Hi, I just purchased a 95 F250 2WD with a 460 EFI. I use it to pull a 29 foot camping trailer. I changed out the stock air filter with a K&N. I retained the stock air box as I see it has a tube that takes in air in front of the radiator. My issue is the stock exhaust is the dual pipes that are together from the muffler and dump out right behind the right rear. I can't put on a mud flap, which i need to do to stop stuff from being thrown up on the new camper, because the exhaust will melt the mud flap, so I stopped at a local muffler shop that has been doing work for me for a long time. They suggested that because the huge cat does alot of sound deadening, they could just go on behind that with a 3" manderal bent single tailpipe and position it so it dumps out past the right rear wheel, giving me plenty of room to put on some big rubber mud flaps. I'm concerned that by not having a muffler, I will lose back pressure and also torque? Is this true? They said that the sound won't be that loud due to the restrictive cat. Is that true? Has anyone gotten this done and does it effect the power and MPG any?

Thanks.

 

I have exactly what you have described, with the exception that I have 3.5" tubing instead of 3. I used a salvaged piece of pre-bent "over the axle"/tail pipe portion off a Ford Diesel (3.5"), then 3.5" tubing, connected to the factory cat.

They are right, that big ol'factory cat does alot of muffling. My truck sounds great and has a nice rumble, but it is NOT loud. If you want a nice sound and to get rid of some of the restriction in your exhaust, you cant go wrong with the plan you have been presented with, IMHO. My neighbors Chevy 2500HD w/6.0 is MUCH LOUDER than my truck and he has his factory (obviously higher flowing) cats and a borla muffler!

Back Pressure? We dont need no stinking back pressure!

The engine does not want back pressure. This is a myth that seems to continually pop up and it is simply not true, the engine is trying to get rid of the exhaust and the more efficiently the exhaust system can do that, the happier the engine is and the more power it is able to make. The only feasible drawback to not having any backpressure would be that the O2 sensor may not be able to get a accurate reading. If however you keep your stock cat though, you should have more than enough back pressure, if not too much. That thing only has a 2.5" outlet. That in my mind is insufficient for a 460ci engine to be breathing through. It would be like you running full blast and trying to exhale through a straw.

The above is just my opinion, but hope it helps.

Eric

 

Thanks for the info. I went ahead and had the 3" put on from the cat back and it sounds great. I had to pull my camper tonight and it pulled much better now that the 55 gallon drum muffler is now in the scrap pile beind the muffler shop.

Can't wait to run it up some hills to see how much more torque there is.

 

glad to hear the good news!

 

I just wanted to update all on how well the exhaust mod went on my 95 F250 with 460. My local muff shop installed a 3" pipe from the cat back. It can get a bit loud under a pull but I can't believe the power increase. Since my original post I have traded my 28 foot travel trailer for a 33 foot 5th wheel. The trailer weighed 4500 and the 5th wheel comes in at 9800. With the open exhaust, I can pull the 5th wheel at 70mph on mostly flat hwy with the cruise on and in overdrive.

I picked up the 5th wheel in Arkansas and had to drive back through Branson MO on hwy 65 to get home. If any of you have traveled hwy 65, there are some pretty steep grades from Branson to Springfield MO, but the old 460, with the overdrive off pulled the 5th wheel up those hills and I only had to go down into 2nd gear once, (which was because I couldn't get a good run at the hill because another 5th wheel was in front of me running 60 and no room to pass in the hammer lane.) Anyway, the wife does complain a little when I'm pulling under a pretty good load in 3rd but it quites back down on the flats OK.

So the old 460 pulls pretty good. Now how do I get better fuel milage? Before the exhaust change, I was getting about 6 mpg driving 65 to 70 loaded and now it's up to about 7.5. I'm also using the FFI MPG tabs, which work great in my other two cars. More power, better milage.

So my question for all you other 460 owners is how to squeeze out more MPG. Do I change the cam? Ignition? I looked at the Banks Power Pack System, headers, air intake, exhaust but man, they are proud of that kit. Over $2k. What other suggestions do you recommend? I have already installed the K&N filter in the stock air box, which by the way does have a stock inlet at the grill so I guess It's kinda like cold air induction. Maybe I should wrap the plastic piping for the intake? The 460 get's plenty warm under the hood.

So, whats next?

 

Welcom to FTE.

What are FFI MPG tabs????

 

They are tablets that you put in your gas tank at every fillup. They help fuel combustion, creating more power so you have to throttle easier, thus saving fuel. Most Gas and Diesel systems will get about 7 to 14 percent better gas milage while reducing emissions a bit. If you want more info, go here and check it out. http://www.toddmosiman.myffi.biz/en/

 

I think you might find this link intersting.
http://www.oag.state.tx.us/newspubs/...uel_prices.txt
and
https://www.oag.state.tx.us/newspubs/weeklyag/2006/0606fuel_prices.pdf.
The Stater of Texas shut down a group making the same clames.
You will get better results doing a tune up and driving a little slower.

 

I did my own test over 8,000 miles and this stuff works and it does not screw up your car. The company behind it did 20 million miles of testing and its EPA approved. The results is at the pump every time for me, but thanks anyway for the info.

 

toadmeister

did u make any changes to your truck i have a 96 f250 7.5l looking to improve my 7mpg