PRH
Well-Known Member
Based on the intake events on the posted “cam card”, the intake C/L is 104.
Engle HEV 3945AS Camshaft
- Thread starter INhondo
- Start date
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B3422w5
Well-Known Member
Howard’s does all the Hughes stuff now
Dale Davies
Well-Known Member
Just do a youtube search for "what the cam companies get wrong".
Been about 30yrs ago now, but I'm pretty sure Engle made Mondello's cams & valvetrain for Olds as well....
I like DV's overall concept, start with LSA and overlap, but I don't if I'd trust it a 100%, one it mainly comes from testing Chev's not saying there's no crossover, 2nd it's based on valve size instead of a heads capability cause he said more know their valve size over flow numbers, but a huge difference between Eg. stock and fully ported 2.02, 3rd Richard Holdener did 108 vs 112 vs 120 on same cam spec couldn't get a 116 on time, 108 had the best curve, 112 not too far off, 120 had a decent loss. I know it was only one test. I don't know if there's a magic formula but I think it gets you in the ballpark. Generally like carbs we kind of knows what works from what's has been working overtime.
I believe Engle made cams for J.C. Whitney back in the day.
Newbomb Turk
Well-Known Member
Sorry, what am I camming for?
DV formula is based on valve (flow) and displacement, basically he says most cam companies are too conservative with LSA, cause most engines are not running enough valve for displacement.
Eg.. A run of a mill 112 lsa cam with a 360, his formula to be optimal that cam would need a 2.56" intake valve which obviously not gonna work, his formula for a standard 2.02" 360 = 107.7 lsa.
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That couldn't possibly be more wrong.....
Newbomb Turk
Well-Known Member
Don’t know what you cam for, but I cam for peak torque, compression ratio and stroke.
Newbomb Turk
Well-Known Member
Could be. But I’ve been using this math for years. Never steered me wrong.
Newbomb Turk
Well-Known Member
Bore size has almost nothing to do with cam duration. Neither does head flow like I said. In fact, I didn’t say it, other people said it and it’s their math. And it works.
Compression is a far bigger factor in cam duration than head flow. As I said, head flow is not in the formula I use.
Maybe it's the way I see it or what level these engines are being built for but cam size seem to be on the lesser variable for a street performance v8 engines, most performance cams people seem to gravitate to is 215-255 give or take say average around 235, cid, 273 to 500+, heads 175 - 325+ cfm. Peak hp 4500 to 6500+ rpm, To me number one factor where that rpm peak will be for a given hp is displacement.
Newbomb Turk
Well-Known Member
Do you know who Patrick Hale is? If you don’t like the math I use, look him up and tell him how wrong he is. It’s math he uses in his computer software.
You can think anything you want. But I have used this math enough times to know it is correct.
Stroke length, compression ratio and rpm at peak torque is what Patrick Hale says is how you determine you’re at .050 timing. I’ve tested it. He is correct.
Or, you can see if you can find a copy of the Don Terrell book where he published enough math to choke a nerd.
I don't know math you use, not saying it's not right, but imagine at least you have a ruff idea on displacement heads and hp while doing the cam math. So you already have narrow down the other main effects, now your fine running your build.
INhondo
Member
It's an old NOS Engle camshaft in an Engle box with a Hughes part number on the end label.
He's a weather man.
Dale Davies
Well-Known Member
1: DV uses LSA as a basis for cam selection. He states this is a starting point. Overlap is then a function of lobe duration. You may get better performance with the correct LSA and a bit less duration.
Regarding the statement of DV's information coming from mainly testing Chevy engines is not exactly correct. Now the shear number of SBC and BBC engines produced makes them highly accessable, so yes he has tested a lot of Chevys. But he has a lot of experience on Ford, BMC and some Mopar among others. Now one point to remember is engines are assemblies of parts essentially the same. Canted valve, hemi, wedge and 4 valve present different characteristics, but within each class they will respond similarly.
2: His formula is cylinder displacement/seat diameter not valve diameter. Thus the intake head diameter × 0.91. DV also says a correction based on quick "off the seat valve motion". This relates to low lift flow. Yes a fully ported head will flow more than an unported or moderate ported head. This will just complement the proper cam LSA selection.
SBC - 128 - (cyl disp/(valve dia × .91))
SBF - 127 - ( cyl disp/(valve dia × .91))
SBM - pick one. They are all inline valve heads.
Canted valve - 132 - etc
3: Richard Holdner's cam test pretty much confirms what DV states.
For corrections, CR will indicate tighter or wider LSA. DV goes into that. Lobe profile and high ratio rockers have a bit of affect, something like .25° to .5°. Rod length/rod to stroke ratio makes virtually no difference. That said a long rod tends to be quieter and aid hi RPM torque (power) while a short rod tends to more noise from piston slap and promotes a slight advantage in low RPM torque.
DV does state that testing single cam engines to determine the best LSA for the combination requires dyno testing and a number of cams with different LSA's to test and then play with advance or retard. This is getting serious at that point and way beyond a street base build would require. But for a race car where every single lb/ft or HP advantage could be the difference between the money or shame, it is important.
Now if you read Billy Godbold's book on Highperformance Camshafts and Valvetrains, he talks EVO, IVC, IVO and EVC with LSA as a consequence. I would expect Billy through his years in the business has a more intimate knowledge of camshafts than most of us could hope for. I did ask DV if he had read Billy's book and if he had an opinion. He wrote back stating his intention to read it and then possibly comment. A discussion between Billy and DV could be interesting.
Bottom line I don't think he's terribly wrong and like the general concept but I yet see anyone prove or disprove him, we all generally agree tighter lsa = more under the torque curve to a point so his formula gonna get you going in the right direction, but how detrimental is it to be a few degrees off his recommendation, he says 30-50+ lbs-ft, I don't know about that. People run some pretty wide lsa on LS engines making great tq numbers. Like to see someone try to prove/disprove it.
Each cam is selected for the task at hand. Using your description above, this I have done for certain (most) engines. Since there street driven. The combination above makes sense for the street.
I’ll have to look up that name. Thanks.
For all engines?
“Choke a Nerd!”
LMFAOROTF!!!
Dale Davies
Well-Known Member
DV states you are better with a cam a degree or two tight on LSA than a degree or two wide. He showed on graphs the torque and power curves. The tighter than recommended dropped a little bit. The 112° LSA cam was way down.
Then there is the Richard Holdner test that showed the same basic results.
Now look into GM Performance and their cams. You can get two cams intended for racing, primarily circle track that are ground on 108°lobe centers. The street intended performance cams are all 114° to 120° lobe centers. That speaks a bunch there. With the flow capacity of the various LS based heads, it follows DV's correction factor of a bit wider LSA for quick off the seat and hi flow. The street engines need to pass emissions testing and also idle smoothly for the general public. A slight idle lope is music to our ears, while many of the general buying public look for "Cadillac smooth".The wide LSA factory cams lower and flatten the torque curve by quite a bit. These engines do not hit as hard off a street light and need to get up to 2500 to 3000 RPM to get "on the ports" in a term borrowed from the 2 smoke crowd. What this is stating is that the combination of large hi flow ports and the cam timing, the engine is a bit lazy at lower RPM but come on strong as the revs come up. These engines still have a bunch of torque down low, but not like the old engines that pulled from 600 RPM.
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TO the OP
Where you install that cam is gonna depend partly on your Static Compression ratio, and partly on your intended usage, and mostly on your combo.
>If you have a low compression engine, you will want to increase the Dynamic pressure by advancing the cam well past it's straight up position.
> if you already expect a high dynamic pressure, you may have to close the intake later, to keep out of detonation on pumpgas.
>Of course factors such as Quench/squish and chamber desin will plasy key roles.
> and finally; a light street car, operating at sealevel, with a high stall and a higher than average second-gear ratio is gonna need a different set-up than than a heavier car, at elevation, with a crippling factory stall and hiway gears. It's all in the combo.
I like that cam. The first thing I always look at these days is the total of compression degrees plus power-extraction. A good target for a streeter is more than 227 degrees. If it has that, it's gonna have the potential to be fuel thrifty on the hiway. This cam has 132.5 before compensation for loss of duration due to lashing. This number cannot be changed, because it is a function of the grind. You can trade compression and extraction back and forth, in a modest window, to solve for tuning issues, for operation targets, or for fuel-economy.
For instance In at 104*, the compression degrees are (working off the advertised, is 121 degrees. leaving 111.5 for extraction. If at this number of 121, your engine detonates on an already fudged ignition timing curve, your next move is to reduce the cylinder pressure. You can do this, in the field, by retiming the cam up to several degrees later, stealing them from power extraction. Say you take 3 addition degrees from extraction, leaving 108.5 back there, and getting 124 degrees of compression. Those 3 degrees might represent up to 9 psi. and say your engine now stops detonating. All is good right?
Yes and no.
It's very good to not have detonation at WOT, so maybe at the New lower pressure, you can put the Power-timing back.
But
let's not forget the loss of extraction time. The WOT torque and power will shift to a new slightly higher rpm, and the loss of extraction at low rpm usually translates to a couple of things; 1) reduced fuel economy, which will be readily apparent in city use because of, the loss of torque down low. and 2) a drop in steady-state fuel economy, usually due to there still being useful energy in the expanding gasses release by the earlier opening exhaust valve. thus,
It behooves you to engineer the Static compression ratio, to achieve the highest Dynamic pressure ratio, working with a preselected Intake closing event, so that the Power-Extraction event can also be properly engineered for street fuel-economy, in these days of the ever increasing cost of fuel. and so, you get the exact right cam timing, the first time.
Now;
I know that I can get very high mpgs with as little as 110* of Power extraction, but it's gonna take a cruise rpm lower than 2000. But in your case, with this cam, the advertised (in at 104*) is 111.5, allowing a bit more hiway rpm. I also know that in the zone of 106 or less, fuel economy becomes atrocious even at 2200 rpm. And, I know that at 116* (what a 318 runs), economy can be off the charts at 65= sub 2000rpm. So the window, working off the advertised, is somewhere between 106 and 116..... so half way is exactly where this cam drops in at, when installed at 104*.
One thing I can tell you is that with an Ica of 57* or less at actual lash. You might have to reduce your Scr, to drop your Dcr out of the detonation zone with open chamber non-quench heads, so hopefully, you already engineered for that.
Where you install that cam is gonna depend partly on your Static Compression ratio, and partly on your intended usage, and mostly on your combo.
>If you have a low compression engine, you will want to increase the Dynamic pressure by advancing the cam well past it's straight up position.
> if you already expect a high dynamic pressure, you may have to close the intake later, to keep out of detonation on pumpgas.
>Of course factors such as Quench/squish and chamber desin will plasy key roles.
> and finally; a light street car, operating at sealevel, with a high stall and a higher than average second-gear ratio is gonna need a different set-up than than a heavier car, at elevation, with a crippling factory stall and hiway gears. It's all in the combo.
I like that cam. The first thing I always look at these days is the total of compression degrees plus power-extraction. A good target for a streeter is more than 227 degrees. If it has that, it's gonna have the potential to be fuel thrifty on the hiway. This cam has 132.5 before compensation for loss of duration due to lashing. This number cannot be changed, because it is a function of the grind. You can trade compression and extraction back and forth, in a modest window, to solve for tuning issues, for operation targets, or for fuel-economy.
For instance In at 104*, the compression degrees are (working off the advertised, is 121 degrees. leaving 111.5 for extraction. If at this number of 121, your engine detonates on an already fudged ignition timing curve, your next move is to reduce the cylinder pressure. You can do this, in the field, by retiming the cam up to several degrees later, stealing them from power extraction. Say you take 3 addition degrees from extraction, leaving 108.5 back there, and getting 124 degrees of compression. Those 3 degrees might represent up to 9 psi. and say your engine now stops detonating. All is good right?
Yes and no.
It's very good to not have detonation at WOT, so maybe at the New lower pressure, you can put the Power-timing back.
But
let's not forget the loss of extraction time. The WOT torque and power will shift to a new slightly higher rpm, and the loss of extraction at low rpm usually translates to a couple of things; 1) reduced fuel economy, which will be readily apparent in city use because of, the loss of torque down low. and 2) a drop in steady-state fuel economy, usually due to there still being useful energy in the expanding gasses release by the earlier opening exhaust valve. thus,
It behooves you to engineer the Static compression ratio, to achieve the highest Dynamic pressure ratio, working with a preselected Intake closing event, so that the Power-Extraction event can also be properly engineered for street fuel-economy, in these days of the ever increasing cost of fuel. and so, you get the exact right cam timing, the first time.
Now;
I know that I can get very high mpgs with as little as 110* of Power extraction, but it's gonna take a cruise rpm lower than 2000. But in your case, with this cam, the advertised (in at 104*) is 111.5, allowing a bit more hiway rpm. I also know that in the zone of 106 or less, fuel economy becomes atrocious even at 2200 rpm. And, I know that at 116* (what a 318 runs), economy can be off the charts at 65= sub 2000rpm. So the window, working off the advertised, is somewhere between 106 and 116..... so half way is exactly where this cam drops in at, when installed at 104*.
One thing I can tell you is that with an Ica of 57* or less at actual lash. You might have to reduce your Scr, to drop your Dcr out of the detonation zone with open chamber non-quench heads, so hopefully, you already engineered for that.
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"He states", I've read and watch a lot of his stuff too, you act like I'm saying he's 100% wrong, I'm just saying I haven't seen an outside source/s verify him with dyno results tilt then I'll take his advice with a grain of salt.
It really don't, there's not much difference between the 108 vs 112, it takes a 120 before there's a major difference, to me it kind of proves him wrong, but it's only one tests.
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