I have a 95 auto with a built trans, full gauges, #6 tst plate, 4" exhaust, and a bhaf. The timing is stock and in the exhaust I have a magnaflow bus muffler that was a straight through, for noise. I'm currently getting approx 13-14 in town and maybe 15-17 running empty on the highway. While towing my 23' trailer I maybe get 10-11mpg. I'm looking at a #10 or #100 plate and bumping up the timing to 15, 2 of the pump shops here in vegas said that that was too much timing, and thinking that the muffler is causing a restriction because it did have baffles. Any ideas????

 

15 is not to high put it at 16 or 16.5. if you look thought the muffler and can look right through it than there is no restriction. as for the fuel mileage try and put amsoil fluids in everything and new filters

 

Thanks for the info, by the way what kind of mpg do you get?? Did you bump the timing on your rig?? Did it help?

 

pretty much stock truck with the 47re we could squeeze 20-22ish on the highway... parasitic loss in the tranmission? and amsoil is expensive; but it's good stuff... puked like 150 bucks or so of it out on the road when a transmission cooler line ruptured... the trans was pretty much pumped dry; replaced the line and put fluid in it, truck drives around like it was just rebuilt... the guy at the transmission shop said he was suprised the truck even went forwards for as dry as the transmission was... so yes; it's pricey but its good stuff. i'd rather spend 150-200 bucks for fluid than pay for another 2200 tranmission OR pay 500 to have the forwards clutches replaced.

 

I'd do back flips if I could 20-22ish, everyone that I talk to says the timing will help but I still am looking for some advice as far as the fuel plate goes. Thanks for the input. By the way Tower I have a 93, Did bumping the timing 1/8 help? and how do you like the 366 spring I have one but haven't installed it yet.

 

mspeer7...
With what I see in the post you made I do not feel that you are too far off for fuel mileage due to the weather conditions you have(high ambient air temps) and the altitude of Las Vegas(almost 2200ft above sea level at Mccarran Intl).15-17 highway mpg in those altitudes and conditions is probably about spot on and they would definitely improve at or near sea level like most of us live at.The higher up you go in altitude and air temp the tougher it is to make efficient power and killer fuel mileage numbers IMO.

As for timing....
If you still have stock head bolts and your haven't o-ringed the head yet in the altitude your running and knowing the air temps,I would say that your pump shop is looking out for your best interest with what they said.However,if you can manage the temps of the motor with your right foot then I would say 15 degrees would be a safe haven for you.I am not sure I would go to 16-16.5 without more air and the head done as with the altitude comes lower oxygen levels and added timing would create higher temps and cylinder pressures.

Now the plate...
If you have a 6 plate and your truck still has the stock P-Pump(the 160hp pump)then the "100" you see everyone tout as the "end all/be all" plate for the P7100 is not for you.If you desire more fuel then slip down to a 5 plate but keep in mind again,altitude and ambient air temps, as you may need to think about feeding the truck more air with a different charger choice.The 6 you have is a 230hp/605tq plate and the 5 is a 255hp/655tq and the latter will raise your emission output.I know you guys out in the Valley are prone to the ''Air ****'s" busting your stones about smoke so you will need to make yours make power more efficiently so problems will not be had.

20-22 mpg out in the altitude would be spectacular and relate to much higher numbers at sea level I just do not think it will come without a price.........Andy

 

I have a bone stock 96 with a auto trans and I get 17-20 mpg with a loaded car trailer running 75 down the interestate. I thought that if you turned these trucks up and kept your foot out of it you would get better milleage out of them..

 

well i haven't gottan the 366 spring yet; but i've heard it is night an day. as for the timing bump... i didnt really drive the truck a whole lot b4 the bump and i'm in the process of refreshing everything so i threw in pump mods... all in all the old girl is pretty ballsy now. granted the bed of the truck is off but when the turbo lites the truck starts to break loose at 20ish mph. i plan on gettin the spring real soon... but the timing bump is easy enough (as long as you have an or can find the correct wrench) or have the tools to accomodate making a specialty wrench. it doesnt really hurt to do it. the 1/8th bump isnt anything crazy and the truck maintains a pretty streetable attitude, temps, and assumably pressures are all in the safe zone... just dont go boosting the living crap out of it w/o the obvious upgrades.

 

you can look at my signature and see,i'm dumping quite a bit of fuel to mine and i get 22mpg around town.get a #100 plate.

 

But you still are pushing more air tho. He has a stock charger. Hammer is right on IMO, Altitude has alot to do with fuel economy, I think he should stay with that plate and upgrade to a more efficiant charger . Im not bashing you so dont take this the wrong way. . maybe a little timing.