Cold weather driving observation

The last few days its been getting colder in the mornings, down to 5C this morning. What I have been trying to do is understand what would/is pulling the mpg down. This morning I put my EBH on for 3 hrs so it got the engine over 40C (past stage 1) the car did not go through the 60sec warm up it and would glide straight away (this did surprise me). So instead of a warm up down my street to the main road I glided 50% of the way. So I assumed I would get a good first 5 mins which was OK about a good normal, but my main observation was that during the glide stages of my journey all was well and got a few 100mpg as normal, but in the stages where I would normally get between 60-70 UK mpg it was down to 50 - 60. As this was my normal route to work it is very predictable.

So to sum up what I thought would be the problem in the cold was the first 5 mins was actually the normal warmed up driving, any ideas what would pull the normal warm driving down. by the way I used the heater sparingly.

Another point I noticed was that the intake temperature was 16C at startup and very slowly over the first 5 mins dropped to about 9C which is about 4C above ambient. I was surprised how warm the intake temp was and how long it stayed above ambient. Could it be as simple as could intake air? (I have my upper grills blocked)

Thanks

Gary

 

<div class='quotetop'>QUOTE(efusco @ Sep 18 2007, 04:31 AM) [snapback]514193[/snapback]</div>

But what surprised me was that it did not do the 1 min warm up, the ignition angle went straight to +. so as I could glide a bit then had a slight incline which the ICE would have to be on so warmed the engine at that point.

Even with a warmed block do you think the engine runs rich, if so how can you tell when it is running normal. The reason I ask is that I thought the first 60 secs running negative ignition was when most the enrichment took place to warm the engine.

Also at what temp would you block more grills?

 

<div class='quotetop'>QUOTE(efusco @ Sep 18 2007, 05:11 AM) [snapback]514196[/snapback]</div>

Is it worth ensuring the battery is at a good SOC when you park up. I can EV the last half mile easily, but it pulls down the SOC 1 bar so the next morning it is about 3-4 bars. I could use the ICE or even force a bit more charge to ensure the next day the SOC is high, what do you think?

Also I posted the other day about taking intake air from behind the rad rather than the side of the engine bay, have you any thoughts on that? or in the could will the rad give of no heat at all. I might hook up a temp sensor to find any warm spots under the hood.

 

<div class='quotetop'>QUOTE(FireEngineer @ Sep 18 2007, 10:21 AM) [snapback]514288[/snapback]</div>

Thanks Wayne,

What I am trying to do is understand what pulls your winter mpg down, as I said this morning I got the engine upto 40C (stage2) with the EBH, so the first 5 minute mpg was just like a hot day or a day warm day with a little EBHeating. The problem was that for the next 30 minutes of driving the mpg was slightly down on a warm day, especially when you could not do a lot of gliding. The point is, is that the engine was a full temp most of the time, conditions were good so what pulled the mpg down, is it just the cold air on the intake. (I will double check TP)

I suppose where I am at is that I am happy I understand warm driving and how conditions effect my mpg (wind, rain, stages etc) I am trying to understand cold driving (temp, EBH, heater use) gives me something to done on my way to work each day, and saves me a lot of money.

Thanks
Gary

 

<div class='quotetop'>QUOTE(David Beale @ Sep 18 2007, 11:20 AM) [snapback]514320[/snapback]</div>

Thanks

Thats what I though but this morning the EBH got the start temperature to over 40C and it did not do the 30-60 second engine run. This is the first time I have got the engine that warm with the EBH. I will try again tomorrow to make shaw I am not mistaken.

Gary

 

<div class='quotetop'>QUOTE(FireEngineer @ Sep 18 2007, 12:53 PM) [snapback]514381[/snapback]</div>

Thanks I will check tire pressure.