We're having trouble getting 5 minutes out of a tank. I that the fuel we use is the culprit; but it makes our engines run cooler, and have the maximum nitro content allowed in Australia. We don't want to change fuel, so we are looking for way to stop us running out of fuel on the last lap without re-fueling. Do exhaust coolers really work to improve fuel economy?

I'm not the smartest cookie around, and I have trouble understanding how it could. The pressure at each end of a hose will be equal at both ends to my way of thinking; regardless of its length, or devices between either end (other than diaphragm valves).

Could someone enlighten me about this, or has anyone had experiences where exhaust coolers have definitely helped?

Kindest regards,
Lars,

Picture of exhaust cooler: If the pictured doesn't show, it can be found by clicking on this link: http://i498.photobucket.com/albums/r...austcooler.jpg

Kindest regards,
Lars.

the question everyone will ask is
what motor
what manifold
what exhaust
what glow plug
what head shimming
is there any mods done to the motor....

the exhaust cooler only gives a few seconds that is all.
engine temp is different for every motor do not be to concerned about it tune preformance not temp.

That's exactly what I would have thought about the exhaust cooler; but it would have put us across the line at Bayside on Sunday, and it is cutting it too fine. No mods, JPI exhaust & manifold (don't know which number), O.S.TZ, O.S.P7 plug (perhaps too cold?) No head shims. Perhaps we could still lean the top end a bit more, its not getting too hot.

Would an O.S. tuned pipe, or a hotter plug help you think? We usually run a Jammin Hyper EFRA 2645 exhaust; as it seems to make the engines run faster, but we're having the same fuel economy problems with that exhaust. We're planning to be at Brendale on Sunday, will you be there?

Kindest regards,
Lars.

Add a head shim; go leaner.

Few things to look into
Clutch And Gearing also affect the run time . And Can alter run time btw 5 to 40 sec . Also not having the bottom needle right effects run time majorly . Economy comes from bottom needle . A bigger exhaust gas outlet on the pipe will give more power but at the cost of run time another thing to look into for run time .

nova or Max 2601 or 2604 with med conical manifold should help. i have used 2652 nova pipe, and i dont get much more power but it uses more fuel. i really think these 2640+ pipes are really aimed for use with Ins Boxes.

added head shim can add more top end revvs, that with leaner mixture, a long straight could see other problems. OS TZ unmodded shold make run time easy, try different pipe and manifold, i have gained 20secs plus just from going back to the 2601.

You can also try non conical manifolt...

]Many thanks to those that contributed to this, I have learned a lot from it. I did not know that most of the fuel economy comes from bottom end; thanks for that info, it makes sense to me. However; I feel that the bottom end is right, it’s set where the revs are just starting to increase at about 1mm throttle from low idling speed, and it gives instant response from low idling speed or higher idling speed (http://www.infinity-hobby.com/main/a...rticles_id=172) at starting. I never muck around with the mid range needle, as I have no idea of how to set it, could adjusting that help?

The gearing and clutch settings are also obviously very important for fuel economy; but the gearing and clutch settings have been set to what my boy wants, after some testing. We don’t really want to change it; I’d be more comfortable with an extra fuel stop than to change to something he’s not 100% happy with.

I will add a shim and get a 2601 exhaust with 5 & 7 fin manifolds, and try that. Also the engine could possibly run with a little leaner top end.

It is interesting that not many here seem to be convinced that exhaust gas coolers would be a significant help to fuel economy. I found an article about it with an actual test from RC Tech Magazine () , after I started this thread. It claims that run time in a helicopter increased by about 33%, and theorises of how it makes it better. Interesting reading; I’m still a sceptic, but we will use exhaust coolers from now on.

Kindest regards,
Lars.

I know this kinda of an old thread..

But does anybody knows who besides novarossi makes the exhaust coolers?
Nova's are way too expensive

Titan make one is around $16 U.S