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11 v coupe auto
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Discussion Starter · #1 ·
I'm happy with the curve, it just seems different from others I've seen. What does yours looks like
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I'm happy with the curve, it just seems different from others I've seen. What does yours looks like
View attachment 159764
Just a comment, assuming your engine is tuned & fueled correctly.

Induction System_CFM Supply Side, versus Piston_CFM Demand Side.

When your Peak Torque RPM moves downwards, that
is a sign that your VE% has become insufficient, regarding
its ability to 'Supply' the CFM 'Demand' for your engine.
 

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To help others to understand your graphs (as well as me..lol)
consider, putting your mods into your signature line.

And while this forum member (just below), is extremely wealthy,
and the cost of mods is 'Pocket Change' for him. . ;) :D

A good signature line to look at, would be @Blades1_99 .

------------------------------------------------------------------

Just a comment; 100% Cylinder Fill, will produce about 755 rwHP (this ranges / varies a bit), mostly due to the engines efficiency, which is directly related to the engines static compression ratio.

As you move past about 87%, of that fill, fuel, mass flow recovery,
tune, etc. all begin to rear their ugly heads.

=> (0.87 * 755) = 657 rwHP.

I normally simply call this number 660 rwHP. . . .

Take Care!
 

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2013 White Diamond sedan A6
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2013 A6 Sedan
Airaid intake w/green filter
Reinforced brick
FIC 1000 injectors
2.5/9.1 Upper/Lower pulley
Flex fuel sensor E85
DSX aux fuel pump
Track attack HX
Varimax HX pump
2" TSP long tube headers w/ 3" x-pipe no cats to stock muffler
NGK Tr7ix plugs and MSD wires
Moroso Catch can
160 Tstat
Dynojet tuned
 

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Premium Member
Joined
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5,524 Posts
2013 A6 Sedan
Airaid intake w/green filter
Reinforced brick
FIC 1000 injectors
2.5/9.1 Upper/Lower pulley
Flex fuel sensor E85
DSX aux fuel pump
Track attack HX
Varimax HX pump
2" TSP long tube headers w/ 3" x-pipe no cats to stock muffler
NGK Tr7ix plugs and MSD wires
Moroso Catch can
160 Tstat
Dynojet tuned
And your Peak HP, at 6,330 RPM, is very close to the 660 rwHP I stated in my earlier post.

And since the engine made 646 rwHP, the equivalent engine rpm to inhale sufficient air (CFM) to make that HP, tells me that the engine inhaled the equivalent air (CFM) associated with spinning the engine to ~10,240 rpm.

So, VE% then is equal to. . .
=> (10240 / 6330)= ~162%

But Cylinder Fill, or %VE, is only at ~86%

---------------------------------------------------

With that pulley ratio, and because your approaching that 660 rwHP, it is
good to see your running E85, and have upgraded your HX.. (y) (y)

One comment, just to be sure you understand something very important;
When running E85, and using a 160° Thermostat, be sure you both check
your Catch Can for water, as well as change your oil frequently. . . .

Cheers
 

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And while this forum member (just below), is extremely wealthy,
and the cost of mods is 'Pocket Change' for him. . ;) :D
Only when compared to a bushman of the Tsavo.
 
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Only when compared to a bushman of the Tsavo.
But, but, but…Bushman don’t own yachts, or have multiple dwellings around the world, or slaves in their kitchen, cooking them meals 24 hours a day, as you do..🤪😜🤣
 

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11 v coupe auto
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Discussion Starter · #11 ·
more current dyno run w/borlas and blower pulley
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And your Peak HP, at 6,330 RPM, is very close to the 660 rwHP I stated in my earlier post.

And since the engine made 646 rwHP, the equivalent engine rpm to inhale sufficient air, to make that HP, tells me that the engine inhaled the equivalent air, associated with spinning the engine to ~10,240 rpm.

So, VE% then
But Cylinder Fill, or %VE, is only at ~86%

---------------------------------------------------
Thanks for the response and the heads up. What prevents the %VE from being 100%? Needs porting and or cam? Sorry I’m no engineer but trying to understand. Also why would water be potentially getting in the catch can? Gaskets breaking down?
 

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You wrote:
"Thanks for the response and the heads up. What prevents the %VE from being 100%? Needs porting and or cam? Sorry I’m no engineer but trying to understand."

First, VE% (not %VE) is related to engine rpm, piston speed, and how well the induction system has been engineered.

That formula is. . .RPM * CID / 3456

Where a 376 CID, Spun to 6800 rpm, will inhale . . . .
=> (376 * 6800 / 3456)= 740 CFM.

Generally speaking, that would be sufficient air to support how much fwHP. . .

Here we should actually use the 'Air Standard Efficiency', or %ASE, which relates %ASE to the static compression ratio. However, because these engines have a roots blower, that tends to change many things.

And since the High-Perf Automotive Industry has standardized their calculations, by stating that it takes 1.5 CFM to generate 1.0 fwHP, we can simply use that 1.5 Number.

Also, if we take the reciprocal of 0.67, we do get the value of 1.5, if we round up. . .

So then; 740 cfm would produce ~(740 / 1.5)= 493 fwHP.

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%VE is a calculation, which relates to how much more the
engines cylinders have been filled, versus what the cylinder
had been calculated to fill.

So a %VE of 120%, tells one that the cylinder was filled to 120%, of what it would take to reach 100% cylinder fill. Whereas, a value of %VE of 87%, which is very common in many high performance street / strip engines, tells one that the cylinder has been filled to 87%.

-------------------------------------------------------------------------------

Regarding what stops an engine from producing over 100%, %VE?
Insufficient engine rpm, which results in insufficient piston speed.

If we do have sufficient engine rpm, and sufficient piston speed,
then one should then begin to look at their induction system.

But that is not the case here, as most on this forum do not shift
at a sufficiently high engine rpm. And since piston speed is a
derivative of engine rpm, the piston speed would also not sufficient
to generate a pressure differential across the intake valve.

-'supply side' of engine, must meet requirements set, by 'demand side' of engine-
And if they do shift at a sufficiently high rpm, is their induction system sufficient enough to 'Supply' enough air, to meet the Piston CFM 'Demand', which is dictated by the piston speed.

Piston CFM Demand then, must be met with a sufficient CFM Supply

--------------------------------------------------------------------------------

You also wrote:
"Also why would water be potentially getting in the catch can? Gaskets breaking down?"

Nope, any ethanol, be it Methanol (wood) or E-85 (corn sugar) attracts water.

We recently had a thread on this forum, where I spent much time explaining all of that.

Typically, the easiest way to find a thread / topic like that, is to go to Google, and type in your question, and add CTS-V Owners Forum to the query,

So,since E85 is 85% Ethanol, it attracts water.

And that water is best trapped in a 'Catch Can', and must be emptied often, much more often than if the engine was running on Gasoline. And it is best to also change your oil and filter at 2,000 - 3,000 mile intervals with E-85.
 
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