Okay here goes, I have a mp8 installed last week, and my mileage seems to be worse like 1-2 mpg worse. Its not the heavy foot syndrome either. When I run my smarty on rp3 it is alot better without the mp8.

Whats the deal?

 

Are you running the MP-8 and rail pressure with the Smarty?

 

No the mp8 is when smarth is on rp1, this in when the mileage is bad, when its good the mp8 is unplugged and the smarty is on rp3

 

What Smarty program, SW, timing, etc are you running?

Approximately what setting on the MP-8? Same Smarty SW and timing when running the MP-8 and without?

When fuel mileage goes down, are you driving relatively slow speed and empty, or higher speeds/loads? How much have you tested mileage, and under what driving conditions? Always hand calculated? You can't rely on the over-head; some modifications will change the reading. Also, could it be winter fuel related and the timing of the MP-8 install is a coincidence?

Check the connectors on the MP-8. It is possible to put one of them in backwards. I know this from personal experience.

Possibly the increased pressure is affecting your timing, and consequently, mileage. The MP-8 and Smarty increase pressure differently. The Smarty increases rail pressure ramp-up; increased pressure at the lower end, but not higher max pressure. The MP-8 increases pressure more at the higher end, and will make higher max pressure. Incidentally, this is why the MP-8/Smarty stack works so well.

Do you have a rail pressure gauge? If not, get one. Drive down the road empty, at constant slower speed (under 40, or so) and see what the RP does when you turn the **** on the MP-8. Do the same test at 75 or pulling heavy. If your rail pressure is 10k, the MP-8 won't change it much, if at all. If RP is 22k, Mp-8 may raise it 3k.

Instead of Smarty RP1, try running default when using the MP-8. Try the MP-8 at different settings to see what works best.

Also, I think that running higher rail pressure on a daily basis is bad for the injectors. I think it's best reserved for the dyno/track.

 

How are you judgeing your mileage??? LIE-O-Meter? If so, this is your problem. A box fools the ECM so dosen't calculate it correctly. You have to judge full to the top and can see the fuel on each fillup.

 

Smarty doesn't raise pressure across the board only ramps it faster. MP-8 raise pressure across the board so a given throttle setting is flowing more fuel with MP-8 than with Smarty RP on 3.

Add the Smarty duration to the MP-8 pressure and you have more fuel being used.

Power stacks are not neccessarily good for efficiency. You have to play with it to find the sweet spot. What setting are you running the MP-8 on?

 

This is hand calculated on the mileage. I drive about 40% city, 60% highway. I am running Smarty rp 1, timing 3, wastgate off, tq 4.

My better mileage comes with mp8 off/ Smarty Rp 3, Timing 3, wg off, tq4
My worst mileage comes with mp8 about 40 to 50%/Smarty Rp 1, Tq 4 Timing 3

I looked at the connectors and my original thoughts were wrong of which the plugs should be plugged in, but from looking at both ends of the plugs there is only one way they can go together right?

 

What program and SW are you running?

The MAP sensor connector can go on backward. Make sure the lock tab goes on the side with the ramp protrusion, not the square one. Usually you get codes or bad popping if the connector is backward.

 

TQ management 4 will kill your mileage unless it is steady on cruise. MP-8 that high is not gonna do mpg or the injectors any good for extended times.

Take the TQ down to 2 and MP-8 at 20-25% and try for mileage then. Somewhat kills the fun factor but it does better in the wallet department.

 

If your not pulling use Timing 2, rp=1, TQ management=2, MP8= 10% and see how that works for you. I get the best mileage with those settings except for the MP8. I set my quad pressure only tune to #1 or off.

 

Running sw7..Okay i will give those settings a shot. Does the Mp-8 effect the timing at all when stacked with the smarty?

 

You're running regular Revo and not TNT?

For the best mileage you'll have to experiment, but mine is best on SW3.

The MP-8 doesn't change timing per se, but more pressure will advance timing, all other factors being equal.

 

Okay I think I understand now lol! I am running the revo software. My truck doesn't get along with the tnt software, if fried my ecm right after installing it the second time, the first time it messed up my TPS. So I am sticking with revo. I wish I could have 4.2 back.....;(