Greg looking at the research you have done, I think the PWM for your electric fans will work as described in the links. As far as it keeping up with the increase in coolant temperature, with what you have planned has many variables. How much increase heat will the exhaust warm the coolant? What will be the heat or temperature drop from the fuel? Also making sure the exhaust does not heat the coolant past its boiling point, which a 50/50 mix is normally around 255-260. I would also think after the coolant/fuel heat transfer the coolant should probably be routed directly back to the radiator for cooling. In theory it would increase the load on the alternator to some degree, but I didn't catch anything in your links that it would be to such an extent to cause adverse effect. Its diffidently an interesting concept you have and I would definitely be interested in the results if you do decide to undertake this project.
Thank you, Mike.
I think the first step already happened - when my Alternator gave up the fight in December, I chose to upgrade to a higher output replacement along with a higher capacity battery (it was due from a free warranty replacement point of view).
Another step happened today - I verified with my spare coolant temp sensor that it's resistance does drop as it gets warmer, so that when engine coolant is above 230 degrees the PWM will be blasting both fans at 100% duty cycle. This is before any additional exhaust heat is added to the cooling system, or any fuel absorbs any of that extra heat.
So - Fans first. Just like making sure that you're going to be able to make a car slow if you're preparing to make it go
Then I think it would probably be a good idea to verify that my cooling system doesn't have a leak. May I ask a question possibly calling on your profession?
Are wire hose clamps like this better at ensuring a seal of something like my cooling system?
I've seen that device before but don't know a lot about it. I personally wouldn't use it, except in emergency, because I would be concerned it would gouge the hose. Worm gear clamps tend to gouge a rubber hose over time also. As far as high pressure hoses go, we use a T bolt clamp. There are plenty of heavy duty hose clamps available online, that can handle a lot more pressure than your standard auto parts store worm gear clamp. When my buddy put silicone hoses on his truck, we used adjustable nut and bolt clamps. One they are much more heavy duty and two because the have a smooth metal band, it won't dig into the hose. He especially wanted this because silicone hoses are expensive. As long as you have a decent idea of size clamp you need, there easy to order. I've include pictures of two different clamps I mentioned.
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Brother, you have my wheela turning and I honestly going have re-read this one a couple of times. I ask for your patience because its like you handed me a rubik's cube and to solve it in the dark lol. One thing about heating the fuel, could a modified oil warmer rigged in the fuel line be a idea to work with or try out? Keep on and hope to hear more about your results.
The assumption, Claudio, is that existing mechanisms in the system will contribute to finding a highly efficient equilibrium alongside our Groove and whatever other mods we have applied to our cars.
one of the main byproducts of combustion is being given away right now - heat. think how much faster a modern car will enter closed loop fuel delivery if some of that heat is applied to the waterjacket. Theoretically that means less fuel burned to get to where the o2 sensors start telling the injectors to trim. also using that heat to warm the fuel before injection will probably mean that it vapourizes more easily, so hopefully that will encourage the computer to trim back pulse durations (the o2 sensors might just see a rich condition more consistently)...and this will theoretically cause the engine to run cooler...so it's not adding significant extra stress to the cooling system or causing premature ageing of an engine or or or. will it burn the oil? no idea. will antifreeze need to be changed more often or the mixture changed? maybe. one step at a time...and small steps at that, right?
you have to be prepared for (initially, while the computer HOPEFULLY learns the "new normal") the cooling system to dissipate what could be a LOT of extra heat on the way there., and in my case my electric fans turn on/of and kick into high gear at set points - I'm thinking it would be better for that to happen sooner, and I think that the best way to do THAT is to make my fans PWM controlled - so I don't melt my engine down to a block of aluminum if recycling exhaust heat into the water jacket/cooling system PLUS combustion heat pushes things to a limit I'd rather not face. and all of this means a cooling system that is fully intact - able to withstand pressures and dissipate heat. with electric fans, that also means added strain on the alternator.
so cooling system first, then warm the fuel...if you get a mileage improvement, THEN add the exhaust heat to the water jacket. Does that make sense to you?
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The following user(s) said Thank You: CLAUDIO CORDOVA
I was just reviewing the Thread here of the mods I've made to my Daily driver, and the successes I've had.
Ron made an interesting point
about the heat exchange that I think supports my theory/hypothesis about using exhaust heat to keep the coolant temp up:
"As the ambient (atmospheric) temperature drops, heat loss from the engine and the exhaust increases. The ECU will force over-fueling of the engine to compensate, as the temperature of the catalytic converter is considered an omnipotent command, overriding all other fuel delivery parameters."
(I've added the bold and italics)
In other words, if the Catalytic converter is seen to be getting too hot by the computer -presumably measured by the downstream o2 sensor(s)- the computer will step in to reduce fuel delivery to cool the reaction in the converter(s). I would assume that this would cause an "update" to the fuel map in the computer; I'm increasingly certain that there will be an "equilibrium point" achieved.