MPG data from a couple of recent road trips:

RDU --> CLT --> RDU + in-town driving -- 340 mi, 10.9 gal, 31.19 mpg
Conditions -- 70 mph top speed, shifting at no higher than 4500. Gas and valvespring conservation

CLT --> GSO --> RDU --> GSO -- 289 mi, 10.5 gal, 27.52 mpg
Conditions -- Avg. speeds between 80 and 90, numerous redline runs, heavy acceleration

Setup -- JDM 4-1 header, 2.5" Jeg's cat, V-AFC, Spec B's, Toda cam gears, AEM CAI, car loaded down both trips. Yack-tuned.

Best observed stock mpg was 24.5 mpg.

 

Very interesting.

 

Actually, I've been getting better gas mileage after I installed my header. I have stock cams right now.

 

The best of both worlds? Amazing! Power meets fuel efficiency...

 

you're getting better gas mileage because you are making your engine more efficient and tuning the af ratio, it has nothing to do with cams. Gas mileage is usually dependent on how much you get on it as well.

 

1. I agree. Big lumps make big power down low, so I don't need *as much* of the engine for comparable performance, if that makes sense.

2. I disagree. Cams are helping the efficiency of the engine. Change only the cams, tune for happy midrange, and I still won't get the gas mileage I'm getting now. Wish I had written down some figures when my car was fully tuned on stock cams - best range was still in the 260 range, and that was taking the tank to 11 gal fillups and driving very calmly.

 

Pat~ Gotcha beat!

First tank: 36.1 mpg
Second tank: 29.3 mpg
Third tank: 31.4 mpg
Fourth tank: Should be filling up within the hour!

I never ran out a complete tank! The first tank was from Raleigh - Spartanburg. Traffic was light, so we were able to maintain a pretty consistent speed (80-85). The second tank was from Spartanburg-Atlanta. This included the entire weekend until we left Sunday morning. Lot of start and stop driving! Third tank was from Atlanta-Gaffney. Was tryin' to stay up with Pete at 90-100 mph most of the way back. Fourth tank should be around 30 mpg as well. I'm still above the "E" mark and have 296 miles on the odometer.

 

Pat, i bet if you put some of dem skunks in you kar you'll get Insight type milage!!!

 

I put 13.00X gallons in the car once, got an indicated 416 miles out of it.
It was a couple needle's width below E.

I TRIED doing the speed limit some of the time (but couldn't stand just about EVERYBODY passing me on the way back from upstate NY).

 

Nice, Chris!! No doubt the header/exhaust are helping you out some.

 

I noticed the same thing when i swapped out my FMU for a hondata mgmt system. I dont have exact numbers... but I wanna say i was getting about 20mpg with the fmu and now i get 25mpg.... and this is on a daily driver making 400hp

 

hey pat, i wonder how much the VAFC is helping . . . that's my next step, before the lumpy goodness.

 

V-AFC is essential, even without cams. JDM 4-1 + AEM + 2.5 cat + V-AFC = 177whp on my car. I'm a big fan.

 

really? awesome . . . i suppose i gotta travel down there to have jack tune it, eh?

right now i've got pretty much the same setup . . . JDM 4-1, 2.5" carsound cat, comptech icebox and the nice 2.5" to 2.25" SMSP reducer for my stock exhaust.

i really have to get a VAFC and dyno the damn thing!

 

JITB and Beer will be required.

 

and that's a problem?