Did anyone do any A/B testing before and after adding CAI and/or cat-back? I'm curious which of these has a positive or negative effect on gas mileage?
Also- which CAI is least likely to cause a CEL on in '08?
Prior to my mods, I was getting between 29 and 31 mpg hwy. Also, keep in mind that your tire width, diameter (which affects weight) and rolling resistance will also make a difference too.
I've not had any CEL's using my Neuspeed CAI.
Specifically, the C2 Motorsports 2.5L Performance Software? Was anyone able to get this done locally? Was it "while you wait" fast to get? I'm concerned about the downtime and risk of shipping my only ECU anywhere.
FYI- I just drove my new bone stock 5 speed CPO '08 SE back from Tucson. Just 225 pounds of me driving with 2 small bags. Here are my stats based on three partial tanks and fill ups:
85 MPH average: 24 MPG
75 MPH average: 27 MPG
70 MPH average: 32 MPG (almost. 31-point-something and change!)
Sweet spot might be 72 MPH to get 30 MPG.
08 2dr Rabbit Tiptronic
No mods except larger sticky tires (245's on lightweight 17's)
Day to day driving, which is 80% stoplights, and 20% cruising 45-60mph, I average 22-24mpg
This is taking it easy too.
When filling up after an autocross, its about 21.
Full on highway driving, I've gotten 35 before, but I was drafting a semi doing 60 most of the trip. Typically though, It will sit around 31-32 cruising at 75-78.
Driving around in the summer I get worse mileage due to the AC being on constantly, during spring and fall I get 26 on my day to day with windows down.
Its amazing how much tire pressure affects these cars. (2010 Golf 2.5, 5-speed)
I have the 17" Goals and normally run around 37 psi. I usually average about 25mpg around town and 30mpg on long trips.
I got my oil changed about a month ago and have noticed a decline in my gas mileage. (like averaging 18mpg in town and highway of 25mpg)
Checked my tire pressure yesterday before I left on a trip and noticed that all four tires had been reduced to about 29.5 psi. (Thanks local VW service dept. obviously they dont realize that with 17" goals, that it is supposed to be at 34 psi!)
Anyway, now they are back to 37 and I got 34.9 mpg on my trip yesterday (55-65 mph)
Keep them tires pumped up, especially with the larger, wider tires!
i am gettin consistent numbers... 25 city and 28 at hwy (80mph)
Want an instant 10% more MPG? Try to find non-ethenol "enriched" fuel. I found some in Ft. Collins, CO and filled my near-empty tank, reset my Scan-Guage, drove to Denver. Normally I get about 32.5 mpg on this highway run as there's a slight elevation gain. This time I achieved 36.2 mpg. I'll continue to seek out more of these gas stations and do more monitoring of the data.
87 Octane gasoline
Best MPG = 46.4 MPG from San Diego to Sacramento
Longest range = 596 miles/tank
That was all back when I was doing >90% highway. Now with 50/50 mix driving and shorter trips, it's quite a bit less now. I was hoping to get my lifetime average up to 40 MPG, but that's not going to happen given my current driving situation.
I haven't been too impressed with the 2.5's city MPG. For the last two years in grad school, all I really ever drove were city miles to and from school. Every tank would amount to about 23 miles per gallon. Now, I'm working about 35 minutes away from my house and have a 65 MPH highway drive every day. I'm consistently seeing between 32 and 33 MPG
EDIT: And all this is on 87 octane. If I use 85 I see about a one mile per gallon drop in both the city and highway.
My last two city tanks were 20 and 21 MPG. Granted, I still have my foot in it from time to time (hey- it's my new car) but I try to drive and shift between 2,000 and 3,000. My commute is only 7 miles each way, which can't be good, but I wonder if something's wrong? Checked tire pressure recently. I do haul around 2 car seats and a stroller, but that can't be 100 pounds of crap.
I like the idea of experimenting with 91 octane, but I wonder if it will pay for itself?
Also considering 0W-40. There is strong suspicion that Porsche specs it to cheat up their CAFE numbers.
Last edited by dcdude; 09-17-2010 at 02:54 PM.
My 07 Jetta 2.5 manual
Average 375-425 a tank winter-summer 87 octane 90% highway
Highway and city mpg don't vary much for my driving
Best ever was 33 mpg
My Fiance's 08 Rabbit 2.5 auto
Average 325-375 a tank all year round 75% city driving 87 octane
We took a trip to Florida in the rabbit and averaged somehow 36 mpg on cruise control doing 80 mph on 87 octane
I think they put pixie dust or something in southern gas