The dangers of hitting redline

[meep]

Originally Posted By: Hokiefyd
Especially for an automatic, I think a redline run is more detrimental to the transmission than the engine. I'm sure the engine could care less (for the most part). It's the transmission that has to handle that WOT/redline upshift. With a 3-pedal car, you can better manage the load on the transmission during an upshift. But most modern vehicles have engine torque management programs that softens engine power during upshifts anyway, to protect the transmission.

Bottom line: wring it out!


agree that the AT takes the hit. in a WOT situation, torque mgt may be disabled for max acceleration, such as a panic maneuver. Even if it's defueled, the AT still has to manage the engine/flywheel/TC inertia during the upshift.

My jeep V6 sounds great WOT, but I don't do it often because 1. it's not necessary, 2. it kills my avg mpg, 3. I plan my merging so that it's not necessary, 4. that 5spd AT is not an inexpensive unit, and under those conditions there's a big surge as it firmly tries to grapple with the spinning engine-- and I can feel the push--- and i know that equates to clutch wear. just doesn't seem worth it.

As to the engine--- there are more forces in play. in automotive use, WOT gets minimal time because you get up to cruise and and then back off. piston/pin acceleration forces are at their highest. weak/tired valve springs could cause a serious problems in they float into a piston. No, I don't see a big problem with it in modern engines, but, well, I've never heard of someone throwing a rod with the cruise set....

M

 

[ryansride2017]

No thanks. First off, if I would take my vehicle to the red line, the last thing I would worry about is the engine. I do a fair amount of maintenance on my own vehicles including bearings, axles, differentials, etc. Why unnecessarily beat on a car when it very well could cost you more in repair costs (and I'm not talking about the engine here)? To each their own I suppose. I'll just continue driving my vehicles in a normal fashion and keep repair/maintenace costs as low as possible.

 

[Craig in Canada]

I WOT and use high revs often (fully warmed), but I don't often actually hit the redline because there's not a lot of useful torque there. My redline is around 6700, I think it's elevated to 7000 by my software, and 5500-6000 is not uncommon for me. It's still strong, fuel efficient and doesn't consume a drop of any fluids with 187,000km on the clock.

The car is a 1998 BMW 528i sport with 5sp manual.

 

[JHZR2]

Originally Posted By: GenSan
Originally Posted By: JHZR2

The thing that gets forgotten is the true long-term effect. 110k is like nothing. What is interesting is the effect on terminal mileage, which I doubt anyone knows.



Only time will tell my friend. I plan on keeping the vehicle for a very long time so I'll let you know every 100,000 miles how it's holding up.

From a native South Jerseyan, who knew your neck of the woods well....say hi to Mr. Columbus for me at the Cooper River Park and have some pancakes for me at the Pop Shop and tuna jaw at Sagami

Look forward to it, and pancakes at the Pop Shop are on the menu for Saturday AM!

 

[Thermo1223]

When I had the TDI as much as I could to keep it clean of any built up soot.

The Subaru, not to much but with the reflash it gets a far amount. I normally only dive past 6,000 when I need that last extra 3-4 mph before the shift.

Redling is not a bad thing as long as you do it the smart way

 

[SLCraig]

I redline my Sattys daily on my commute, and then on the way home.
They're fine

 

[rslifkin]

I pound on the Jeep a good bit. It's a lot of fun, and doesn't get to redline anyway. Redline is 5300 rpm, tranny shifts at 4600 at WOT, as the power falls off fast after that. It's fine for the tranny, as it pulls a lot of timing, etc. on the shifts (even at WOT). However, it's probably a bit hard on the u-joints and rear diff, as at WOT in 2wd, it'll chirp the tires just after the 2nd gear shift when the torque management kicks the power back in.

In a properly running engine, there's nothing wrong with running it hard (up to and including redline), as long as you're not cruising around at redline all the time.

 

[expat]

For an 'Italian tune up' it's not necessary to take the engine to the red line, Two minutes at 4000 rpm will have Far more effect (cleaning carbon etc. than a second or two at 6k+.
(Your revs may vary!)
With most cars (road cars) there is very little reason to rev to the Red line, as someone said, torque is normally falling very rapidly as you approach the RL, Short shifting (a little) will normally get you down the road more quickly.
The only time I RL my car is during a 'Slalom' (Timed competition between cones in an enclosed area) Where it may be quicker to extend the revs than make a shift, only to have to shift down again an instant later.

 

[IndyIan]

If you look at torque at the wheels, pretty much all cars accelerate fastest with redline shifts. Even though torque is falling off, going to the next gear produces less torque to the ground.
But probably like you, I don't like the feeling of redlining a car with the torque starting to fall away...

 

[Spazdog]

Sheesh, my Integra GS-R saw 8000 rpm virtually every day of it's life.

I mean I had to make certain that the intake was still switching to the short runners and vtec was still crossing over to the big cam lobes. It was for diagnostic purposes!

Sold it with just over 200,000 miles on it. Still ran well.

 

[FZ1]

Well,It's gonna put more stress on everything,than driving it easy. I never red line my bikes or my car. More worried about a $4,000 transmission in my 02 Accord V6 automatic,than redlining it.

 

[Craig in Canada]

Originally Posted By: IndyIan
If you look at torque at the wheels, pretty much all cars accelerate fastest with redline shifts. Even though torque is falling off, going to the next gear produces less torque to the ground.
But probably like you, I don't like the feeling of redlining a car with the torque starting to fall away...



That kind of blanket statement can't be made consider all of the different engines out there. I've driven plenty of vehicles where when the upshift occurs there's a definite butt-dyno increase in acceleration in the new, higher gear. It all depends on the engine design.

You need to integrate (i.e. calculus) the area under the torque curve and combine that with the gear ratio map to determine maximum acceleration through the gears.

 

[bigmike]

Originally Posted By: ryansride2017
No thanks. First off, if I would take my vehicle to the red line, the last thing I would worry about is the engine. I do a fair amount of maintenance on my own vehicles including bearings, axles, differentials, etc. Why unnecessarily beat on a car when it very well could cost you more in repair costs (and I'm not talking about the engine here)? To each their own I suppose. I'll just continue driving my vehicles in a normal fashion and keep repair/maintenace costs as low as possible.


+1

I'm glad I'm not purchasing some of the vehicles being mentioned in this thread.

 

[subiedriver]

I rarely exceed 4000 rpm in my Subie, that's where the torque peak is, hp peak is at 4600 rpm, so a 4K shift point is in the meat of the powerband. Day to day driving, I'll shift it at 3500-3800 rpm.

 

[Thermo1223]

Too scared of using all the HP you payed for, that is a good one!

 

[OVERKILL]

My one 302 (the one in the Capri now, 2nd body for the same powertrain) saw redline pretty much daily for I imagine most of its life. Definitely during the 100 or so thousand Km's I put on it.

And of those 100,000Km's I put on it personally, a good 50,000 of them were making 100HP more than stock at about 1,000RPM higher than stock. Limiter is 6,250, red was 5,500IIRC, and she'd be shifted at 6K. The dyno curve never actually fell off.... But the stock limiter was in place, so taking it past 6K would mean you'd be into the limiter if you were power-shifting.

That engine still looks like new inside. No bore wear (visible cross-hatching) awesome oil pressure....etc. Now, it is on its 3rd transmission since I bought it however, LOL! But the engine wasn't complaining

 

[morris]

first off iam not a automobile historian, nor am i automobile expert. i just play one on tv, lol. second, i like chryslers more than other brands, how ever i DONT hate other brands. every brand has its week point and its strong point. i hope what iam about to say is worth reading. in 1964 chrysler made a hi performance engine of 273 ci a four barrel carb, solid lifters. was not put in chrysler bodys was put in dodge darts, plymouth barracudas. the idea was a hi performance engine must have solid lifters. in 1968 chrysler made a 340 ci, 383 ci, 440 ci, hi performance, but with hydraulic lifters. why hyd lifters on hi performance engine? what happens is that as the engine rpm go up the lifters will pump up and flote the valves and the rpm levels out well below the damage rpm. this gives them warranty insurance. and this did work.

 

[CBR.worm]

My car spends a lot of time near RedlIne. i am one of those guys who will hold a gear on the limiter instead of shift up and down to save 5 seconds of REDLINE.

This has been the case with most of my cars and have not had any ill effects within the 200k miles I keep them,

On the flip side, I know that internal stresses are exponentially higher at Redline than even 1000 rpm lower.

If the engine has a weakness it is liable to show up at maximum RPM.

Also cars like mine tend to make max HP at redline.

 

[Colt45ws]

I go WOT on a regular basis, though the redline and rev limit are actually limited by the 12" torque converter Ford stuck in the base civilian Vics which will start to balloon over 5400RPM.
As far as transmission slippage, that can be fixed.

 

[bigmike]

In all my years of driving, I've needed WOT a handful of times. I'm just curious as to what the purpose is if it's not needed?

I know alot of people hammer the pedal from red light to red light, especially in the morning. I must have a cushy job where if I'm late a few minutes (which is rare), it's not a big deal.

Some people must have some snob of a boss standing with a stop watch just trying to fire someone who walks in the door 30 seconds past their official hours.

Why not allot more time in the commute and take life easy? Have some satisfaction to cruising.