how your cam LSA effects your compression ,torque , DCR



Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » August 11th, 2013, 9:42 am

Good Reading Grumpy. Thanks.
Read some more links later today.
Like the way you prioritize links you deem most important.
Top to bottom order.

Tony Mamo is smart from AFR.

He misses out what other aspects are taking place inside of s performance race engine.

You cover the groundwork better than all online Grumpy.

Few ever talk about Peak Volumemetric efficiency Numbers of 98-130% Normally aspirated that can be obtainable. Water brake or Electric Shunt Eddy Current brake engine dyno measured
BSFC # too

Warren Brownfield changed the Hotrod world.
Not AFR.
AFR uses his research & work.
Started in 1970.
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » August 11th, 2013, 9:55 am

Warren Brownfield was contracted to Hand Port Cylinder Heads for Pontiac's SCCA Trans Am Race series.
Pontiac Ram Air 4 "614" heads.
The 303 Giant intake port Ram Air 5 Tunnel port head would not comeon hard till 8,500 RPM'S.
Races lost in 1969.
Warren had his choice of heads to use & port.
He chose the 614 Ram Air 4.
1970-1/2 Midel year out for 2nd year Pontiac Trans Am.
Engine pulled super hard throughout the powerband.
180cc stock intake port volume.
Jerry Titus of Racing Fame driving the newly rededigned Trans Am.
Accident. He died behind the wheel of his TA.

Warren Brownfield took his experience learned
Started Brownfield Racing Cylinder Heads.
Thingd changed forever n the SBC Hotrod Race World.

Brian R.
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » August 11th, 2013, 10:11 am

most of you guys know Im an old geezer that still remembers buying cams from crane cams when they were located in hallandale Florida on Dixie highway
http://www.pbase.com/image/94649615
and I well remember BROWNFIELD cylinder heads advertized in the back of hot rod magazine and GENERAL KINETICS CAMS
which were in the late 1970-1980s the hot ticket, at some point in the mid 1980s brownfield was merged WITH or purchased by AIR FLOW RESEARCH
http://www.flickr.com/photos/lightning7 ... /lightbox/

HERES A RELATED POST BY TONY AT AFR
I have typed this on various boards and I will type it again here

Heads are the star of the show....everything else plays a supporting role with the camshaft certainly the "lead" in the various supporting roles to consider (induction, exhaust, fuel system, ignition, etc.)

With a really great set of heads you can almost miss every other player in the build and still have above average results when the smoke clears.

Miss the heads though and you can nail everything else in the build and only produce so-so results.

Heads represent the greatest restriction in the airflow pipeline and due to that fact represent the largest source of all your gains.

Look into any high end form of motor sports and you will see the most prep time and attention is focused on the heads (when discussing the engine build at least).

Alot of folks think any of the big name heads will produce similar results and that is a fallacy (the better amongst them do narrow the gap considerably though)...they want to believe that because the price is less some of the time but in the end you typically get what you pay for.

The stuff I do in the afterhours at home is for the guys that understand that and are willing to pay that little extra to get the "ten-tenths" from them so to speak....to gain an added edge that most folks dont have....I have to assume most of the people I help recognize the role they play.

I spend a ludicrous amount of time prepping the heads for a personal build (and toiling over a zillion other details as well)....but the cylinder heads without a doubt are the cornerstone/foundation of every build."
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » August 11th, 2013, 12:01 pm

If You haven't noticed Grumpy, I like , admire, & respect old Geezers.
Because they lived it, Raced hard , and have much experience

Crane Cams is back.
Several NHRA Super Stock Records set using Crane grinds in Poncho Pontiac V8 engines .
Smokey Yunick used Crane Cams in NASCAR winning engines .

I was taught by an old timer.
Why I have rhe knowledge in my brain.

Been looking for Original Brownfield 180 heads
Never ported or repaired .
New Old Stock Preferred .
Nothing else desired.
$$$ Set aside to but when I find them.
Rare Now.

I don't care what my generation uses. AFR195's.
Good for them.
They still loose the drag race against a hot running 5.0 Mustang 306ci Tremec 5-speed with 4.10 gears.
Turned high 10's. 1/4 mile.
Normally aspurated. No nitrous.
Trickflow street heads used .
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » August 11th, 2013, 12:11 pm

THANK YOU! I TRULY DO APPRECIATE the INCITE and informational support you provide
and very much appreciate the sites financial assistance a great deal.
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » August 11th, 2013, 12:18 pm

grumpyvette wrote:THANK YOU! I TRULY DO APPRECIATE the INCITE and informational support you provide
and very much appreciate the sites financial assistance a great deal.


Thank You Grumpy.
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » August 12th, 2013, 11:31 am

I had a couple guys ask individual e-mail questions on this thread, so I realized I need to drop back to some basic concepts that seem to be over looked
duration on a cam lobe is the factor that determines how many degrees the valve is off its seat and potentially flows gasses in or out of a combustion chamber over the piston.
lift on the cam lobe obviously dictates how far the valve opens ,
but its duration that determines how long its open, and once a valve lift exceeds about 1/4 its diameter its flow rates close to maximized, so the longer its kept over that lift ratio the more effectively it will flow . but remember the longer the duration used on the intake valve the further the piston moves in its rotation.

USE THE CALCULATORS

http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php
Image
but keep in mind the port flow rate is restricted by both the intake cross sectional area and the duration , or time the valves off its seat WHILE theres a significant pressure differential between the intake port and the cylinder, the intake runner can be designed to induce inertial pressure in a set rpm band, but its the exhaust flow that's far more influential at helping to drag in the next intake charge into the cylinder as its fast moving gasses exit the exhaust, thus the overlap period is vitally important to maximizing cylinder fill efficiency, once you reach the rpm range where there's a significant inertial energy level in both the intake and exhaust to draw in and cause the exiting gases to be drawn out of the cylinder.
if you do some research you quickly find that the engines power curve very closely relates to its cylinder fill efficiency,
Image
you also find that the intake port cross sectional area and valve size plus the cam duration ,lift and overlap have a huge effect on the engines ability to operate efficiently art any rpm range, because of either flow restriction if the port cross sectional area or cam timing are restricting flow or low port gas velocity levels, if the compression ratio,exhaust scavenging ,engine displacement or cam timing are not maximizing the flow rates in the ports

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tighter LSA tend to increase the OVERLAP but thats not always the case
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DURATION AND LSA are NOT necessarily related
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related info you might want to read thru carefully
http://www.epi-eng.com/piston_engine_te ... torque.htm

viewtopic.php?f=52&t=5154

http://www.veryuseful.com/mustang/tech/ ... enging.pdf

viewtopic.php?f=52&t=148&p=34936&hilit=curtain#p34936

viewtopic.php?f=52&t=8460

viewtopic.php?f=52&t=727

viewtopic.php?f=52&t=3729&p=9689&hilit=ramp+acceleration#p9689

viewtopic.php?f=52&t=333

viewtopic.php?f=52&t=2627&p=6780&hilit=ramp+acceleration#p6780

viewtopic.php?f=52&t=181&p=5342&hilit=ramp+acceleration#p5342

viewtopic.php?f=52&t=1489&p=3360&hilit=ramp+acceleration#p3360
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » January 14th, 2014, 1:11 pm

your going to find that reading thru the links will be useful

http://www.stockcarracing.com/techartic ... ewall.html

http://www.popularhotrodding.com/tech/0 ... ction.html
and in general , Id suggest matching the cams duration and lift to the application, going as high on the displacement and compression ratio as you can, and when selecting a cam for a street/strip car, going a bit on the low side of a given suggested duration range and with a tighter LSA tends to give the most useful power band on a street/strip engine ,and installing cams STRAIT UP, vs 4 degrees advanced, in many applications, but be aware that most cams tend to be made on a wider LSA with more duration, because a LONGER listed duration, and still maintaining a fairly decent idle quality on a cam seems to help sales more than actual power in a useful power band.
and yes obviously you must use well matched ,carefully thought thru,components , in the engine's exhaust,transmission, drive train gearing etc. that match the applications intended rpm and power band to be able to see the results the difference in cam timing can potentially make,

Image

example, heres a solid roller cam from crane that Ive seen used several times on 12:1-13:1 compression 496 big block engines, that has always produced good power.
but youll never see that power if you select restrictive heads,intake or headers or gear the car so it won,t operate efficiently in the intended power band, a cam like these two below needs to be matched to cylinder heads and an intake designed to take full advantage of that .714 lift and ports that flow more than 350cfm, matched to headers that will efficiently scavenge a 496-540 displacement big block chevy above 5500rpm. slap a good performance cam like these linked too below, in an engine with a restrictive intake , small carburetor, on stock peanut port heads and matched to a restrictive stock exhaust and either cam will potentially result in a real "dog" that can barely function. keep in mind one of the strong points of that tighter LSA cam timing is only useful if the exhaust scavenging of the cylinders is efficient in the intended power band, and effective at drawing in intake flow during valve over lap.

Image

Heres a very similar cam, but having seen several friends try both cams I can tell you the first one was preferred by the three guys I know who tried both cams and yes swapping ROLLER cams between guys cars to test them out is rather common among several of my friends
Image
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » April 23rd, 2015, 10:25 am

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » April 24th, 2015, 5:49 am

grumpyvette wrote:http://www.hotrod.com/how-to/engine/1506-lobe-separation-angle-explained-and-how-it-affects-horsepower/
Image

These LS-X Engines behave Similar to A Pontiac. 400- 455 Engine Grumpy.
108 Lobe Separation was the Winner.

Pontiacs Perform Strong with 112-102 Lobe Separation. Cams.
Bigger the Cubes, 455 Preferred , The Tighter the Lobe Separation you can use.
Its really the Long crank stroke and Very high piston speeds in Feet pet second traveled doing the work.
Altering Rod center to center lengths 98 degree Lobe Separation cams can and have been used in 455's and a Race Winner.
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » April 24th, 2015, 6:00 am

All the Power in the world does no good if the tires can not hook up Grumpy.
And Driver cant handle either .

Dialed in Combo and Car and Driver.
Summed up fast.
Lots involved as you know too.
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Re: how your cam LSA effects your compression ,torque , DCR

Postby grumpyvette » April 24th, 2015, 9:02 am

most of the more popular current cams are designed much more for easy compatibility with EFI and the related SENSORS, and rather comparatively smooth low rpm idle characteristics than simply too maximize the engines power curve,thus the old muscle car rolling burble or rumble in the exhaust sound is also reduced.
thus the use of the now rather common, wider 112-116 LCA vs the older design cams with the tighter 104-108 LCA angles.
that are far less sensor friendly,due to low rpm reversion pulses that tend to drive sensors in EFI rather crazy, but the tighter lobe center angles are usually better when you use a carburetor as a source for atomized fuel, and the tighter LCA also tend to maximize the exhaust scavenging thus they get a bit more efficient cylinder fill and burn maximizing the engine efficiency.
the issue is also complicated by the current need by the manufacturers to reduce exhaust emission levels and the tighter LCA is a huge problem in that re-guard for the manufacturers in that below about 2000rpm theres a marked increase in emissions if you use a tight LCA in a cam design along with enough duration to maximize peak higher rpm power.
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: how your cam LSA effects your compression ,torque , DCR

Postby 87vette81big » April 24th, 2015, 1:00 pm

I am aware if down faults of tight LSA Cams with EFI Grumpy.

There is a way to Tune EFI I have read Tight LCA Used.
Alpha Numeric EFI Programming.
Just the Coolant Temp sensor and TPS Used.
All out Racing only.
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