The L2501 Turbo is ready for testing and tuning!
To accomplish this task, I’ll be using a Pyrometer to analyze the exhaust gas temperatures. Why do we care about EGT’s again? What do they tell us? We’re using a pyrometer to test and tune the engine because the EGT is an indication of how hot the combustion process is in the cylinders and the amount of “after burning” that is occurring in the exhaust manifold. The pyrometer measures these conditions in real time. The EGT is also directly related to the air/fuel ratio and the general consensus is the leaner the air/fuel ratio is, the lower the EGT. And the richer the air/fuel ratio is, the higher the EGT will be. Therefore, in most cases, excessively high EGT’s means over fueling. Meanwhile keeping the EGT’s a bit leaner, will lower EGT’s and can actually improve fuel economy. Something to keep in mind. Most diesel experts recommend a maximum of 1,200-1,300 degrees of EGT and emphasize that you do not want to maintain temperatures above 1,300 degrees for any length of time. In theory, by using a Turbo to increase air flow in a diesel engine, fuel can be added in a calibrated manner to increase power while maintaining an acceptable air/fuel ratio that does not create excessive EGT’s. That’s the objective.
It wouldn’t be fair if I didn’t include a baseline EGT test. So, without further delay here are the EGT readings I recorded when 100% stock.
L2501 HST 4WD (LA525 Loader w/ 66” QA Bucket, Liquid Tire Ballast) - ALL STOCK, NO MODIFICATIONS (40* ambient temperature).
Recorded EGT’s:
Idle = 200-300*
Traveling on flat ground (M) = 300-500*
Loader and grading work (M) = 500-700*
Traveling up hill carrying medium load (22* Slope, 40% grade) (M) = 600-738*
Peak EGT = 738*
Now, let’s compare the Turbo EGT’s but, with the factory fuel setting. NO ADDITIONAL FUEL HAS BEEN ADDED. We just installed the Turbocharger system and ran the tractor.
L2501 HST 4WD (LA525 Loader w/ 66” QA Bucket, Liquid Tire Ballast) - TURBO SYSTEM - 4PSI - Factory Fuel Setting (83* ambient temperature).
Recorded EGT’s:
Idle = 250-275*
Traveling on flat ground (M) = 275-500*
Loader and grading work (M) = 500-625*
Traveling up hill carrying medium load (22* Slope, 40% grade) (M) = 575-700*
Peak EGT = 700*
As you can see, nothing really has changed. The EGT’s heat up a bit quicker but, overall, the temperatures are running around 0-75 degrees cooler with the Turbo installed combined the factory fuel setting. I’m assuming this is because there is more air getting forced into the engine with the same fuel volume. Right now, with the Turbo and factory fueling, there is zero smoke coming from the engine, regardless of conditions. The engine is using all the fuel it can get.
We’re just getting warmed up!
Let’s add some fuel!
I started with a 1/2 Turn, counter clockwise to increase fuel volume. This setting resulted with a peak of 6 PSI and 3 PSI of sustained boost pressure. No smoke was observed during testing and surprisingly, EGT’s dropped under load going up the hill in (M) gear. Strangely, maximum EGT observed was 631 degrees. Weird.
More puzzling, I wasn’t happy seeing only 3 PSI sustained and I began questioning why I wasn’t maintaining more boost pressure. Was it fuel? Or, was it something related to the Turbo system? At this moment I started questioning the capacity of the OEM intake assembly and air filter. Could it flow enough air for the Turbocharger? I quickly removed the OEM intake assembly and ran the Turbo open-air (no filter) to see if the factory air intake assembly was causing a restriction.
The tractor did in fact pick up an additional 1 PSI of boost both peak and sustained with the same fuel setting, but only 1 PSI. 1 PSI isn’t monumental. This proved a few things; one, using the OEM air cleaner assembly and filter is perfectly acceptable. Two; with such a small gain in boost pressure, it isn’t worth using an aftermarket performance air filter, especially considering the air filtration issues. And three; I need more fuel. I reinstalled the OEM air cleaner assembly and prepared for additional testing.
I gradually increased the fuel volume to 1 full turn, counter clockwise. This setting resulted with 7 PSI peak and 4 PSI sustained boost pressure. No smoke was observed during testing. That’s not enough sustained PSI. I still wasn’t pleased with the results.
L2501 HST 4WD (LA525 Loader w/ 66” QA Bucket, Liquid Tire Ballast) - TURBO SYSTEM - 7 PSI - Fuel setting, 1 Full Turn (75* ambient temperature).
Recorded EGT’s:
Idle = 275-300*
Traveling on flat ground (M) = 300-500*
Loader and grading work (M) = 500-630*
Traveling up hill carrying medium load (22* Slope, 40% grade) (M) = 500-640*
Peak EGT = 640*
I then increased the fuel volume to 1 1/2 turn, counter clockwise. This setting resulted with the same 7 PSI peak but, 5 PSI sustained. Now we’re getting somewhere! There was some smoke observed at startup and a puff or two during operation. Not bad. I was happy to be making progress, but, still unhappy with the results.
L2501 HST 4WD (LA525 Loader w/ 66” QA Bucket, Liquid Tire Ballast) - TURBO SYSTEM - 7 PSI - Fuel Setting, 1 1/2 Full Turns (82* ambient temperature).
Recorded EGT’s:
Idle = 250-300*
Traveling on flat ground (M) = 300-500*
Loader and grading work (M) = 500-630*
Traveling up hill carrying medium load (22* Slope, 40% grade) (M) = 500-641*
Peak EGT = 641*
Shockingly, the numbers really aren’t that different. Why? I just can’t place enough load on the tractor to make it work hard enough to sustain boost pressure. Even going up my big hill in (M) gear carrying a load isn’t enough to maintain a load on the tractor. Crazy!
Continued on Post #22!!!
Mike
