Non taken but for sake of argument valve float in your big american non interference v8 wasn't an issue but old slightly modified fiats would rev to 8500-9000 rpm and they where interference engines.Basically idiot could rev them to death.That is why i sad it's better to hit cut off then experience valve float.Not that is important for last 30 years.
How bad is it to hit the redline frequently?
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Originally Posted By: Turk
It's good to blow the Carbon out once & a while...
But affect on engine??
Go read some Used Oil Analysis reports from "Artem". He frequently floors his cars & runs them at very high RPM's. His wear #'s are very low.....
Turk is right, I run all my vehicles HARD when I get the chance. I'm one of those who wants to enjoy that 20, 30 or $40,000 vehicle I purchased. Driving it "carefully" in order to preserve it for the next guy is hilarious to me.
We purchased our 98 Toyota Camry V6 new in 97 and the car has seen it all over the last 17 years. I can't even count the amount of times I hit the SPEED LIMITER in it (on a closed course, of course
)
I even manually shift the auto tranny to run the engine to the actual redline / fuel cutoff because the ECU shifts about 300rpm shy of the redline.
The car currently has 250k on the original drivetrain and runs Great! Shifts smooth thanks to synthetic transmission fluid changes since new and doesn't smoke or burn much oil during 5k invervals.
My last performance oriented car was an 07 Civic Si with an engine that had an 8,000rpm redline. The factory fuel cutoff was 8,250rpm and I modified the engine and tuned it to rev to 8,600rpm. During dyno testing / tunning the engine actually saw 8,800rpm as per the data logs.
I raced that car at the track (time attack) and not a single day went by when I didn't rev it to the 8,600rpm rev limit.
The engine showed stellar lab results from the UOA and ran flawlessly when it was sold after 115,000 miles of ABUSE.
I have no doubt in my mind that the next guy will EASILY run the engine to 200,000 miles or more.
I also have an 06 Scion tC 5 speed that has 120,000 miles and has been bouncing (literally) off the rev limiter since the wife bought it with 10k on the clock. It's also modified and gets driven HARD on the street.
Our new Mazda 3 hatchback with 2.0L Skyactiv engine was practically redlined outta the dealership during my test drive, before I bought it. A day also hasn't gone by when the wife or I haven't redlined that engine. 7,000 miles and counting. We plan to run the car to 150,000 before we sell it for a bigger car due to a second kid that we plan on having in a year or two.
Why are you guys worrying about engine wear? There are a TON of performance cars that have 150,000 miles + of abusive driving and most of those engines are modified and put out more power then stock. If those engines haven't chewed through the piston rings, then your regular daily driver will certainly not fail from it because of your "occasional" trip to redline as you attempt to blow out the spiders and cobwebs from your exhaust system because it barely gets hot from your 2,000rpm daily cruising. Hahahaha.
I challenge anyone to pull an oil sample from your car during your regular granny driving and then follow it up with an oil sample of you running the engine harder during the next oil change. You will barely see an increase in metals, if any.
It's good to blow the Carbon out once & a while...
But affect on engine??
Go read some Used Oil Analysis reports from "Artem". He frequently floors his cars & runs them at very high RPM's. His wear #'s are very low.....
Turk is right, I run all my vehicles HARD when I get the chance. I'm one of those who wants to enjoy that 20, 30 or $40,000 vehicle I purchased. Driving it "carefully" in order to preserve it for the next guy is hilarious to me.
We purchased our 98 Toyota Camry V6 new in 97 and the car has seen it all over the last 17 years. I can't even count the amount of times I hit the SPEED LIMITER in it (on a closed course, of course
I even manually shift the auto tranny to run the engine to the actual redline / fuel cutoff because the ECU shifts about 300rpm shy of the redline.
The car currently has 250k on the original drivetrain and runs Great! Shifts smooth thanks to synthetic transmission fluid changes since new and doesn't smoke or burn much oil during 5k invervals.
My last performance oriented car was an 07 Civic Si with an engine that had an 8,000rpm redline. The factory fuel cutoff was 8,250rpm and I modified the engine and tuned it to rev to 8,600rpm. During dyno testing / tunning the engine actually saw 8,800rpm as per the data logs.
I raced that car at the track (time attack) and not a single day went by when I didn't rev it to the 8,600rpm rev limit.
The engine showed stellar lab results from the UOA and ran flawlessly when it was sold after 115,000 miles of ABUSE.
I have no doubt in my mind that the next guy will EASILY run the engine to 200,000 miles or more.
I also have an 06 Scion tC 5 speed that has 120,000 miles and has been bouncing (literally) off the rev limiter since the wife bought it with 10k on the clock. It's also modified and gets driven HARD on the street.
Our new Mazda 3 hatchback with 2.0L Skyactiv engine was practically redlined outta the dealership during my test drive, before I bought it. A day also hasn't gone by when the wife or I haven't redlined that engine. 7,000 miles and counting. We plan to run the car to 150,000 before we sell it for a bigger car due to a second kid that we plan on having in a year or two.
Why are you guys worrying about engine wear? There are a TON of performance cars that have 150,000 miles + of abusive driving and most of those engines are modified and put out more power then stock. If those engines haven't chewed through the piston rings, then your regular daily driver will certainly not fail from it because of your "occasional" trip to redline as you attempt to blow out the spiders and cobwebs from your exhaust system because it barely gets hot from your 2,000rpm daily cruising. Hahahaha.
I challenge anyone to pull an oil sample from your car during your regular granny driving and then follow it up with an oil sample of you running the engine harder during the next oil change. You will barely see an increase in metals, if any.
Originally Posted By: SHOZ
Originally Posted By: IndyIan
But higher bearing loads must create higher oil flow velocities in the bearing and cause more wear. Is it significant in a happy engine with a conservative rev limiter, probably not. But it you take a high mileage engine and keep it WO near the rev limit all the time, it will fail faster that if you babied it.
But if the vehicle is geared correctly who does that, keeping it at high rpms? The last vehicle I drove like that was an early 60's International Scout that had a top spreed of around 55mph, rpm limited.
Guys like me autocrossing old beaters, I've seen/heard a few old engines that didn't sound quite as happy and the end of the day, as they did at the beginning. They were on their way out anyways, but WO and redlining does accelerate that process.
Originally Posted By: IndyIan
But higher bearing loads must create higher oil flow velocities in the bearing and cause more wear. Is it significant in a happy engine with a conservative rev limiter, probably not. But it you take a high mileage engine and keep it WO near the rev limit all the time, it will fail faster that if you babied it.
But if the vehicle is geared correctly who does that, keeping it at high rpms? The last vehicle I drove like that was an early 60's International Scout that had a top spreed of around 55mph, rpm limited.
Guys like me autocrossing old beaters, I've seen/heard a few old engines that didn't sound quite as happy and the end of the day, as they did at the beginning. They were on their way out anyways, but WO and redlining does accelerate that process.
In Europe hill climbing is popular and i know few drivers and their cars (golf gti,clio sport etc.).This cars are redlined for a 5 to 8 km at time and after a season they all need rebuild.
Originally Posted By: IndyIan
Originally Posted By: SHOZ
Originally Posted By: IndyIan
But higher bearing loads must create higher oil flow velocities in the bearing and cause more wear. Is it significant in a happy engine with a conservative rev limiter, probably not. But it you take a high mileage engine and keep it WO near the rev limit all the time, it will fail faster that if you babied it.
But if the vehicle is geared correctly who does that, keeping it at high rpms? The last vehicle I drove like that was an early 60's International Scout that had a top spreed of around 55mph, rpm limited.
Guys like me autocrossing old beaters, I've seen/heard a few old engines that didn't sound quite as happy and the end of the day, as they did at the beginning. They were on their way out anyways, but WO and redlining does accelerate that process.
If the motor is already worn enough or otherwise near failure, it'll definitely go sooner when pushed hard. However, when everything is within proper tolerances and operating as it should be, the difference in life between gentle use and hard running is a lot smaller.
FWIW, as far as piston ring wear, last time we did a cranking compression test on the pair of 454s in the boat (run much, much harder than they'd ever see in a car), no cylinder read under 145 psi on lukewarm engines (~110 - 120 coolant temp) with no oil in the cylinders. A few still hit the 155 psi the manual specs for a new engine.
Keep in mind, normal cruising speed for these motors is ~3200 rpm at 2/3 to 3/4 throttle. They had about 1200 hours on them when we did that test, probably between 800 and 1000 of which was at cruise with a few excursions above that and the rest of the time spent around 1100 - 1300 rpm with the throttles barely cracked. And this is with carbs too, and marine carb setups usually run kinda rich for safety. Not to mention, they run pretty cold by most standards (which should make wear worse), as they have oil coolers with no thermostats and the t-stats in the cooling system are 143*, so they sit around 145 - 150* at idle and under light load, around 170 - 190* at cruise, depending on water temp (heat exchangers are a little on the small side).
Originally Posted By: SHOZ
Originally Posted By: IndyIan
But higher bearing loads must create higher oil flow velocities in the bearing and cause more wear. Is it significant in a happy engine with a conservative rev limiter, probably not. But it you take a high mileage engine and keep it WO near the rev limit all the time, it will fail faster that if you babied it.
But if the vehicle is geared correctly who does that, keeping it at high rpms? The last vehicle I drove like that was an early 60's International Scout that had a top spreed of around 55mph, rpm limited.
Guys like me autocrossing old beaters, I've seen/heard a few old engines that didn't sound quite as happy and the end of the day, as they did at the beginning. They were on their way out anyways, but WO and redlining does accelerate that process.
If the motor is already worn enough or otherwise near failure, it'll definitely go sooner when pushed hard. However, when everything is within proper tolerances and operating as it should be, the difference in life between gentle use and hard running is a lot smaller.
FWIW, as far as piston ring wear, last time we did a cranking compression test on the pair of 454s in the boat (run much, much harder than they'd ever see in a car), no cylinder read under 145 psi on lukewarm engines (~110 - 120 coolant temp) with no oil in the cylinders. A few still hit the 155 psi the manual specs for a new engine.
Keep in mind, normal cruising speed for these motors is ~3200 rpm at 2/3 to 3/4 throttle. They had about 1200 hours on them when we did that test, probably between 800 and 1000 of which was at cruise with a few excursions above that and the rest of the time spent around 1100 - 1300 rpm with the throttles barely cracked. And this is with carbs too, and marine carb setups usually run kinda rich for safety. Not to mention, they run pretty cold by most standards (which should make wear worse), as they have oil coolers with no thermostats and the t-stats in the cooling system are 143*, so they sit around 145 - 150* at idle and under light load, around 170 - 190* at cruise, depending on water temp (heat exchangers are a little on the small side).
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