No there aren’t. I’d be fairly certain that there are no street engines in excess of 100% VE at 6000rpm, and I’m positive that there aren’t any if we’re talking about larger (5.0L +) v8’s.

Maximum VE happens at torque peak, and it will only exceed 90-95% (more typically in the 80’s with a 2 valve engine) on any engine with some sort of ram effect. By the time you get to HP peak and redline you’re more likely to see ve’s in the 65% or evne lower range. Even boosted engines which see ve’s in excess of 100% for much of their power band only see that if you measure volume before the compressor, if you measure it after the compressor (taking into account the density ratio of the air being moved) you’ll see roughly the same VE as you would NA.

Grossly oversimplified, yes. If I was attempted to cover every contingency I’d end up writing a book, or at least a few hundred pages. Within the context of this discussion, very accurate. All approximation was done to the side of ‘big airflow increases will help,’ as opposed to what I was trying to demonstrate. Yes, if EVERYTHING else was taken into account the end result would be different, the flow #’s would be smaller. In the end the conclusion would be the same.

Depends on the application. GM just released some new big block marine engines, and there is always talk about bigger truck engines. Yes, efficiency is the goal, but not at greater expense.

And yes, BMW is a perfect example. It’s a perfect example of a manufacturer that HAS to use the latest technology to satisfy their customers, but not necessarily to satisfy their customers need for performance. Lucky for them, most of their customers are willing to pay big $$$ for that technology and rarely if ever will put it up against a decidedly low tech LS6 or Viper at the drag strip.

Yes, the technology will eventually come, but it’s doubtful that it will come in the context of performance, but in a combination of market pressure and emissions/fuel efficiency goals (ex, the new restrictions just imposed last week on large SUV’s). Remember, the LS_ wasn’t designed so much with the f-body/vette, but for the full size trucks. The Chrysler V10 and new hemi – also for their trucks…. We get performance as a side effect of what the truck market does, not vice versa. As long as they can get bigger and more powerful without relying too heavily on the duramax/powerstroke/Cummins, we’ll see beefier performance engines.

 

So what are you saying exactly? That I'm a liar?? I told you that I've seen numerous examples of normally aspirated engines in excess of 100% volumetric efficiency. You're saying I haven't? Excuse me for being just a little bit offended.

You sir are incorrect. Here are some dyno sheets for you to learn from.
The first is a 'large' displacement 379 cid race motor (larger than your 'large' 5.0 v8). This was a bracket motor we built last year. This engine made power to 8200 rpm so we'll start the numbers at 5600 and go in 400 rpm steps. The dyno was set at 100 rpm steps but that would take alot more time than I wanna spend.

5600
air density, 93.4 ** air fl. (# per hr) 2422 ** cfm 566 scfm 606 ** a/f % 12.0 ** VE 97.6% ** Fuel F (# per hr) 200

6000 (peak torque)
air density, 93.4 ** air fl. (# per hr) 3026 ** cfm 707 scfm 757 ** a/f % 12.7 ** VE 113.8% ** Fuel F (# per hr) 238

6400
air density, 93.4 ** air fl. (# per hr) 2938 ** cfm 686.4 scfm 734.9 ** a/f % 11.7 ** VE 103.5% ** Fuel F (# per hr) 251

6800
air density, 93.4 ** air fl. (# per hr) 3213 ** cfm 750.6 scfm 803.6 ** a/f % 12.4 ** VE 106.6% ** Fuel F (# per hr) 260

7200
air density, 93.4 ** air fl. (# per hr) 3476 ** cfm 812 scfm 869 ** a/f % 12.2 ** VE 108.9% ** Fuel F (# per hr) 284

7600
air density, 93.4 ** air fl. (# per hr) 3544 ** cfm 828 scfm 886 ** a/f % 12.3 ** VE 105.2% ** Fuel F (# per hr) 289

8000
air density, 93.4 ** air fl. (# per hr) 3594 ** cfm 840 scfm 899 ** a/f % 11.7 ** VE 101.3% ** Fuel F (# per hr) 309

8200 (peak horsepower)
air density, 93.4 ** air fl. (# per hr) 3619 ** cfm 846 scfm 905 ** a/f % 11.6 ** VE 99.5% ** Fuel F (# per hr) 311

I have the dyno results from a 401 cid street motor (586 hp @ 6500 rpm) somewhere and from memory, that motor was also well over 100% VE. I'll dig it up later and post for the naysayer. The previous engine uses nothing extremely fancy in the induction department. A cast aluminum Brodix HV1802, a Jean Dittmer design which was left untouched. Draw your own conclusions.

Quote:

Grossly oversimplified, yes. If I was attempted to cover every contingency I’d end up writing a book, or at least a few hundred pages. Within the context of this discussion, very accurate. All approximation was done to the side of ‘big airflow increases will help,’ as opposed to what I was trying to demonstrate. Yes, if EVERYTHING else was taken into account the end result would be different, the flow #’s would be smaller. In the end the conclusion would be the same.

Sorry, but I don't feel you're qualified to write such a 'book'. I personally wouldn't read it. Nothing to feel offended about though... I'm not qualified either.
Best of luck in your studies.

-Mindgame

 

BTW, here's that article on the Joe Sherman 306 Ford I mentioned. http://www.jason.fletcher.net/tech/sherman/400pg4.jpg

Tough to read, but you'll notice that the article say that Joe's motor "never dropped below 100% VE with either intake"... referring to the Vic Jr and Performer.
I'll find that other dyno sheet and post it later.

Happy learning.

-Mindgame

 

I don’t think that I ever said or implied that you were a liar, but I did say that you were incorrect, and now I will also say that your responses are deceptive (only you can tell us if that was unintentional or intentional). You stated ‘street engine’ and it could be argued that we’re talking production engines, yet you post examples of a ‘race engine.’ (your own words).

For that matter your ‘race engine’ example doesn’t even disagree with that I said. It does produce peak VE at peak torque, where it obviously is bennifiteing from a ram tuning effect, and the only reason that the VE isn’t lower at peak HP is that it’s already at 8200rpm and it was probably running into other restrictions at that point (valve train stability or other harmonics), and if it wasn’t for that peak hp would have been higher at a higher rpm with a lower VE.

As far as I can tell you’re just posting to argue without a real point or valid argument.

WRT to Joe Sherman, that man and some of his knowledge in the area is in a category with very few other people, fewer still that actually talk about what they know.

 

Deceptive? Is it deception to clearly state that the engine in that example was a "race engine" used for "bracket racing".... that in your opinion is "deceptive"?? Please... thou dost try too hard.
Also, let's try not to stray..... there was never a mention of "production engines"... let's keep this where it originally was, on the subject of "street engines", which encompasses a little more than stock OEM stuff.

You said that you are, "fairly certain that there are no street engines in excess of 100% VE at 6,000 rpm". I find that somewhat hilarious, because there is this degree of uncertainty in your response yet you are so adamant to defend it. I'm sorry to tell you that you will not always be right and neither will I but I'll always be confident in my answers.
Here is the dyno sheet from the "street engine" I mentioned earlier. I'll use 500 rpm steps for this one and narrow it down to the bare necessities.

3000 rpm
258hp 450lbs-ft 92.2% VE

3500
304/471 94.6% VE

4000
372/512 98.2% VE

4500
464/539 103.5% VE

4800 (peak torque)
479/554 107.3% VE

5000
495/542 106.6% VE

5500
536/530 105.1% VE

6000
569/512 102.7% VE

6300 (peak hp)
582/492 100.3% VE

That's a street engine... AFR 215 RR heads, a mechanical roller cam, Vic Jr intake, 1 7/8 headers....... Not too far off what alot of people on this board are running.

Quote:

For that matter your ‘race engine’ example doesn’t even disagree with that I said. It does produce peak VE at peak torque, where it obviously is bennifiteing from a ram tuning effect, and the only reason that the VE isn’t lower at peak HP is that it’s already at 8200rpm and it was probably running into other restrictions at that point (valve train stability or other harmonics), and if it wasn’t for that peak hp would have been higher at a higher rpm with a lower VE.

Did I ever disagree with your "Peak VE usually occurs at peak torque" statement? No, I did not. That is not where this arguement lies. I believe everyone who's picked up a copy of Hot Rod magazine understands very well the fact that peak tq and peak VE coincide with each other.
By the way, how many high performance race engines have you built or is this all... theoretical?

Quote:

As far as I can tell you’re just posting to argue without a real point or valid argument.

I beg to differ. I have never argued just for the sake of arguement. I argue because you are making generalized statements that say to me.... this guy must have just started learning this stuff and is a little astray. Besides, you will never learn anything from someone who agrees with you all of the time. I don't mind a little arguement here and there... too many people on this board fear it and would rather sit back, disagree and stay quiet for fear of making a mistake. Most would rather parasite off of our more knowledgable members responses. Then pass that knowledge off as their own. See it all the time here and it's one of the reasons I stay away from message boards.

If you have some hard data to the contrary then I'd love to see it. Nothing personal in any of this... might need to grow a thicker skin before it's all over though. Besides, I think I can drag up some BBC dyno results (a 502) that made better than 100% VE and about 700 lbs-ft of torque.

-Mindgame

 

Probably the single best post that has ever hit this board.

I learn new stuff every day b/c of the guys on here and really appreciate their help. I am guilty of the passing info along, but i do make sure that i say where it came from. But studying this stuff on my own on a daily basis, off the boards, is where I get most of what i do know.

You learn more from your mistakes than your accomplishments, that's something you can't argue with. Hell, I still remember questions/answers from tests i failed way back in 3rd grade, yet i couldn't tell you jack about the final i made a B on 2 weeks ago. A "good arguement" (no pissing matches) on the boards is beneficial to everyone.

Keep it up and keep it clean guys....

 

I won't argue with learning things, I don’t think any of us would be here if we weren’t interested in learning things or picking up new ideas. What’s bugging me is that mindgame is trying to say ‘you’re wrong’ giving an example that is out of context which still ends up still agreeing with my overall point. The fact is that there isn’t anything to argue except the fact that he appears to want an argument.

Oh well…

 

same here and i should come here more often.

 

You may or may not already know this, but I figured I would point it out just in case . But, it is a bit late and I'm a bit tired, so if I get any of this wrong I apologize in advance.

The ram tuning effect is otherwise known as a Helmholtz resonator. The resonator actually being the intake manifold. The goal is to get the resonance to become in phase with the intake pulses, thus boosting VE. At any rate, it is very possible to obtain > 100% VE if you design everything to take advantage of the resonance effect. Personally, if I was going to shell out fat cash to build an engine, I would definately allow for this in order to maximize my efforts.

Wow, I'm a little more tired than I thought, so I hope I said this all right

 

Yep. Been building loudspeaker enclosures in my spare time for most of my life. Mostly stage and studio monitors for bands and recording studios as well as bass cabinets/sub boxes for bands and nightclubs. Lately it’s been studio monitors for a ‘high concept’ movie production co, somewhat similar to the Alesis Studio I’s and experimenting with aperiodic bichamber sub boxes (think direct radiating driver with 2 chambers and 3 ports behind it tuned to 2 different frequencies giving it a broader and flatter response curve then most vented boxes.

Anyway, the Helmholtz resonator is tuned by changing the volume of air in it which tunes it for a specific frequency (as the port cross section gets larger the length needs to be greater to tune for the same frequency). When tuning a intake runner/port with this in mind you need to compare the velocity of the air flow in the port to the tuned frequency of the port and the reflection at the end of the port helps push the air along a little harder (I’m not sure that that was at all clear). Each subsequent reflection off either end of the port acts as another tuning point, progressively getting weaker (2nd order creates a pulse strength of roughly 10%, 3rd- 7%, 4th- 4%). First order reflections would be strongest but would require port/runner lengths in excess of what could realistically be packaged. Very few work for the 2nd order (the over 25” runners on a TPI intake make the second order fall around 5300rpm range, outside of the effective airflow potential for that intake/heads/cam on an L98 350), but most tune for 3rd and 4th order (past that they get weak enough that the increase is virtually unmeasurable with any statistical accuracy).

This is much harder to accurately calculate for an engine then a speaker (it’s actually simple for a speaker) because of the changes in pressure over the dynamic range of the engine. You can change the tuning frequency by even changing something that would appear unrelated like the TB (because it would present a larger or smaller restriction to the engine changing the pressure in the runners). Somewhere I’ve got a spreadsheet that I made up that estimates the tuning frequency based on some empirical #’s sorta tempered with the math to come close…

 

Do note that VVT aside, the LS1 gets about the best mileage of any engine in its HP range. Compare an M3 engine (3.0 L, VVT, 333 HP) v a 5.7 L 405 HP Z06 engine-the Z06 gets as good or better mileage ratings on city and hwy, and makes more HP! The LS1 has a fabulous cylinder head and intake design, even with its crude OHV layout, and ultimately, I'd worry much more about my cylinder head design than VVT. Who cares if the engine has bigger displacement? Irrelevant. One day we'll have electric or gas pressure operated valves with computer control like has been tested in F1 engines , but till then, cylinder heads are the name of the game! IF cost is a factor (and it always is), spend the money on the heads, not the VVT

 

Well.. one thing I am seeing is that more domestics are coming with DOHC cam engines and not pushrods...

Look at the northstar engine... its beeing put more and more on more cars.

If the LS1 is so great (and I think it is, having a z06) why dont they use it on the luxury cars???

On another sidenote...

Mercedez AMG class now is having 493HP and uses 3 valves per cylinder... not 4 (if not mistaken)

 

I don't think it's so great, but others do. Really it's an AWSOME set of 2valve heads on a mediocre engine.

The reason that you don’t see them in luxury cars is that on the NVH scale it’s a rough running bitch, which is something that you don’t want to see/hear/feel in a luxury car

 

Any engine that can make 1.5 hp per cid on mild modifications is a great engine in my opinion.
And I bet it'd be just as smooth as any other V8 luxury car with an even milder camshaft. Most of the other luxury cars in the GM lineup have their own engine development thing going on... Buick, Olds, Cadillac.

-Mindgame

 

i was searchng around eaby and found a old hot rod mag or something like that thet had "uel overhed chevy heads" on the cover. it was from like the 60s. if someone had the tools you cna make your own heads and use vvt. but its easier jsut to build a 355 and throw twin turbos on