Interesting...the piston crown you mention does look "complicated" .I've read similar findings from other tuners..So in a way, a dish instead of individual valve reliefs would be better according to Larry Widmar...Do you think this is a blanket statement, would a hemi. ,shallow angle 4 valve and a wedge all be affected the same?panic wrote:I hate to be the wet blanket (but it's the role I was meant to play, don't you agree?) but that Faberge egg of a piston dome shown above is properly called "not ready for prime time".
All those jewel-like precise "as CNC machined" sharp edges are trip wires that cause flow to fall on its face, move away, etc. and follow some path other than the one you intended.
If you're really lucky, that mistake will reverse another mistake (too much overlap), but it's more likely that it will produce the other effect: overlap flow is both delayed and reduced, and the engine will produce more peak power with a tighter LSA (which would be detrimental with a less intrusive piston dome, or reduced static CR).
No professional engine builder should use pistons in that state, except as window dressing for the unwary buyer.
A specific real-world example: Larry Widmer's work on the Honda B16 4-valve DOHC has shown (at least to his satisfaction, and he's smarter than I am) that a single slot connecting the 2 intake valve reliefs improves power despite the chamber volume increase and resultant loss of static CR - the flow leaving the valves improves by getting dome material far away from them whenever possible.
</rant>
NA Engines: Factors that increase torque
Moderator: Team
Re: NA Engines: Factors that increase torque
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: NA Engines: Factors that increase torque
This Arias piston is from a Natural Gas (Research Octane number ~130) program I carried out a number of years back on a 2.5 L. 4 cylinder engine. The goal was to arrive at the optimum CNG compression ratio by dynoing it with successively lower CRs via whittling down the large initial dome. Looks more like the peel of an orange that the combustion-ideal sphere of the orange itself!
With the short duration stock cam, cranking compression at 17:1 was literally off the scale and the the engine wouldn't crank on the starter; it had to be spun up by motoring the electric dyno. (And yes, it knocked. Next round at 14.5:1 was OK, but still marginal for cranking.)
With the short duration stock cam, cranking compression at 17:1 was literally off the scale and the the engine wouldn't crank on the starter; it had to be spun up by motoring the electric dyno. (And yes, it knocked. Next round at 14.5:1 was OK, but still marginal for cranking.)
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Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: NA Engines: Factors that increase torque
With NG, isn't it amazing how well NG runs extremely lean?MadBill wrote:This Arias piston is from a Natural Gas (Research Octane number ~130) program I carried out a number of years back on a 2.5 L. 4 cylinder engine. The goal was to arrive at the optimum CNG compression ratio by dynoing it with successively lower CRs via whittling down the large initial dome. Looks more like the peel of an orange that the combustion-ideal sphere of the orange itself!
With the short duration stock cam, cranking compression at 17:1 was literally off the scale and the the engine wouldn't crank on the starter; it had to be spun up by motoring the electric dyno. (And yes, it knocked. Next round at 14.5:1 was OK, but still marginal for cranking.)
What did you find you had to do with A/F and ignition in term of energy and type of system - CD or induction - type of spark plug and timing?
Re: NA Engines: Factors that increase torque
That particular program didn't get much farther. It was being tested on a double-ended electric dyno and the engine on the other end suffered a 'rapid and comprehensive unintended disassembly' that trashed the dyno. By the time it was up again the project was back-burnered by critical production work.
in later production targeted work, we found as much as 4,000 volts more firing voltage was required for both CNG and propane, but the stock system proved adequate. (On bi-fueled vehicles, the need for a tune up was always signaled by misfire on the gaseous fuel.) AIR, spark advance was only a few degrees different, mostly just a bit faster 'curve'. For emissions reasons, lean burn was not an option.
in later production targeted work, we found as much as 4,000 volts more firing voltage was required for both CNG and propane, but the stock system proved adequate. (On bi-fueled vehicles, the need for a tune up was always signaled by misfire on the gaseous fuel.) AIR, spark advance was only a few degrees different, mostly just a bit faster 'curve'. For emissions reasons, lean burn was not an option.
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: NA Engines: Factors that increase torque
Would somebody hunt down a link to the late Mr. Fueling's 454 BBC aluminum torque truck head. It might help a lot here.
And fwiw, a Mr. Ray T. Bochaz(Sp?) wrote two back to back tech articles that were published in onna the old mags.
The articles were about how some kids at a Tech School, (Wyotech? seems to come to mind), that were given a new 502 to play with and the jist of all this is that they wanted to run it at 12.1(?) to 1 CR on 87 octane pump gas and hopefully hit something like 700 T.
They used Mr. Fueling's heads to do it.
They didn't reach 700 T, but I think they hit 650 or T using something like a 220(?), sorry, I forget, cam.
But imho, to max torque "FOR FUEL OCTANE RATING USED", use small combustion chambers so that the CR can still be OK because of using flat-top pistons, and next long rods!! As well as low duration at .050" lift. Cam here, no more than GM's great old -929 is a heck of an old torque cam...
An intake like E-Brock's old SP-2P intakes and also, "SMALL", 4-tube long tube headers come into play here too!
Please look up Mr. Fueling's head!!!
He was the, "head man", before he died!! He was in on the old Olds Quad-4 head, land speed record head, and both Ford and M/B had patent infringement cases filed against them by him because he did both, 3 and 4-valve head design way early on.
pdq67
And fwiw, a Mr. Ray T. Bochaz(Sp?) wrote two back to back tech articles that were published in onna the old mags.
The articles were about how some kids at a Tech School, (Wyotech? seems to come to mind), that were given a new 502 to play with and the jist of all this is that they wanted to run it at 12.1(?) to 1 CR on 87 octane pump gas and hopefully hit something like 700 T.
They used Mr. Fueling's heads to do it.
They didn't reach 700 T, but I think they hit 650 or T using something like a 220(?), sorry, I forget, cam.
But imho, to max torque "FOR FUEL OCTANE RATING USED", use small combustion chambers so that the CR can still be OK because of using flat-top pistons, and next long rods!! As well as low duration at .050" lift. Cam here, no more than GM's great old -929 is a heck of an old torque cam...
An intake like E-Brock's old SP-2P intakes and also, "SMALL", 4-tube long tube headers come into play here too!
Please look up Mr. Fueling's head!!!
He was the, "head man", before he died!! He was in on the old Olds Quad-4 head, land speed record head, and both Ford and M/B had patent infringement cases filed against them by him because he did both, 3 and 4-valve head design way early on.
pdq67
Re: NA Engines: Factors that increase torque
Jim Feuling was a self taught innovator and genius of his time at cylinder head technology. the Feuling Centerfire 454 truck head for the Vortec 7.4L engine actually also received a 50 state CARB certified emissions approval and was found to be 25% more emissions efficient than the best GM head.
You can read
The Good Ones always seem to die to young!
You can read
and see some of his accomplishments and innovation. Feulings family still operates the company as a motorcycle racing parts company. I also think Jim Feuling did some great motorcycle cylinder head development for Harley Davidson and Buell !About Us at http://www.feulingparts.com
The Good Ones always seem to die to young!
The Older I Get, The Dumber I Get 
Re: NA Engines: Factors that increase torque
Including a 150" Harley-based 'W3'.Newold1 wrote:... I also think Jim Feuling did some great motorcycle cylinder head development for Harley Davidson and Buell !
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: NA Engines: Factors that increase torque
http://www.camaros.net/forums/18-engine ... ohacz.html
By me!
"The first article from Mr Bahacz's on the fueling system was in the April 1997 issue of Popular Hot Rodding on page 34.
I didn't buy the mag with the "Coates" rotary valve article, but that was it.
Mr Bahacz wrote parts one and two of an article in "Engines" by the Hot Rod Performance Series (Display Until 4/24/2000 date on the shelves) where a bunch of "kids" (with great respect) at Nothwestern College, Lima, OH did a buildup on a 502 using the fueling sustem. The project was "kind of" snake bit (as aren't all projects) but the overall gist of the program was very promising, (like very low SBFC numbers on 87 octane gasoline with a C.R. of about 12 to 1, and unbelievable torque.
I think these articles came out originally in Car Craft.
These got me thinking about two articles in Pop Hot Rodding about building engines that run on low octane fuel but have high C.R.'s by using very small compression chambers, flat top pistons and long rods if you could fit them and afford them.
One article was on small and big block chevys and the other on a pair of "blue oval" engines.
It said to take the smallest combustion chamber head you can find and plane it .100" more to minimize chamber volume. This along with a flat top piston "supposeably" makes the engine more efficient in the combustion process and so it doesn't preignite or detonate. Has anybody done any engine building using these techniques???"
pdq67
By me!
"The first article from Mr Bahacz's on the fueling system was in the April 1997 issue of Popular Hot Rodding on page 34.
I didn't buy the mag with the "Coates" rotary valve article, but that was it.
Mr Bahacz wrote parts one and two of an article in "Engines" by the Hot Rod Performance Series (Display Until 4/24/2000 date on the shelves) where a bunch of "kids" (with great respect) at Nothwestern College, Lima, OH did a buildup on a 502 using the fueling sustem. The project was "kind of" snake bit (as aren't all projects) but the overall gist of the program was very promising, (like very low SBFC numbers on 87 octane gasoline with a C.R. of about 12 to 1, and unbelievable torque.
I think these articles came out originally in Car Craft.
These got me thinking about two articles in Pop Hot Rodding about building engines that run on low octane fuel but have high C.R.'s by using very small compression chambers, flat top pistons and long rods if you could fit them and afford them.
One article was on small and big block chevys and the other on a pair of "blue oval" engines.
It said to take the smallest combustion chamber head you can find and plane it .100" more to minimize chamber volume. This along with a flat top piston "supposeably" makes the engine more efficient in the combustion process and so it doesn't preignite or detonate. Has anybody done any engine building using these techniques???"
pdq67
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user-23911
Re: NA Engines: Factors that increase torque
On the subject of natural gas, it's one of the best fuels.
I've had 2 cars running on it over about a 10 year period.
With medium/ low CR it'll never knock. You can lean out the AFR to the point where it just cuts out.
You can over advance the timing to the point where it shakes, like it's trying to run backwards.
But it won't knock and you won't break the engine.
The downside is that there's a noticeable lack of power, you can make up for that with a turbo.
Then there's the short range. depending on tank size, about half what you'll get with petrol.
These days the thing seems to be HHO injection.
It seems to have some similarities to water injection but also similarities to CNG because CNG contains hydrogen.
I don't think anyone on here has brought it up?
I've had 2 cars running on it over about a 10 year period.
With medium/ low CR it'll never knock. You can lean out the AFR to the point where it just cuts out.
You can over advance the timing to the point where it shakes, like it's trying to run backwards.
But it won't knock and you won't break the engine.
The downside is that there's a noticeable lack of power, you can make up for that with a turbo.
Then there's the short range. depending on tank size, about half what you'll get with petrol.
These days the thing seems to be HHO injection.
It seems to have some similarities to water injection but also similarities to CNG because CNG contains hydrogen.
I don't think anyone on here has brought it up?
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NewbVetteGuy
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Re: NA Engines: Factors that increase torque
I must be misreading what you're saying....pdq67 wrote:http://www.camaros.net/forums/18-engine ... ohacz.html
By me!
"The first article from Mr Bahacz's on the fueling system was in the April 1997 issue of Popular Hot Rodding on page 34.
I didn't buy the mag with the "Coates" rotary valve article, but that was it.
Mr Bahacz wrote parts one and two of an article in "Engines" by the Hot Rod Performance Series (Display Until 4/24/2000 date on the shelves) where a bunch of "kids" (with great respect) at Nothwestern College, Lima, OH did a buildup on a 502 using the fueling sustem. The project was "kind of" snake bit (as aren't all projects) but the overall gist of the program was very promising, (like very low SBFC numbers on 87 octane gasoline with a C.R. of about 12 to 1, and unbelievable torque.
I think these articles came out originally in Car Craft.
These got me thinking about two articles in Pop Hot Rodding about building engines that run on low octane fuel but have high C.R.'s by using very small compression chambers, flat top pistons and long rods if you could fit them and afford them.
One article was on small and big block chevys and the other on a pair of "blue oval" engines.
It said to take the smallest combustion chamber head you can find and plane it .100" more to minimize chamber volume. This along with a flat top piston "supposeably" makes the engine more efficient in the combustion process and so it doesn't preignite or detonate. Has anybody done any engine building using these techniques???"
pdq67
CR of 12:1 on 87 octane??!? at normal temps? Without a GIANT BEAST of a CAM?
Just because it's got a tiny chamber and a flat top piston?
Is the Mazda SkyActiv platform using any of these techniques? (Just recently found out the european version is running 14:1 on US 92 octane equivalent fuel... How the heck!!?)
Adam
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user-612937456
Re: NA Engines: Factors that increase torque
What about free torque? As discussed in the David Vizard Seminar I just attended there is a lot of torque left on the table by things like ring and cylinder wall preperation, windage oil taking a rollercoaster ride on the crank, rods and bottom of the piston. Parasitic rotational friction can be as much as 40-50 FtLbs of torque if you can reduce it to 20 FtLbs there is an easy 15 FtLbs or more(20+) for free. Internal balance(not external) the rotating assembly for sure that is usually a given but have you considered over balancing a few grams 20-30 or even 50 grams. As a balance job is done dry in real world the piston botom an connecting rod is coated with an oil film. The piston especially on the down stroke. I can see in an average medium cube build as much as 30 plus FtLbs easily over all to be gained. I can't give all DV's secrets away or there would be no need for his seminars lol but in most builds I have become aware of a lot of power and torque left on the table before you even start to consider induction and cam events.
Re: NA Engines: Factors that increase torque
NewbVetteGuy wrote:pdq67 wrote:http://www.camaros.net/forums/18-engine ... ohacz.html
By me!
"The first article from Mr Bahacz's on the fueling system was in the April 1997 issue of Popular Hot Rodding on page 34.
I didn't buy the mag with the "Coates" rotary valve article, but that was it.
Mr Bahacz wrote parts one and two of an article in "Engines" by the Hot Rod Performance Series (Display Until 4/24/2000 date on the shelves) where a bunch of "kids" (with great respect) at Nothwestern College, Lima, OH did a buildup on a 502 using the fueling sustem. The project was "kind of" snake bit (as aren't all projects) but the overall gist of the program was very promising, (like very low SBFC numbers on 87 octane gasoline with a C.R. of about 12 to 1, and unbelievable torque.
I think these articles came out originally in Car Craft.
These got me thinking about two articles in Pop Hot Rodding about building engines that run on low octane fuel but have high C.R.'s by using very small compression chambers, flat top pistons and long rods if you could fit them and afford them.
One article was on small and big block chevys and the other on a pair of "blue oval" engines.
It said to take the smallest combustion chamber head you can find and plane it .100" more to minimize chamber volume. This along with a flat top piston "supposeably" makes the engine more efficient in the combustion process and so it doesn't preignite or detonate. Has anybody done any engine building using these techniques???"
pdq67
I must be misreading what you're saying....
CR of 12:1 on 87 octane??!? at normal temps? Without a GIANT BEAST of a CAM?
Just because it's got a tiny chamber and a flat top piston?
Is the Mazda SkyActiv platform using any of these techniques? (Just recently found out the european version is running 14:1 on US 92 octane equivalent fuel... How the heck!!?)
Adam
PLEASE READ ME AGAIN!!
Please hunt the two articles that Mr. Bochaz made and read them!
Right, 12.1 CR on 87 octane!! The heads had a peanut chamber with little-bitty valves and the sparkplug was in between the necked down portion between the two valves of the peanut shape!
Mr. Fueling's aluminum 454 torque truck heads are real winners!
They were designed to be used up to something like 4,000 rpm for WORK TRUCK 454 engines! Max. T was at 3400 rpm if not mistaken and at that it was about 100 pound foot higher than stock! Hell, Mr. Fueling created the heads for the Quad-4 Olds land speed record engine!
Too bad only a hand full were sold!!
The last time I looked, a guy had a new pair for sale for like $2500.
The Tech Kids ran them on a 502 instead of a 454 and regardless there were some, "glitches", but nothing out of the ordinary!!
I contacted Mr. Bochaz on the web and got to talk to him over the phone, great guy by me!!
Again, would somebody post up pictures of Mr. Fuelings heads for me.....
I have tried to stir the pot so to say about putting 409 "W" engine heads on a 454 that WOULD HAVE TO HAVE matching piston dishes to run them and I figure everybody laughed at me!!
And fwiw, I read where the old 427 "W" engine had about the best sucking heads and top end out there back in those days!!!
pdq67
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user-23911
Re: NA Engines: Factors that increase torque
If you take 0.100 inch off a ford head, you'll have ever lasting ongoing headgasket sealing problems until you scrap the heads and replace with stock ones...been there done that.
Chances are you won't even know what's wrong apart from topping it up every day.
If you're not having headgasket problems, you're not making much power.
Chances are you won't even know what's wrong apart from topping it up every day.
If you're not having headgasket problems, you're not making much power.
Re: NA Engines: Factors that increase torque
The Skyactiv engine is direct-injection and with a bowl-in-piston combustion chamber that is reminiscent of diesel engine combustion chambers. They are getting away with such high compression by keeping the fuel in the center of the chamber so that the outer reaches (where detonation happens) don't have enough fuel to go kaboom.NewbVetteGuy wrote:Is the Mazda SkyActiv platform using any of these techniques? (Just recently found out the european version is running 14:1 on US 92 octane equivalent fuel... How the heck!!?)