I just picked up a 2001 and I would like to replace the turbo with one that'd get me best fuel mileage. The truck is just used for work as a daily driver in the city and on highway. No racing, no Towing.

 

You won't see any significant mileage benefit from a new turbo. The only compelling reasons for changing out to a different turbo are:

1. Existing turbo is broken
2. You've increased fueling (injectors, etc) and the existing turbo is inadequate to burn all the fuel
3. You're unhappy with the boost characteristics of the existing turbo and want something different (quicker spooling, more full-throttle air, etc)

For an '01, easy mileage gains can be had with a simple timing box like the old Edge EZ or similar.

You seem to have done quite a bit with your '06--what gave you the best mileage increase on that truck?

 

I think this new 2001 has an upgraded turbo, the guy said it cost about 600 bucks. It's like a larger Holset or something. The truck also has an Edge Juice with attitude programmer. The turbo does not produce much boost under load - 16 PSI.

What gave me the best mileage and my 06?… Not modifying it...Lol! My 06 currently does 16 miles per gallon when towing or unloaded on highway. Still breaking in the new engine though. Going to also try a different guy's EFI live tunes too...

In all honesty, the best mileage I got in my 06 was 19 miles per gallon, with Diablo sport programmer on performance and Garrett stage two ball bearing turbo...

 

16 psi under load--is that full throttle? I would certainly expect more than that under full throttle. Might be worth checking for boost leaks or wastegate problems. Does it smoke after the turbo spools up?

Sounds like the existing turbo is either a HX-40 or a 35/40 hybrid maybe.

 

Nothing about this sounds right. I dont know of an aftermarket turbo for only $600 and a stock truck is going to put out around 20+ psi of boost without the help of a tuner. Add a Juice and you're going to be well in the 30+ psi range. Sounds like you have some misinformation, bogus gauges, or someone's lying to you. They joys of buying used stuff.....

 

The stock hx35 will have the wastegate set somewhere around 20psi and will not go higher unless modified with a boost elbow or wastegate rod adjustment. This cannot be done without throwing overboost codes and going into "limp". It is hard to make much more boost on stock fueling anyway. All high end chips do boost fooling, and about half the cheapos do too (power puck does not, Edge does).

The size of the hx35 turned up, IMO is close to ideal until you get around 35psi and at least 400 crank hp, then it starts having trouble keeping up. Unless you can fuel enough to capitalize on the bigger turbo, all you get is worse performance going bigger.

If you are NOT going to do any fueling mods, the hy35 might actually perform better since is will spool slightly faster. But a better mod for efficiency is like noted above- add some fueling, or better yet a chip with some timing and fueling like the EZ. Exhaust leaks from cracked/warped exhaust manifolds can really harm performance, but it'd have to be pretty bad to not achieve full boost *at all* so I'm gonna venture there's some kind of fueling problem- I'd check the lift pump sooner than later.

 

I don't think there are any boosts or exhaust leaks. Have had quite a bit of experience with my gen three. I think the turbo is just too big... Not sure what it is yet because I took the truck in for provincial inspection and of course, it didn't pass: airbag module.

My plan is to put in a Steedspeed manifold with a Borg Warner EFR turbo. Always wanted to try one of those.

What are the better programmers for this 2001 Gen 2?

 

A Smarty, for sure. However if funds are tight, then a used Edge EZ or Comp would probably be the way to go.