Fuel Milage on modified 300SD
 

I feel like opened exhaust and intake , romove EGR , other top side mods
including boost to 13psi should increase milage as you need much less throttle to maintain speed ...what are your thoughts ???
Thank You David

300SD 81
69 6.3
2X 70 6.3

Your correct but don't expect miracles. An intercooler and more efficient turbo should help too.

I gained a few MPG when I swapped my GT2056V for the stock T3

Stock intake should be fine, make sure you're using a WIX brand filter and NOT a K&N
Exhaust is only marginally restricted, drop the muffler for a nice diesel growl.

Unless you have a California emissions equipped car....which has a trap oxidizer killing your exhaust flow.

The best thing I did for hwy mileage was to lift rear end 2 inches.So with full load of luggage,family the car still sits a little higher in rear.

Please take out that k&N it the worst filter ever seriously if you can see through the filter then its bad!!!!

[if you can see through the filter then its bad!!!![/quote]

Dang,I thought if you can't see thru it,its bad.
I guess I'd better take off oiled foam cover too.

this increases your cross-sectional area. Increasing drag, decreasing mileage. How many miles do you drive with the trunk filled up?

There are measured amounts that can be beneficial for highway speeds. But the force from the wind at a given speed should make the car ride level to minimize the drag coefficient.

Not with the front end sticking up like a sail.
I guess nobody here from the 70s,we jacked up rears to make wind glide over windsheilds.
Last post I quit,all people do is tear people down.

Well, not from the 70's, but had a friend with a 'cuda and a hemi in it.

I thought was a muscle car thing, its not so much for highway mileage, but for acceleration. Cars with heavy acceleration loads send their rears down easily, you dont ever want your front end higher than the rear.

Rear tire clearance on muscle-cars, and to counter the front lift / rear dive under heavy acceleration, more of a drag-race thing.

For better fuel mileage the best thing is to lower the car, less air under the car is better (ex: all racing vehicles except swamp buggies). And level, you won't ever see a high-tail on any racing car whether imsa, nascar, indycar, trans-am, etc., etc. The high spoiler thing is different, it actually slows the car on straights because of wind drag, but the drag is worth it for the increased downforce = better cornering ability.

Anyone remember the Chapparel C-2 with one pedal to level the rear wing for straights and tip it up for turns? Gotta love that guy!

sorry you feel that way, perhaps it is in the reception. We like to discuss, and sometimes we get too excited. Arguing is another term for it.
We are all learning here, and everyone has some insight.