Just curious how you aggressive/passive you guys drive your Coupe. I normally hover around 2500 but I've never gone past 4500 before.

A curious question:

Most Japanese cars don't have low end torque that's why you gotta rev the sh*t out of the engine before you get some power. My buddies tell me that it's ok to rev a Honda, Toyota, Acura engine to say 5500-6800 rpms because they are designed to handle high rpms (for instance, the Celica or RSX)

Now, is it true that these engines are designed to handle such friction and heat from high revving? What do these engines have in them that make them sustain such stress?

I always thought that revving ANY engine to such extremes would wear out the motor faster than normal. Am I right?

 

I hit the rev limiter often.

 

Yeah, same here. Whenever I feel aggressive, I usually hit redline on gears 1 and 2 while accelerating, sometimes getting 3rd near the red depending on the situation. (Uses automatic). [I forgot to mention I do this to cook rice most of the time ]

Actually, according to my friend's mechanic, the reason why Euro engines need very few mods (compared to Japanese cars) is that Euro engines are tuned better than the Japanese ones. Because roads like the Autobahn exist throughout Europe, Driving for extended periods of time near the redline is a very common occurence. It is not the same case in Japan. That is why Euro cars should last better near redline for hours on end vs. their Japanese counterparts.

On a side note, the Road & Track car testers couldn't note any significant difference between automatic track test times vs. manual times (i.e. 0-60, quarter mile, etc.).

PS, one time I was racing a friend in an ML 320, actually hit the rev limiter while going 60 MPH in 2nd gear(!). The part about the fuel line cutting is very true, the engine went dead for a split second and I threw the gear selector into 3rd and continued the race...

 

6800 rpm (pet peeve alert: "RPMs" is redundant, it would stand for revolutions per minutes) is nowhere near extreme for many modern engines. Heck, some production bike engines aren't even making power until then, you could almost consider that their "low end"! Even my '73 Jensen Healey redlined at 7200rpm.

Friction and heat are (generally) not the problem of high revs. Piston speed and valve train problems are.

Piston speed is related to the stroke of the engine, so if you want an engine that revs to the sky, you typically build it with a relatively short stroke. High piston speeds lead to high acceleration forces approaching top dead center, which stresses con rods and wristpins and pistons and bearings and...

"Valve train problems" usually means valve float, which is related to weight of the components and how fast you're trying to accelerate them. A heavy valve will float sooner than a lighter one, unless the spring is heavier, which leads to higher spring forces, which is harder on the cam and other components, etc etc etc... and of course if you have a pushrod engine you've got the pushrods and rockers to worry about also. (We'll leave the conversation about desmodromic valvetrains out of this post...)

Just for reference, Honda has built some production streetbike engines in their Japanese market 250cc models that redline around 18,000rpm. The piston and connecting rod will fit in the palm of your hand, and they have virtually no low end torque, but when they're spinning at peak power, holy cow... and even a big performance V-twin (1000cc) will spin to at least 10,000rpm with no real problems.

Truth is, most car engines are so understressed when it comes to specific power output that it's kind of silly...

 

I've hit 11,000 RPM on a Honda and 9,500 rpm on a Triumph sport bike (you didn't say in an MB). On my coupe the revlimiter is at 6,200. Use the dyno below as a guide as to when to shift, for me optimal performance shift points are about 5,800-6,000 rpm.

 

On the coupe it is 6200rpm, which I have seen many times. On my old Nissan Pulsar twin cam it was 7500, and my old 240Z that I built to race it was 8500rpm! The Honda S2000 red lines at 9000rpm. A built RX-7 can rev over 12000rpm with no damage. On many cars the limiting factor is the accessory drive like the water pump and the alt can't handle the revs. Many times there is no advantage to reving higher as the power band is rolling off at those high revs. Look at the power curve to see when the shift is optimal.

 

I've had my C240 (6-spd) up to around 5500 rpm a few times. One time I was punching it after I made a right turn on red (should have been plenty of time by an ahole was coming up on me). I was in 2nd and was looking in the rear view for a second. By the time I glanced at the tach, I was nearing 6000! I regularly take it to 3500-4000 for shifts to 2nd and 3rd. Anything much lower leaves you below the power curve in the next gear.

 

Honda engine like NSX, S2000, Integra Type R etc. used many of the F1 design and technology. Btw, F1 engine are design to rev up to 18,000 rpm. One thing that i don't understand about Ferrari F1 engine are so reliable but i heard that their production cars are not that reliable at all. Any Ferrari owner out that can verify this? Maybe is just hater talking.

 

First gear i shift around 4000rpm
Second gear about 4000rpm

Then rest of the gears about 3000rpm. There have been couple of times when merging on the highway not paying attention i hit around 6200rpm or maybe higher in 3rd gear. I also hit around 6200rpm in 4th gear once.

Heck when racing 6000rpm's.. Anything above that i find is useless. The shift points on this car is about 5800-6000rpm.

 

i easily hit 5000rpm on 1st gear before shifting. after that shifting occurs around 4000-4500rpm
i occasionally hit 6000rpm on 3rd gear while merging into freeway and i felt the car was choking (could be uneven ramp pavement).

 

@ 500 miles I was already red lining it at around 3-4th gear on manual but that was on an open road in SI. On Auto I try to keep it below redline but sometimes punks just want it, so I have no chocie but to kill there cheap **** buicks and civics..

 

I usually shift between 3k and 4k but I have had the need to rev it to about 6k or more depending on the situation...

 

ya but the question is how much mileage have u already got.... my **** is still fairly new [about 1200] and its already gettin abused.

 

I've never gone past 4500 too...

Mind you, that IS redline on the diesel

Mark

 

Um... Congratulations???

 

Interesting tidbit of information - the stroke of an F1 motor is about 1 cm.

Cheers, BT

 

Knowing that a Euro engine gets max torque and HP around 4800 rpm and a Jap engine gets max torque and HP around 6800 rpm, and assuming my driving style is that of a speed demon (always pushing the car to it's max rpm to achieve max torque and HP) which engine would last longer?

 

It's not that easy. The generic answer is whichever is stressed less, and there needs to be more information given to figure that one out.

The generic answer also overlooks shortcomings in specific designs. Perhaps the valvetrain isn't up to snuff in one design, or the cooling is marginal, or there are issues with the lubrication system, or...

Keep in mind there are bike engines out there spinning 10,000 rpm+ that last 100,000 miles with proper maintanence. I'd hazard a guess that most sportbike engines expire due to neglect or crashing than actually wear out... to base longevity estimates simply on operating rpm can be misleading.

That being said, a higher revving engine will typically be more maintanence intensive, but high maintanence does NOT mean low reliability...

 

Do you have a photo of your bordeaux red? I love that color on the C230!

 

No photos of the car yet, I've been too dang busy.

I had planned on buying a black car (again) but saw a bordeaux C320 and thought it looked nice. The longer I have my C230 the more I like the color.

But getting back on the subject, I ran across an interesting little site this morning.

High revving engines? How about a 20,000rpm redline? And, 22,000 should be possible with a little development!

See for yourself: http://www.motobykz.co.uk/Drysdale/D...e_WSB_2004.htm

 

trench, others, I'm just curious. If the stroke is just 1 cm, does that mean that the crankshaft has no more than 1 cm of travel from TDC to 180 degrees? That would make for one tiny, tiny crankshaft in a 3.5 L motor. What am I missing?

 

I spoke with a F1 fanatic and here's my understanding:
Race teams don't like to publish the bore and stroke specs for obvious reasons so any info is fuzzy. He had seen an F1 piston/crank setup and the sroke appeared to be around 2 inches.

By my calculations (please correct me if I'm wrong) a 10 cyl engine with a 1cm stroke would need to have 19.5cm (7.7 inch!!) diameter pistons to get up to the regulation 3.0 liter displacement.

 

So, a cylinder bank with 5 cylinders would be 38.5" long (not including liners, space between cylinders, water jacket space, etc.) Something doesn't add up. A 1 cm stroke is only 0.3937"

 

Typically engines have a stroke to bore ratio somewhere between 0.6 and 1.4. F1 is crazy so who knows where they are actually running at, but it sure isn't a stroke/bore of 0.05! (1/19)

If we take 0.6 as a lower limit, a 2" stroke would equate to a 3.33" bore.

Figuring a 10 cylinder, 3 liter engine, a 2" stroke would lead to a 3.41" bore.

So... a stroke of around 2" is reasonable, but again, F1 isn't "typical" so I'd have to ask around for a reality check... (and please forgive the mixing of units and general sloppiness with significant digits!)

P.S. I've sent a question to a friend who should know these things. Whether or not he'll share the details is quite another story.