Ideal lambda for LT4

[BMWMD82]

Just looking for some feedback on WOT lambda targets on the LT4 engine. I keep hearing that you can actually get KR from an overly rich mixture, but have not really heard when this is likely to occur.

I have always run my engines on the richer side for safety, and have been targeting .80 to .81 lambda on my LT4. Is this rich enough to cause any issues? Also, should I be worrying about injection timing on a lightly modified engine?

Thanks

[paulsmithsr]

Where it makes the most power

[BMWMD82]

I am not worried about making maximum power. Just want something safe that is not going to trigger KR from being too rich, as I have heard can happen.

And I do not have access to a dyno, so that is not an option right now.

[Ben Charles]

.80-.81 is fine.... not too rich and safe...
I make max power little leaner, but that?s not going to hurt anytging at that lambda

[BMWMD82]

Thanks. That is what I wanted to know.

[JnJSpdShop]

Just looking for some feedback on WOT lambda targets on the LT4 engine. I keep hearing that you can actually get KR from an overly rich mixture, but have not really heard when this is likely to occur.

I have always run my engines on the richer side for safety, and have been targeting .80 to .81 lambda on my LT4. Is this rich enough to cause any issues? Also, should I be worrying about injection timing on a lightly modified engine?

Thanks

Worry about injection timing when your injection ms values are pushing over 5.0

[HNK]

JJSS, so would I be correct in modding the areas of the soi where the inj pulse goes over 5 in?? I was told before that upto 6ms we r fine...
thx

[Higgs Boson]

JJSS, so would I be correct in modding the areas of the soi where the inj pulse goes over 5 in?? I was told before that upto 6ms we r fine...
thx

4.8 ms is about where stock is. you are fine at 6. all it means is you are starting to push the stock system past stock levels and how far you want to go is up to you. pushing SOI higher starts spraying an open exhaust valve and starts draining pressure from your fuel rails as you demand longer spray times. i never go over 359 soi at full wot.

the ecm will lengthen spray time on it's own, or move it earlier on it's own to avoid spraying through spark as well. it will also retard spark lead to keep injection and spark away from each other. when it is pulling timing, advancing injection, losing rail pressure, going up in ipw, etc you can consider yourself losing control of fueling.

everyone deals with it differently, I have seen people run 9ms and 12Mpa and be ok with it. I want at least 20Mpa at WOT so I go to supplemental fueling quicker.

[HNK]

👍 thank you

[BMWMD82]

Good stuff guys. I will have to pay attention to that.