Revving your engine ...

Much like my 91, my 93 miata gets very angry and stubborn if I don't smack the rev limiter at least once when I take it out.

Depends on the engine, but most will be perfectly fine.

There is a ton of math involved, but the inertial forces on things like rod bolts, piston pins, and pistons are exponential with their velocity. So factors like piston weight, pin material, rod/stroke ratio, etc will have a large effect on how "happy" it is at higher rpms. For instance, a 302 Chevy has long-ish rods, short stroke, and relatively light pistons. So it is a lot happier at 6000 than a 366 Big Block with its massive pistons and long stroke.

Even with two different engines - both with a 6000 rpm redline - have different thresholds. Just for kicks, let's say one is a 2.0L VW and the other is a 2.0L Toyota. They'll both be just fine at 6000, but one might have exponentially higher inertial loads than the other, meaning it might become damaged faster than the other.

It sounds like your GenCoupe might be in need of an Italian tune-up.

¯\_(ツ)_/¯ wrote: Depends on the engine in question of course, but my approach is typically that they put the rev limiter where they did for a reason- don't sit there bouncing off it, but as long as the thing is warmed up any part of the tach that isn't red is fair game Notable exception- Toyota 22r/re. Revving them to 5k+ consistently apparently makes them throw rods, if LeMons cars are any indication.

Ive been revving 22rs till the valves float for 20 years. No problems here.

Klayfish wrote:

¯\_(ツ)_/¯ wrote: Notable exception- Toyota 22r/re. Revving them to 5k+ consistently apparently makes them throw rods, if LeMons cars are any indication.

Hondas have that reputation in LeMons too, but I think it's a lot to do with the drivers. People think because they're reliable street engines that you can run them to 7k rpm multiple times per lap and hang it there. We run a Honda and have had tremendous reliability with it. But we don't bang it off the limiter, we shift a bit before. Keeps the engine nice and happy.

Rev limiters kill engines.

It's a safety device, not cruise control.

Message Received... STOP BEING A PUSSY

Got it...

In reply to Nis14:

Haha, funny it didn't even bob costas you.

RedGT wrote: What would that theory be? Just curious. heat or vibration tempering something, somehow?

I had to go and find the reference, as it has been a while.

http://imsretrofit.com/ims-101/

So what can be done to minimize the likelihood of an IMS failure? Although a greatly debated subject, most experts agree that more frequent oil changes every 6 months or 5,000 miles is a good first step. Secondly, actually driving your Porsche more often and avoiding higher gears to keep the revs above 2500-3000 rpm is another good step to take to improve the life of the ball-bearing in the intermediate shaft. Although there is limited data, the general trend is that lower mileage vehicles with infrequent oil changes or driven light-footed (as in run at low speed/engine rpms) are most likely to suffer a failure rather than those cars that are driven hard and well-maintained. Lastly, use of premium engine oil such as Motul’s 8100 X-Cess 5w40 (which is a Porsche approved oil) or Joe Gibbs DT40 can also provide added protection to all critical engine components. Along with more frequent oil changes, the addition of a magnetic drain plug coupled with close inspection of the oil filter and magnet at these shorter intervals may help owners identify a failure in its early stages, but later models using the single row bearing can fail with little warning. When inspecting the filter and magnetic drain plug, ferromagnetic debris from the intermediate shaft bearing can be identified easily, appearing like silver glitter. Larger debris than this is indicative of a complete failure. When using the Spin on Filter Adapter & FilterMag, a filter cutter is used to inspect the full flow filter.

Joe Gearin wrote: You can shift before the redline? Interesting........

You know who shifts before redline? Quiters. Quiters.

The ECM in my Fiesta won't let me rev above 3k in neutral, but loves the go over 6k when in gear. The Zetec in my ZX2SR would easily go to 7.2K., spent lots of time near there at track days.

Older engines had a built in rev limiter. The hydraulic lifters.

RossD wrote:

Joe Gearin wrote: You can shift before the redline? Interesting........

You know who shifts before redline? Quiters. Quiters.

^^^^ Magazine worthy!

Also more anecdotal evidence that my 289k miata has held up for 17 autocrosses and 1 track day in the past 2 years. Planning on another 7-10 this summer.