engine and cam software

engine and cam software

Joined: December 11th, 2010, 3:10 pm

September 1st, 2011, 8:09 pm #1

Anyone using software that they find truly useful when picking engine components and selecting camshaft profiles? All input appreciated. Thanks, Chuck
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Joined: May 20th, 2005, 4:48 pm

September 2nd, 2011, 12:28 am #2

They're all generally about 7-8% higher than actual dyno results. As far as picking camshafts, EA Pro and Desktop Dyno seem to get the hp peaks pretty close, which is a function of duration. They can also show broader or peakier torque curves, which is a function of the LSA.

Other than that, one of the best things you can do is to ask an engine builder for help, or forum members who have tried a specific camshaft in an application.

Brent Lykins
B2 Motorsports, LLC






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Joined: January 10th, 2002, 5:53 pm

September 2nd, 2011, 6:22 pm #3

Anyone using software that they find truly useful when picking engine components and selecting camshaft profiles? All input appreciated. Thanks, Chuck
I use EA plus and find it very useful for comparisons.

http://performancetrends.com/Engine-Analyzer-Plus.htm

1967 Falcon 4 door 351C-4V
1970 Mustang 351C-2V
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.
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Joined: February 17th, 2004, 11:02 pm

September 3rd, 2011, 12:24 am #4

Anyone using software that they find truly useful when picking engine components and selecting camshaft profiles? All input appreciated. Thanks, Chuck
> Anyone using software that they find truly useful when picking engine components and
> selecting camshaft profiles? All input appreciated. Thanks, Chuck

I use Dynomation. I let a friend test it against his copy of Engine Analyzer Pro
and he prefers Dynomation, primarily due to the built in cam optimizer (under the Pro
Iterator tool menu). You can tell it to optimize peak or average (between two RPM points)
power or torque and it will run a series of approximately 9000 simulations varying LSA,
intake and exhaust duration within user specified lift limits and ramp rates. It does a
coarse grid search followed by a fine grid to find the optimal cam specs. I use the
average HP under the curve between shift point (typically 500 RPM past the power peak
RPM) and the RPM the engine will drop back to during the shift. That gives the best
average acceleration at WOT. The program is bundled with a cam database from most of
the big cam companies. It will search the cam database for cams with timing around a
user specified tolerance of the optimized cam (or any other cam you wish) so you can
test off-the-shelf grinds against the custom cam specs. There are also other built in
optimizers for things like induction. In my dyno testing, it has been very accurate on
peak power when using accurate flow bench and dimensional data but optimistic on peak
torque. The RPMs of the predicted versus actual peaks have been very close. Dynomation
releases free updates periodically.

I wish I had this software when I picked the cam for the dyno mule. I misunderstood
Vizard's LSA suggestion and narrowed the LSA of the canted valve heads when he suggested
increasing it by 2 degrees. I got Dynomation after selecting the cam and sure enough its
LSA matched Vizard's suggestion. Re-optimizing the cam using the Pro Iterator, it looks
like the dyno mule cam is down 40+ HP to an optimal cam of similar RPM range. Vizard's
cam rules for stroker engines include narrowing the LSA for increased stroke and, again
Dynomation agrees with the 351C dyno mule cam being much better suited to a 393C than a
351C. I've since used it to design a number of cams and the owners have been very happy
with the results.

Dan Jones
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Joined: October 1st, 2004, 1:55 pm

September 6th, 2011, 4:28 pm #5

Dan,

So, what LSA should you have used 111?

Its interesting, if you look at Dave Vizards writings he uses a higher LSA for cams than what he recommends in his LSA charts; Im sure you have read the famous Popular Hot Rodding article where he builds a 441 HP hydraulic cammed 350 Chevy motor. That cam was ground with a 108 LSA, yet if one uses his LSA chart, the optimal LSA for that cam/motor is 106 - 355 cubes ÷ 8 = 44.375 ÷ 1.94 (intake valve) = 22.87. If you take the product of 22.87 and cross index it on his LSA chart you get an LSA of 106. Yet Vizard uses 108. Im sure that he uses the larger 108 LSA to compensate for what he viewed as the non-optimal exhaust system with mufflers used in the test, though he doesnt mention it in the article.

If we take the same approach as above for a 355 CID Cleveland we end up with a recommended LSA of 109.25. Interesting. If we make an adjustment for a sub-optimal exhaust system we end up with an LSA of 111.25 for a high performance street motor.

But wait we have forgotten to add an ADDITIONAL 2 degrees to the LSA for the use of canted valves in a large headed small cube motor: that would result in an LSA of 113 degrees based on Vizards methodology! Maybe the Ford engineers in the 1960s werent so far off the mark after all. 113 sure seems awfully wide for a high performance cam, but maybe not. A Dave Vizard acolyte would have a hard time arguing with using a smaller LSA based on the logic laid out by Dave himself. But maybe I have misinterpreted something, so please help me out if I have I dont want to lead anyone astray. I know that your Dynomation model adjusts quite negatively for wider LSAs, but this creates what appears to be a philosophical conundrum assuming I havent completely misinterpreted all of this.

I think this makes the 107 LSA in the 351 test mule seem severely tight, and perhaps this explains the lower output. I always thought that the horsepower level in the mule seemed low given the supporting hardware. Going to a 111-113 LSA would also help the idle characteristics considerably, which Im sure were a little grumpy! A 111 LSA would decrease the overlap from 68 to 60 degrees, and a 113 would decrease overlap to 56!

Id appreciate any thoughts you might have on this Dan
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Joined: February 17th, 2004, 11:02 pm

September 9th, 2011, 4:39 pm #6

> Its interesting, if you look at Dave Vizards writings he uses a higher LSA for
> cams than what he recommends in his LSA charts

His charts are a simplification of the cam selection software he uses.
The cam selection software has much more detailed information including
head flow data, port and runner dimensions, even things like desired idle
vacuum levels. I use his simplified rules as a starting point for Dynomation
simulations. Dynomation will iterate on cam specs

> If we take the same approach as above for a 355 CID Cleveland we end up
> with a recommended LSA of 109.25. Interesting.

That's the same number I got when I went to design the cam for the 351C
dyno mule and where I made the mistake. I went 2 degrees narrower when
the suggestion was to go 2 degrees wider, based upon the canted valves.
That was before I had Dynomation. Now I model the engine in Dynomation
and use the iterator to optimize the cam specs for the maximum average
(not peak) power over a specified RPM. I'll further iterate on LSA to
determine the sensitivity to the LSA. In something like a stroker
Cleveland in a Pantera, I don't typical add the 2 degrees to the LSA
as it is not generally needed. In a heavier vehicle with automatic
transmission, I generally do but I check the sensitivity first. For
best average power, it's best to be too tight than to be too wide.

> I think this makes the 107 LSA in the 351 test mule seem severely tight,
> and perhaps this explains the lower output.

Yes. When I optimized the cam using Dynomation, the peak power went
up by approximately 40 HP. With the flow numbers from the heads we
did for Glen Hartog's 408C (closed chamber 4V with short side radius
work), the simulation predicts 476 HP @ 6000 RPM. The prediction
for the same engine with ported C302B heads is 531 HP @ 6000 RPM
(assumed a bit more aggressive ramp rate). Optimal LSA's for the
two engines are in the 109 to 111 degrees range with similar intake
duration but shorter exhaust duration on the high port heads.
I've toyed with purchasing a new cam for the dyno mule but I'd have
to re-baseline the 4V results for comparison against the other head
types. I've got a 403C (4.005" bore x 4" stroke) with high port heads
going together soon (block, heads, intakes and other bits at the dyno
with stroker kit on order with Brent Lykins). I'm waiting on the
flow bench numbers for the A3 heads but it'll get a custom roller
cam designed using Dynomation. We've used it recently with good results
on both a 408C with CHI-4V heads and a 393C with ported Aussie 2V heads.

Dan Jones
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Joined: October 1st, 2004, 1:55 pm

September 9th, 2011, 6:13 pm #7

Thanks Dan for the responses, they make sense. I guess I'll be calling you when I need my next cam
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Joined: December 11th, 2010, 3:10 pm

September 11th, 2011, 12:44 pm #8

> Its interesting, if you look at Dave Vizards writings he uses a higher LSA for
> cams than what he recommends in his LSA charts

His charts are a simplification of the cam selection software he uses.
The cam selection software has much more detailed information including
head flow data, port and runner dimensions, even things like desired idle
vacuum levels. I use his simplified rules as a starting point for Dynomation
simulations. Dynomation will iterate on cam specs

> If we take the same approach as above for a 355 CID Cleveland we end up
> with a recommended LSA of 109.25. Interesting.

That's the same number I got when I went to design the cam for the 351C
dyno mule and where I made the mistake. I went 2 degrees narrower when
the suggestion was to go 2 degrees wider, based upon the canted valves.
That was before I had Dynomation. Now I model the engine in Dynomation
and use the iterator to optimize the cam specs for the maximum average
(not peak) power over a specified RPM. I'll further iterate on LSA to
determine the sensitivity to the LSA. In something like a stroker
Cleveland in a Pantera, I don't typical add the 2 degrees to the LSA
as it is not generally needed. In a heavier vehicle with automatic
transmission, I generally do but I check the sensitivity first. For
best average power, it's best to be too tight than to be too wide.

> I think this makes the 107 LSA in the 351 test mule seem severely tight,
> and perhaps this explains the lower output.

Yes. When I optimized the cam using Dynomation, the peak power went
up by approximately 40 HP. With the flow numbers from the heads we
did for Glen Hartog's 408C (closed chamber 4V with short side radius
work), the simulation predicts 476 HP @ 6000 RPM. The prediction
for the same engine with ported C302B heads is 531 HP @ 6000 RPM
(assumed a bit more aggressive ramp rate). Optimal LSA's for the
two engines are in the 109 to 111 degrees range with similar intake
duration but shorter exhaust duration on the high port heads.
I've toyed with purchasing a new cam for the dyno mule but I'd have
to re-baseline the 4V results for comparison against the other head
types. I've got a 403C (4.005" bore x 4" stroke) with high port heads
going together soon (block, heads, intakes and other bits at the dyno
with stroker kit on order with Brent Lykins). I'm waiting on the
flow bench numbers for the A3 heads but it'll get a custom roller
cam designed using Dynomation. We've used it recently with good results
on both a 408C with CHI-4V heads and a 393C with ported Aussie 2V heads.

Dan Jones
The cam specs in the initial post under Camshaft Mystery" to see if you can come up with a reason for the low vacuum levels. I have spent days trying to understand why vacuum is so low. Any input is appreciated. Thanks, Chuck
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Joined: October 1st, 2004, 1:55 pm

September 12th, 2011, 6:09 pm #9

I'm not sure if you meant me or Dan, probably Dan, to respond, but any way here is what I think:

"Lunati 41199LUN, same as 411A1LUN other than LSA, solid flat tappet, .558/.580, 238/248 @ .050, 272/282 Adv., 110 LSA installed at 106."

This cam has a very moderate overlap number of 55 degrees. 55 degrees is on the lower end of high performance street cams. Many high performance street cams that came from the OEM's had higher overlap numbers. Normally a cam like this should produce a reasonable to good amount of vacuum, probably in the 14-18" area. However, what you have working against you is the higher amount of duration @ .050 (238/248) which essentially means that for the amount of time that the valves are open, which is on the medium side, a lot of mixture is being allowed into the combustion chamber due to the aggresive lift of the lobes. This is normal for a solid cam. The more densely packed cylinders of an engine with more duration at .050 will contribute to more low end "grumpiness" during the low end reversion process that occurs during the overlap phase. As reference, 238 degrees of duration in a solid cam looks more like 230 degrees in a hydraulic cam due to the valve adjustment needed for the solid lifters (the gap, so this cam looks like a 230/240 hydrauic cam, generally.
What compunds the problem further is that this is a relatively high lift cam, also. Again, more charge being allowed into the combustion chamber will cause the idle characteristics, and vacuum, to worsen. Think of it as having a window in your home open during a serious rain storm. Will more water get into the home if the window is halfway open, or all the way open? (That's a rhetorical question) Clearly with the window all the way open more moisture will get in. Similarly, if 2 cams have the same advertised duration but one has higher lift and more duration at .050, the one with more lift and duration @ .050 will have more negative effects from overlap because there is more mixture to back up into the intake at idle and make it "grumpy", "choppy", "lopey" - you pick the descriptor.

Essentially, what I'm saying is that although the cam may have only 55 degrees of overlap, it probably is going to act more like a cam that has more overlap because the lift, and duration @ .050 is a little more aggresive.

However, having said that, I think that 10" of vacuum is low, I think that 12" at 900 RPM's would be the low end of that cam. This is a fairly popular grind, one that many people purchased and used through the old Crane Cam's company - I think it looks a lot like the old F238. Maybe start another thread asking what people remember this cam to idle at and what vaccuum it pulled. I'm sure some people are still using this cam from Lunati and Crane and the Lunati cam that you have.

Also, many of the issues around vacuum at idle revolve around fuel delivery or ignition. Have you tuned for vacuum? If you have those 2 systems checked (fuel and ignition) then you have to begin looking at any other area in the motor that is allowing air pressure to escape and therefore decreasing the engine's ability to creata a vacuum.

I hope this helps (probably not), and I think you should poll some other folks on this site who have used the same of similar cam and see what there reults are/were so that at least you will have a baseline.

Good luck!
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Joined: December 11th, 2010, 3:10 pm

September 12th, 2011, 9:20 pm #10

for taking the time time to share your insights on the topic. The distributor is set and I have capped/plugged every possible source for a vacuum leak. I'm still mystified about the poor idle quality. The car runs great so the cam stays but, it looks like I'm buying a vacuum pump to run the brakes. Thanks Again, Chuck
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