V8 Owners - What is your Avg. MPG?

[98GT-40P]

Originally posted by DarkFox1
I'm on michelin LTX M/S 235/75R15 on 15x7s I dont know anything about the tire, it was a free swap off the firestones..

I purchased the same tire. It has excellent all-around use tread and Michelin is highly regarded for reliability and treadwear.

When I purchased my set in June of 2001, they offered me three choices on that model for 235/75/15. The cheapest (and free replacement) was a standard load (35psi max), next up was the XL (44psi max), and finally the most expensive, a C load (50psi max). I sometimes tow a 4800 lb trailer on rough fire roads and really wanted the extra plies in the sidewall, so I paid a little more for the C load. It says LT235/75/15 on the sidewall (LT for light truck). If yours says P235/75/15 on the sidewall with a 35psi max, then you have the standard load (P for passenger car).

BTW, the door sticker on my '98 reccs standard load P235/75/15 with inflation pressure of 30psi. I just chose not to follow that recc because of my specific use patterns.

Darkfox, what does your tires say on the sides?

 

[LowdPypes]

They... lmao... you mean me. After speaking with Ford and powerdyne, I came to the consensus that I did not need new injectors at 6lbs nor did I need any fuel upgrades. Supposedly, and I could have been told wrong, that in 1998, the v8 explorer's fuel system was bumped up. After numerous reviews and complaints about the mileage and other issues, they stepped it back down in 99. The fuel pump was, I think, 190lph in 98, which is plenty good for a blower. If you have any other thoughts, lemme know, I'm very interested.

take care... Lowd

(I never run lean... ever... when I am at the track and I plunge down on it, it stays in the green all the way through to the 1/4 mile line.)

 

[DarkFox1]

p235/75/15 blah! this isn't a car! its a truck! oh well, so much for my lead.. I was thinking maybe my tire psi was too low and causing my low mileage heh

 

[98GT-40P]

Does anyone have a written source for what '98 Mountys have? I've never been able to find out. 190lph pump and 24lb injectors? if so, then it should handle the 6lb centrifugal. FWIW, 5.0 Mustang GTs only have 19lb injectors (Cobras have 24lb) and people usually upgrade to a 190 pump when they go blown or nitrous. Sometimes they will go to 24lb or 30lb injectors if they're really boosted or have high shots.

Funny you heard that the '98s were different. Is that why the FRPP catalog has a different item number for superchargers from '98 as different from '99 and up 5.0s? This is interesting.

Maybe since the impeller is always spinning and you're always pushing a little boost, you're mass air is reading more volume via faster cooling of the filament and the computer then has to richen it up a bit to make the air:fuel ratio appropriate -- thereby causing worse fuel economy than a normally aspirated engine?

Increased unsprung weight from your rims no doubt also contributes some to worsened fuel economy [and longer braking distance ]

BTW Lowd, did your Mounty come with stainless steel headers or the cast iron ones? Mine are cast iron and a mechanic told me once "to keep the Mercury owners happy with lower sound levels, they went with iron on some of the production. Explorers, with their different clientle, will be stainless steel." I'm not sure if he knew what he was talking about, but every '98 5.0 Ex I've seen has ss headers. Are mounty owners a bunch of blue-hairs? I wonder what else is different about '98s?

FWIW, when I tightened my super-loose (3 and 1/2 full turns on one of them) header bolts and nuts on the passenger side, my pinging immediately went away (must have caused it to run too lean), my low-end torque improved, my 1/4 mi best went from 16.35 to 16.08 (1.75 60' woo hoo!), but I lost 1mpg average.

 

[98GT-40P]

Originally posted by DarkFox1
p235/75/15 blah! this isn't a car! its a truck! oh well, so much for my lead.. I was thinking maybe my tire psi was too low and causing my low mileage heh

"The guy with the passenger-car tired LEMONeer" Just ribbin' ya!!

Looks like you're going to have to stay under 35psi

 

[james t]

the mounty should have 19's the same as the explorer. what color are they? ill bet they are yellow...

you can run stock injectors with a blower IF you run the FMU (fuel management unit) that comes with the blower. you can tune it much better if you ditch the FMU and go to bigger injectors (way bigger). then you up the fuel with boost via the computer programming.

Lowdpypes- you have a charger. it should get about the same mileage as stock on trips, but would more than likely be bad around town. this is just a byproduct of having a high hp sport ute.

 

[LowdPypes]

Definetly has 19lb injectors but from what I was told, it has a larger fuel pump and that is why it says:

"larger fuel pump or Powerchip NOT required"

I also was having problems with my FMU so it is not on there either right now. Never runs lean though...

Question, if I never run lean, should I mess with the fuel system? Shouldn't the only time I mess with it be when it is running lean? Just a thought...

98GT-40P - When I bought my Mounty, I looked all over for stats and stuff then C&D finally sent me something but I think it was WAY off.... it said something about 1/4 mile being 15sec at 99mph which mad no sense. Who knows... I make it faster cause I like to... lol...

PS
(cast iron)

 

[LowdPypes]

1/4 mile stat from this past Sunday 14.7... damn tires... damn AWD...

"Lowdpypes ain't so loud at the dragstrip." - Cody

I ran her 6 times, each against someone and won every time. 2 of those were Lightnings

(this guy was running the 454SS engine...)

 

[Tom G]

99 2WD 3.73 5W30 Mobil1 Michelin LTX MS 32 psi

17 MPG back and forth to work

19 MPG trips

12.2 MPG pulling my boat (I put the rear tires @36 for towing)

 

[98GT-40P]

14.7 is a good time if you were just on the blower. if you also sprayed, would've expected low 14's. C&D must have been testing a special aftermarket Mounty. I've seen 16.2 alot in the mags. Although, Motor Trend has the new Mounty at 15.6!! That's pretty darn fast for an SUV. I remember the late 1980s when automatic IROC Camaros were turning 15.6.

So you're cast iron too? I guess we Mercury owners are a bunch of old fogeys!! Any Explorer owners out there with cast iron? Or all you all stainless steel?

BTW, I launch at 3300 rpms to cut the low 60' times. Tried both neutral drops and brake torques. What 60' did you have with that 14.7?

I agree, don't run lean, it's too dangerous (I think our pistons are hyperuectectic, not forged). What A:F are you running on the dyno? Mine runs around 12-12.5 at cruising and acceleration (all stock). It must be programmed to run pretty lean though at low rpms/gentle accel (15-20:1 ratio). It richened up to 10:1 at WOT above 3500rpms.

 

[WannaXP8]

sucky..thats all I got to say..

 

[LowdPypes]

didn't spray that day, but last time I went, a 75 shot dropped my time a little over a second in the 1/4. I don't know a whole lot about A/F but I'm learning. I'm getting ready to run a new exhaust with the MIL, so hopefully, that will give me some more air flow. Personally, I guess I would rather have the cast iron over the stainless... JMO...

 

[rscamaro73]

Been driving 30 miles each way to work, and dropping off 2 people on MY way to work. So, I drive about 60 miles each day, with the longest stretch being 8 miles on the PA Turnpike. ALOT of stop & go city driving in the 99 XLT 5.0.

Averaging about 14 MPG right now but I gotta do a tune-up. I drove from San Diego to Pennsylvania towing my 73 Camaro and averaged 19 MPG...go figure.

 

[coolchris]

i get 9mpg - 11mpg city

 

[xfreak]

Ill get around 14-17 in the city, it really depends on traffic. on the highway, around 20-21. Its kinda funny I was on a road trip about a month ago and driving back from Orlando, I was caravaning back with a coworker who was driving a V6 4Runner. Although we have similar sized tanks I went about 35 more miles before empty.

 

[xfreak]

Lowd pypes do you have any pics under the hood?Great job on that truck, its freakin sweet!

 

[SVO LOU]

I think the biggest factors are gas type, ie winter gas blends (I know NY has this), and aftermarket size tires (and the speedo/odo not being re-calibrated afterwards to reflect the change).
Has this been said before, this is a hella-long thread.

Lou.

 

[BBQMAN]

I usually average about 15 with a good mix of highway and back roads. Lately since my son was born though I've been trucking home late and have been getting about 13.5...but I'm movin' it too. So all in all I'm not doing too bad.

 

[LowdPypes]

Originally posted by xfreak
Lowd pypes do you have any pics under the hood?Great job on that truck, its freakin sweet!

checkout my profile/website/picture gallery.... and thanks man.

 

[hrbib21]

Well, I just installed my brand new MAC Products air intake so we'll see if the mpg goes up. HOPEFULLY, it will.