Correct Diesel Tuning All You Need To Know To Get Improved Power And Economy From Your Diesel

Correct Diesel Tuning All You Need To Know To Get Improved Power And
Economy From Your Diesel

Diesel tuning is​ more important than we think. Lets get down to​ the​ basics.

Diesel is​ distilled crude oil (Distillate). Unlike what most ‘Hollywood’ movies promote of​ a​ diesel truck hitting a​ wall and​ exploding like a​ small nuclear bomb, oil does not readily ignite, particularly a​ liquid form. if​ we atomise it​ though, it​ will burn readily. the​ diesel principle relies on air being compressed to​ approx. 500PSI. This in​ turn heats the​ air, turning it​ into the​ igniter (diesels don't have igniters such as​ spark plugs). Heard of​ a​ glow plug? Glow plug only glow on cold start-up to​ help warm up the​ air in​ the​ combustion chamber. a​ bit like when you are pumping up a​ push bike tyre, the​ pump gets warm.

Ok, so you now have very hot air and​ you inject diesel in​ through an​ atomising injector. as​ soon as​ the​ diesel leaves the​ injector and​ enters the​ extremely hot air the​ diesel ignites and​ combustion begins. Put a​ poor atomising injector in​ the​ picture and​ you have a​ different story. Because it​ is​ not atomising the​ diesel enough, the​ fuel volume burns erratically and​ slowly as​ the​ flame burns through the​ large droplets of​ oily fuel. if​ you were to​ light up a​ drum of​ oil, you would see a​ similar effect of​ slow burning and​ smoke. You can imagine that by now the​ timing of​ the​ combustion process is​ also upset. Add lower injector pressure than normal, due to​ age, and​ you have the​ timing of​ the​ fuel ignition point changing even more (injector opening too early). the​ injectors doing this alone can make a​ diesel smoky and​ sluggish. On a​ cold morning, the​ combustion is​ even further retarded due to​ cold cylinders and​ cool combustion and​ you also get hard starting.

This scenario changes completely with correctly set up injectors. Remember the​ drum of​ oil? Well, if​ you could fill the​ drum with a​ misty vapour of​ oil and​ light it​ up, you would not only get a​ large bang but it​ would be over within a​ flash. a​ good injector sprays fuel out as​ a​ mist and​ the​ fuel burns rapidly and​ relatively clean as​ the​ droplets are so small that they burn with a​ puff! a​ correctly set injector pressure also means the​ fuel is​ being injected at​ the​ correct time.

Now, the​ injectors are perfect but the​ injection pump could be slightly out of​ tune. Timing has to​ be set. if​ it​ is​ too early the​ vehicle can smoke and​ become quite ‘diesel noisy’ and​ if​ it​ is​ too late, the​ vehicle can feel sluggish. Imagine the​ spray of​ fuel as​ a​ fist about to​ hit the​ piston. if​ it​ is​ hit too far before top dead centre it​ would not only hurt your fist and​ the​ piston but it​ would make a​ louder than normal bang as​ the​ two things hit head on. if​ the​ piston had gone past top dead centre and​ was hit, the​ force of​ the​ hit would be going down with the​ piston so you would have too little
impact on it. So you can see why timing is​ critical for​ maximum hit effect! Other things need to​ be checked like the​ fuel volume delivered by the​ pump. Too much is​ power but with smoke, too little is​ low power with absolutely NO smoke and​ just right is​ in​ the​ middle of​ smoke and​ no smoke! There are a​ few more complex settings on the​ pump that are checked and​ adjusted but these are the​ main ones.

Well, there are 6 injectors supplying fuel to​ the​ engine (Imagining it​ being a​ 6 cylinder diesel). Looks like it​ has no problems getting fuel, but what about the​ important part that we forgot about, AIR? has to​ draw the​ air through a​ maze. Filter, pipes, inlet manifold and​ a​ tiny inlet valve. This has to​ happen in​ a​ split second and​ the​ piston going down has to​ do all the​ sucking. That’s the​ governing part of​ a​ diesel engines performance. Remember more fuel for​ more power is​ just more smoke! So we have to​ do something about the​ air to​ keep things clean. This is​ where a​ Turbo system comes into its’ own with Diesel engines. With a​ huge amount of​ air now available due to​ the​ turbo supplying air right to​ the​ inlet valve, the​ piston only has to​ suck air from there. Lets not forget that 1 cylinder has a​ suction stroke many times a​ second, so these fallacies of​ air being forced into the​ engine and​ blowing heads off with a​ turbo are only that! Now that we have more air, the​ fuel system can be set up according for​ more power. [WARNING- This is​ where the​ whole equation can come adrift with overheating etc. Things have to​ be set up by a​ professional and​ a​ professional that knows his JOB!]

One last note; the​ diesel system that is​ on all 4WD diesels was designed to​ run on a​ fuel with certain burning characteristics. We don't seem to​ be getting fuel in​ Australia meeting all these requirements. We have new vehicles smoking that obviously are not designed to​ smoke when running on real diesel. So when setting up a​ fuel injection system for​ tuning we have to​ take the​ burning characteristics of​ this poor diesel into consideration. Try to​ get your fuel from a​ reputable and​ 'known brand' garage and​ keep your receipts. if​ you have problems, you then have as​ much 'come-back' on the​ fuel garage as​ you have with a​ faulty product from a​ shop.

Safe 4WDriving,
The Diesel Experts

Footnote: the​ modern diesel has come a​ long way from its beginnings!! Well…so we are all lead to​ believe!! That’s where it​ all stops. in​ fact about the​ only thing that could compare is​ reinventing the​ round wheel!! That’s right. Nothing has really changed. a​ diesel still needs fuel and​ air. Even though we now have trendy things like ‘Common-rail High Pressure Injection and​ Electronics controlling everything, it​ is​ still the​ same old principle. the​ only major change appears to​ be the​ repair costs… as​ usual. Most ‘high tech’ injectors now cost over $2000 each and​ are ‘throw away’. Most Injector pumps are becoming ‘throw away’ at​ around $6500. Where will it​ end??

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