Winter vs summer tune

Single Tank WVO systems and blending SVO WVO to thin it.

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Winter vs summer tune

Postby johnvegburner » Mon Mar 03, 2014 5:05 pm

Has anyone noticed that their diesel engine runs much smoother and quieter during the summer months? I get easier starting, smoother running and less combustion clatter when the ambient temps are above 25*C (77*F). I would like to experiment with intake temps during this coming winter (southern hemisphere here), so am thinking about pipe-ing warm underbonnet air to the aircleaner inlet. I already run a snorkel for cold air induction (this is an s.u.v. or f.w.d. vehicle). My plan is to weld another entry pipe into the aircleaner housing and run a tuned length of pipe to an underhood location which would then give 2 air intake pipes. The combined hot and cold air should result in a reasonably warm intake temp which may not be ideal for ultimate performance, but should promote a more complete combustion event, which is always a concern when running heavy oil fuels.
I should mention that the Helmholtz effect is very strong in a diesel engine as the intake is always at "wide open throttle", and we should be taking advantage of this free energy to help improve volumetric efficiency.
I did an experiment some years ago on an Isuzu c223 Isuzu engine which gave mixed results, I ran the single induction pipe to a location right behind the radiator in order to try the hot air theory, the result was a very quiet smooth engine, however, after 15 minutes of driving (on a cold day (15*C /60F) the heat build-up was too great, and performance dropped considerably and the engine ran too hot for my liking as well. Now that I have an intercooled turbo 4jg2 Isuzu engine that has an E.G.T. gauge fitted I am in a better position to play around with various set-ups. The Helmholtz effect results from any sudden expansion of intake area, so the aircleaner canister promotes a strong pulse which we can tune to operate at a particular engine rev range. Previously I have tuned the pipe length to work at cruise (3000 revs on a previous Toyota engine), the pipe length (from the aircleaner to the opening of the inlet pipe) for these revs was approximately 5 feet, my present engine cruises at 2600 revs so I will experiment with a longer pipe to get the best effect at cruise speeds. Obviously the complication of having 2 intake pipes is going to make tuning interesting, I may be able to have 2 different lengths to get a broader (yet less effective) boosting range, I wont know until I try it out. I would be interested to hear if someone else has tried these mods, and what effect they got!
Single tank used veg oil burner. Isuzu Trooper 4jg2T engine
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Joined: Sat Mar 01, 2014 7:43 pm
Location: Melbourne area Australia

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