Larger cam installed, same VE Table... richer or leaner?

[Goldfinger911]

Ijust upgraded the cam in my 383 LS1. I went from a 230/240 .600" 113lsa to a 242/248 .617" 112lsa +2 adv. Besides changing valve springs, nothing else was changed. I left everything the same with the tune. Prior to the cam swap, I had my tune within 1-1.5% across the VE table. It ran great and the AFR's were very constant.

As soon as I started the car with the new cam, instantly rich. Like by a few points. The tune that used to idle at 14.7:1 not idled at 12.5:1.

I would think that it would be leaner with everything left alone. Does this make sense? Or do I just have my thinking backward.

Oh, also I am running a pure OLSD tune. Thanks.

[5.7ute]

What you are seeing makes sense. Especially if there is a significant increase in MAP kpa at idle.

[LS1_Dragster]

Your MAP with less vaccum is now using a part of your table that was used for accelerating before. You have to remap your table now.

[TFZ_Z06]

Your MAP with less vaccum is now using a part of your table that was used for accelerating before. You have to remap your table now.

Gotta agreed w/LS1_Dragster. I'm guessing you are at least 10kpa or so higher at idle.

Note, I run OLSD also. I was thinking about a cam almost exactly like you put in. Have you noticed any signficant changes in top end power or have you got that far?

[Goldfinger911]

Yup. Thats everyone. That makes a lot of sense. And, you were right.. I am idling at exactly 10kpa higher than the old cam.

Regarding changes in power... yes. I instantly felt a difference. There is definitely a little less midrange power, however above 5000rpm it absolutely rips. I used to rev to 6800-7000 with the old cam, but the pull was between 2000 and 5000. Now, the pull starts at 4000 and it pulls really strong to 7000. I have 4.11 gears so the higher powerband is easy to use. :) One more thing I notice is then I am sitting at a stop light in neutral, and I just zing it. The shift light comes on almost instantly. It revs a more quicker or more freely.

Besides, it sounds much meaner at idle. :) I opened up the cutouts in the garage and about filled my pants. :) It was shaking the wrenches in my toolbox. Hahaha. So far I am very happy.

Thanks again guys, Time for some more AutoVE fun times.



Gotta agreed w/LS1_Dragster. I'm guessing you are at least 10kpa or so higher at idle.

Note, I run OLSD also. I was thinking about a cam almost exactly like you put in. Have you noticed any signficant changes in top end power or have you got that far?