Modded Mustang Forums banner

1 - 15 of 15 Posts

·
Scoot'in
Joined
·
1,201 Posts
Discussion Starter #1
I was just wondering now. How much can you rev your engine when its cold. I think I heard thru the grape vine that you should'nt really do that too much.....

:dunce:
 

·
Registered
Joined
·
1,107 Posts
Don't rev it until it warms up. At least let it warm up a little. There is a lot of moving parts and different metals that expand at different rates. I see so many dumb shits rev the crap out of their engine right after starting it up :facepalm: Another thing I hate is when people slam it into Drive as soon as they fire it up:facepalm: You wouldn't jump out of bed and run 10 miles without stretching first, right?
 

·
Registered
Joined
·
56 Posts
Just curious.. What makes you wonder about this?? I wouldn't recommend revving a car up when cold but im not gonna lie ive done it before lol. Normally i wouldn't rev it up past 2000 rpms if it was cold though. When I start my car up I just let it do its thing till its warm, no need to rev it, but sometimes my car use to serge (I think that's what it's called) and fluctuate its idle when warming up


Sent from my iPhone using AutoGuide.com App
 

·
It'll buff out...
Joined
·
5,379 Posts
Just curious.. What makes you wonder about this?? I wouldn't recommend revving a car up when cold but im not gonna lie ive done it before lol. Normally i wouldn't rev it up past 2000 rpms if it was cold though. When I start my car up I just let it do its thing till its warm, no need to rev it, but sometimes my car use to serge (I think that's what it's called) and fluctuate its idle when warming up


Sent from my iPhone using AutoGuide.com App
I wonder about this also, mostly because its freezing out side and it takes a 2000 v6 at least 20 minutes to warm all the way up
 

·
Registered
Joined
·
2,561 Posts
It's just not good for your engine. It takes a while for everything to get lubricated properly and warm up. Most wear on your engine occurs during start up anyway.
 

·
Scoot'in
Joined
·
1,201 Posts
Discussion Starter #6
Ya I kinda knew that you shouldnt rev it hard initially... let it warm up.. but I have no apprehensions in driving off after I start up. I am not going to sit and wait for the car to warm up before driving....
 

·
Registered
Joined
·
2,561 Posts
Ya I kinda knew that you shouldnt rev it hard initially... let it warm up.. but I have no apprehensions in driving off after I start up. I am not going to sit and wait for the car to warm up before driving....
It's not like you have to sit for 10 minutes, let it idle at least a minute or two before you begin driving. I typically start my car as soon as I get in that way it's warming up while I get situated. Still though, I don't get on it until my water temp is up to normal temperatures.
 

·
Registered
Joined
·
401 Posts
I jump in my car, start it, let it run for about 30 seconds and off I go. These aren't 1960's cars that have to sit for an hour until warm. The biggest reason those cars needed to warm up was because as soon as you threw them in drive they'd die on you. We have the advantage of fuel injection and as long as your oil is flowing you're free to begin you commute! No way I'm wasting 2 or more minutes of my life every day to warm up a car that simply doesn't need it.

Now, sitting there revving a freshly started car to the moon is just idiotic! I see ricers do this all the time. They'll start their cars from dead cold and bounce it off the limiter a few times.
 

·
Registered
Joined
·
3,352 Posts
Now, sitting there revving a freshly started car to the moon is just idiotic! I see ricers do this all the time. They'll start their cars from dead cold and bounce it off the limiter a few times.
There was a kid at work that did this with his Accord, ALL THE TIME. Said it sounded cool and then races off like an angry bee. He paid the price and blew his engine. I warned him.

Let the engine warm up a bit before speeding off. I wait for the idle to level out before driving off. Even then i go easy for the first few miles. Your engine will thank you in the longrun. So will your wallet.
 

·
Admanistrator
Joined
·
13,320 Posts
What's the science/mechanics behind that higher revving time before the engine levels off in RPM's? When I start it in the mornings the RPM's are about 1250 ish (give or take, but definitely higher than normal) for about 30 seconds, then they level off to ~800.

I assume it's to help get everything lubricated and warmed up, but does anyone know the specifics?
 

·
Want Camels?
Joined
·
1,041 Posts
What's the science/mechanics behind that higher revving time before the engine levels off in RPM's?
I know basics also, one of the reasons as you said, is too lubricant and warm up, but the cold start as far as I know happens so the engine sensors can wake up, it starts at high rpm's so more fuel and air can go inside until all sensors are connected with the computer or whatever.. I believe in this actually because in my dad's Benz it takes less time to go from high to low rpm at start, modern sensors/computers wake up faster than previous/older models
 

·
Bo Baustin
Joined
·
13,134 Posts
I'm trying to recall a thread I read like 6 years ago on the CBR forum... I can't remember exactly but it seemed like when the car is warm and running, the crankshaft actually floats on oil between the bearings. When it is cold it has contact with them. So reving a cold engine would effectively increase engine wear when there is the most of it.
 

·
Registered
Joined
·
3,352 Posts
The way i see it is this. Cold oil is thick and doesnt flow very well. It most certainly wouldnt circulate very well. The engine will get hot but oil circulation is less than ideal. Oil thats been warmed up starts to flow much easier. It would then circulate much easier. The oils serves as a lube and also regulates heat (much like coolant). Letting the engine idle for a minute helps both the engine and the oil. Gaskets expand with heat and contract when cold. Speed off with a cold engine and those gaskets may not do thier job. Maybe they will but maybe they wont. Why chance it? A cold engine with cold oil revved to high hell could sputter and die. Why? How? With little to no oil circulation, parts can overheat and the engine could sieze up. This is bad for any engine whether its made of iron or aluminum. Parts can bend and/or break. Do yourself a favor and let the engine warm up for atleast 30 seconds to a minute. The engine really does depend on it.

What about the idle? Letting the idle settle lets the computer run through its cold start tables. There are different tables for cold and warm starts anyway which is why the idle is high when cold but 'normal' when warmed up. The a/f ratios have changed. You could drive off right away if you really wanted to, the computer should be able to compensate. But way back when i drove carb i had to let it 'kickdown' before driving off. Maybe it was just the tune as it was a beat 81 Granada with a straight six. Ive been letting the idle settle ever since out of habit really, even with EFI. But if it gives the oil time to warm up, its a win in my book.
 
1 - 15 of 15 Posts
Top