Ok, So after the recent threads on high flow heads, I feel I need to make a disclaimer... I'm not trying to start a war here!

I am mearly curious as to what you folks with high flow heads are getting in terms of MPG depending on your driving style.

Yes, I realize it's not a mod meant to do anything more than add TQ and HP, but I'm curious as to this bi-product.

My gut tells me that an engine that flows better is more efficient.

I bet when you guys aren't punching it (does this happen? ), you're getting slightly better fuel economy?

 

Well my personal experience is that my milage has increased significantly. Prior to the install I was getting around 23mpg for city driving and 28mpg on the highway. Now I am getting 28-30mpg around town and over 30 on the highway.

This is a calculated value as well, not based off the MFD.

 

AZMCS-could the turbo instead of sc account for some of that?

 

If true (that a head with improved flow characteristics increases fuel economy), that would be an interesting cost-benefit calculation. With the price of gas (at least in CA) pushing $4.00/gallon in some areas, a 20-ish% improvement might pay for the cost of the head (especially if the price of gas continues to increase...).

 

My highway milage has gone up significantly. I'm now getting 36mpg on long runs. Around town my milage dropped, but my grin grew huge.

 

It would take a few years, but that is valid. It's easy to setup in a spreadsheet. That will be one of selling points to SWMBO when the time is right. The beauty of this logic is that as gas prices increase, the head pays for itself sooner.

 

My first long drive with the head was to AMVIV.

Before on long highway runs I averaged around 27. On the trip to AMVIV I averaged around 30.

Longboard

 

Seems the mileage increases a few MPG when the Head is installed, Or so my customers are telling me..

Just me......................................

Thumper

 

Are you sure that's an accurate sample? Triple digit speeds arn't exactly fuel efficent .

 

I get between 22 and 24 mpg in town (Up from 20-22 before install) and 32-36 on the highway (Provided i'm just cruising at 65-70). If i'm cruising at more reasonable speeds (Keeping up with traffic) at 75-80 I get ~28 mpg. I'm a pretty fast driver, especially in town, my milage reflects .

 

If that head yields 30mpg at triple digits, I'm signing up now.

 

hey i just seen in u signiture that ur getting a new header n exhaust on the way. i was wondering since the obx has a pretty gud rep, why the switch, oh, and btw, wud u sell me ur obx?

 

The design of the new header/exhaust is just much better. I have no gripes about the OBX, I purchased it knowing it would only be temporary . When it comes off my car it will go up for sale .

 

Lets just say i've heard 28 mpg at pretty darn close to triple digits .

 

STREET - Combined City/Highway - Average MPG

Before: *20 mpg with JCW tune (6800rpm redline)

After: *20 mpg with custom tune (7500 redline)

RACE TRACK / AUTO-X - Average MPG

Before: 10 mpg w/JCW tune (6800rpm redline)

After: 8 mpg w/custom tune (7500 redline)

*Yes thanks, I'm a lead foot...

 

Wow Nate...I'd love to have your motor My cruise to the Dragon bested me 27mpg...of course, I like to keep her between 3700-4000rpm...

My runs at the Dragon averaged around 23...so it doesn't seem to matter how I drive...

 

An improvement from 25 to 30 MPG, assuming $3.00 gas, would take well over 100,000 miles... With $6.00 gas, it would take over 60,000 miles.... I don't think my wife will buy it...

 

I drive a lil slower on the highway I guess, that and use the cruise control, I find that really helps stretch a gallon of gas

As to the motor, it's might be available soon, you already know what I've got coming....

 

Are you the first in line for the wooden box?

 

stroker?

 

Don't worry...I'll catch up to him soon enough...

 

Here's a chart I generated to show the time for a set of mods to pay off if the gas mileage improved roughly 10%. The blue circles are the curve for an improvement from 30 to 33 mpg; the red triangles for an improvement from 27 to 30 mpg. The cost of the mods was estimated to be $5800. The trend that is readily apparent is that the higher the cost of gas, the faster the mods pay off.

Have fun modding!

 

Nice looking chart you whipped up, astrochex!

What is the assumed number of miles driven per year? 12K?

 

Thanks.

17K miles / year is the assumption.

Maybe modding is good for the wallet.

I can send the spreadsheet to anyone just send an email or PM with contact info.

 

Q for your guys. Did you calculate your MPG or use the computer? If you upgraded the injectors, I believe it will mess up the computer MPG output. There is a thread here some where. Not trying to rain on any parade, just curious.

Regardless, if you can install a performance product and improve efficiency is always a good thing. Isn't that what we tell our significant others when we buy performance....er I mean products to improve the efficiency of our cars? :p I can see it now..."honey, the Mini seems to be getting worse mileage. So and so's car gets XX MPG with this part, just think of all the money we will save...it will pay for itself." (more true now with todays gas prices).