I know that our cars are sports cars and are designed for high revving, but I was just wonderin if it is bad to drive at high RPMs every day, many times. (like over 5K) a lot?! Is that bad?

 

yeah, bad for your wallet in that you will spend more on gas...haha

 

It's bad to cruise for extended periods at high RPM, but performance engines actually like to be revved as opposed to lagged. My 2005 G just had the first (3,750) service check & oil change and I've noticed that the performance has improved dramatically from the first 1500 miles. I'm sure this is related to the engine breaking in and also because I too rev the engine to 5500 during hard accelerations.

 

Premature engine wear.

 

I've heard that it's hard on the timing belt to accelerate hard on a regular basis, in fact hard acceleration / deceleration is going to be hard on the transmission, brakes, etc. That may part of what Texan1 means by "Premature engine wear.” Otherwise I don't think that running a well-warmed-up engine at below redline rpms would do any harm.

 

The VQ35DE, like nearly all Nissan engines over the last 15 years or so, uses chain-driven overhead camshafts that are good for several hundred thousand miles. Even if the VQ used a timing belt, they're typically so overengineered nowadays due to the vast majority of engines being the "interference" type (that is, pistons will crash into valves if the belt breaks, crashing your wallet and your opinion of the manufacturer) that the typical service life of 60,000 miles is grossly conservative.

Run your engine hard with no concerns. Most engine wear today takes place at cold start-up before oil has a chance to circulate into the cylinder heads. Piston ring, valvetrain and bearing wear is practically negligible during fully-warmed driving of any type, assuming reasonably clean engine oil is in the crankcase and is being pumped properly.

Interestingly, Nissan's SR20DE engine in my wife's G20 (and my old Sentra SE-R) had problems when hooked to automatic transmissions with premature camshaft failure due to sludge and varnish build-up in the oil galleys. Most of these failures occurred in cooler climates (particularly the Pacific Northwest) in cars that were driven very conservatively. Oil changes were often performed regularly, many by Infiniti dealers per Nissan guidelines. However, these failures rarely occurred in cars either a) equipped with manual transmissions, or b) equipped with automatics but driven hard, with lots of revs.

Our theory on SR20DE.net, supported by Infiniti/Nissan techs, was that putting some revs into these engines kept the oil galleys clean through increased oil pressure and operating temperatures. Light-footing an automatic car around town, where revs rarely got above 2500 and even then just momentarily, never produced any real oil pressure, and the tiny little galleys eventually clogged up with varnish and sludge due to inferior venting by the PCV system and the increased humidity and cooler temperatures in certain geographic regions. Oil change frequency had no bearing on the passages clogging up due to their narrow design. Only fully synthetic motor oil like Mobil 1 and Amsoil seemed to resist sludging up in these situations.

So, again, IMHO rev the thing and enjoy it. You won't wear anything out prematurely if you perform Infiniti's recommended maintenance (i.e. change the oil and filter every 3750/7500 miles) as required.

 

I really appreciate JKWright's informative post. I was not aware that the VQ35 had a timing chain, as opposed to a belt. And I do agree that overly conservative driving can, on occassion, be more harmful than a driving regime that stresses free reving.

However, I stick by my point that aggressive stop and go driving can be very hard on the engine, transmission and brakes. And to that point, whether belt or chain, the cam connection is prone to wear when under the high stress forces of jack rabbit starts, same is true for the transmission, and when decelerating rapidly, the brakes. Just an observation. I think there's a lot of room for wear and tear due to JKWright's correct observation that these engine's are grossly overengineered (I mean very durable )

Cale

 

Well, as I've owned my G35 for less than a month, I don't feel I can't comment on Infiniti/Nissan products, so take this for what it's worth.

My previous car was a Hyundai Tiburon. Had a peppy rev-happy inline 4 and a 5speed. I owned the car for 5 years and put 70K miles on it. Routinely revved it up to redline, jackrabbit starts, stop and go traffic, hard braking etc. in daily use. Plus autocross, performance driving schools and lapping days (Portland Intl. Raceway is FUN!). The things I noticed needed more attention because of my aggressive driving habits.

1) Transmission/differential gear oil. The original 75w-90 mineral based lasted about 30K. It poured like water when I drained it. The Redline sythetic MTF held up much better over the next 30K.

2) Brake fluid, high brake temps reduces fluid effectiveness. Keeping new fluid in the calipers means bleeding the brake system every 6 months and full system flush every 2 years.

3) Brake pads. Buy some good quality ceramic pads with high cold coeff. of friction. I used and recommend Raybestos QuietStop. Get used to brake dust.

4) Engine oil. High revs cause high sheering forces at a molecular level...it breaks down the oil much faster. Even full synthetic like Mobile 1, though the sythetics hold up to this abuse much better than mineral oil. Check and change your oil often. Learn to spot the signs of oil breakdown and change it even if you haven't reached the milage limit.

5) Tires will wear faster. keep 'em balanced and rotate every 5000 miles to get the longest life out of them. E.g. Other tiburon owners got 5-7k miles less on their tires than I did. Same car, same tires. The only difference was the frequency of tire rotation.

6) Ignition system. Plugs and wires will wear out faster. I'm not sure why but they did. This is the one that surprised me.