pre heater on L series

[spike]

ok so my pre heaters gone and every other car i have here its gone too, im not interested in going and buying a new genuine one or even a second hand (if i can find one) does anyone have any other options and ideas?
i was thinking a mandrel bend stainless steel with silicon hose but im not sure that will work.
options?

[purp]

Are you talking about the air intake pipe that takes warm air from near the exhaust?

[spike]

yep thats the bit, ive always known them as pre heaters, but i suppose warm up pipe sounds good too

[purp]

The one I have is very flimsy foil and wire type thing. I would have thought a brand new one would be a lot cheaper than stainless steel and silicon hose?

[fredsub]

unless if your in sub 15degC region much, I doubt the pre-heater does much good.
Cooler air, means more dense air, more oxygen hence improved combustion and more power. I recall removing mine on the L, and not being the worse without it. Has me now thinking, there is no preheater on the EJ engine ?

[spike]

yes the ones i have lying around are basically a foil tube, cant remember the wire though. the reason i dont want a foil one is that they never seem to last, even if i can get another one
Main reason is for start up, the carby has a choke but to help the choke it sucks pre-heated air. On the Ej all where fuel injected and totally computer controlled this is why i believe it doesn't have the need for the pre-heater.

from a performance point of view maybe your right, the maximum weve had around here lately has been around 20 which is ok at 3 in the arvo but im leaving early and getting home late. Also in a quest for fuel economy this will save using the throttle on start up

[fredsub]

the pre-heater relies on exhaust heat, so at start up that reason is typically
moot.
and so just use less throttle at start if your worried about economy.
The biggest factor in your fuel economy is your driving foot you know......

[purp]

unless if your in sub 15degC region much, I doubt the pre-heater does much good.

Sub 15 much? It has barely been getting above that at mid day here...

[olddog642]

[quote="spike"]yes the ones i have lying around are basically a foil tube, cant remember the wire though. the reason i dont want a foil one is that they never seem to last, even if i can get another one

I got one for Scamp from a well known parts and accessory joint it lasted for ages and didn't cost all that much. From memory about $6 for a metre precut length.
Hylton

[spike]

the pre-heater relies on exhaust heat, so at start up that reason is typically moot.

actually you have a reason i never figured that..........

[Busdriver]

An added benefit of this tube was to prevent a phenomenon known as carby ice, whereby in cold climates and at constant throttle openings, as in cruising down the highway, the combination of high levels of moisture in the air and low atmospheric pressure in the carby resulted in idle jets that were iced over and cars that would stall when the throttle would be released. Naturally fuel injection fixed this problem. Also used to happen to a Kawasaki that I had, watercooled of course.

[Silverbullet]

That is true, also happens/happened in airplanes with carby engines. I think this is why there is a coolant channel leading directly to the base of the carbie, at least in the EA81's, I'm assuming the 82' still has it?

Something I'd like to know about the pre-heater pipe; is it directing warm air into the air box all the time? From memory there is a solenoid type thing at the top of the pipe in the air-intake snorkel part of the air box so I'd assume the answer is no. But on mine there is nothing, does that mean I'm losing out on a precious few HP from my engine?

[Busdriver]

You are right Silverbullet on both counts, there is a coolant chanel under the carby on EA82's and that all horsepower from these engines are precious. Also, they did have a flap to shut off the preheater flow and bring in fresh air in warmer climes, because as mentioned above that cooler air is denser and therefore prone to delivering more power when burnt inside the engine.

[spike]

An added benefit of this tube was to prevent a phenomenon known as carby ice, whereby in cold climates and at constant throttle openings, as in cruising down the highway, the combination of high levels of moisture in the air and low atmospheric pressure in the carby resulted in idle jets that were iced over and cars that would stall when the throttle would be released. Naturally fuel injection fixed this problem. Also used to happen to a Kawasaki that I had, watercooled of course.

yes thats one point, had that happen to me on the suzuki last year (mighty mouse, motorkahana car) when you feel it happening all you can do is open the throttle wider, then wider so you run on the secondary only (yes i was sitting at 140)There is a water passage in the air intake to fix this problem on the subaru but then you need to take into account lost power when its not needed due to heating the intake charge.

silver bullet- yep you want to be sucking cold air when you can and warm when you need. Im not sure what the go with the twin carb is, but when i get bored and build one it wont have anything to compromise it

[discopotato03]

The idea of these air heaters is purely one of cold running drivability with typically leanish mixtures . Fuel turns to a vapor more easily in warm air and single carburettors and manifolds were never the ultimate air and fuel distributors (between cylinders) it all helped . You should view a single carburettor as a "wet" manifold system where multipoint injection sprays atomised fuel typically directly at the inlet valves . Manufacturers went through all kinds of contortions trying to get carbys to meter fuel accurately and keep it in suspension all the way to the chambers . If the manifold wasn't warm the fuel would try to drop out of suspension and condense on the internal walls , fuel arriving as big drops doesn't burn properly and just goes through the engine as unburnt hydrocarbons .

Water heaters are used to stop icing the throttles in places that are cool and humid . High air speed through small throttle openings is the cause .
Also BTW fuel injected engines often have throttle heaters for the same reason .
With part throttle cruising charge air temp is not so important , at full throttle the air doesn't spend enough time in the TB to make much heating difference .
None of these EA engines is going to give stellar fuel consumption in std form . No ones going to sink thousands into high tech engine management systems for them because its not economically viable .
With running costs its $ per Km that the focus not mpg or L/100Km . If you got 40 mpg on expensive race fuel it wouldn't make for economical running cost wise .

A .

[spike]

oh god now where getting into thermal dynamics again...... ive been talking to gill cameron too much about the whole rough versus smooth thing.

i didn't expect that FI engines would need them, being so close to ports.
oh i understand that im not going to beat any records in it, im basically looking at saving money to upgrade for next years season (had to duck out this year due to funding at lack of navigator)

but that last sentence has me, there is some talk that the use of premium fuel and the added modifications that can be allowed with it are more economical than using poorer quality fuel.
This doesn't mean that i will be using the AVgas or elf in it, you can only get a very limited supply so it inst worth it, but premium pump fuel may be.

[El_Freddo]

I say just get a cheap replacement pipe and be done with it.

As for best economy I've heard recently from a mate that his research found the EA82s ran most economically when run on the lowest grade of fuel you can find at the bowser and leave out the cool running thermostat. These engines were not designed to run on 98RON because it was not around at the time.

My 5c

Cheers

Bennie