using SF Air Turbine to determine Header problems

[maxracesoftware]

 

using the SuperFlow Air Turbine to determine potential Header problems
 
1st example : SBC 401.0 cid = 4.125x3.750
SBC 401.0 cid = 4.125x3.750
after new Port Work + 2.125 int valves + Hurricane Porting
10:1 CR Chevron Super Unleaded 93
950 HP Carb
34 deg btdc
------------------------------------
change=add on collectors for 24 inch total

RPM
3800 = gained +61.6
3900 = gained +81.3
4000 = gained +79.5
4100 = gained +75.5
4200 = gained +68.2
4300 = gained +56.6

[maxracesoftware]

1st example : SBC 401.0 cid = 4.125x3.750
SBC 401.0 cid = 4.125x3.750
after new Port Work + 2.125 int valves + Hurricane Porting
10:1 CR Chevron Super Unleaded 93
950 HP Carb
34 deg btdc
------------------------------------
change=add on collectors for 24 inch total

RPM
3800 = gained +61.6
3900 = gained +81.3
4000 = gained +79.5
4100 = gained +75.5
4200 = gained +68.2
4300 = gained +56.6

[maxracesoftware]

using the SuperFlow Air Turbine to determine potential Header problems

2nd example : BBC 468 4.310x4.000
BBC 468 4.310x4.000
#990 Open Chamber 2.300/1.880
Edelbrock Victor 454-R w/Moroso open-hole spacer
Holley 0-9375 1050 92/92 jets
C-14 Race Fuel
36 btdc
Lunati solid roller .817/.778 286/304 112 on 110 CL
12:1 CR Arias
Jesel Belt
Milodon oil pan 7qts 20/50 Valvoline
Custom made Headers 2.125x28.5 4.000x9.250
Moroso 3-vane vac pump
-----------------------------------
add on collector extensions for 19.5 inch total

4500 = gained +65.6 5000 = gained +104.7
4600 = gained +74.4 5100 = gained +110.4
4700 = gained +76.9 5200 = gained +95.8
4800 = gained +86.7 5300 = gained +91.1
4900 = gained +98.8 5400 = gained +55.0

[maxracesoftware]

using the SuperFlow Air Turbine to determine potential Header problems

2nd example : BBC 468 4.310x4.000
BBC 468 4.310x4.000
#990 Open Chamber 2.300/1.880
Edelbrock Victor 454-R w/Moroso open-hole spacer
Holley 0-9375 1050 92/92 jets
C-14 Race Fuel
36 btdc
Lunati solid roller .817/.778 286/304 112 on 110 CL
12:1 CR Arias
Jesel Belt
Milodon oil pan 7qts 20/50 Valvoline
Custom made Headers 2.125x28.5 4.000x9.250
Moroso 3-vane vac pump
-----------------------------------
add on collector extensions for 19.5 inch total

4500 = gained +65.6 5000 = gained +104.7
4600 = gained +74.4 5100 = gained +110.4
4700 = gained +76.9 5200 = gained +95.8
4800 = gained +86.7 5300 = gained +91.1
4900 = gained +98.8 5400 = gained +55.0

[maxracesoftware]

using the SuperFlow Air Turbine to determine potential Header problems

2nd example : BBC 468 4.310x4.000
BBC 468 4.310x4.000
#990 Open Chamber 2.300/1.880
Edelbrock Victor 454-R w/Moroso open-hole spacer
Holley 0-9375 1050 92/92 jets
C-14 Race Fuel
36 btdc
Lunati solid roller .817/.778 286/304 112 on 110 CL
12:1 CR Arias
Jesel Belt
Milodon oil pan 7qts 20/50 Valvoline
Custom made Headers 2.125x28.5 4.000x9.250
Moroso 3-vane vac pump
-----------------------------------
add on collector extensions for 19.5 inch total

4500 = gained +65.6 5000 = gained +104.7
4600 = gained +74.4 5100 = gained +110.4
4700 = gained +76.9 5200 = gained +95.8
4800 = gained +86.7 5300 = gained +91.1
4900 = gained +98.8 5400 = gained +55.0

[af2]

interesting! going to use this next year on the 403 to see the 1/4 mile difference.

[maxracesoftware]

interesting! going to use this next year on the 403 to see the 1/4 mile difference.

it depends on your RPM Range ?? ... to see greatest benefits from getting the Collector Length correct !

RPM effects :
the Lower the RPM Range ... the greater the Event times .... the longer the Primaries and Collector Lengths
need to be to "Time" the returning negative wave pressure to center on TDC-Overlap
Low RPM Range Engine Combos suffer the greatest lost in TQ and HP if Collector Lengths are wrong .

obviously , the Collector length was a mile off in both example Engines above .

the higher the RPM Range .... the lesser the Event times ... the Shorter the Primaries and Collector Lengths
and an additional effect is = the TQ and HP numbers do not suffer as much , as if it were a very Low RPM Range Engine .

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

additional Info :
years ago , i had a MaxRaceSoftware Forum User post he lost right at -90 Rear Wheel HP on Chassis Dyno
after to switching to custom side pipes on BBC Corvette,
i plugged all his info into PipeMax v3.98 at that time
and told him his Exhaust system length now was exiting at the "Worst" possible Harmonic Length

He could have saved a bunch of Time + Money if he would have 1st used PipeMax ,
as at that time , he had PipeMax v3.98, but did not use it

[maxracesoftware]

"the EGT is the System's Speed ( Speed of Sound FPS ) you have to work with,
and the "Timing" of the returning negative pressure Wave @ TDC-Overlap is where huge amount of TQ and HP gains are ,
so the earlier EVO event is ... the longer the Primary Tubes need to be .

a "Hunting analogy" :
the faster the Duck flies ... the more you lead the shot with your Shot Gun

so basically ...
if you shoot too soon , you don't hit the Duck ( TDC-Overlap )
if you shoot too late, you don't hit the Duck either !
if you shoot at the correct time , you hit the Duck , and win the TQ and HP prize ! "

* same effects for Collector Lengths or entire Exhaust System lengths

-------- this sure applied to those 2 example engines above !

[ptuomov]

What’s the best way to estimate how much charge actually gets trapped in the cylinder and how much flows straight thru to exhaust?

[maxracesoftware]

What’s the best way to estimate how much charge actually gets trapped in the cylinder and how much flows straight thru to exhaust?

if your Engine Dyno has accurate Fuel Consumed Lbs/Hour readings
and you also need to input each Dyno Pull's Weather conditions, and have accurate Flow Bench CFM Numbers,
then plug everything into PipeMax v4.50.... make PipeMax's Peak HP exactly matchup your Engine Dyno's Peak HP,
and make PipeMax's Fuel Consumed reading exactly matchup your Engine Dyno's Fuel Consumed reading,
and same thing with the BSFC value ... adjust the Air/Fuel Ratio a little at a time until you get exact matches
between Fuel Consumed and BSFC and Peak HP .... then look at how much Intake System CFM and VE% it takes for that matchup .

*** i forgot to mention these very important input values :
you must measure your Cylinder Heads intake and exhaust Port CenterLine Lengths and each's Port Volume CC's
then plug in that info into PipeMax ... then adjust each Port velocity FPS until you get an exact
matchup in PipeMax calculated Port Volume CC -to- your actual Port Volume CCs
... use must use a Class "A" Burette for accuracy .

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

more Air Turbine info :

Only use the Air Turbine on a few Dyno Pulls to see if Collectors or exhaust system has any problems
if no real problems, remove it for rest of Dyno Pulls ,
reason :
[1]= the Air Turbine restricts Air entering the Carb(s) around the sides of the Veunturis entries .
Carbs like to breathe from along sides , not just straight down direction like the Air Turbine would force Air .
If the Carb is too small for the RPM Range of the Engine , the Air Turbine can further cause a loss in TQ and HP .
If the Carb is OK or too large for the Engine , you probably will not see any difference in TQ or HP with or without the Air Turbine

[2]= since the Air Turbine body has pretty much "Length or Height" ,
it can sometimes affect Intake System Tuned length one way or another , meaning increase or decrease VE , TQ, and HP
at some RPM points .

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

in the engine examples above ,
you would look at "VE% increase Rates" for exhaust system problems .
If Air Turbine shows VE% in the 80's or 90's during 1st lower RPM Ranges , then jumps to 110's + VE% quickly in later RPM Ranges,
then Exhaust system length is wrong .

just compare VE% numbers and "RATE of VE% increase" , in middle range between Peak TQ RPM -to- Peak HP RPM
-VS- lower RPM range , to see if theres problems .

[FC-Pilot]

Thanks for the tips on how to better use our dyno to its fullest.

Paul

[maxracesoftware]

Thanks for the tips on how to better use our dyno to its fullest.

Paul

thanks Paul, ... glad you found the Info to be useful !

more Info :
i have a "Blow-thru Fan" system above the Engine in a 4Ft x 4Ft Wooden Box , its a 3-Phase 22,000 CFM Hi-Pitch Fan
and my back doors measure 6ft wide x 7 ft tall ... so the Dyno room exit is plenty large enough to not cause Air pressure rise .
i measured Dyno Room inches of water pressure with Fan on and entry door closed = 0.5" inch water rise
so the Room is not being pressurized from the Fan CFM , so no boost to TQ or HP readings .

with the "Blow-thru Fan" system + my Shop being in the country , ( no problems with Neighbors complaining of noise )
i don't need to use any Dyno Mufflers + extra Dyno hookup tube lengths to rear of Collectors .

if you are in the City , or you need to hookup extra length pipes from Dyno Mufflers to ends of Collectors,
its very possible you won't see the correct effects of the Air Turbine readings ???

i highly recommend any extra Dyno hookups to ends Collectors be at very least twice the diameter of the engine's Collector OD
so you can see correct effects of Air Turbine readings

Ideally you would want to run the Engine on the Dyno
exactly with the Customers Headers ( and with his complete exhaust system if he has one )
as its in his RaceCar , as it runs down the Dragstrip !!! ( that is , no extra Dyno hookups if Dyno Room can maintain clean Air )
.... otherwise , you can get incorrect VE%, CFM, TQ, and HP readings , that won't correlate to Dragstrip ET Slip Data .

even more Info :
in both SBC and BBC examples above , i just put on the closest Collector add on tube i had lying around the Shop,
and "both" examples above are no where maxed-out on their Header Specs , so you can see lower RPM Range VE% is still
relatively too low -VS- Mid-Range to Higher RPM Range 's average VE% number !
Both those 2 Engines could have made more TQ and HP with correct Header Specs .
and the BBC had way too much Duration , especially on the Exhaust side , so the wrong Collector Length killed the bottom-end TQ

[David Redszus]

"the EGT is the System's Speed ( Speed of Sound FPS ) you have to work with,
and the "Timing" of the returning negative pressure Wave @ TDC-Overlap is where huge amount of TQ and HP gains
are, so the earlier EVO event is ... the longer the Primary Tubes need to be .

How did you determine exhaust gas sonic velocity?

[FC-Pilot]

"the EGT is the System's Speed ( Speed of Sound FPS ) you have to work with,
and the "Timing" of the returning negative pressure Wave @ TDC-Overlap is where huge amount of TQ and HP gains are ,
so the earlier EVO event is ... the longer the Primary Tubes need to be .

Now, does the use of methanol have enough of an effect on the egt that it could create differences in tuned lengths as predicted by your software? I have an older version. I guess I need to pay up for the latest version to make the most of the info you have posted. Thanks again for the insights.

Paul

[maxracesoftware]

"the EGT is the System's Speed ( Speed of Sound FPS ) you have to work with,
and the "Timing" of the returning negative pressure Wave @ TDC-Overlap is where huge amount of TQ and HP gains
are, so the earlier EVO event is ... the longer the Primary Tubes need to be .

How did you determine exhaust gas sonic velocity?

Sorry , the equations are "proprietary",
i can't Post a Source Code example ,
but they accurately predict Exhaust System specs .

What's also interesting is :
testing various Collector Lengths , (this is : no extra Dyno exhaust hookups to Collector ends )
you can put on a Collector Length that matches up to the 4th Harmonic Length, and gain a lot of TQ and HP in most cases ,
then put on a Collector Length thats longer , but is half-way between 4th and 3rd Harmonic and loose TQ and HP ,
then put on an even longer Collector that matches the 3rd Harmonic length , and gain back TQ again !
You can also see these effects at the SF Air Turbine readings !

Same sort effect if you put the Customers entire exhaust system
and see if it matches up to the 2nd or 1st Harmonic Lengths .
If you are dead-in-the middle halfway between Harmonics ,
it hurts TQ , but if you are very close or dead-on to the Harmonic Length, it increases TQ and HP .

Theres some exceptions to this :
[1]= Overscavenging during Overlap Period
[2]= worst are : Overscavenging + way too fast local area velocities in the Intake Port or even in the Manifold Runner sometimes
............ Overscavenging + way too fast local area velocities will causes pumping losses,
the Engine will not make the correct amount of Peak HP the Flow Numbers suggest !
So that if you "Fix" the way too fast local Port velocity areas , the Engine will like PipeMax predicted Harmonic Lengths .
If you don't Fix the problem , its probably not going to like PipeMax specs .
PipeMax is setup to always predict Diameters and Lengths to give you highest scavenging of Exhaust ,
but there are cases where highest scavenging will hurt HP , especially after Peak HP RPM !

You can tell if Intake Port FPS is going to be way too fast by Probing with Pitot Probe in Flowbench tests .
You can also get a very good indication from the "input value" in PipeMax v4.50
for both the Intake and Exhaust Port :
CSA = Intake Port Cross-Sectional Area Velocity in Feet Per Second ( FPS )
CSA = Exhaust Port Cross-Sectional Area Velocity in Feet Per Second ( FPS )

CSA Velocity FPS = ( Intake Port CFM * Intake Port CenterLine Length * 39.3289536 ) / Intake Port Volume CC
CSA Velocity FPS = ( Exhaust Port CFM * Exhaust Port CenterLine Length * 39.3289536 ) / Exhaust Port Volume CC

PipeMax included Files :
this Cylinder Head's Intake Port "average FPS" is on very edge of Pumping Choke losses
Sonny_Leonard_BBC_1006cid_8000RPM_2150HP_6200RPM_1550TQ

same thing with this example : ( this Combo is actually just into a Intake Port Choke condition, thats its being limited by )
NHRA_SuperStock_SSAH_Class_Hemi_8600RPM_991.6HP_6600RPM_664.6TQ

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

There's 48 included example simulation files with v4.50 ,
and these Files pretty much cover a wide range of RPM and Engine types
and PipeMax v4.50 models all 48 very accurately ,
but you need to input accurate Data !

i ran hundreds more Simulations , and narrowed down to 48 included examples ,
the "Recently Open Files List History" will Save a History of up to the last 100 Files Opened
which makes it convenient when you testing a bunch of Engine Combinations for correlations !