Is is bad for your engine to stay in vtec? Its a long drive to work for me. Sometimes its early in the morning and I can get away with 100mph, but vtec starts kicking in. Is is hurting anything cruising at that speed with vtec engaged?

 

Are you serious? Whya re you driving 100 MPH to work?

 

Im in the country, long straight 2 lane roads with no traffic. I keep finding myself cruising around 100. Plus, it is a 45min ride to work if I drive the speed limit.

Any help on the question of if this is bad for the engine?

 

Thats great until "bambi" runs out in front of you... screech..... screech.... boom...

Your gas mileage... stats show that for every 5 mph you drive over 50 mph, you're paying an extra 26 cents per gallon for gas..

 

It will wear on your valvetrain components much quicker.
Higher RPM creates more heat, breaks down oil faster, breaks down seals and rings faster, just wears things out...faster.
No one needs to drive 100mph on a public road regardless of traffic or no traffic. On a country road if you hit a deer going that fast it will destroy your car, hurt you, and who knows how long you will be in the ditch before someone notices you. "I'll swerve and miss it". No you wont, cause you will jerk and at that speed lose control.
Is saving 10mins on your drive really worth all that? It's not to me.

 

So in order to get that 31mpg claimed on the window sticker, keep it around 50mph?


Aside from the safety aspect and fuel economy, damage to engine?


Before I purchased my EM1 I was driving my wifes accord, at 100mph was turning 3.5k rpm and obviously not hitting vtec so was never a problem.

 

Equation for Wear

Wear Rate = (K/H)*p*v

Where
K = wear coefficient (dimensionless)
H = Surface Hardness (MPA/ksi)
p = surface interface pressure (MPA , ksi)
v = sliding velocity (mm/s or in/s)

Higher RPM means higher sliding velocity which means a higher wear rate.

K depends on oil condition and surface condition.
p depends on spring pressure
H depends on material and surface treatments.

Source:

Juvinall, Robert C, et al, "Fundamentals of Machine Component Design," Third Edition, pp 374.

 

I was going to say redline or near redline causes extra wear like race engines. The difference being we usually want our cars to last decades before rebuilds while race cars are rebuilt say every 400 passes or so.

If you don't mind rebuilding your engine sooner than later, run it like a race car all the time.

 

you're just beating on your engine....killing it faster, and adding to the stereotype of 90's Honda owners.

 

This is the most damaging of them all

 

Thanks for the feedback guys.

I figured it couldnt be good for it.

 

Nothing is good for an engine. It doesn't heal itself. Anytime it's on, you're wearing it out.

100mph with a B16A2 trans is like...6k RPM? The crank is spinning at 100 times per second. So yeah, there's some extra wear. The secondary cams are larger, so the valvetrain takes more of a beating. Oil gets hotter....but probably isn't an issue unless you're holding it at 6k for hours. It's not an appreciable amount of wear....but you have to be reasonable. Oil consumption will also be higher...so check your oil often.

All in all, it would require more maintenance...but you're not killing the engine. It's a 77mm stroke motor. 6k RPM? Who cares? You're not really hurting it much. I'm guessing you're sitting at that RPM for maybe 10-15mins MAX at one time. No big deal. Everyone worries way too much.

 

Well put. OP did ask if it was bad. I think my reply should have been more along the lines of not necessarily bad, but it is a little harder on the engine.

Others seemed to be more focused on the safety aspect of speeding on the non freeway roads. Which is a fair point too.

 

My personal opinion is that it IS bad. Does it mean it will destroy your engine immediately? Not likely. It will most likely end up being a slow death to an already aged engine.

 

I wouldn't worry about hurting it. Just adjust your maintenance schedule to compensate.

There's way worse things you can do to your motor.