Rogue
Well-known member
How about a pad on the side of the tank, like on an old Brit bike?
The Thigh Burner
- Thread starter double_entendre
- Start date
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Yea, thinking about it 130 is pretty warm against skin so maybe the hot fuel returning to the tank might make the tank feel warm. I still don't think this is the real source of the "hot tank" problem, though, because the air blowing thru over the top of the engine is a lot hotter than that. I think the hot air heats the tank more than the returning fuel and as the tank empties there is more of the tank metal that is not kept at the fuel temperature. The part of the tank above the liquid will get as hot as the air flow over it.
I'll mention it again that I sealed up the panel behind the radiator so that no hot air from the rad or from over the exhuast pipes can get thru to the top of the engine or the tank area and improved the hot air removal from the fairing with the spoiler tabs added to the gill area and completely eliminated any heat problems. I'm not cooling the fuel at all but my tank stays pretty much at ambient temperature from what I can feel. The bottom of my tank is insulated with the oft mentioned blanket but if hot return fuel were the problem you would think that the insulation would keep the heat inside the tank making it warmer instead of cooler....
The idea of cooling the fuel is certainly worth a try to see what happens with no other modifications but I don't think it will do much for tank heat and there are certainly easier ways to beat the heat than rigging up a fuel cooler circuit. The other point is that cooling the fuel to make more power or anything like that is pretty much BS unless it prevents another problem like vapor lock.
It is interesting that hot fuel actually makes MORE power in many applications. The ultimate goal in any induction system is to introduce the fuel and get it completely atomized by the time the spark plug fires. Contrary to popular belief port fuel injection is not particularily good at atomizing fuel. Not very good at all. Given the goal of atomizing the fuel down to the molecular level the fuel injector squirts in gobs of fuel. The atomization comes from heat and mixture motion/turbulence. Port fuel systems inject when the intake valve is CLOSED to get the most dwell time for the liquid fuel on the hot intake valve and intake port walls for maximum vaporization before the intake valve opens and the intake charge starts to move into the cylinder. Additionally, working against the process of creating a nice homogeneous charge inside the chamber at ignition is the fact that all the fuel for that charge enters the cylinder with the very first moment of air as the valve cracks open. The rest of the charge is pure air that has to then mix with the fuel inside the chamber. This is why carbs worked so good as they metered fuel continuously into the charge creating a more homogeneous mixture continually flowing into the chamber. Which gets us to the point of why "hot" fuel works so well in fuel injected engines. The hotter the fuel is when the injector opens the more it flashes into vapor as it enters the port from the injector. The more atomization that occurs here, the better the homogeniety of the charge is and the more complete the burn and the more HP the engine will make. I worked with some guys running drag cars many years ago that set and held NHRA records in pure stock that actually ran "fuel heaters" by winding coils of fuel line around the radiator hose to preheat the fuel so as to make it vaporize quicker on injection. Those were throttle body injected cars but the idea is the same. It would always blow the other drag racer's minds who were used to cool cans and cooling the fuel as much as possible to see the fuel heaters on those cars.....LOL.
I'll mention it again that I sealed up the panel behind the radiator so that no hot air from the rad or from over the exhuast pipes can get thru to the top of the engine or the tank area and improved the hot air removal from the fairing with the spoiler tabs added to the gill area and completely eliminated any heat problems. I'm not cooling the fuel at all but my tank stays pretty much at ambient temperature from what I can feel. The bottom of my tank is insulated with the oft mentioned blanket but if hot return fuel were the problem you would think that the insulation would keep the heat inside the tank making it warmer instead of cooler....
The idea of cooling the fuel is certainly worth a try to see what happens with no other modifications but I don't think it will do much for tank heat and there are certainly easier ways to beat the heat than rigging up a fuel cooler circuit. The other point is that cooling the fuel to make more power or anything like that is pretty much BS unless it prevents another problem like vapor lock.
It is interesting that hot fuel actually makes MORE power in many applications. The ultimate goal in any induction system is to introduce the fuel and get it completely atomized by the time the spark plug fires. Contrary to popular belief port fuel injection is not particularily good at atomizing fuel. Not very good at all. Given the goal of atomizing the fuel down to the molecular level the fuel injector squirts in gobs of fuel. The atomization comes from heat and mixture motion/turbulence. Port fuel systems inject when the intake valve is CLOSED to get the most dwell time for the liquid fuel on the hot intake valve and intake port walls for maximum vaporization before the intake valve opens and the intake charge starts to move into the cylinder. Additionally, working against the process of creating a nice homogeneous charge inside the chamber at ignition is the fact that all the fuel for that charge enters the cylinder with the very first moment of air as the valve cracks open. The rest of the charge is pure air that has to then mix with the fuel inside the chamber. This is why carbs worked so good as they metered fuel continuously into the charge creating a more homogeneous mixture continually flowing into the chamber. Which gets us to the point of why "hot" fuel works so well in fuel injected engines. The hotter the fuel is when the injector opens the more it flashes into vapor as it enters the port from the injector. The more atomization that occurs here, the better the homogeniety of the charge is and the more complete the burn and the more HP the engine will make. I worked with some guys running drag cars many years ago that set and held NHRA records in pure stock that actually ran "fuel heaters" by winding coils of fuel line around the radiator hose to preheat the fuel so as to make it vaporize quicker on injection. Those were throttle body injected cars but the idea is the same. It would always blow the other drag racer's minds who were used to cool cans and cooling the fuel as much as possible to see the fuel heaters on those cars.....LOL.
double_entendre
Well-known member
Christ. Even odot wouldn't put minipads on the sides of his gas tank.
:lol:
*grins, ducks & runs*
Bob
Huntington Beach, CA
I'll reply back to the rest when I'm more sober & coherent
but in the meantime, I'll give you $100 if you can persuade someone on the Forum to put a Sterno can under his tank to try to increase HP. :lol: Bob
Huntington Beach, CA
JimLor
Well-known member
jestal - can you provide a little more information on sealing the area behind the radiator? Such as, what area, what material did you use? I've got the front wheel/forks off right now and this would be a great time to try this out.
Thanks. Jim
Thanks. Jim
Sure. It is pretty invasive to get to the area I'm talking about which is why not many people have looked at it I'm sure.
With the lower fairing parts off you can see the radiator and the mounts for the radiator. When you remove the radiator you can see a black plastic panel above the radiator. It is curved and fitted (somewhat) to seal off the area between the top of the engine and the frame and to duct the air coming thru the radiator downward and out the gills in the lower fairing. That curved plastic piece does not seal well on any of the mating surfaces. To remove it take out the screw on each side. The plastic part also routes hoses and wires so it is a bit of a pain to remove and install but that is also part of the reason that it doesn't seal well.
I had the whole thing out and could view it easily to discover all the gaps. One problem is that the plastic piece is only supported on the very ends so it tends to sag or bow a little in the middle opening up more gaps. First thing I did was to pop rivet a straight piece of 1/4 inch angle iron aluminum across the bottom of the plastic to make it straight and rigid. I sealed the back side of the plastic to the cam cover with a piece of automotive high density foam tape. Additionally, I drilled two small holes in the panel and laced a tie wrap thru the panel and around one of the coolant fittings to draw it back firmly against the cam cover in the middle where there were no fasteners before. The top edge of the panel I sealed with more foam tape around the edge. Several of the holes for hoses and such were filled with bits of foam tape. Once reinstalled with the modifications and tie wrap in the middle the panel looks just like it did before but seals off the area above the engine completely so that the hot radiator air and air from the pipes has to go out the gills.
This augments and completes the "cromits heat fix" that has been described before for the sides of the engine and fairing. The other mods just didn't go far enough as they left the main source of hot air around the upper panel wide open.
Add the little spoilers to the gills to help suck the hot air out where it is supposed to go and you are good to go. https://www.fjrforum.com/forum//index.php?s...amp;hl=spoilers
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JimLor
Well-known member
Thanks jestal!
