Z06ster

I was hoping to get some opinions if this is normal or not...

I recently upgraded my LS6's stock cam for a cam with following specs:

Intake Exhaust
0.581 0.588 Gross Valve Lift
220 228 Duration @ 0.050

Lobe Separation of 115


In addition to that, my injectors were upgrade from 40lb to 60lb


Now for the issue. While these numbers are a little rough, I have noticed my combined highway/city mileage went from around 18 MPG to 11 MPG. Does this seem excessive or is this normal given the described changes?

(To qualify... despite the new performace, I'm not going hog wild... my driving is pretty much the same).

Thanks

bullitt4110

Sounds like tune needs some adjustment, mileage shouldn't have changed much if any.

dankhts

get a good tune! You may notice a bit of a drop in fuel mileage but not as much as you have! I've noticed a drop in fuel mileage with every mod I've made, starting 1st with a cat back, than a full exhaust system, then the heads/cam/intake, then the TC and gears, etc... but then again, if I drive it "normal" there's not a lot of diff.... rear tire wear has drastically increased as well along with the rest of my mods...

mobius

mine dropped about 3-4mpg around town and 2 highway. I also gained 1 one highway lowering car 2"

corvettebob1

That's pretty much the same cam I have .581/.592 224/230 112* I installed it with a set of Patriot stage III heads last year and had a S/D tune done and drove it to Sandestin.
With the cruise set on 70 mph I averaged 31 mpg the best I have ever gotten.

Now coming back home was another story.

dykz34

Are you doing the math at the pump or are you using the DIC for MPG information? Once you change injectors, the DIC is no longer accurate.

firefighter813x

How do you like the A&A stage I cam? Does it sound stockish??? It should with -6* overlap.

HPS

You need to have the VE and MAF re-tuned. You mpg should stay relatively close to stock when tuned properly.

Chris

Z06supercharged

OMG I bet he never knew he had a A&A stage 1 cam! So kind of you to point that out...

Z06ster

Fellas.... thank you very much for your answers on this thread. I will have the tune looked at.

To respond to some of the comments....

Strictly at the pump... didn't look at the DIC at all. Looked at how much gas was left in the tank at the time of fill up.

You are correct... I would describe the CAM as "mild". There is a definite lope to it, but it is not aggressive. I was looking for something a little more but was advised against it because of the difficulty of passing California's tough smog laws and the concern about loosing low end torque with the stock LS6 heads. There is enough noticeable sound difference from stock, I am happy with it.

This CAM was added as "blower cam". I found out by asking A&A about CAM options when I was getting my supercharger swap out (that's a topic of a yet much longer thread I haven't written yet).

Again... thanks for all the comments and responses everyone.

corvettebob1

Did the math at the pump, and the dic is pretty close since my tuner scaled it for the 60# injectors.

firefighter813x

Is this guy serious?

I just asked the OP about his cam. Based off of memory it seems to be the A&A stage 1 cam. I have considered this cam and wanted an opinion. Grow up.