Cool Runnings - Lip Spoiler?

[rusgb]

Hi all (happy new year),

I got the lip spoiler put on to my Chimaera at the end of last year. I have noticed the bonnet wobble go (which was the plan) but also noticed a dip in running temperatures. This may be a good thing in the summer months but I have a slight concern.

This is my first winter with the car and it is not going above 50 degrees, even on a longer run. I drove down to Heathrow, usual 70~ mph cruise for 2hrs and the temp was below 60 the whole way. The mpg has also dropped off my about a 3rd. I guess this is due to a richer mix being pumped in whilst cool.

If I stop moving the temp will come up and the fans come on at the 87-92 ish range as they should... (this has happened once in about 3 months).

Has anyone else experienced this? Is this winter running or my new spoiler being too efficient or a broken temp sender somewhere?

Any help is always very welcome! Rus

[Tiredoldgeezer]

I have this at the moment, see my thread Ive got one Ive got one.... below this for some ideas from other guys Driven the car 250 miles in 2 days and the temp never got above 50

[Chris71]

Hi,

Slightly o/t, but can you quantify the drop in mpg; what did it go to/from?

[rusgb]

I used to get 250 miles before feeling I should refill. At which point, with what was left in the tank (7 litres ish) I was getting about 23 mpg. Now I am getting about 170 miles before the panic sets in and calculations point to about 16 mpg!

I always seem to fill 50 litres. I think it holds 57 - although one day I just about made it to the petrol station (to odd noises from the fuel pump in the boot) and put 57.5 litres in!

Rus

Calculations done here: http://www.torquecars.com/tools/uk-mpg-calculator....

[Chimpafrolic]

Its all here chaps:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by Chimpafrolic on Monday 17th January 15:00

[Chris71]

rusgb said:

I used to get 250 miles before feeling I should refill. At which point, with what was left in the tank (7 litres ish) I was getting about 23 mpg. Now I am getting about 170 miles before the panic sets in and calculations point to about 16 mpg!

That's about what I'm getting at the moment. I think winter temperatures just cause the fuelling to go haywire perhaps.

[Chimpafrolic]

Chris71 said:

rusgb said:

I used to get 250 miles before feeling I should refill. At which point, with what was left in the tank (7 litres ish) I was getting about 23 mpg. Now I am getting about 170 miles before the panic sets in and calculations point to about 16 mpg!

That's about what I'm getting at the moment. I think winter temperatures just cause the fuelling to go haywire perhaps.

When I first got my Chim (& before I fitted my rad blind) I also experienced a noticeable drop in economy in the winter months .

After fitting the radiator blind outlined in my link above I was back to 27mpg on a run with the original TVR 4.0HC chip (Or 25mpg on a run with the Tornado chip )

The added benefit is the heater actually works properly too

I can now drive my car on a freezing cold day without needing to wear gloves and a big winter coat.

Just a couple of weeks ago I went on a 200 mile run up north at a steady 80 leptons with the outside temperate hovering between zero & 1 degree.

The ice warning was active all the way but even in shirt sleeves the heater kept be very toasty

The other thing to consider is that cabin temperatures drop significantly due to cold air flow entering through the bulk head, the faster you go the more of the icy cold air gets forced into the cabin.

Just run the back of your hand around the dash and you can feel the cold air coming in, In my case it was at it's worse in the area of the stereo aperture (head unit fitted).

So you find yourself turning the heater up until it's on full, then if your car is running too cool that icy cold air forced into the cabin starts to beat the struggling heater.

I have now discretely blocked the lower half of my grill aperture (facelift model) which helps stop the wind blast entering the cabin and seems to have little or no affect on the cooling.

I got this tip from the Cerbera boys who also block off the two small apertures under the front indicators, apparently the icy draught gets forced into the inner wing area through these holes and ultimiately finds its way into the cabin.

If you do this and block off the right amount of the radiator the car will not only run better, it will deliver better economy and be much more comfortable to drive at speed in the winter months.

Hope all this helps?

[rusgb]

Great stuff, as always! Thanks for the help. You have eased some of my worries. I'll have a think about a rad blocker...

Do you know if there are mechanical downsides to the rich fuel mix being pumped in and to running a cold motor?

Rus

[Chris71]

Chimpafrolic said:

Blanking off part of the radiator

Hadn't thought of that! The heater is another good point - I've been running around with the hood up (desperately hoping no Griff owners see me doing so!) for the past few hoons as the heater is barely adequate with the roof off.

[Chimpafrolic]

rusgb said:

Great stuff, as always! Thanks for the help. You have eased some of my worries. I'll have a think about a rad blocker...

Do you know if there are mechanical downsides to the rich fuel mix being pumped in and to running a cold motor?

Rus

Glad it helps Rob & Chris.

To answer your question Rob, if you run too rich you are not only wasting fuel (& its way to expensive for that), but you are also washing the oil from the bores and that will significantly accelerate bore wear.

The unburnt fuel also ends up mixing with the engine oil in the sump significantly diluting it into an ineffective mixture that will struggle to do the job of lubricating the mains & big ends ect.

A rich mixture will also promote carbon deposits in the combustion chambers, this can also reduce the working life of your engine oil as one the jobs of the oil is to hold carbon in suspension ready for when you change it (that's why it turns black).

Other issues with an overly rich mixture can be fouled plugs, detonation (pinking) from glowing carbon deposits and poor performance.

To be honest I doubt you are running so rich that all this should worry you too much, running rich is not good but running too lean is truly disastrous.

Theoretically the perfect air fuel ratio for combustion is 14.7:1 (that's 14.7 parts of air to 1 part of fuel), this is according to the rules of stoichiometrics and is often hotly debated.

If your car is running too cool it will likely be running too rich.

The basic rule used by engine tuners is "run cool for performance, run hot for economy" but like most things in life its actually not that simple.

All you really need to do is get the engine to run as close to the 80 to 90 degrees window as you can at all speeds & during all ambient temperatures, the fuel injection system will do the rest.