To redline or not to redline? (RPM)

[SteveSRT8]

Originally Posted By: Gasbuggy
All my cars see redline on every trip I take. If they don't it's usually because of a passenger, bad weather, or it's an ultra short trip.


Likewise in sig car and street toy, seldom in other vehicles like vans and trucks. Except for the Wife's RAM, which is the silkiest engine I have ever owned.

In my sig car the factory power peak is at 6400 rpm. So is the stock shift point. Just raising the limiter 200 rpm makes the car a tick faster through the gears, it is noticeable.
Done many a trip bouncing off the limiter...

 

[Eddie]

I ALSO AGREE 100%

 

[philipp10]

Originally Posted By: CT8
Originally Posted By: AcuraTL
There's no "blowing the carbon out" in modern cars. There's nothing to blow out
Really nothing to blow out?


I belive he is correct....there should be NOTHING to "blow out". That maybe happened in the 1970's....lol

 

[spackard]

Meanwhile, I've seen small airplanes do full-throttle tests prior to flight,
and locomotives do self-tests and stationary generators do full load tests into load banks.

Do you really want to find out the equipment can't perform fully during a controlled
test, or during actual use?

Since the passenger car can't do stationary load tests, it doesn't hurt
to do occasional redline runs, for safety. Climbing a steep hill is about
the only way to do that, but in So. Cal. regular traffic seems to keep the
pedal depression constant, so they climb hills very slowly. Tractor-trailers excluded.

If you're going to do a top-speed run you should do a good inspection beforehand
of everything. Kind of stupid to do impromptu top-speed runs - maybe you picked
up a nail in a tire, or one has a sidewall bubble, pressure is low, or hose is weak, or ball joint
is heavily worn.

Do your friends do full brake testing occasionally also? Like, several full throttle
pulls followed by full brake until stopped tests?

There's adrenaline and then there's fear adrenaline.
I'd like to minimize the latter.

Seems like BMW (et. al.) are usually product-placed in an action movie where the guy
is giving it his 100% while everything around him is just missing from
ruining his entire getaway. The guys who buy these sports cars must
be thinking about just such a scenario, even a little bit, and buying
enough car to overcome their driving skill deficiency.

On the other hand, the engineers, aviators, genset mechanics, and race car mechanics are preparing for the
worst, and are minimizing that fear adrenaline.

 

[Gasbuggy]

Originally Posted By: Lubener
There's no reason to redline an engine. It also is hard on the transmission.


Let a car exude it's full potential.

 

[SwampSurvivor]

My Jeep 4.0 seems to like it! One of these days it's probably going to change it's mind.

Don't particularly care for those situations where I'm spinning a 16 year old , 205000 mile engine at 5000 RPM but sometimes you need to do it in the mud. I don't like mud either.

 

[EchoTech1945]

I think the RPM limiter and TOP SPEED limiter should be "tested" at least once a month.

 

[edyvw]

People on BMW forums are right, and that stands for all other Euro cars.
Take into consideration that those engines are running at 5-5.5K rpms every day when people commute on Euro HWY's.
Make sure you have good oil in (preferably Castrol 0W40, Pennzoil 5W40 etc or other BMW LL-01 oil), OEM or MAHLE or MANN oil filter, warm up engine slowly first, and then hit it hard.
I am redlining my diesel every day several times and does not use a drop of oil, works perfectly.

 

[Alex_V]

A dozen times a day, every day? No. 2-3 times a week (assuming daily driven)? Yes. It's very possible for an engine to get "stoved up" by never being really taxed in the right way. If you have faith in your car's engineering and your maintenance/lubrication, it should only help it to find a winding, secluded road and really put it through its paces every once in a while.

 

[robertcope]

As often as possible.

The good news is that the E30 and E46 are well known. A little research will tell you everything you need to know about making them solid. There shouldn't be any guessing or wondering.

robert

 

[01rangerxl]

I don't think there's any real need to "red line" an engine, but using it throughout its RPM range is a good idea.

Ford actually has a bulletin for 4.0L OHV engines that suggests going over 3000 RPM during regular driving...
Quote:
Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

http://www.fordrangerforum.com/how-to-submissions/101393-decarbon-ohv-4-0-ford-tsb.html
The red line on the tach is around 4500 RPM on these engines. It's easy to not go past 3000 RPM though.

 

[neo3]

Originally Posted By: 01rangerxl
I don't think there's any real need to "red line" an engine, but using it throughout its RPM range is a good idea.

Ford actually has a bulletin for 4.0L OHV engines that suggests going over 3000 RPM during regular driving...

http://www.fordrangerforum.com/how-to-submissions/101393-decarbon-ohv-4-0-ford-tsb.html
The red line on the tach is around 4500 RPM on these engines. It's easy to not go past 3000 RPM though.

From that link:
Quote:
4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.

How does that work? The main purpose of premium fuel is to decrease the chance of knock.

 

[DoubleWasp]

Incomplete combustion, due to the higher octane fuels being harder to burn. If you don't have a high compression engine, mid and premium are doing nothing for you, as you are stacking up carbon deposits until you're getting knocking on any fuel.

 

[SteveSRT8]

Note that carbon knock is different from pre-ignition knock. Hence the Ford recommendation above...

 

[neo3]

Originally Posted By: DoubleWasp
Incomplete combustion, due to the higher octane fuels being harder to burn. If you don't have a high compression engine, mid and premium are doing nothing for you, as you are stacking up carbon deposits until you're getting knocking on any fuel.


According to this paper, lower octane fuel (87 vs 93) produces higher carbon deposits:
http://forms.gradsch.psu.edu/diversity/sroppapers/2003/HallettDionne.pdf

 

[SteveSRT8]

Originally Posted By: neo3
How does that work? The main purpose of premium fuel is to decrease the chance of knock.


Premium fuel will not reduce carbon knocking, only pre-ignition. They are two very different conditions.

 

[bulwnkl]

Originally Posted By: SteveSRT8
Premium fuel will not reduce carbon knocking, only pre-ignition.


I agree that premium will not reduce carbon-induced pre-ignition, however you seem to be using the terminology differently than I was taught. How I was taught is:
--Pre-ignition is when carbon deposits, overheated spark plugs, or something similar light the air-fuel mix before the plug fires (often near BDC). It is essentially silent, and destroys engines extremely quickly. Higher-octane fuel has no impact on pre-ignition, because pressure is not what causes it.

--Detonation is the circumstance wherein end-gases spontaneously detonate due to heat and pressure, always AFTER the spark plug has fired and normal combustion is partially completed. Detonation makes the engine ring audibly, and most on-road engines will actually tolerate quite a fair amount of it. Most car owners (and owner's manuals) call it 'spark knock.' Fuel of a sufficiently high octane rating will reduce or eliminate detonation.

This page is a pretty good description of how I was taught in school:
http://www.contactmagazine.com/Issue54/EngineBasics.html