PyroFlick

I've searched this topic, and found a few vague references to not hitting VTEC until engine is warm, but I haven't been able to ascertain how warm (time or bars on meter).

Also, if you hit VTEC when cold, is this bad on the engine, or will it protect itself?

TIA

Tugz_S2K

3 bars....if cold it will protect itself.

jwa4378

Engine will stop you if the car is not warm enough. Wont rev past 6K or so. Wait til you got 3 bars on the engine temp. You dont want to be winding out a cold engine.

Wait for 3 bars.

Wisconsin S2k

depending on how cold the engine is, you may even want to wait a few more minutes even after you have reached 3 bars. while the ECU will let you vtec once the coolant hits 140F your oil may or may not be warmed up properly at that point, so some advise to wait just a little longer.

Bane

I wait till the transmission starts shifting like butter before I engage VTEC. This is usually 5-10 minutes longer than when the engine coolant is up to temp. The transmission oil is about the same viscosity as the engine oil, so I figure it's a good (and relatively safe) estimate.

PyroFlick

Thanks for the useful info. Don't know why this isn't in the owner's manual.

Been an owner for just over a week and loving it

xviper

It doesn't have to be. Honda has made sure you don't hurt the engine by putting in that cold temp limiter. Honda has done the thinking for you.
I'm beginning to sound like a broken record but I'll say it again ..................
If the ECU will let you VTEC, then you CAN VTEC. This occurs when the coolant temp is at about 140 degrees (or 3 bars on the temp gauge for pre-'04 cars).
You don't have to warm it up a little longer to be safe. THE OIL TEMP DOES NOT HAVE TO BE AT 140 DEGREES. Honda has determined that when the coolant temp is at 140 degrees, the corresponding oil temp (whatever that may be - and it DOESN'T matter whether or not you know what that number is) will put the oil viscosity and flow characteristics in a place where it will function in the desired task asked of it.
Those of you who like to wait a bit longer to "warm" up the oil some more, go ahead if it'll help you sleep at night, BUT YOU DON'T HAVE TO. Why second guess the people who designed and built this car? If Honda didn't think it was safe to VTEC when the coolant temp is at 140, don't you think they would have put the limiter to something higher? They can do that, you know. They have the technology.

BTW, if you use a non-recommended oil viscosity, all bets are off.

carrnut21

at least 10 minutes, got to let the oil, diff, and tranny fluids come up to temp because they take much logner then the just the coolant to heat up

mxt_77

Question: Does our car have an oil temp sensor in it, or just coolant? If we don't have an oil temp sensor in our car, then I would disagree with your statement. Sure, Honda may have determined that the risk of damage to the engine is low enough that they can rely on the coolant temperature to determine when to disable the cold rev-limiter... but that doesn't necessarily mean that it's "safe" to rev just because the ECU will let you.

I believe that Honda was just too cheap to put in an oil temp sensor and make use of it to determine when to disable the cold rev-limiter, figuring that it wouldn't be used frequently enough to make it worthwhile. But, that doesn't necessarily mean that they did any calculations to determine that the oil will be up to operating temp at the same time that the coolant is at 140 degrees.

Just because the ECU lets you do something doesn't mean that you should do it.

mikegarrison

Did you even bother to read XViper's post?

A couple of miles (one warmup lap on the track) is usually more than enough.