cat dyno results

Checking the history, its a 475 1650 from the factory. Does not look like london branch took you fuel to top of spec. The heavy haul file will give abit more power but usually the fuel mileage drops. A custom file is the best way to go, some BXS engines never got fuel mileage.

 

1796 rpms at 61 mph is that right?

 

Dyno pulls are done in direct gear which is usually 11th 9th, or 8th.

When I pull doubles I lose about 3/4 to 1 mpg due to the rolling resistance from the extra axles.

 

The heavy haul file may help fuel mileage slightly. The reason for this is that it has a slightly different power band and allows you to drive the truck in a wider RPM range without sacrificing fuel mileage compared to the standard truck files. Whether you'll see an improvement or not, is a guessing game. I don't believe it would make iit worse though, unless your using high engine RPM while shifting and driving. As far as hurting the engine, don't worry. Whether you use the CAT Heavy Haul file or a modified PDI file early engine failures aren't what either of them want to sell. I've sold many of the PDI tunes without premature engine failures. The cost of doing the modified file is $1850 plus shipping costs, unless I can arrange for you to meet a PDI employee to tune the ECM on the truck.

 

that is no lie. Why some do alright and others are so bad, nobody can give a good answer. The best thing to do is a modified file as DDS said..........it will improve the fuel mileage

 

There is so littlte difference in the two dyno runs in both power and fueel used that I don't think you'll see much of a difference on the road. The GPH of fuel used went down in the 1400-1500 RPM range while increasing Hp by 1-5 Hp. The 1600-1700 rpm range fuel useage went up with no power gain. Keep the RPM at 1400 RPM for the best fuel mileage while cruising.


Increasing torque helps fuel mileage if you don't increase Hp at the same time.

The Wheel Hp was significantly different between the dyno runs, do you know why?

 

You would be money ahead to pay it and pay interest on a charge card. As a proud owner of a PDI tuned acert its worth it at twice the price. Just dont tellem at PDI.

 

Your measured wheel hp is way up, using about the same fuel,

old Wheel HP 350 404 429 428 399 ( these are 1200 to 1800)

new Wheel HP 526 549 528 492 442 ( these are 1800 to 1299)

Should notice a big difference, did you bump it to a 1850 torque?
(Looks like the dyno operator was out of the throttle for the fuel measurements to make the dyno report look good for Cat)