I'm in the process of repairing my 04 CTS-V and have two options for the motor. A stock LS6 with headers and exhaust or a LS6 with a magna charger, 2.8 pullies, 60lb injectors, ported heads and dyno tuned. My question isn't so much about power output but MPG.
Can someone post real time MPG numbers for each set-up? Highway and city. I really don't need another gas hog already have a driveway full of them. Don't think I could enjoy the car too much if it's eating fuel( less then 20 mpg hwy) less than 15 city
thanks
BobH

 

depending on how you drive id expect 14/15 city and around 21/22 hwy fromw hat ive read.

 

I consistantly get about 17 MPG with Maggie, Tune, 90mm TB, Corsa. Instant MPG on freeway @ 70 mph usually shows around 20-21 mpg. I highly recommend the Maggie option. It is well worth the couple of mpg decrease.

 

Most of the MP112 maggies on V1s come with 42lb injectors.
That is what I have on a LS2, but there are a few guys with more.
I get high 19mpg to 23+mpg consistently.
Doing the 1,3,5,6 shifts or 2,4,6, shifts, helps get me . . 21+mpg.

 

I lost about 2 MPG highway going to headers but lost nothing when the maggie went on.

Of course that's just theoretical. In reality, it's hard to keep your foot out of it so mileage did suffer.

 

Why would lose MPG with a free flowing exhaust??? Always thought you would pick up mileage.
What kind of MPG numbers are you getting?
This car has 60 lb injectors
Thanks
BobH

 

On an N/A car, the O2 sensors see a lean condition and add fuel to compensate. It's my understanding that headers reduce boost, so you have to increase the compressor speed to compensate. Not sure what effect that would have on a boosted car.

With a new tune for the headers, it should at least return the mileage to stock, but with a good new tune, it should see an increase.

 

My 05 came with 60lbs from magnacharger. I saw an approx 1.5-2mpg decrease, but it is hard to stay off the gas with the maggie around town. I do think I suffer from only having a decent tune, however.

 

This.

 

I see about 12-15 mpg..

 

At road-load conditions (i.e. part throttle), the stock manifolds actually to an excellent job at scavenging the cylinders and providing decent efficiency hence MPG.

At WOT conditions, the LT headers with equal-length primaries do a better job of scavenging. WOT MPG with headers ~2. WOT MPG with stock mans ~1.8.

I'm just guessing as to MPG, but you get the idea.

Oh, yeah, my maggie came with 60 pounders, too.