After cam install what affects bad gas mileage? I put a 224/228 cam in my car w/ LT's, 3600 stall and LS6 intake and am now getting about 13 mpg with normal driving in the city and was wondering if this is normal? It wasn't tuned by a professional, but my buddy is pretty knowledgeable when it comes to HPTuners and I've pulled the plugs and O2's since the install and it does not appear to be running rich. Any tuning suggestions or inputs on a fix for this problem. I know we had to adjust the TB blade for it to idle better, but I filled up my tank of Friday and only put 40 miles on the car and it's down to 3/4 of a tank. This seemed a little crazy to me. Any inputs would be greatly appreciated. |
The converter is probably hurting your mileage more than the cam. If most of your in town driving is at speeds where the 3600 converter is not locked, that will kill your mileage. Sometimes driving in 3rd where the converter will lock at a much lower mph instead of OD will help. |
Originally Posted by 2xLS1 The converter is probably hurting your mileage more than the cam. If most of your in town driving is at speeds where the 3600 converter is not locked, that will kill your mileage. Sometimes driving in 3rd where the converter will lock at a much lower mph instead of OD will help. your converter not locking will cause DD mileage to go down but you just need to deal with it if you want a fast A4 |
what they said. I have a 228R cam, stage 1+ LS6 heads, 30lb injectors, racetronix LS1/6 kit, and ALL bolt-ons...but I have a manual. I'm getting average 24mpg city/highway. |
Another element is, even if the long tubes aren't making your fuel trimming whacked, any air shoot-through to the exhaust will make you trim toward the rich side to make up for elevated exhaust oxygen content. That's a cam overlap deal, you probably have a little. Idle and low cruise are where you'd see it. It may not be anough to foul plugs, you can still burn "clean" at (say) 13:1 actual mixture. A wideband reading at idle would tell you about the trim-point. Another issue is, the long tubes' thermal shedding makes the sensors slower and the proportional fueling then swings wider about the center; more time in more nonideal mixture ranges makes worse fuel use. But then, with a similar converter now and a smaller one previously, I have seen 15, 16MPG mixed as a rule. |
Thanks for all the input. It looks like this is something I'm just going to have to live with. I will try the driving in 3rd for awhile and see if that helps. |
Originally Posted by zspot98 Thanks for the input so. It looks like this is something I'm just going to have to live with. I will try the driving in 3rd for awhile and see if that helps. |
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