Voodoo13

I recently finished a DIY install of a Vararam and XS Power headers. I noticed that the gas mileage went from about 19.8MPG to about 18.2 MPG. I did the Vararam first and it made no difference, but adding the headers it changed. It makes sense to me that this is correct since you are pushing more air through the engine it will consume more fuel. Just wondering if this is what I should expect and if anyone has had a similar experience? I had read some posts that report the opposite, that mileage would improve.

Doug

Vetteman Jack

First question to ask is has your driving habits changed - i.e., has your right foot gotten heavier after the mods?

Many do report a slight increase in mpg but you just never know.

Voodoo13

I seldom drive with fuel economy in mind, that's true, but I have the same sized rock on my right foot as before, perhaps even less as it has been raining like mad here in Vancouver since the mod. I drive the same route every day at about the same speeds - 70% highway at 55-60 MPH.

f6john

I would assume a tune is in order. It doesn't seem you were getting very good mileage anyway. The consensus I have gotten from reading the forum is that headers require at least a mail order tune.

grantv

Hey from Kelowna! I get 19.6 fairly heavy footed city driving in my Z06, your mileage should be better I'd say, and my experience tells me headers should have improved it. Get a mail order tune, but maybe... do a tune up also?

Voodoo13

The plan is to do a dyno tune once I get new plugs in and it seems like it runs stable, which it does now. Talked to Cory at K&M in Abbotsford about a tune and he seemed to know exactly what I wanted and was talking about, so looking forward to that experience and more so for the results.

I don't think anything else changed except the headers, Vararam, and new plug wires unless I screwed up somewhere and never noticed which is quite possible. I actually changed the plugs and cracked two, so changed them all back to the originals for the time being. Other than plugs and maybe cleaning up the MAF & TB before sending it on the dyno, any suggestions?

Hey Grant, if you are near Vancouver and have some time, I am just in Steveston, drop on by.

momo20

my 03 Z06 after I installed my vararam it does take it 50 to 60 miles for the PCM to relearn the new air flow that it is seeing..but I did notice a increase in my fuel economy from hwy 30 mpg to 32 to 33 mpg...hell even with the supercharger installed I still see 30 mpg when I am out of boost

C5Wolfe

When I installed XS Power long tubes on my old "99" it made my highway mileage go from 29-30 to 32-34 mpg! In my opinion, you have another issue somewhere because your car should get better mileage that it does. to you and good luck!
P.S. I did get a dyno tune done after the header install.

TX Z06 02

Did you go catted or catless xpipe with rear sims? Shouldnt really matter cause the front O2's are what makes A/F changes, but sounds like it is seeing a lean condition and dumping fuel.

Voodoo13

Looks like the jury is in - mileage should go up so something is wrong somewhere. I'll start with a tune up and go from there.

I went with the cats, front o2 sensors are ok, and look lively on the scanner, but for the price I think I will just change them out for new ones, since I have 65K on the car.

I've driven about 500 miles since the Vararam install, and 300 since the headers.

Voodoo13

Supercharger - that's a good idea. Does this ever end?? LOL