Rev Limiter

KARNUT · July 18, 2021

Every vehicle I've owned in the modern age, wouldn’t hit redline without tuning. Even with tuning there’s only so far it would go. In park I couldn’t say.

Ge0rge · July 20, 2021

OMG, that comment had me cracking up. My music likely didn't help it but I didn't have it cranked up though at the time, was not on the highway yet, lol. I do have a 600w Rockford Fosgate Amp and 10" Sub under the seat for those long ass rides.

Edited July 20, 2021 by Ge0rge

Ge0rge · July 20, 2021

I am still confused about being in Manual 1 and what the truck should do to save itself. I now know it won't auto shift but should fall flat on its face. When I noticed it the tach was pegged. I checked the oil and everything looked good. It was a fresh change but I changed it just do to be safe, May not mean anything but I figured it could not hurt.

Edited July 20, 2021 by Ge0rge

truckguy82 · July 20, 2021

9 hours ago, Ge0rge said:

I am still confused about being in Manual 1 and what the truck should do to save itself. I now know it won't auto shift but should fall flat on its face. When I noticed it the tach was pegged. I checked the oil and everything looked good. It was a fresh change but I changed it just do to be safe, May not mean anything but I figured it could not hurt.

You did zero damage. There are people who hit the rev limiter everyday.

I mean the 6.2 has the cutoff at 6k rpm, and it’s the exact same engine as the one in the corvette, and that cuts off at 6600rpm.

You did zero damage at the cutoff and it could probably run through an entire tank of gas bouncing off the rev limiter, well if you had enough cooling.

truckguy82 · July 20, 2021

2 hours ago, truckguy82 said:

You did zero damage. There are people who hit the rev limiter everyday.

I mean the 6.2 has the cutoff at 6k rpm, and it’s the exact same engine as the one in the corvette, and that cuts off at 6600rpm. It just shows they are conservative.

You did zero damage at the cutoff and it could probably run through an entire tank of gas bouncing off the rev limiter, well if you had enough cooling.

Dunno how to delete this with stupid mobile format

Edited July 20, 2021 by truckguy82

newdude · July 20, 2021

On 7/18/2021 at 8:05 AM, truckguy82 said:

Well it’s good info to know when you drive a vehicle with a 6k rpm redline and the identical motor in another vehicle goes to 6600rpm.

I'm not sure why you keep bringing this point up. Who cares if its identical? If you took a 6.2 truck and re-tuned the redline to 6600rpm, you will gain nothing.

One is tuned and mapped to pull its 5800lbs curb weight and 12,000lbs, the other a 3600lbs 200mph sports car.

JimCost2014 · July 20, 2021

14 hours ago, Ge0rge said:

I am still confused about being in Manual 1 and what the truck should do to save itself. I now know it won't auto shift but should fall flat on its face. When I noticed it the tach was pegged. I checked the oil and everything looked good. It was a fresh change but I changed it just do to be safe, May not mean anything but I figured it could not hurt.

If you broke/hurt something, you would know.

You would have a CEL and reduced power mode (limp), or it would not run at all.

truckguy82 · July 20, 2021

3 hours ago, newdude said:

I'm not sure why you keep bringing this point up. Who cares if its identical? If you took a 6.2 truck and re-tuned the redline to 6600rpm, you will gain nothing.

One is tuned and mapped to pull its 5800lbs curb weight and 12,000lbs, the other a 3600lbs 200mph sports car.

Because it means we know for a fact they put the rev limiter far below what the engine is actually capable of spinning without damage. Which also means they probably did the same thing with the 5.3 considering it has a similar power-band and architecture. Which means the OP probably doesn’t have to worry, which is the entire point of this thread

KARNUT · July 20, 2021

A famous person once said. Your heart only has so many beats until it wore out. That was the answer Rush Limbaugh gave when ask about exercising. And why he didn’t. The same goes for an engine. Sure briefly hitting the rev limiter in gear and shifting usually wouldn’t grenade an engine. There’re not built to live up there for any sustained amount of time. Otherwise race teams would never need to refresh their high dollar engines as often.

truckguy82 · July 20, 2021

1 hour ago, KARNUT said:There’re not built to live up there for any sustained amount of time. Otherwise race teams would never need to refresh their high dollar engines as often.

Pretty sure there are some boat builders and owners that would disagree.

Race engines are totally different, the perfect race car engine blows up as it crosses the finish line.

KARNUT · July 20, 2021

21 minutes ago, truckguy82 said:

Pretty sure there are some boat builders and owners that would disagree.

Race engines are totally different, the perfect race car engine blows up as it crosses the finish line.

I’ve done my share of racing and heavy hauling my equipment with gas and diesel one tons. Diesels last because they make power at low RPMs. The gas rigs, 390, 454, V-10s lasted half of what my diesels did because of RPMs. My drag race cars never used max RPMs. I used high TQ lower RPM cams to make power. Small blocks 6K, big blocks 5K. I never raced boats. I imagine they went through them often. I only blew one engine in 40 years. Ram V-10. I couldn’t handle mountain passes at almost redline in third gear. The same truck with the diesel no problem. Lower RPMs same TQ. Your analysis of a perfect race engine is amusing.

truckguy82 · July 20, 2021

19 minutes ago, KARNUT said:

I’ve done my share of racing and heavy hauling my equipment with gas and diesel one tons. Diesels last because they make power at low RPMs. The gas rigs, 390, 454, V-10s lasted half of what my diesels did because of RPMs. My drag race cars never used max RPMs. I used high TQ lower RPM cams to make power. Small blocks 6K, big blocks 5K. I never raced boats. I imagine they went through them often. I only blew one engine in 40 years. Ram V-10. I couldn’t handle mountain passes at almost redline in third gear. The same truck with the diesel no problem. Lower RPMs same TQ. Your analysis of a perfect race engine is amusing.

I was thinking more along the lines of professional racing, and lasting until the finish line is well known saying.

I wasn’t talking about racing boats either. You said engines don’t like being at max rpm for a long time, well that’s exactly what they do in boats. The literally put car engines, small block v8’s just like ours, into boats and they can and will sustain high rpm for hours.

Max rpm is an arbitrary number the manufacturer decided to limit the rpm too. Evident by my point that they limited the l86 to 6k rpm. I mean, yeah obviously 6k rpm is worse than 2k rpm. But a blanket statement of saying they are “not built to stay up there” simply isn’t true.

what there not design to do is stay up there without shitloads of cooling, which is probably why your v10 blew up

Edited July 20, 2021 by truckguy82

truckguy82 · July 20, 2021

25 minutes ago, KARNUT said:

Your analysis of a perfect race engine is amusing.

“The perfect racing car crosses the finish line first and subsequently falls into its component parts."

-- Ferdinand Porsche

Is it still amusing coming from the founder of the most successful racing company that was ever created.

Edited July 20, 2021 by truckguy82

KARNUT · July 20, 2021

1 minute ago, truckguy82 said:

“The perfect racing car crosses the finish line first and subsequently falls into its component parts."

-- Ferdinand Porsche

8 minutes ago, truckguy82 said:

I was thinking more along the lines of professional racing, and lasting until the finish line is well known saying.

I wasn’t talking about racing boats either. You said engines don’t like being at max rpm for a long time, well that’s exactly what they do in boats. The literally put car engines, small block v8’s just like ours, into boats and they can and will sustain high rpm for hours.

Max rpm is an arbitrary number the manufacturer decided to limit the rpm too. Evident by my point that they limited the l86 to 6k rpm. I mean, yeah obviously 6k rpm is worse than 2k rpm. But a blanket statement of saying they are “not built to stay up there” simply isn’t true.

what there not design to do is stay up there without shitloads of cooling, which is probably why your v10 blew up

Back in the day I used to shift when the valves floated. Adding a sun tac my small block Chevys usually made it just past 5K stock. Same with my small block Plymouth’s. I don’t think redlines are made up. It’s when the HP drops. Back to the original topic. You stay away from max RPMs they last longer. Especially these Frankenstein engines.