sbc 421 dyno results

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CamKing
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Re: sbc 421 dyno results

Post by CamKing »

GARY C wrote: Tue Mar 20, 2018 1:10 pm
When you think about it, 'what's happening where' near the opening and closing points is far more important re how the engine performs than whether the very peak of the mountain is skewed a few degrees this way or that.
Thats what I found interesting with this info from an EMC competitor, obviously it takes testing to narrow things down to a few degrees but it can pay off.
Glad to see Comp Cams has finally made it to the 1980's :lol:
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Re: sbc 421 dyno results

Post by 77cruiser »

Like this. Might be rough on parts. :)
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Re: sbc 421 dyno results

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MadBill wrote: Tue Mar 20, 2018 12:53 pm When you think about it, 'what's happening where' near the opening and closing points is far more important re how the engine performs than whether the very peak of the mountain is skewed a few degrees this way or that.
This is what lead me to change my way of defining lobe centerline.
We did a bunch of dyno testing on different engines, using both our symmetrical lobes, and asymmetrical designs. When we moved the cams for optimum power, the one commonality between the asym and sym cams were the opening and closing points. Where the asymmetrical cam worked best, had the max lift at an earlier point then where the symetrical cam worked best, but the opening and closing points were the same. Now if I used the max lift to define centerline, I wouldn't be able to recommend the same centerlines for a asymmetrical cam, as I would a symmetrical cam. It would also be very confusing for my customers to understand why they would need to go to a asymmetrical cam on a 103 LSA to replace the symmetrical cam on a 107.
By using the mid point between the opening and closing points to define lobe centerlines, a 304/312 seat duration cam on a 108 LSA, with a 104 ICL is going to have the same RPM band, asymmetrical or symmetrical.
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Re: sbc 421 dyno results

Post by Truckedup »

On the opening post of this thread, look at the fuel used per HP per hour on the Dyno sheet.., it's insanely low, like lower than a Diesel.. What's with that?
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Re: sbc 421 dyno results

Post by CGT »

Truckedup wrote: Tue Mar 20, 2018 2:23 pm On the opening post of this thread, look at the fuel used per HP per hour on the Dyno sheet.., it's insanely low, like lower than a Diesel.. What's with that?
Yeah, noticed that.
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Re: sbc 421 dyno results

Post by treyrags »

The bogus BSFC was the first thing I noticed. Looks like one inlet was not being measured.
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Re: sbc 421 dyno results

Post by 77cruiser »

CamKing wrote: Tue Mar 20, 2018 1:47 pm
GARY C wrote: Tue Mar 20, 2018 1:10 pm
When you think about it, 'what's happening where' near the opening and closing points is far more important re how the engine performs than whether the very peak of the mountain is skewed a few degrees this way or that.
Thats what I found interesting with this info from an EMC competitor, obviously it takes testing to narrow things down to a few degrees but it can pay off.
Glad to see Comp Cams has finally made it to the 1980's :lol:
Comp in my pic.
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Re: sbc 421 dyno results

Post by lekid »

This is the same dyno that I went on (me and George dynoed back to back).

It is a new dyno and still lots of kinks to fifure out by the owner/operator.
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Re: sbc 421 dyno results

Post by cpmotors »

Water feed issue or smoothing setting in Wyndyn? Very erractic graph that looks like load issues to me? OP have a video of the pulls we can see and hear?
Made some nice power.

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Re: sbc 421 dyno results

Post by MadBill »

Smoothing's a bit of a double-edged sword; too much can make a beautiful-looking French Curve that conceals a lot of useful engine data or clues re dyno issues.
In this case, I'd suspect the latter. I saw a 'curve' a little like that for a 358" SB2.2 when the water valve hadn't been reset after the previous testing of a 16:1 676" Hemi..
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Re: sbc 421 dyno results

Post by LB9GTA »

[/quote]
You must of misread what I wrote. I've always told all my customers, to never use max lift to degree the cam, and to always use the .050" opening and closing numbers on the cam card. That's why I put the .050" opening and closing numbers in a big box, in the middle of my cam cards.
[/quote]

Haha! I called Mike about this, and he reminded me that I couldn't check the numbers b/c it was a asymmetrical cam.
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Re: sbc 421 dyno results

Post by LB9GTA »

cpmotors wrote: Tue Mar 20, 2018 9:36 pm Water feed issue or smoothing setting in Wyndyn? Very erractic graph that looks like load issues to me? OP have a video of the pulls we can see and hear?
Made some nice power.

Image
Sorry, I was nervous and forgot to take vids! Rookie mistake.
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Re: sbc 421 dyno results

Post by maxracesoftware »

lekid wrote: Tue Mar 20, 2018 7:44 pm This is the same dyno that I went on (me and George dynoed back to back).

It is a new dyno and still lots of kinks to fifure out by the owner/operator.
LB9GTA » smoothing setting in Wyndyn?
Looks like WinDyn Graph is set to just "Line" ?? so its a Linear Spline Curve Fit

just have Dyno Operator right click on the WinDyn Graph, a PopUp Menu appears ,
click [Plotting Method ]
choose "Spline" which will be a simple Cubic Spline Curve Fit Method
it will give a little better looking Graph between Data Points

Also , depends on WinDyn version
he might have 5 or up to 9 Levels of Smoothing ??

i use 0 Level, no smoothing on my Dyno tests, i like to see what the Engine is really doing or at least as close to possible
however, i do use Cubic "Spline" Fit , along with 0 zero smoothing

in other words, i record or gather the actual Dyno Data at 0 zero Filter smoothing
then just use Cubic "Spline" choice to fit the Curve between the actual TQ and HP Data Points
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Re: sbc 421 dyno results

Post by racear2865 »

maxracesoftware wrote: Wed Mar 21, 2018 12:19 am
lekid wrote: Tue Mar 20, 2018 7:44 pm This is the same dyno that I went on (me and George dynoed back to back).

It is a new dyno and still lots of kinks to fifure out by the owner/operator.
LB9GTA » smoothing setting in Wyndyn?
Looks like WinDyn Graph is set to just "Line" ?? so its a Linear Spline Curve Fit

just have Dyno Operator right click on the WinDyn Graph, a PopUp Menu appears ,
click [Plotting Method ]
choose "Spline" which will be a simple Cubic Spline Curve Fit Method
it will give a little better looking Graph between Data Points

Also , depends on WinDyn version
he might have 5 or up to 9 Levels of Smoothing ??

i use 0 Level, no smoothing on my Dyno tests, i like to see what the Engine is really doing or at least as close to possible
however, i do use Cubic "Spline" Fit , along with 0 zero smoothing

in other words, i record or gather the actual Dyno Data at 0 zero Filter smoothing
then just use Cubic "Spline" choice to fit the Curve between the actual TQ and HP Data Points



I also collect all my data on every run with no smoothing. You can always smooth later, but I want to see all the data bumps. if you have to, u can put in a spread sheet and what ever you desire. Sometimes the provided software want give you enough. You only get what they feel u want.
reed
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Re: sbc 421 dyno results

Post by greywolf »

Curious as to why you stopped the dyno pull at 6500 with pump gas.
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