kbosch74

He all.

I have a '07 Type S auto. I am past the break in period. On occasion, when driving a bit spirited in the manual mode, I have hit the redline, and of course the car steps in, cuts out at this point, and prevents me from going further and messing it up.

My question is, since the car does step in and prevent me from going into the redline area, am I doing any damage?

This is never intentional, I just sometimes bump into that just before/around shifting.

Thanks for any responses.

reloaded

its alright..but the less the better. You doing that occasionally isn't going ruin anything..but constantly cruising while it bounces off the rev limiter is bad. THat's what you should make sure y ou don't do.

ChucksCL-S

I have read here in the past that hitting the rev limiter sends a pretty good shock thru the drivetrain with the majority of the on again-off again jolt hitting the tranny. The engine can take it and our half shafts seem to never break, so I'd say keep this in mind. Of course I have an 03' CL-S with the famous glass tranny. Just my 2CW!

mishar

Only to your 0-60 time.

kbosch74

OK...thanks all.

juruki

iTrader: (2)

Does your TL-S cut off at 7k rpm?

Atrain

You have an automatic transmission which has a torque converter. The torque converter has a "K" factor and maximum rpm it can spin before it starts to balloon and grow on its axis. Most factory converters are very junk and basically are good enough for stock power levels.

The rev limiter is there to prevent damage to the driveline more so than the engine. If you over spin the engine you over spin the transmission and torque converter. If they converter balloons enough it can sometimes drop the thust washer and cause a disaster. Will the TL do this? I can't say for sure...but I bet Acura didn't want you to find out jackassing around on the streets.

Manual cars also have rev limiters but in reality it's to protect from an over rev of the engine.

A-Train

kbosch74

Right around there, yes.

ChuckDu

Hmmm, I did not know this. In you opinion, how much higher could Acura set the 6MT TL rev limiter without doing engine damage due to valve float?

geekybiker

Ummm except for the fact that most damage done to engines via over-revving is through mechanical over-revving. That's something a rev limiter does absolutely nothing about.

On a stock car, the rev limit probably has as much to do with where the power band is as anything like valve float. I would be surprised if your couldn't raise the rev limit another 500 rpm on most production vehicles without worrying about float. however without cams, raising you rev limit is pretty pointless.

ding069

the purpose of the rev limiter on a tl (and most cars) is to prevent damage, mostly to the drivetrain as noted, and it usually kicks in right after the peak HP in the band. If you go past the rev limiter, you are actually losing power and creating excess wear/tear.

note: this is regarding a stock car without performance mods

Atrain

Here is what I can tell you from plain old experience. There are multiple factors that cause the engineers to limit the revs electronically by cutting out fuel and spark.

On an automatic car it is almost always due to the torque converter ballooning. There is no way to get around this unless you build a good soild torque converter which mostly none of the OEM cars makers do for production vehicles. With a decent converter (anti-ballooning plates, brazed fins, smaller diameter, etc) you can spin much higher.

Now valve float is something that most engines will have if they are run well past their redlines. Not the redline on the tachometer which BTW is almost never accurate. I've seen cars that show 5,500 rpm redline and when data logged thay actually hit the redline at 5,250 rpm or so. I'm talking about their mechanical redlines or the limits of the valvetrain.

Most OHC engines are capable of spinning faster than OHV configurations, not all...but most. Nascar engine prove this theory wrong of course. OHV...9,500 rpm...WOT for hours. The valvetrain is very expesnive on the engines but they do spin very high and make power up there.

Now, I have no clue where the TL or TL Type-S engine mechanically redlines nor do I pretend to know. I can tell you this...it is WAY past the redline you see on the tack. Is there power to be had up there? Most likely not!

The supercharged guys would be lifting the intake valves off the seats near redline if it was near floating. They have not complained. There is enough seat pressure and overlap to keep things in check.

The question does the Type-S AUTO have the same limiter as the Type-S Manual?

A-Train

Jim in Oregon

That's what it's there for...to protect the engine from over revs. I wouldn't worry about it.

I run my BMW M3 at the track and I'm always hitting the limiter. I'm concentrating so much on my friving line that I sometimes forget to see the tach approaching the redline. It cuts in....and I shift....no problem.

ironviet

Ok just FYI fuel cutoff and rev-limiter are 2 very different things that have a similar goal-- to prevent over revving causing internal parts to fail. Usually the valves go first by being bent.

I do not know of any production vehicle aside from exotics and those with the electronically controlled sequential gearboxes with launch mode (usually reserved for the EU market) that have a rev-limiter. A rev-limiter will permit you to rapidly bounce at the predetermined rpm and maintain maximum power. You will usually see or hear this at a drag strip with modified cars having them. Ignitions such as MSD have that option too.

A fuel cut-off is ecu controlled and cuts fuel at a manufacturer's predetermined rpm. What will happen is that once you reach this point you'll notice a temporary loss in power which can take seconds to recover from.

In my experience with Honda engines I think the valve springs and valves are able to exceed the stock fuel cutoff by a minimum of 600 rpms but I am not sure where the max would be. By anything more than 600 we went with titanium valves and springs. Now this experience of mine was with the B16,B18, and H22 Honda engines with new ECU's.

Though I would never suggest this, but if you really want to know what would happen if you go beyond the redline, shift back a gear when you hit redline in any gear other than 1st. This is called a mis-shift and can only be done on a manual tranny. Remember don't try this ever!

geekybiker

Toyota MR2 came in SMT in the US. Both Audi and VW have the DSG transmission which is effectively a SMT. The M3 came in SMT and I wouldnt call that exotics.

The "rev limit" you're talking about is usually called launch control. I had it on my subaru that I install replacement link ECU in. Its a one time lower rev limit that you set via a button, or sometimes a combination of control presses. There is also valet mode on some ECu's which is a lower continuous rev limit (say 3k) to allow people to park your car but not screw around with it. Really important if you have a heavily modified car that can be fragile.

ironviet

I never said the M3, Audi's, and VW's were exotic cars. Here is what I wrote "I do not know of any production vehicle aside from exotics and those with the electronically controlled sequential gearboxes with launch mode (usually reserved for the EU market) that have a rev-limiter." I referred to 2 different cars, exotic being one and the other electronically controlled gearboxes. Yes I was referring to launch mode in these systems. I know on M3's in europe they have this option. U.S. M3's must have software to enable it. I am sure there are others but I know the Enzo, the F430, M3, and M5 have it in europe.


Hey that's awesome that you had the button. Was your's an external device or part of an ignition, ecu, or something?

geekybiker

Mine was part of the ECU. It was a replacement ECU that I programmed from scratch. Also had an option to enable flat shifting which had a seperate rev limit when the clutch was depressed. Allowed you to never lift on the gas while shifting and keep the rpm ideal for the next gear.

sukeet

One of my friends saw my car and all of a sudden decided to test the car limits, which I did not mind until I heard the engine go out and come back in. He did this about 3-4 times within a minute or so while the car was in park.

I know that the engine could turn off to not to damage the engine, but do you think it did damage to the engine at all? I am unfamiliar with V6 and acuras, and would like an opinion from anybody!

Bearcat94

6800, IIRC. Rev limiter seems to cut in right at the red line. But, with the auto in SS, because of the delay, you've got to anticipate it and shift a bit before the redline.

teamsorad

This is true. I use to have a Honda Accord with a H22A Prelude engine with a Spoon Ecu. The stock redline was 7500, but my ecu had no fuel cut off so I would always go close to 8k RPM.

One time while racing a Supra on the highway had 3rd gear maxed getting ready to shift to 4th but threw it (powershifted) into 2nd instead. Not sure how high the engine went, but luckily it didn't blow up.

3rd gear maxed then to second, engine made the worst noise I've ever heard

JsL138

In light of this topic...I just had to post this classic video.

http://youtube.com/watch?v=Tx4wYE-0ubA

Turbonut

iTrader: (1)

I'd shoot him!

geekybiker

Very very very unlikely any damage was done. I mean its not something you want to sit there and bounce off the rev limiter for minutes straight, but I wouldnt worry about hitting it. Even daily.

94eg!

That is a VERY bad idea when the engine is cold. If not, I wouldn't worry about it at all...


On a side note about rev limits, Team Honda Research had their 04 TL's electronic fuel cut modified inside the ECU so the engine wouldn't come back on in the same gear in the event rev-limiter was hit. The idea was to save the 6MT from the terrible shock of repeated on/off engine torque at max rpm & wide-open-throttle. This car was setup for a 25 hour endurance race...

mishar

Hitting the rev limiter is not any worse than getting close to it, but both are not actually good for engine. At those rpm’s pistons are under 1000 g forces about 450 times per second. If you add 12 tons of explosion force at full throttle 60 times per second at each piston, you get quite hostile environment.

donc

One of my friends saw my car and all of a sudden decided to test the car limits, which I did not mind until I heard the engine go out and come back in. He did this about 3-4 times within a minute or so while the car was in park.

You do mean EX friend don't you????

sukeet

Well I'll let him off the hook because he had a few bottles of beer inside his system and I haven't seen the dude in like 2 years.

As for all your answers, thank you. Now I can sleep well at night

xtasea24

I hit my rev limiter from time to time when I'm in the passing zone and manual mode... usually when I'm not paying enough attention to my RPM and more on the road itself... I'd say you're not doing any harm if you're not doing it all of the time... that being said... the car isn't intended to be driven near the red line all of the time and this is why hitting that mark all of the time would deem early breakage in the future...