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[Webby the Bear]

as per title... and we're talking about the car not me, although after the amount i've scoffed this weekend (weekend away) i feel very fat 

i've been testing the car lots and lots, especially performance... i want to make sure that since the top end rebuild it's running well. i'm touch wood completely satisfied that it's running well. had a trip to cambridge at the weekend and it was running beautifully,

i got this little issue though....

when i first start it up i expect there to be immediate power if i demanded it. so cold start from overnight, then immediately floor it..... when i do this it feels ever so slightly lethargic. it will go, but theres just that little bit lacking. as soon as its been running for 5 mins its fine and will kick down and bomb when i want it.

however am i being a bit too expectant of a 14 year old car or am i right that it shouldnt be lethargic at all?

are omegas like this? are other cars like this? is there saomething wrong.

your thoughts as ever greatly appreciated

[Broomies Mate]

Don't do it.  Engines and Transmissions are not designed to be thrashed when cold.

In answer to your question, the Transmission is more sluggish when the ATF is cold. 

[Entwood]

as per title... and we're talking about the car not me, although after the amount i've scoffed this weekend (weekend away) i feel very fat 

i've been testing the car lots and lots, especially performance... i want to make sure that since the top end rebuild it's running well. i'm touch wood completely satisfied that it's running well. had a trip to cambridge at the weekend and it was running beautifully,

i got this little issue though....

when i first start it up i expect there to be immediate power if i demanded it. so cold start from overnight, then immediately floor it..... when i do this it feels ever so slightly lethargic. it will go, but theres just that little bit lacking. as soon as its been running for 5 mins its fine and will kick down and bomb when i want it.

however am i being a bit too expectant of a 14 year old car or am i right that it shouldnt be lethargic at all?

are omegas like this? are other cars like this? is there saomething wrong.

your thoughts as ever greatly appreciated

VERY bad idea .. ALWAYS allow an engine to fully warm up BEFORE making it work hard ... allows oil to reach all the right places, minimises temperature/pressure stresses within the engine and actually makes the engine run better. A cold engine will suffer from fuel condensing in the inlet, so not reaching cylinders in the correct fuel/air mix - think why we used to use a choke flap to reduce airflow, now all done electronically.

Basically, what you are doing is BAD NEWS for the engine, both in terms of performance and longevity.

and that's before we talk about transmissions ......

Watch any motorsport, they ALWAYS fully warm the engines before doing anything with them.. for a reason

[Webby the Bear]

Thanks Entwood. i thought this so its not often i do it. but i did it this morning just for testing purposes.

so basically its normal to have this lethargy until its all toasty uner the hood?

[Entwood]

Thanks Entwood. i thought this so its not often i do it. but i did it this morning just for testing purposes.

so basically its normal to have this lethargy until its all toasty uner the hood?

Yup ... the fuel is injected before the inlet valves .. if the inlet valves and surrounding metal is cold the fuel will condense and remain outside the cylinder, therefore there is too little fuel in the cylinder when it fires giving reduced power.

Add to that the fact that cold air has a greater mass than warm air, and the engine actually needs MORE fuel not less to run better ..

In the old days, open the choke flap too early and the engine stalled for the same reasons. The choke reduced the amount of air so maintaining the fuel/air ratio .. all done electronically now.

Best way to use a cold engine is a light throttle for a few miles, sitting idling doesn't get the heat in fast enough, heavy throttle works the engine too hard ... so light use until the temperature is up to normal... that way the whole engine is in the right condition to do some serious work ...

[Webby the Bear]

Excellent explanation! thanks mate. ill go easy in the mornings now 

[Andy B]

....
In the old days, open the choke flap too early and the engine stalled for the same reasons. The choke reduced the amount of air so maintaining the fuel/air ratio .. all done electronically now. .....

Ah! The old manual choke ....... and then there was the so called much improved auto chokes, so improved that there was generally a manual conversion for them! 

[05omegav6]

Excellent explanation! thanks mate. ill go easy in the mornings now 

At the very least you should wait for the tempgauge to move

....
In the old days, open the choke flap too early and the engine stalled for the same reasons. The choke reduced the amount of air so maintaining the fuel/air ratio .. all done electronically now. .....

Ah! The old manual choke ....... and then there was the so called much improved auto chokes, so improved that there was generally a manual conversion for them! 

Don't even get me started on Solex carbs I have only ever stalled two automatic cars, both 2.8 carb Granadas one was mine, the other I was considering buying, must have stalled 15 times in a mile

[Andy B]

Excellent explanation! thanks mate. ill go easy in the mornings now 

At the very least you should wait for the tempgauge to move

....
In the old days, open the choke flap too early and the engine stalled for the same reasons. The choke reduced the amount of air so maintaining the fuel/air ratio .. all done electronically now. .....

Ah! The old manual choke ....... and then there was the so called much improved auto chokes, so improved that there was generally a manual conversion for them! 

Don't even get me started on Solex carbs I have only ever stalled two automatic cars, both 2.8 carb Granadas one was mine, the other I was considering buying, must have stalled 15 times in a mile

I have to admit that once I'd set up the auto choke on my Cortina's twin down draught Webber it worked reasonably well ..... once I'd discovered that there were bits missing from it. 

[philhoward]

I agree - no gunning until the temp gauge moves (at least).

Could be that it runs a limited map until it's got "some" heat into it?  I recall the autobox on my old 2.0 deciding that holding the lower gears was a good idea (was for the cat, I guess) - didn't do the rest of the engine any good (died shortly after - as did its replacement..) so I used to use the winter setting for the first half a mile to stop it doing it. 

[slowboy]

ditto to rest

[Nick W]

I have to admit that once I'd set up the auto choke on my Cortina's twin down draught Webber it worked reasonably well ..... once I'd discovered that there were bits missing from it. 

That was my experience with the various Pinto engines I had; set it up according to the manual, and forget about it. Not worth converting to manual when it works so well.

[omega3000]

Best way to use a cold engine is a light throttle for a few miles, sitting idling doesn't get the heat in fast enough, heavy throttle works the engine too hard ... so light use until the temperature is up to normal.

+1 

You fancy another re-build steve  Besides engine sounds snarly when cold 

[Webby the Bear]

Best way to use a cold engine is a light throttle for a few miles, sitting idling doesn't get the heat in fast enough, heavy throttle works the engine too hard ... so light use until the temperature is up to normal.

+1 

You fancy another re-build steve  Besides engine sounds snarly when cold 

  not really mate. but I just assumed it *should* go well from cold and I thought that as long as I had good oil pressure then there wouldn't be a problem in caining a cold engine........ im still learning though