K-Spaz

I spent a 'boatload' of time learning how to get an idle proper. It's 10x as difficult as all other tune aspects. It infuriates me that all the info on the web is guys saying 'Set the idle to 1100 rpms and see if that stays running". Wtf?

Here's a LS1 with 12 degrees of overlap and a 650 rpm idle.

buckmeister2

You are correct, 919, but if he is filling up when there are about 3 gallons left, as many people do, he is getting 8-10 miles per gallon city. That is horrible. Based on same premise he is get about 22 on the highway, still low, but depends on his driving style.

Absolutely, he needs, and can easily get, MPG. Then, we could compare apples to apples.

sobe88

While you may drive in the city a lot, cam + tune can certainly decrease your mpg, I would see about finding a local tuner to help you do a data logged street tune.

Stock LS2 for me was able to see 32mpg hwy and 20mpg - 28mpg city, that was nice.... But now that it's a built 402 stroker, aggressive cam, s/c, etc. etc. I can easily see 10-16mpg city and 18-24mpg hwy. The price we pay for modifying.

K-Spaz

You're down nowhere close to where the op is at. His tune is fubar'ed.

sobe88

Thus the tuner recommendation.

danziger

Agree with above that tuning done for the street in addition to dyno is key and could be the problem. Not too many tuners willing to spend the time and effort getting a really solid tune.