I just bought a 90 f250 non turbo diesel,the exhaust on it now is 2 1/2 to the muffler and 2/14 muffler and tailpipe,the muffler is the auto zone 9.99 deal,I am sure it is killing the power,the truck runs good but I feel there is more to be had,What should I run on it?? any brands recommended? 2 1/2" or 3" any help would be appreciated,thanks,Tim

 

Go with 3 inch and a see through muffler / resonator.

 

Thanks,any good brands?

 

try walker exhaust website they have a glasspack that bolts up to where the old muffler was. runs about $80 with a tip. put this set up on my 94 f350 4x4 7.3L idi and it sounds mean.

 

They also make a straight thru resonator that works good but I lost the number....

 

Will this really help a non turbo diesel? what about a k&n filter?? I build fast gas engines,I know how to make them fast but this diesel thing is new to me.I am trying to get the most out of what I have until I buy my powerstroke in a year or two.Thanks,Tim

 

think of a really big airpump. air in / air out.
unlike a gasser, open (no back pressure) exhaust is best on an oil burner. straight thru mufflers (or none if you can stand it) should open her up nicely. true duals even more.
i hear 3" is best, bigger is overkill. your downpipe is the biggest restriction, but larger is available.
Gibson makes a darn good product.
but your best bet is more than likely a local shop - probably cheaper too.

more air in is a good idea also, but i've seen a report that shows the k&n to be overrated - i run a similar amsoil filter & keep it clean.
search for 'soup bowl' or 'ram air'... opening up the restrictive OE intake will do wonders.

 

I run a K&N and straight pipe and there is not much power gains, but I love the sound of teh str8 pipe. Wish I would have done it from the start instead of spending the money on some muffler that made the truck sound like crap.

 

I reworked my Y-pipe and changed to 3" from the y back, and fabricated my own high flow muffler, and it sounds good and increased the power and efficiency. It can now run a 30' 5 horse slant down ther road and across mountains and still run 12 MPG no problem. I usually run fuel additive as well, but on that run, my sister was running it, and she doesn't put the additive in like I told her. I can bump it up to 15 mpg by adding the additive.Here's a link that will show you some of my work. https://www.ford-trucks.com/forums/s...d.php?t=303449

 

I am going to try to do something this weekend with it,The truck just seems to stop pulling around 2000 with a load,and goes a little more with no load,it pulls hard and just stops like it hit a wall,I can guarantee the 2 1/4 inch car muffler and exhaust have SOMETHING to do with it.

 

The 2.25" ID exhaust was stock from the factory.
A 3" pipe from in front of where the two pipes come together and a see thru muffler will wake the engine up.
After that look at the air intake system.
Most of the stock intake snorkels were way to small.
Also if you have a soup bowl on the bottom of the air cleaner lid, it has to go.

2000 RPM is just above the max torque RPM on the 7.3.
A free flowing intake and exhaust will extend the torque curve and increase the HP.

K&N filters are fine, but the maintence they require is more than I want to deal with.
When you service the filter, you wash it. Then you spray oil on the filter element.
Once the oil is soaked up by the dirt the filter is stopping, the dirt goes right thru the filter.
I am in dust daily, servicing the filter more than once a week was to much hastle for me.

 

I did a 3" exhaust with a dyno max bullet today,I like the performance gainbut I am not too crazy about the poppy cheery bomb sound,Any other good sounding mufflers out there for these?
I also noticed that I tried to pull the truck past 2200 and the truck just stops pulling like someone shut off the key,I am going to do a Mechanical fuel pump so I know it is good tomorrow,what about the injection pump? The symtom to me seems like a fuel pump so I am starting there,anby suggestions??

 

How's the smoke when you're on the floor?
How's the rattle when it's cold?

You might be able to tweek the timing up a bit and give the fuel screw a slight turn. If you put a pyrometer in the exhaust you can play with that stuff and try to get some more without burning it up.

 

Definitly open up the exhaust and try out the Fram Air Hog, they are supposed to be an awesome filter. If you don't mind the noise, you could turn the air cleaner into an open element design, but that can get pretty loud and it gets old fast on long trips.

I actually run the Vortex 3"in dual 2.5" out muffler (a.k.a Ravin' Z-55 3"/dual 2.5") and it actually has a nice sound, alot nicer than the straight pipe.

 

How do you do the timing on a diesel? whetre is the fuel screw? What should the exhaust temps be?