i find myself in 3rd gear on SS mode a lot.

after 6000 rpm it crawls to 7000 rpm and i am often in this spot for a pretty long time (10-15 seconds?) at 6,500 rpm on 3rd gear i am hittting almost 120mph and the car sounds insane with all my mods..

so... is this a bad thing to keep the car on the vtec band for so long while slowly inching to 7k rpm?

edit - thread title should be: too long on vtec bad?

 

More Stress to Engine ?

 

why don't you just downshift? You're leaving your engine at 7K for that long just to hear the sound?

 

I am no expert in engine or car, but I think if you go into high RPM frequently, you should make sure you get good quality engine oil and filter to be on the safe side.

 

umm maybe you should not drive so fast.
I'm way under-VTEC'ed

 

i don't leave it at 7k just for sound.. i am still accelerating, not like i'm leaving it there, eventually, when i'm just about on redline i shift into 4th gear..

what i am trying to say is while WOT on 3rd gear the vtec band is long all the way to redline.. so im wondering if stretching 3rd gear while on vtec is a bad thing...

 

I'm guessing what others are trying to say is by what you are saying you're not helping your engine to be long lived. In other words it sounds like instead of going up & down the rev band (i.e. not hitting 4th, etc.) and driving at 120 mph in 3rd it's 50/50 which will die first - You or your engine. Not to be too rude here but if it is you please try not to take anyone else with you, especially someone in another car.

 

I think downshifting would be bad...shifting up to the next gear would probably be a better idea ;-)

As for the engine longetivity, I'm not sure. The way I see it, our engines have one profile (non-vtec) for fuel consumption, and the vtec profile for power when you need it. The honda engineers probably consider "needed power" to be when you're overtaking or accelerating to highway speeds.

I'm sure the engine can take it (otherwise they would have reduced the vtec range and lowered the redline). But doing it often would put lots of stress on the engine. You might want to upgrade the internals (sleeves, etc).

I used to live in vtec on one of my accord's...my TSX is too new for me to go into vtec yet, so I'm not sure if that 3rd gear is right, or if you're just in the wrong gear for the speed...

 

obviously it takes much longer to redline on 3rd gear then it does on 1st or 2nd gear. so again, all i'm really asking is it OK to redline on 3rd gear even though it takes a while to get there...

 

It's fine to be in VTEC for any length of time as long as you have good quality oil (and change it at or before the recommended intervals), and your cooling system is in perfect working order.

I've always lived by the mantra "maintain it well and it'll treat you well", so by that standard, if you maintain the car well, and drive within its limits (ie: not over redline and not over the speed rating of the tires! LOL), then you will be OK.

Please drive safe, though. I've lost a friend through a high speed car accident. I never wish having to go through that on anyone.

 

120mph in 3rd? Wow is that true? I dont see how it is. The top mph in 3rd for the MT is 80mph, and I know when I WOT in 3rd it doesnt take me long to get to 7000rpm

 

AT ratios are spaced wider than MT (they only have five of em) and even their first gear is taller than ours. Their third gear is nearly identical to our fourth (AT3 = 1.08; MT4 = 1.03).

 

(correction: their final drive is also different, but even accoutning for that, AT's 3 = 4.79 and MT's 4 = 4.90, still quite close.)

 

Why don't you just stick to automatic mode for most of the time? Sounds like you are wasting a lot of fuel.

 

Interesting, Thanks!

 

I thought the top speed of 3rd for an AT was about 110 mph

Do you have the reflash?

 

Is too long on VTEC bad - I would say probably yes. The exaust valve is still closed when the brunt of the explosion occurs (they can adjust the valve timing by changing the cam profile - hence the term VTEC mode) this allows for a more full burn with greater power stroke output. I would think the stress would be on the top end of the engine because of the exaust valve being closed longer.

Since your in VTEC mode you are over 6000 rpm (04 and 05 models, I'm not sure about 06 version); either way your reving hard. High rev means moving parts are really moving. Compared to revving at 3000rpm with the same engine lubricant you will be putting more stress on the bottom end (bearings, crank, rods, etc.) and head. On the other hand its good not to bog the engine down by being in the tallest gear and too low a speed and it is also beneficial to get into high rpm to expel carbon build up occasionally.

My advise: The biggest impact of the VTEC is in 1st and greatest worthwhile ouput is in 2nd. In third with the auto its not as great a feeling and I would rather shift up then hold on to 7K.

Hope that helped. But, i'm no engineer so who know!

 

Putting constant stress on anything for a prolonged period of time will cause damage Period. No matter what it is.

 

+1 and personally, i kinda think it makes you look stupid when ur driving by and your engine sounds like its about to die from strain. =)

 

That's a pretty broad statement... everything on the planet is under gravitational stress constantly. That doesn't seem to be causing damage to things like anvils and rocks.

 

well..think of the gravity we have on earth as IDLE on an engine (700 rpm to say). rev the engine to 7000 RPM, 10 times idle or 10 times gravity and then you'll probbaly see harm done.

A rock or anvil has no moving parts though...an engine has many so it's not a fair comparison persay. But your right..my statement is probably a bit too broad. but you get my point though right? hahahaha :p

 

My friend Vtec too much in his 99 Accord and he needed to get his catalytic converter replaced cause it wore out prematurely.

 

That's because he was running rich at WOT in highcam. The excess petrol was going into the cat and killing it.

As for the thread starter, it is not a matter of in or out of VTEC. It is the RPM and load. Since the K24A2 is a long stroke engine, there is more stress on your liners and rings at high RPM. Even with little load (maintaining RPM), the high linear velocity of the piston still causes wear.

 

i hit 105 on 3rd on 6600 rpm

AT

 

your stressing the engine more than is needed. the engine is made to handle it but then why put that much undue stress on the engine. dont get me wrong im all for zoom zoom. but what is the need for 120+???

 

you gotta use it sometime
Euro's speed limit is like 120+ haha

it's not like you'll break it

 

I certainly hope your at the track when doing 120mph - Otherwise your the one who is insane - street racing and high speed street/freeway driving sucks.

If you constantly wanted to hear VTEC engage, you bought the wrong car. You should have bought an '06 Si.

 

It's like a lot of other things: you use it or lose it. Except...I don't know if that applies here. Talk to a Honda mechanic instead of one of us. One of the writers from Road and Track magazine, Dennis Simmantis, wrote a few times that "revs don't come free" when comparing high revving engines, to engines with larger displacement that will typically run at lower RPMs.

You could say that a motor running at 7,000 rpm has done more work per unit of distance than a motor running at 2,000 rpm. I'm not an engineer, and probably pissed a lot of people off already. But just enjoy your car.

 

Yeah, for mechanical systems, higher stress while parts are moving accelerates wear. If you look at something like an old clock movement, one can run continuously for how many centuries without replacing any parts? It will even keep "good" time (adjust weekly). If you made them one run 10 times as fast, with a heavier pendulum, and higher spring rate, it would leave brass shavings in the bottom of the case.

 

You are correct, sir. (Well, technically, it hasn't necessarily done "more work" as this depends on the relative power outputs of the two engines at their respective speeds, which also depends on the throttle position and ambient conditions at that time as well as other factors like headwind and drivetrain losses... but if you were using the English definition of work and not the physics jargon definition, you were right.)

In fact, our very own owner's manual notes that the Maintenance Minder service intervals are calculated by counting engine revolutions, not miles driven.