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In this section we will try and feature our most asked technical questions. Click on the subject you want to review. We will be adding additional subjects as a service to our customers.

AIR FILTERS

CAM PLATES

EXHAUST GAS TEMPERATURES

ENGINE WARM UP

EXHAUST SYSTEMS

FUEL FILTERS

IDLING

INJECTORS

TRANSMISSION

TURBO BOOST


FAQ

AIR FILTERS

Q: Is a foam type filter as good as the O.E.M. paper or a pleated cotton/oil type filter?
A: First of all lets discuss foam type filters. Foam filters may flow well when new but will rapidly clog with dirt and air flow will be reduced dramatically. If you were to take a paper or cotton pleated style filter and stretch the material out you would see the surface area of the filtering material would be as much as 10 times the surface area of the foam filter. More surface area = greater performance over much longer cleaning or replacement intervals.

Q: What advantage will a cotton/oil type filter give me over the stock paper filter?
A: An oil/cotton type filter like a K&N air filter will out flow your stock paper filter. A K&N filter can be serviced and re-used many times.
 
Q: Some one told me a K&N type filter does not filter out dirt as well as the O.E.M. filter because they found oil on there turbo impeller blades. Is this true?
A: This a common misconception almost all K&N filters are over oiled by the installer. Over oiling the filter will allow oil to be sucked out of the filter and in to the turbo.

CAM PLATES

Q: What is a cam plate where is it located and what does it do?
A: 94 - 98 Dodge trucks amongst other vehicles are equipped with a Bosch P Pump. This pump has a device sometimes referred to as a fuel stop plate, cam plate or torque plate. This plate basically controls the amount of fuel available based upon engine r.p.m.
 
Q: Can adjusting the stock cam plate do the same thing as one of your cam plates?
A: Diesel Dynamics Cam Plates are designed to increase torque at low and mid range r.p.m. without over fueling at high r.p.m. Moving the stock Cam Plate will over fuel at all r.p.m.'s. The graph below is fairly typical of a cam plate adjustment.
The red graph shows power and torque all stock. The green graph shows the gains from adjusting the cam plate .040. As you can see the graph shows basically a mirror image of the stock graph with marginal gains. The blue graph shows a Diesel Performance of Utah Cam plate kit installation. As you can see the increases in torque and power are dramatic. More power at lower r.p.m. spells more efficient towing performance and better economy.

 

EGT

Q: What is EGT and how does it effect my engine?
A: EGT stands for exhaust gas temperature. A diesel engines EGT rises as fuel is added. The more fuel, the higher the EGT.
 
Q: Should I monitor my EGT?
A: At Diesel Performance of Utah we are big believers in monitoring EGT. Power modifications will normally raise EGT levels somewhat.
 
Q: Where should I measure my engines EGT, before the turbo or after the turbo?
A: Diesel Performance of Utah recommends measuring EGT before the turbo in the exhaust manifold. Through extensive dyno and road testing Diesel Dynamics have found that the difference in EGT before and after the turbo is not consistent. Saying there is a difference of 300 deg f may be true only some of the time. We have measured differences of up 550 deg f during certain running conditions.

There are many who contend that if the thermocouple tip breaks it will pass through the turbo and damage the turbo. We have never seen a tip break off. We would also point out that most light aircraft EGT probes are located pre turbo. It would be our opinon that if the F.A.A. allows aircraft manufactures to place thermocouples pre turbo, it can not be that bad.
 
Q: What EGT range should my vehicle run at?
A: While running down the road on level ground with no head winds EGT's usually run between 6 - 8 hundred deg f. When going down hills often EGT's will run as low as 200 deg f. Pulling up long hills often EGT's will run up to 1000 - 1100 deg f. 1350 deg f is considered to be maximum allowable EGT and should never be exceeded. Exceeding 1350 deg f will damage your engine.
 
Q: Is it a good idea to let my EGT drop before shutting my engine down?
A: Yes your EGT should drop down to around 300 deg before shutting your engine down. This will eliminate the possibility of warping your turbine housing. This also allows your turbo to spool down before shutting down. Your turbo may spin for longer than a minute after shut down. The turbo relies on oil engine oil pressure for lubrication with engine off there is no oil pressure!
 
Q: Does altitude effect my EGT?
A: A diesel engines fuel delivery is not effected by altitude. Available oxygen decreases as you increase altitude. This decrease in oxygen will have an effect on air fuel ratio and cause EGT to rise. It is not uncommon to see increases of 200 deg f going from sea level to 5000ft. This is where the Air BullDog hood can help tremendously.

ENGINE WARM UP

Q: Should I let my diesel powered truck idle until it reaches running temperature before driving?
A: No. You may find some diesel engine trucks will not even reach normal running temperature while idling. It has been proved that most engine wear happens upon engine startup and engine warm up. 60% of all carbon deposites found in a diesels combustion chamber are deposited when the combustion temperature is cold. Diesel Dynamics recommends starting your truck and once EGT has stabilized start driving at light throttle openings (low load) until water temp reaches 160 deg F. This allows for a fast warm up and also allows your drive train to warm up with the engine.

EXHAUST SYSTEMS

Q: Should I upgrade my trucks exhaust system when I upgrade my engines power output?
A: It is important to understand that even if an exhaust system does not increase power it may allow more flow lowering EGT. It is important to understand that matching exhaust flow to increased engine fuel system performance modifications is extremely important. Keeping EGT down to acceptable levels is key to a good working performance package. A good quality 4'' exhaust can work wonders on your truck if modified.

FUEL FILTERS

Q: At what mileage intervals should I replace my fuel filter?
A: Manufactures recommended intervals for fuel filter replacement are o.k. but do not allow for bad batches of fuel that may be encountered. We have often seen filters plugged in one bad fill up. If experiencing low power and lower than normal EGT shortly after fueling have some body check the fuel filter pressure differential. Testing this will show a clogged filter immediately.


IDLING

Q: Is it a good idea to leave my engine idling?
A: Letting your engine idle for extended periods is not good for your engine. When your engine is idling, the cylinder temperature is colder than almost any other running condition. Fuel is often not burnt completely by the combustion process. When you are driving your truck down the, road cylinder pressure is increased and piston ring seal is increased. When your engine is idling piston ring seal is at its worst. Extended periods of idling cause fuel to pass by your compression rings and contaminate your oil with fuel.

We discourage idling for periods greater than ten minutes.

INJECTORS

Q: Will bigger injectors give my engine more power?
A: Within reason injectors with larger nozzle discharge holes will increase fuel flow rendering more power. Increasing nozzle hole size excessively will eventually cause injector fuel atomization (plume) to deteriorate causing excessive smoke poor fuel economy and wash down cylinders. Diesel Dynamics hand built blue printed True Torque injectors undergo an advanced flowing process that polishes the injector nozzle discharge holes. This process dramatically improves plume distribution. Power, torque and economy are greatly improved.

TRANSMISSION

Q: How much power can my Ford or Dodge pick up truck handle without transmission upgrades?
A: Diesel Performance of Utah recommends that automatic transmissions are upgraded when power is increased 70 hp or more. We recommend clutch upgrades on manual transmissions when power upgrades of 90 hp or more are installed. Both Ford and Dodge automatics suffer from a torque converter that has an excessively high fluid stall speed. What this means is that a large percentage of power and torque never get to the ground where it counts. Diesel Performance of Utah transmission torque converters and clutches are designed to get the most from your truck.

TURBO BOOST

Q: Should I monitor my turbo boost?
A: Yes we believe that monitoring turbo boost is important. Monitoring boost and EGT levels can be of great diagnostic value. Manifold leaks, waste gate malfunctions, air filter restriction, exhaust restriction and poor fuel delivery are just a few of the problems that can be diagnosed.
 
Q: Should my turbo boost be increased when modifying my fuel system for higher power?
A: Yes if increasing fuel delivery turbo boost should also be increased. When adding fuel for improved performance EGT levels will increase. Increasing turbo boost will lower EGT. A basic rule of thumb is that for every 4lbs of turbo boost increase EGT will drop 100 deg f.

This page was reprinted and edited with permission from Diesel Dynamics.