I have a 5.4 4x4 Screw that came stock with 265's. I have recently put MTR 305's on and can tell a big difference if power loss. I'm atrributing this to the 3.55 gears. Would the superchip provide enough of a performance increase to negate me feeling the need to swap to 4.10's? How much more would I be spending on fuel?

 

Your prolly only going to get 20 ponies or so from the chip so I wouldnt expect it to compensate for the larger tires. Hell I have a supercharger and larger tires and its still a dog off the line. Im definatly looking into 4:10's myself.

 

Can anyone tell me how much of a mileage improvement the Superrchip program is giving vs running the stock at 87?

 

Adding bigger tires is like gearing up (ie: from a 3:55 to a 3:08), you are not making "less power", tire size has nothing to do with engine performance in and of itself.
Unless the tires are alot heavier, it is most likely the "gear Effect" you are feeling. Bigger tires don't allow for a faster "Reving" engine, similar effect of a gear change.
An increase in torque will help, and maybe adjusting for tire size might have a positive outcome with the EEC also.
I had a formula for figuring RPM, gear and tire size,(I'll have to find it) I put a smaller diameter tire on my stang, a 2" decease was like dropping another gear. It has 3:55's, however by switching tire size from stock, gave the same rpms as the stock tire height with 3:73"s.
It works in both directions.

 

Hi SC02

About all i can add...i got .90 mpg more. With the variables..freeway/city..stop/go etc..maynot be consistent. Of course its really bad mpg when you first install chip.

Some get better mpg/some dont. As i recall any mpg you may get has to do with how the chip retunes the engine thru pcm.

To buy a chip for just better mpg...i dont think thats cost effective. Althou i think maybe some payback is possible.JMO

Good luck...OT

 

I agree, I wouldnt buy a chip unless I was going to 92 oct and taking advantage of all it can offer. If your goal is simply fuel economy then switch to electroc fans. I got 19hp at the rear wheels(via dyno) by putting in electric fans.

 

Well if I go with a gear swap I'll have to reprogram the computer anyway...I'm just wondering if the high octane programming would be worth doing for me? I don't want to spend abunch of money on high octane fule just to drive around daily. But then again if that programming was enought o negate the need for a gear swap then maybe...

 

Hi SuperCrew02,

Many people have found themselves in your position, with taller tires and trying to avoid the gear change by adding more raw power. And for some that can indeed work, it depends primarily upon just how much taller the new tires are, and the driver's perception of his/her performance needs.

Adding more power does not "fix" the basic issue of the engine now turning fewer rpms for a given speed, however, depending on just how much taller your new tires are over stock, you may find that another 10%-12% more power (which is what you'll get form either the Superchips Micro Tuner or the traditional Superchips module) does enough for you to allow you to avoid the gear ratio change, many people have indeed taken that route. I woulnd't say that's the cure for 35" tires being run with 3.55 gears of course, but up to about a 32" to sometimes even a 33" tire, a number of vehicle owners have been happy enough with the results from the Superchips tuning that they did not do the gear ratio change.

The best thing to do would be to give us a call when you get a chance, and we can go over this with you specifically, and let you know if you have a realistic chance of avoiding the gear ratio change in *your* situation, so you can give it some thought, etc. You're right, you do need to have the PCM program altered to fix the speedometer, odometer and shift points anyway with those taller tires, so you might as well pick up some power while you're at it.

To give you an idea of just what the additional gasoline costs are to run your vehicle on premium gas using the Superchips tuning as compared to running on the factory program on 87 octane, it's not more than a maximum of $100 per 10,000 miles driven, and for many people it's even less. So for those driving 15,000 - 20,000 miles per year, they generally spend about $2-$3 more per week for gasoline, as the cost delta between 87 & premium does not change no matter how high gas prices go, the national average is always right at 20 cents per gallon. Assuming a 20 cent per gallon cost delta and a 50-50 mix of city & highway driving, the additional fuels cost are not more than $100 per 10,000 miles driven, so it's really a much smaller amount than people think until they do it.

Give us a call if you like, & we can go over all the details & specifics of your situation.