RE: Tuned LS7 V8 surpasses 11,000rpm | Time for Tea

[seefarr]

NFC 85 Vette said:

annodomini2 said:

Making an engine rev to those kinds of RPMs isn't the issue, it's still producing useful torque at those kinds of RPMs.

It depends a large amount on the valve train design. Cam-in-block engines do tend to struggle above 9k rpm. Stud mounted rockers often get swapped out for a shaft mounted system, and push rod design ends up leaning toward what we use in fuel engines. Anything to stop the tips getting mullered, and the push rod itself soon becomes anything but straight.

Pffft. Armchair Internet experts really get my goat. What would you know about running a 6.8L pushrod engine at 9k rpm, Mr Vette?



Oooooh. Right.

[Dr G]

SturdyHSV said:

Or 7 litres in capacity (haven't watched the video yet (no headphones) I'm just assuming it hasn't been de-stroked))

He says in the video it's now 358 ci so just over 5.7 litres. Takes nothing away from the achievement.

Can see them selling a few of those if it's durable enough to market.

[SturdyHSV]

shinjuku said:

Simonium said:

I’d like to know precisely what it is about this noise that people like so much. I’m not interested in the implications of the sound, but the sound itself.

I think it's the multitude of resonances. like multiple notes in a chord, harmonics. A choir, a symphony.

It'd be interesting to know whether it's something inherently in our nature, or just something learned. So for example if petrol V10s were the norm, would we all find them as irritating and st as 4 cylinders sound, and lust after the ropey drone of a 4 pot? I mean, that seems extremely unlikely but it's worth considering if we just associate 'nice' engine sounds as 'nice' because they are rarer and generally in more evocative vehicles, more powerful etc.

I think there's something quite basic about our enjoyment of engines, especially noisy ones. In terms of nature, loud noises mean danger, and perhaps it's related to things that 'roar' and have a wide range of pitches / sounds generally being dangerous as well? Certainly if you ask me a lot of multi-cylinder engines at middling revs / throttle openings have a very animalistic sounding 'roar' to them, is it simply the thrill of escaping danger etc. that excites some people.

I love the throb of a Subaru boxer 4, but it doesn't illicit a physical response, whereas the wail of a 5, 8, 10 or 12 cylinder can easily make my arm hairs stand on end. Although not a flat plane V8, just sounds like two angry 4 pots...

Perhaps it's not that complicated at all, who knows

[SturdyHSV]

Dr G said:

He says in the video it's now 358 ci so just over 5.7 litres. Takes nothing away from the achievement.

Can see them selling a few of those if it's durable enough to market.

Ah OK, that's thoroughly destroked then, LS7 is 4.185" bore and 4" stroke for 427ci, so maybe a 3.25" stroke? Rest of the LS range is 3.622", bet there's not been a lot of demand for a 3.25" de-stroke kit

[Gojira]

Is it sensible or practical - almost certainly not....

Is it worth doing, just to see what happens? Hell yeah!

[tdm34]

Utter lunacy, but you have to applaud him, epic noise....

[sidesauce]

SturdyHSV said:

It'd be interesting to know whether it's something inherently in our nature, or just something learned.

Personally I think it's more likely something learned than something inherent in all humans. Certainly,there are certain sound types we almost all universally respond to but from the point of view of personal taste, I don't think noisy engines are one of those "universal" sounds, at least not in a positive way...

[MParallel]

SturdyHSV said:

It'd be interesting to know whether it's something inherently in our nature, or just something learned. ...

Tell you what, I have no idea, but your post had me thinking of the Honda V10 F1 going around an oval (easy to find on youtube) and just thinking about that fit, just had my hairs stand up.

No joke.

Specially when it's on the other side of the track from viewer's point. Not as loud, but just the pitch, the brute force you just feel, like it's splitting air atoms. Brrrr....

here it is. This just tickles my spine and nerves. Put on some headphone for extra kick.

https://www.youtube.com/watch?v=YBxw4whvBiA

[Dr G]

SturdyHSV said:

Ah OK, that's thoroughly destroked then, LS7 is 4.185" bore and 4" stroke for 427ci, so maybe a 3.25" stroke? Rest of the LS range is 3.622", bet there's not been a lot of demand for a 3.25" de-stroke kit

I would argue that an 11k redline carries bigger bragging rights than a 427 badge

[SturdyHSV]

sidesauce said:

SturdyHSV said:

It'd be interesting to know whether it's something inherently in our nature, or just something learned.

Personally I think it's more likely something learned than something inherent in all humans. Certainly,there are certain sound types we almost all universally respond to but from the point of view of personal taste, I don't think noisy engines are one of those "universal" sounds, at least not in a positive way...

Well indeed but I wasn't necessarily saying that we respond in a 'basic' way and like the sound, in much the same way many people don't like other forms of sensory excess, be it g forces, heights, darkness etc., simply that perhaps the more complex sound signatures of higher / uneven cylinder counts are more akin to a legitimate and organic 'danger' sound

Even if that was the case, I would agree though that there is then a learned enjoyment of that sound through exposure and association etc.

[marksx]

MParallel said:

Tell you what, I have no idea, but your post had me thinking of the Honda V10 F1 going around an oval (easy to find on youtube) and just thinking about that fit, just had my hairs stand up.

No joke.

Specially when it's on the other side of the track from viewer's point. Not as loud, but just the pitch, the brute force you just feel, like it's splitting air atoms. Brrrr....

here it is. This just tickles my spine and nerves. Put on some headphone for extra kick.

https://www.youtube.com/watch?v=YBxw4whvBiA

Oh my

[Boosted LS1]

Glorious sound!

[Streetrod]

Take my money!!!! I need that engine in a streetcar

[J4CKO]

sidesauce said:

SturdyHSV said:

It'd be interesting to know whether it's something inherently in our nature, or just something learned.

Personally I think it's more likely something learned than something inherent in all humans. Certainly,there are certain sound types we almost all universally respond to but from the point of view of personal taste, I don't think noisy engines are one of those "universal" sounds, at least not in a positive way...

A very interesting question that I have pondered, I think its a mixture, even non petrolheads seem to enjoy the sound of certain engines, even a 4 cyl diesel can be learnt to be enjoyed as it is associated with your taxi arriving.

But a loping V8, my missus says that sound gets her every time, but its only certain ones, usually Muscle car type noises and not say AMG ones.

I think even newborns respond to rhythm and certain sounds, even when music is played to babies in the womb there is a response and they reckon babies can be born and recognise songs from before they were born, and an engine is a sort of music, well, good ones are and even st sounding engines mean the car is working, silent ones mean either broken on electric.

[ephemera]

There is a really good paper by an engineer from FEV in Germany investigating this topic and explaining the acoustics from an engine in relation to musical theory.

https://saemobilus.sae.org/content/2003-01-1508/#a...

[The Wookie]

MParallel said:

Tell you what, I have no idea, but your post had me thinking of the Honda V10 F1 going around an oval (easy to find on youtube) and just thinking about that fit, just had my hairs stand up.

No joke.

Specially when it's on the other side of the track from viewer's point. Not as loud, but just the pitch, the brute force you just feel, like it's splitting air atoms. Brrrr....

here it is. This just tickles my spine and nerves. Put on some headphone for extra kick.

https://www.youtube.com/watch?v=YBxw4whvBiA

How close was Taku to shoving in the wall off the line like a mustang pulling out of a cars and coffee meet?

[tdm34]

MParallel said:

SturdyHSV said:

It'd be interesting to know whether it's something inherently in our nature, or just something learned. ...

Tell you what, I have no idea, but your post had me thinking of the Honda V10 F1 going around an oval (easy to find on youtube) and just thinking about that fit, just had my hairs stand up.

No joke.

Specially when it's on the other side of the track from viewer's point. Not as loud, but just the pitch, the brute force you just feel, like it's splitting air atoms. Brrrr....

here it is. This just tickles my spine and nerves. Put on some headphone for extra kick.

https://www.youtube.com/watch?v=YBxw4whvBiA

That genuinely reminds me of the noise of Junkers JU87 Stuka dive bomber...

But the greatest racing engine noise has to be this.......

https://www.youtube.com/watch?v=fBWk-lkcrLY

Edited by tdm34 on Thursday 28th November 21:48

[big_rob_sydney]

Streetrod said:

Take my money!!!! I need that engine in a streetcar

Just on that, I'd be curious to know what an engine like this would cost.

[BogBeast]

big_rob_sydney said:

Just on that, I'd be curious to know what an engine like this would cost.

I imagine the rocker setup and valves/retainers are probably the most exotic, Valve springs are probably custom designed. Pushrods and lifters are probably well specced performance parts. I would guess Comp Cams would be keen to be able to sell a kit - there would be plenty of takers. The rest of the engine is probably a well-balanced steel short stroke kit from Crower or the like. Gain, not cheap not excessively expensive... .

Perhaps not as much as you would think at terms of bits of metal - Ultimately it depends if the man from the EFI University wants to see some money back for his IP/time and effort. Or would he open source it?

[anonymous-user]

seefarr said:

Pffft. Armchair Internet experts really get my goat. What would you know about running a 6.8L pushrod engine at 9k rpm, Mr Vette?



Oooooh. Right.

Ah but it only drives in a straight line, and was built in an old shed from WW2

Back to the LS7; the benefit with American V8's in the last 20 years or so is that many parts companies are setup to provide relatively bespoke, custom spec parts at sensible prices (custom pistons are between $600-900, rods around $1500). When you consider the inherent design of these engines dates back to the 1950's and 1960's, the changes over time have been mainly in materials, which allowed bigger, more aggressive cams, higher compression and higher revs.

An all singing, all dancing Jesel (or Comp Cams) shaft mounted rocker system isn't as expensive as one might think (about $1200 for Comp Cams stuff). Chevy stuff has always been relatively affordable, certainly compared to the Chrysler based kit. A rocker assembly for something like the Corvette will cost around $5000, and that's just rocker arms, shafts & stands. Granted, it has to cope with fairly high cylinder pressures and spring pressures, but the main thing is that the cheapest way of making power has always been a Chevy in either Small or Big Block form.

In any event, whichever flavour of poison, a sharply tuned Chevy, Ford or Mopar makes a gnarly noise, that might not be as delicate and operatic as an F1 engine, but has a charm in its own way.