixture to get it to ignite and burn properly.
This means you probably cannot run a stoichiometric [chemically correct] mixture of 14.7:1 with your long duration cam. You need to run richer. So you tune your idle by ear rather than with a narrow band EGO [oxygen] sensor. And make sure you are not allowing EGO correction at idle if you have a rowdy cam! It will be trying to “correct” your mixture back to a lousy idle. If your engine will not idle well at stoichiometric mixtures, set the EGO Active Above RPM to a few hundred RPM above your idle speed. This will ensure that MegaSquirt® does not try to lean the mixture back to stoichiometric to compensate for your adjustments.
Another tip you can try if you have a large overlap cam is to pinch off the MAP hose slightly while the engine is idling, and see if the idle quality improves. If so, then try a restriction in the MAP vacuum line. This has the effect of damping the vacuum pulses that the MAP sensor sees. Start with a ~0.040" (1.0mm) restriction in the line. You may have to experiment with restrictor sizes to see what works best for your system.
