What RPM range gives the best fuel mileage on a f250 PS ext.cab 4X4 with 3.55 gears. Going to take a 200 mile trip next week, mostly interstate driving..with a 70 mph speed limit.

At 65 mph turning apx. 1750...@ 70 mph... 2000rpm and at 75 about 2150

PS....I still got a dang fuel leak some where under the filter housing


Since I installed the New Turbo wheel with the 86 mm height it runs about 3 to 6 psi boost on flat road at 70 mph. I never saw that type of boost before on my truck.

Also I got this loud whistle coming from under the hood...I think it is from the turbo wheel making the noise coming from the air filter intake. When getting down on the truck I hear the noise getting louder as the boost goes up....say at 25 psi boost the trans shift gears the noise gets much louder as the rpms drop down and the boost falls back to 15 psi.

Is this noise normal for a wicket style wheel....or is it just a loose nut between the steering wheel and the seat

 

With an auto transmission 1450 RPM, about 55 MPH with 3.55 gears in overdrive.

 

Jim! You want Joey to be a grandpa at 55mph?? LOL

Under 2K and you will be good.

 

You coming to see me?

 

Empty, at 65mph I'm getting 18 to close to 20 mpg, depends if the road is flat or not. At 70mph it drops some. I wouldn't worry about it. Drain a tank, fill it up again and check your mileage. It may surprise you.

 

I wish I was Bill.....LOL It would be nice for someone with your expertise to drive my Ol' Truck....Not counting all the Goodies that I could stash away in the glove box, ash tray and under the sun visor

I got to work the Raleigh Gun show this weekend....Then Monday the trip to the Coast to surf fish for a week, that will be the 200 miles one way

I like to run about 6 to 7 mph above the posted speed limit.....except in towns and residential areas ....no speeding there....Oh well there goes the fuel mileage

I could ride my Motorcycle...Triumph Rocket III and not worry about the fuel..but it does not have a windshield on it...

What about the Turbo noise from under the hood????
No one is running the 86mm Wicket wheel in there turbo??

I like the turbo whistle when it came out of the exhaust......now it all comes from under the hood..

 

Glenn, just answering the question ...
Think MADVAN (rip) told me that.

 

Agreed, you will get the best fuel economy between 55 and 65 MPH. These trucks aren't exactly built for aerodynamics and the faster you go the higher the aerodynamic drag is. That being said, driving my truck home from Georgia when I bought it I averaged right around 18 MPG doing 70-80 the whole way, with the cruise on much of the time. That being said, the best I could ever do with the old truck was about 16 MPG unloaded on the highway (at about 70). I think the E4OD makes a difference (hurts the fuel economy) and so does the age of the engine.

As for the turbo sound, is it just a whistle or what? Is that wheel different than the regular Wicked wheel? Is it the WW2?

 

I was just giving you a hard time Jim . I sure do miss MADVAN.

 

I hope I get 14-15 mpg going to the coast.. I think it gets around 10 mpg pulling the horse trailer with the wife driving it.


As for the Turbo wheel...I think it is the WW2 wheel

my 1995 PSD...had a stock wheel in it, also I believe to be the wicket wheel. The guys with the newer 7.3 replaced the new 11 blade wheel to reduce surging by using the 6+6 older type wheel



The wheel in the center is the one that was in my truck that the DuraLite air filter killed...It made good boost and had an awesome sound coming out of the tail pipe....I run a 5 inch open exhaust all the way back from the down pipe

The wheel on the left is the one I bought for $40 off of ebay...That is the one that is in the newer model 7.3's......no turbo whistle and not much boost either....very sluggish.

The new shinny wheel on the right is 86 mm high where the stock ..."Broken wheel" is 80 mm high.

The whistle sound it makes is very hard to describe...Like a turbo spooling up to a some what loud sound as the truck changes gears....the rpms drops back but the whistle sound gets much louder as if it was a blow off valve for the turbo

I will try to get some sound recording of it some how...I am getting use to the new sound it makes....Kinda like it....LOL....never heard any other PSD sound like that for sure. Plus I do not remember running 5-7 psi boost running down a flat road...with the cruise control on at 70 mph.

 

I have heard from some other who have run billet wheels (like the WW2) that they make some pretty unusual (and awesome) sounds. It could be too, that what you're hearing is a boost leak somewhere, though if you're seeing numbers like that I doubt you're leaking much. I have always understood that the original "Wicked Wheel" is more or less an identical piece to our stock wheel and, as you have said, some SD owners would go to that wheel to reduce surge. I'm not entirely sure what the one on the left is. 5-7 PSI cruising isn't bad either, but it's important to remember that boost = fuel so you're probably using more fuel at 5-7 PSI than you would be at 3-4. I guess time will tell!

 

Joey, do you still have the factory orange silicone intake boot on the turbo? If so, make sure it hasn't split anywhere. They usually split on the bottom right where it hooks to the turbo.

 

Bill

Yes it is the orange ones on the truck....after it warms up here ...I'll go out and check.....high 30's to low 40's here.....yes I am a Woo Woo

What do ya'll replace them with.....Factory one or do you use something different

 

DIY

The guy I got the wheel from.....on the left said it was a SD wheel .

He said that he rebuilt turbos and got all these wheels from dealerships that changed out the SD wheel to the Old style wheel that we have on our stock trucks. He also said he had about 40 of them on hand

The only good thing about the SD wheel was I could change it out without taking the turbo off the pedestal.....I changed it out by just removing the outer turbo housing cover 4 8mm bolts..

The New WW2 billet wheel ....I had to remove the whole dang turbo to install it

 

Here you go:
Riffraff Diesel: Riffraff 94-97 Turbo Intake Boot
This is a really nice piece! I have one and it is a lot more stout than the OEM piece.

I see. I guess I have never seen the stock SD turbo wheel before. I have been told in the past that you couldn't get the compressor cover off the turbo at all without pulling from the engine, so I am surprised you were able to do that at all!