Location: Denver International Airport, Colorado USA
Posts: 385
In all honesty I always thought the addition of an after-market cam and gas mileage dropping was a highly exaggerated claim. I guess at idle with less vacuum and higher MAP obviously fueling is affected. And at WOT with more airflow on hand, more injector/fueling is required.
But with a lot of cams, take a look at their VE Tables below 2000 Rpm's. A majority have less airflow/fueling requirement than stock.
To the OP..114 vs 112 is really a negligible difference in terms of power and gas mileage (on the 224). On a M6, the 112 LSA will give you a slightly more noticeable lope.
Perhaps on a cam only setup and totally aggressive driving your gas mileage will drop 1-3 mpg on the highway. But to give you some encouragement; on my H/C setup I routinely get 26.5 mpg on the highway at 80 mph (5 mph over Colorado speed limit). Granted I am getting some help from the thinner air, but with 2 overdrives 95% of these cars can get 24+ mpg on the highway with an aftermarket cam if properly tuned.
IMO, the 224 on a 112 LSA will work for you. Just get a full tune, including your VE Table, MAF, etc. You might have better luck keeping it at closed-loop to keep your cruising AFR at ~14.7 and let Trims do their magic.
M6=112 LSA Don't let anybody talk you out of this. I ride rush hour bumper to bumper traffic on the Dan Ryan slow_way. No problems. I get 18 MPG all around which is exactly the same when stock long ago. Check TA Pics in my sig and you can find the dyne graph in there somewhere.
__________________ 2000 Pewter T/A M6 NHRA option
Corsa, FRA,!CAGS, MTI clear lid, Royal Purple, BMR STB, BMR boxed SFCs, BMR boxed LCAs, BMR adjustable TA, ASP pulley, Strange 12 bolt w/4.11's, Kook's LTs and cats, LS6 intake, MTI 75mm TB, Spohn 32mm solid front sway bar and 25mm solid rear sway bar, BMR tunnel brace/ds loop, BMR PHB, SLP Bilstein shocks, Comp Cams 224/224 112 581/581, Raptor shift light, Pro 5.0 shifter, SJM linelock
