Cruising regularly at 4000 rpm

[humfrz]

Originally Posted by Jordanwolf

Aren't variable compression ratio engines like brand new?

Good observation......

Yep, the concept is only about 20 years old.


humfrz

[ermax]

Let’s just say pressures did drop as revs built. That doesn’t mean the rings suddenly loose their spring effect and stop their contact with the sleeves or even reduce their outward force. I mean you could pull the plugs out but that wouldn’t prevent the rings from doing their job. If pressures dropped it would for sure drop the load on the bottom end but there isn’t any metal to metal contact in the bottom end anyways. The rods essentially ride on oil unlike the rings which are essentially scraping oil off the cylinders (why we don’t have purple smoke out the back).

Still can’t wrap my head around the pressures dropping on an engine that builds power all the way to redline. Not doubting anyone, just can’t wrap my head around it and would love to hear more.

[Tokay444]

Originally Posted by ermax

Let’s just say pressures did drop as revs built. That doesn’t mean the rings suddenly loose their spring effect and stop their contact with the sleeves or even reduce their outward force. I mean you could pull the plugs out but that wouldn’t prevent the rings from doing their job. If pressures dropped it would for sure drop the load on the bottom end but there isn’t any metal to metal contact in the bottom end anyways. The rods essentially ride on oil unlike the rings which are essentially scraping oil off the cylinders (why we don’t have purple smoke out the back).

Still can’t wrap my head around the pressures dropping on an engine that builds power all the way to redline. Not doubting anyone, just can’t wrap my head around it and would love to hear more.

Max cylinder pressure is at max torque. Not max horsepower.
Cylinder pressure is dynamic and in direct relation to valve timing and ignition timing.

[Jordanwolf]

Originally Posted by humfrz

Good observation......

Yep, the concept is only about 20 years old.


humfrz

I haven't really heard of them being applied to cars besides the infiniti so far.

[humfrz]

Originally Posted by Tokay444

Max cylinder pressure is at max torque. Not max horsepower.
Cylinder pressure is dynamic and in direct relation to valve timing and ignition timing.

Yep, for sure ....... as with any four cycle, internal combustion engine.

(intake-compression-power-exhaust)




humfrz

[Tokay444]

Originally Posted by humfrz

Yep, for sure ....... as with any variable valve timing, variable ignition timing, internal combustion engine.

(intake-compression-power-exhaust)




humfrz

[TorontoNat]

Originally Posted by Clipdat

Did you not get the memo that the most fun in this car happens between 4-7k RPM?

Why would you be only getting to 4.5k rpm when you're "really pushing it"? News flash, you aren't really pushing it.

This is truth. @op so you mean to tell me you've never downshifted into 3rd on the highway and floored it from 5K to 7K...... or pulled 2nd gear all the way up... Wait has your engine ever even seen redline??? These were designed to be pushed past the limit. Your engine is fine lol.

[humfrz]

Originally Posted by Jordanwolf

I haven't really heard of them being applied to cars besides the infiniti so far.

Oh, my bad ...... I meant 1920 ...... not 20 years old ......

From Wiki:

"The first VCR engine built and tested was by Harry Ricardo in the 1920s".


humfrz

[humfrz]

Originally Posted by Tokay444

Yes, including that kind too ......


humfrz

[ermax]

Originally Posted by Tokay444

Max cylinder pressure is at max torque. Not max horsepower.
Cylinder pressure is dynamic and in direct relation to valve timing and ignition timing.

Right but it still climes (torque) almost all the way to redline.

I still feel like the number of times the rings runs up and down the cylinder would have an impact on wear. I mean the ring closest to the skirt is called the scraper ring for crying out loud. It's job is to scrape the oil off the walls so it doesn't end up in the combustion chamber. It's spring loaded to press outward onto the walls. This can't possibly not cause more wear when doubling the number of times it passes in its lifetime. You also can't tell me rings/skits have an infinite lifespan. If that was the case you wouldn't see all these boy racers in Honda's blowing smoke all over the place. I can also tell you form first hand experience from my Integra. At 200k I was burning one qt per day (not an exaggeration). It wasn't leaking, it came out the back. I left a smoke screen and crap all over the cars behind me. Why did it do this, because I drove the piss out of it. I was one of the boy racers never cruising under 4K.

[StraightOuttaCanadaEh]

Originally Posted by TorontoNat

This is truth. @op so you mean to tell me you've never downshifted into 3rd on the highway and floored it from 5K to 7K...... or pulled 2nd gear all the way up... Wait has your engine ever even seen redline??? These were designed to be pushed past the limit. Your engine is fine lol.

If I'm on the highway, I'm usually shifting from 6th to 5th. Usually by the time the on ramp ends, I'm either in 5th or 6th depending on the impending need to overtake. If I see no traffic coming up, I chill and let her get to 130-140 at her own pace. Sometimes I feel like having fun and stretch it out in 3rd to 7K, but that's for a few seconds and I wasn't worried about that. 10-15 minutes at 4K was what I was concerned about.

[StraightOuttaCanadaEh]

Originally Posted by ermax

Right but it still climes (torque) almost all the way to redline.

I still feel like the number of times the rings runs up and down the cylinder would have an impact on wear. I mean the ring closest to the skirt is called the scraper ring for crying out loud. It's job is to scrape the oil off the walls so it doesn't end up in the combustion chamber. It's spring loaded to press outward onto the walls. This can't possibly not cause more wear when doubling the number of times it passes in its lifetime. You also can't tell me rings/skits have an infinite lifespan. If that was the case you wouldn't see all these boy racers in Honda's blowing smoke all over the place. I can also tell you form first hand experience from my Integra. At 200k I was burning one qt per day (not an exaggeration). It wasn't leaking, it came out the back. I left a smoke screen and crap all over the cars behind me. Why did it do this, because I drove the piss out of it. I was one of the boy racers never cruising under 4K.

I tend to agree with your posts. Your conclusion just makes more sense logically speaking. I don't know, we might be wrong but it just seems to be common sense.

[Jordanwolf]

Originally Posted by humfrz

Oh, my bad ...... I meant 1920 ...... not 20 years old ......

From Wiki:

"The first VCR engine built and tested was by Harry Ricardo in the 1920s".


humfrz

It's not exactly commercialised though?

[ermax]

Originally Posted by TorontoNat

This is truth. @op so you mean to tell me you've never downshifted into 3rd on the highway and floored it from 5K to 7K...... or pulled 2nd gear all the way up... Wait has your engine ever even seen redline??? These were designed to be pushed past the limit. Your engine is fine lol.

Again... the thread is talking about "cruising". Not passing... not racing... not accelerating just for the freaking hell of it (me). Hahaha.