Anyone using Fuel-Miser pre-cups ?

[sailun]

Is anyone using the fuel miser pre-cups in their heads, and what kind of real world results are you seeing ?

I'm more interested in the increased fuel economy benefits, and hoping for similar power.

Anyone seeing consistant +2, +3, +4 mpg ? Assuming no other changes to motor.

[6.5TDTahoe]

Mr Jim Bigley gave a dissertation in a feature article about the effect precups on power & fuel economy. Several years back but it is surely lurking here somewhere. Search it out!!

[Robyn]

The early 6.2 engines were introduced in the full sized trucks, Burbs and Blazers as a mileage getter.

These engines had very small precup ports as well as smaller internal cup dimensions.

The combination of small cups and the settings of the Injection pump all combined to produce some very good mielage numbers.

Using a set of the small port cups in a 6.5 is quite possible.

The part that is not a given is how the combination of the small ports along with the injection pump settings on a 6.5 with the DS4 are going to work.

You will likely see some improvement in the MPG.

I used a set of the "T" cups in my 6.5 build for my DaHoooley

The small port cups along with a good free flowing exhaust system and a chip/reflash of the electronics could produce some very good numbers.

There are some programs that are designed for MPG rather than big Power.

I am not aware of anyone here who has really gone after the MPG end of things.
Usually everyone is looking for the last tidbit of HP from their 6.5 and the mileage just falls wherever it lands.

Have fun and keep us posted.

If you do a project on this, keep good records, take piccy's along the way of the various parts and document everthing.

Do a writeup and share it with us.

Missy

[Edahall]

I have one of those early 6.2 diesel engines and still running the original 82 heads with cracks and all. It came with only 130 hp stock so when I took possession of it, I started working on it to help with power since it was also used to tow a 26 ft Airstream. However, all the modifications not only increased power but also increased fuel economy. It has a lot of similarities to your 6.5 so you might want to take a look at my signature that lists all the things I did to it. The small precups is definitely a step in the right direction. I see you've got 3.42 gear ratios. You would probably get better fuel economy with 3.08's. However, you could achieve about the same thing by using 16 or 17 inch rims and tall and skinny tires to bring down the RPM's. Also, with the boxy front end on my 82, I get a big penalty in fuel economy at 70 mph. When fuel was cheap, I didn't worry about it and would get about 24 mpg at 70 mph but with fuel prices higher I drive between 60-65 and enjoy 30 mpg and 900 miles between fuel ups. So far, I'm getting 25.5 mpg with the Cummins Suburban so I would say the 6.2/6.5 engine is better sized for achieving high fuel economy on these vehicles.