I've got a 99 Limited Runner with (what looks like) a 2nd gen supercharger and TRD catback exhaust.

My city gas consumption is about 16 miles/gallon everytime I fill up. I completed most of the 60k mile servicing myself.
I believe the highway consumption is around 19 miles/gallon.

Is this consumption typical for the supercharged Runners (3.4L)?

Also, I've noticed that there is somewhat of a grinding noise when I'm on throttle. It's not metal to metal grinding, but I thought it may be the supercharger since I'm used to running turbocharged vehicles. Does the supercharger need the fluids replaced? I remember reading that the supercharger should be good for 100k miles before changing out the fluids (or lubricant).

Just working out the kinks before I go on a road trip.

J

 

That all sounds pretty typical, except the mileage is a bit on the high side

The grinding noise you hear is gear lash in the supercharger. It is quite normal and after a while will sound like music to you. The nose gear on the charger is considered to be a "sealed" unit. That is, you don't have to conduct regular changes on the fluid. The figure I heard was 80,000 miles, so your 100,000 miles was not far from the mark. The only time that you would need to change the fluid earlier is if you are experiencing the fairly common leak around the front pulley. If you see that the nose cone is coated with a fine spray of oil from the fan blowing it back, the nose will need to be removed, the seal replaced and the oil topped up.

 

The supercharger came with the truck when I bought it used a few months ago.

It seems that the installation manual states to set the timing back a bit.

Could I advance the timing to stock timing settings and use a S-AFC to adjust for fuel?

I bet there is a lot more power to be extracted from the supercharger.


J

 

There are many options that you have for increasing the amount of power that the charger gives you. For the most comprehensive list, check out Gadget's site at; http://www.gadgetonline.com/.

TTORA members have experimented with larger injectors, a variety of fuel management systems, 9.5 pulleys and intercoolers. It's all in how much money you want to spend and what kind of risks you are willing to take with your engine.

I am not sure which manual you have. I have been through mine pretty extensively and have not seen anything regarding setting the timing back. Since the timing is controlled by the ECU computer, it's not like the old days when you could rotate the distributor for more advance.

 

i was just wondering how you guys figure your highway mileage... I keep a pretty detailed fuel log. Each time i fuel up I record the date, station, pump#, fuel type, gal. purch., gal. used, price/gal, fuel total, total miles, mpg... something im missing? LOL. Anyways, do you guys just pretty much estimate when it comes to splitting up your city and highway mpg? Peace.

--Mike

 

I normally do a mix of city and freeway driving too, so I generally jsut give one figure, say it's for mixed driving and leave it at that. But, once in a while, I get a chance to take a long trip and I can figure the mileage from that. The same thing for a tank used purely off road.

With my current configuration, the best mileage I have gotten is 17 mpg, the worst was 6.

 

yup, same for me, i have it at mixed and leave it at that. My best has been 16.7182mpg, and my worst 13.3217mpg if you cant tell I have a detailed log lol. I am not supercharged (yet) but I am not an excessive speeder, but I like to lay down on the accelleration so im sure I could be getting better mileage if I were to drive more fuel friendly. lol Peace.

--Mike
:bounce2:

 

I haven't been keeping logs However, I do watch my mileage pretty closely, and I have been averaging 18 mixed driving..but I will be driving all the way to washington state this weekend..I will keep a log so we can see just how highway affects it. I will also be towing a 3,000 lb boat all the way back to Phx so I'll have mpg's for that too