VE #'s to high?
- Thread starter Larry
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If you aren't getting runaway injector PW readings (like 95%) and your actual A/F ratio is at/near target, then your fuel pump (and fuel delivery) is probably fine.
Since you have 83# injectors, I'm guessing you have a fairly hopped-up engine (and therefore a high volumetric efficiency), so you could very well be at an actual VE of 90% or slightly higher. If that's the case, having your table read 94% is still within a few percent, I'd be happy with it.
If you are running lean (actual A/F < target A/F) or if your O2 correction is maxing out, then you may be having some issues...
-Bob Cunningham
bobc@gnttype.org
Since you have 83# injectors, I'm guessing you have a fairly hopped-up engine (and therefore a high volumetric efficiency), so you could very well be at an actual VE of 90% or slightly higher. If that's the case, having your table read 94% is still within a few percent, I'd be happy with it.
If you are running lean (actual A/F < target A/F) or if your O2 correction is maxing out, then you may be having some issues...
-Bob Cunningham
bobc@gnttype.org
Craig Smith
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Sounds OK to me. As long as the O2 correction is minimal like Bob said I don't think there's anything wrong with that at all.
Craig,
How high can we realistically expect to set VE's before we should be concerned? I have some in the 110-120 range. And I'm not done tuning, so they might go even higher...
It's possible that I don't have enough injector, but I don't know for sure. I'm just wondering what the signs might be at the ECU and when I should get concerned with VE's being high.
Thanx!
Bryan
How high can we realistically expect to set VE's before we should be concerned? I have some in the 110-120 range. And I'm not done tuning, so they might go even higher...
It's possible that I don't have enough injector, but I don't know for sure. I'm just wondering what the signs might be at the ECU and when I should get concerned with VE's being high.
Thanx!
Bryan
The way to tell if your fuel system is too small (inadequate fuel pump, lines too small, whatever) is that if you keep turning up the VE #'s (keeping the injector open longer) and the engine still runs lean.
If you injector duty cycle is maxing out, then the injectors are probably too small.
If your fuel pressure drops off at high injector DC%, then your fuel pump is probably inadequate.
You have to watch the interaction between target & actual A/F mixture, O2 correction, and injector DC% to get a good feel of how the fuel system is performing. (You should have all of these parameters on your datalogging screen, in addition to VE.)
-Bob Cunningham
If you injector duty cycle is maxing out, then the injectors are probably too small.
If your fuel pressure drops off at high injector DC%, then your fuel pump is probably inadequate.
You have to watch the interaction between target & actual A/F mixture, O2 correction, and injector DC% to get a good feel of how the fuel system is performing. (You should have all of these parameters on your datalogging screen, in addition to VE.)
-Bob Cunningham
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