in the summer you want a cold air feed, as the warm air is less dense then cold air
its a well known fact

since in the winter - cold dense air is been sucked in - the car has to fuel more to compensate to give a good fuel to air ratio

How about for the winter swapping to a warm air feed?
as surly it means it'll use less fuel - and since warm air fed in - it should help the engine warm up a little quicker

So possibly Getting a Hot Air Feed from Near / around the Mani-cat could save fuel this winter? Surly you only need a little pipe to just take it from A to B from the stock airbox?

Any thoughts on weather todo it or not?

ziggy

I think the hot air pipe from manifold is only to help with cold starting, helps get the engine up to tempurature quicker on cold mornings.

I think it would be better having a cold air feed all the time...

colinf1 said:

I think the hot air pipe from manifold is only to help with cold starting, helps get the engine up to tempurature quicker on cold mornings.

I think it would be better having a cold air feed all the time...

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I found my car sits for ages on the cold line - taking a few miles to start showing signs of warming up
so Surly giving it a little Hand will help esp with fuel on start up

I know cold air is the way forward - but will hot air running Be a problem? It'd be no different i believe if you ran a k&n filter ontop of the engine?

might take a few ponies away, but its wet and cold - you dont need more power

Ziggy

I think your theory is sound. Just needs to be tried .

On all EFI engines, the correct fuel/air ratio is calculated by the ECU using information from the engine temperature, and air inlet temperature sensors. If you were to "fool" the ECU by introducing hot air at the air inlet temperature sensor while the engine temperature was cold, it's likely that insufficient fuel would be injected to compensate for fuel that condenses on the cold cylinder walls. This could give you poor starting and poor driveability during the warm up phase.

Depending on the complexity of the OBD system, it may also generate an "implausibility" fault code.

Should be easy enough to rig something up on a temporary basis to test your theory though.
.

colinf1 said:

I think the hot air pipe from manifold is only to help with cold starting, helps get the engine up to tempurature quicker on cold mornings.

I think it would be better having a cold air feed all the time...

Click to expand...

The purpose of the hot air pipe (activated automatically or by a manually operated Summer/Winter lever on the air filter inlet of older cars) is to prevent ice crystals forming in carburettor venturis and some SPI injector housings. It doesn't help with cold starting.

If you think about it, when starting the car, the manifold, and therefore the air around it would still be cold so there would be no advantage.

Davren said:

The purpose of the hot air pipe (activated automatically or by a manually operated Summer/Winter lever on the air filter inlet of older cars) is to prevent ice crystals forming in carburettor venturis and some SPI injector housings. It doesn't help with cold starting.

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Essentially to prevent something like this


OP I'm sure Fiat factored that aspect when designing the car in the first place

Yes soon as the engine is starting - its Running cold all around
but really takes about 30seconds for the engine to emit enough fumes to heat the mani-cat up a little bit

if the engine then started sucking in that heat as well - surly it'd okay

I realise it used temp sensor and Lamba to tell what to mix up
But surly if the car is sucking warm air in - it knows that?
So it knows less fuel is needed?

Ziggy

At the end of the day it's all about mass - getting as much air in as possible with the correct mass of fuel. Miles per kg makes more sense than miles per litre.
Induction systems use MAF mass flow meters and turbo inductions use coolers to get the density up so there is more air in the cylinders.Heating the induction just reduces the power available and efficiency of the process. Fuelling systems add whatever is required for the mass of air in the pot.
In the old days you had to switch over to warm air for the winter to avoid carburettor icing and you always lost three or four mpg as a result. If you forgot, the car would just die on the open road.

So really - its not worth it?

Shame - as the idea is great esp to save money, but really when its broken down it just makes it worse?

maybe just worthwhile unclipping the Nozzel off the end and leave it there, that way it gets only a touch wamer and we'll have to see if that work or not

Ziggy

Never trust theory - do it yourself and see what happens - then your talking from experience. It's not beyond the bounds of possibility that a little warming could improve things - only one way to find out.

whats the reason behind people putting there standard air box back on in winter?

and keep there gsr untill it gets warmer again

Butcher said:

whats the reason behind people putting there standard air box back on in winter?

and keep there gsr untill it gets warmer again

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coz you use a ton more fuel

I never noticed the difference.. Did use a little more but then I had lots more power.

People are paranoid about sucking up water / slush which is plain rediculous.

You will get a more efficient burn using cold air as its more dense so contains more oxygen mass than warm air. Apart from on a very cold engine, this more than out-weighs the thermal losses.

You're more likely to save a wee bit of money (and improve engine life) by blanking off some of the radiator.

If the thermostat is working it wont make any difference and you risk it overheating in a traffic jam. If the 'stat is in doubt flush the system and fit a new stat along with some decent antifreeze..

WhiteSei said:

If the thermostat is working it wont make any difference and you risk it overheating in a traffic jam. If the 'stat is in doubt flush the system and fit a new stat along with some decent antifreeze..

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Stat is brand new when i replace HG about 1.5months ago
refilled with a Nice Strong mix of about 50/50

As i think my old one was sticking a little bit untill engine got really warm - so slowly kept cooking the HG
But its just a thoery as the head didnt warp, so why my HG blew no1 knows - just age proberbly

Ziggy

WhiteSei said:

If the thermostat is working it wont make any difference and you risk it overheating in a traffic jam. If the 'stat is in doubt flush the system and fit a new stat along with some decent antifreeze..

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How so?

A stat is either open or closed. If it is closed there is no flow to the radiator (or, on most cars, the heater).

Most stats open at around 87C. This is about the bare minimum for oil to operate efficiently. Ergo, the less cooling air that is available to the rad (blanking part of it off) the quicker the oil will heat up (something like 100 - 105C is optimum for the oil). This reduces engine wear and increases fuel efficiency.

Of course, there is a potential risk of overheating in traffic, which is why I say partially blank it off.

In days of yore, all the better cars had perfectly good thermostats and thermostatically controlled radiator blinds....................

the problem i had is the outside temp was soo cold
When sat in traffic when it was cold - having the heaters on full blast to keep me and the car warm / clear, that my temperature gauge would start going back down
As the extreme outside is too much
I do think yes possibly blocking on Section on the Grill Style bumpers would be better
As there will be plenty of air flow - if car gets too hot the fan will kick in When sat in traffic

Ziggy

I did this on one of my old cars a while back because it was seriously overcooling, tried thermostat etc but no better, so i just took the pipe off the intake of the air box so it fed from the bay and it worked great,
faster warm up better heater
Also don't forget a car runs on basically "choke" till the engine gets past a certain point so it'll eat fuel and if ran cool for long will cause possible blow by and head gasket going
So i say go for it, end of the day we were dealing with -22 at one point and show me a car that will over heat in that kinda temp.

Tell you what also works like a treat, a K&N induction kit, sit's straight onto the throttle body and pulls lovely warm air in, don't sound too bad either.