Single Cylinder Engines

General engine tech -- Drag Racing to Circle Track

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Re: Single Cylinder Engines

Post by pcnsd » Tue Mar 13, 2018 9:23 pm

This is the exhaust system data from PipeMax.

Cylinder Ignition Interval = 720 degrees 4800 RPM Hertz frequency = 40.0 Hz
Target EGT= 1457.3 degrees F at end of 4 second 600 RPM/Sec Dyno accel. test
12.915 CID Exhaust System operating RPM Range from 2800 to 5300 RPM

--- Single Primary Pipe Specs --- ( Low to Mid-Range RPM Torque and HP )
Diameter= .840 to .965 Total Length= 40.2 to 42.4 inches long
--- 2-Step Primary Pipe Specs --- ( Low to Mid-Range RPM Torque and HP )
1st Step Dia. inches= .840 Length= 20.1 to 21.2
2nd Step Dia. inches= .965 Length= 20.1 to 21.2
--- 3-Step Primary Pipe Specs --- ( Low to Mid-Range Torque and Hi RPM HP )
1st Step Dia. inches= .840 Length= 20.1 to 21.2
2nd Step Dia. inches= .965 Length= 10.0 to 10.6
3rd Step Dia. inches= 1.090 Length= 10.0 to 10.6

--- Single Primary Pipe Specs --- ( Mid-Range TQ to Higher RPM Horsepower )
Diameter= 1.040 to 1.165 Total Length= 40.2 to 42.4 inches long
--- 2-Step Primary Pipe Specs --- ( Mid-Range TQ to Higher RPM Horsepower )
1st Step Dia. inches= 1.040 Length= 13.4 to 14.5
2nd Step Dia. inches= 1.165 Length= 26.8 to 27.9
--- 3-Step Primary Pipe Specs --- ( Higher RPM Horsepower, possible TQ loss )
1st Step Dia. inches= 1.040 Length= 13.4 to 14.5
2nd Step Dia. inches= 1.165 Length= 13.4 to 13.9
3rd Step Dia. inches= 1.290 Length= 13.4 to 13.9

Note-> all Pipe Diameters are OD and based-off .0625 inch Pipe thickness

---- Primary Pipe's Harmonics ----
1st Harmonic = 173.8 inches long ... typically never used
2nd Harmonic = 66.5 inches long ... longest recommended
3rd Harmonic = 40.2 inches long ... highly recommended , best Torque Curve
4th Harmonic = 28.3 inches long ... shortest recommended
5th Harmonic = 21.5 inches long ... typically never used
6th Harmonic = 17.2 inches long ... typically never used
7th Harmonic = 14.1 inches long ... typically never used
8th Harmonic = 11.8 inches long ... typically never used

---- Collector's Harmonics (includes Intermediate, Muffler , TailPipe) ----
1st Harmonic = 183.5 inches long ... longest with Mufflers and TailPipes
2nd Harmonic = 91.8 inches long ... longest recommended with Mufflers
3rd Harmonic = 45.9 inches long ... more bottom-end Torque
4th Harmonic = 22.9 inches long ... highly recommended , best Torque Curve
5th Harmonic = 11.5 inches long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 5.7 inches long ... reduced Torque , not recommended


*************************** Metric Units ***************************
Cylinder Ignition Interval = 720 degrees 4800 RPM Hertz frequency = 40.0 Hz
Target EGT= 791.8 degrees C at end of 4 second 600 RPM/Sec Dyno accel. test
0.2116 Liters Exhaust System operating RPM Range from 2800 to 5300 RPM

--- Single Primary Pipe Specs --- ( Low to Mid-Range RPM Torque and HP )
Diameter= 21.342 to 24.517 Total Length= 1020.9 to 1076.4 MM long
--- 2-Step Primary Pipe Specs --- ( Low to Mid-Range RPM Torque and HP )
1st Step Dia. MM= 21.342 Length= 510.4 to 538.2
2nd Step Dia. MM= 24.517 Length= 510.4 to 538.2
--- 3-Step Primary Pipe Specs --- ( Low to Mid-Range Torque and Hi RPM HP )
1st Step Dia. MM= 21.342 Length= 510.4 to 538.2
2nd Step Dia. MM= 24.517 Length= 255.2 to 269.1
3rd Step Dia. MM= 27.692 Length= 255.2 to 269.1

--- Single Primary Pipe Specs --- ( Mid-Range TQ to Higher RPM Horsepower )
Diameter= 26.422 to 29.597 Total Length= 1020.9 to 1076.4 MM long
--- 2-Step Primary Pipe Specs --- ( Mid-Range TQ to Higher RPM Horsepower )
1st Step Dia. MM= 26.422 Length= 340.3 to 368.1
2nd Step Dia. MM= 29.597 Length= 680.6 to 708.4
--- 3-Step Primary Pipe Specs --- ( Higher RPM Horsepower, possible TQ loss )
1st Step Dia. MM= 26.422 Length= 340.3 to 368.1
2nd Step Dia. MM= 29.597 Length= 340.3 to 354.2
3rd Step Dia. MM= 32.772 Length= 340.3 to 354.2

Note-> all Pipe Diameters are OD and based-off 1.588 MM inch Pipe thickness

---- Primary Pipe's Harmonics ---- ( Lengths in MilliMeters )
1st Harmonic = 4413.5 MM long ... typically never used
2nd Harmonic = 1689.0 MM long ... longest recommended
3rd Harmonic = 1020.9 MM long ... highly recommended , best Torque Curve
4th Harmonic = 718.9 MM long ... shortest recommended
5th Harmonic = 546.8 MM long ... typically never used
6th Harmonic = 435.6 MM long ... typically never used
7th Harmonic = 357.9 MM long ... typically never used
8th Harmonic = 300.5 MM long ... typically never used

---- Collector's Harmonics (includes Intermediate, Muffler , TailPipe) ----
1st Harmonic = 4661.1 MM long ... longest with Mufflers and TailPipes
2nd Harmonic = 2330.6 MM long ... longest recommended with Mufflers
3rd Harmonic = 1165.3 MM long ... more bottom-end Torque
4th Harmonic = 582.6 MM long ... highly recommended , best Torque Curve
5th Harmonic = 291.3 MM long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 145.7 MM long ... reduced Torque , not recommended
- Paul

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Re: Single Cylinder Engines

Post by pcnsd » Tue Mar 13, 2018 10:22 pm

What PipeMax suggest adding SCR to the existing set up gets you.. .5-.8 HP. This shows 10.2:1 compression.
Predator212 Higher SCR.png
Other thoughts in no organized manner.

EnginePro suggest the bottom end might spin up to 15krpm in the short term, so I believe that others may be getting to 10k, but it ain't gonna happen with the stock head. My number crunching suggest the intake port and valve will fall flat somewhere in the 6-6.5k range. Look at the Valve to Bore ratios. The intake valve is very small for a Hemi. The exhaust valve is just smallish in comparison.

The VM22 roundslide is about perfect for the existing combo. To justify going to a VM 24 mm you need to get the port and valve to flow over 72CFM@ 28" at max valve lift and keep the velocity reasonable. I won't say it is not possible but it is unlikely without a bigger valve and a lot of work.

Is the timing adjustable? If so, you may find some power by carefully advancing the total advance.

Do you know how to perform the "Pour volume" static compression estimate? If you know the pour volume, you know the SCR. It is likely higher than 8.5:1
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Re: Single Cylinder Engines

Post by pcnsd » Wed Mar 14, 2018 9:42 am

This is the estimate of what a lot of porting work might get you to. It is in general a happy face estimate, meaning that reality maybe somewhat less. Based on your current lifts values, it suggest your intake flow will top out at less than 70 cfm (69.2). This is what limits you to 6000-6500 rpm from peak HP. As already mentioned you are somewhere between 45 and 50cfm now at max lift. All numbers are at 28" H2O.
Predator 212 cylinder head flow estimate.png
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Re: Single Cylinder Engines

Post by mekilljoydammit » Wed Mar 14, 2018 4:58 pm

I'm working on this for fun, mainly to prove techniques for casting other stuff, but I found in Solidworks anyway, if you cant everything right, you can make valves from a GX390 class engine fit in a custom head. Bottom line there, at the edge of the seats, is a 72mm bore, like the 224cc variants. 35mm intake, 32mm exhaust.
New Head.JPG
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Re: Single Cylinder Engines

Post by Bow » Thu Mar 15, 2018 12:41 am

Paul,

WOW.. Thank you for that information and running the simulation. I was art of teh group buy, so I now have those software programs at my disposal, as soon as I figure out how to use them.

I might ask you for those files, if you stashed them.

it is interesting that your "Stock" engine guesstemate was so close to the advertised numbers on the engine specs, but a little disappointing is I only gains about 4hp in $250-$300 in parts! :D

Like they say, HP isn't cheap

You asked about the timing... the ARC Billet flywheel advances it to 32 degrees, from the Stock 24 degrees.

My "header" that I built is 1"ID for 19", then Steps to 1.5" through a 12" straight thru glasspack type motorcycle Muffler.. 31" total length from the head to the atmosphere... obviously a tad shorter than the 40"-42" length PipeMax stated... damn...

Mekilljoydammit:

I know bigger valves are an option, but casting a head... man the is a bit more than I have time for! LOL The are guys the mill Billet heads for these engines for Minibike drag racing, and that have so incredible builds...

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Re: Single Cylinder Engines

Post by mekilljoydammit » Thu Mar 15, 2018 9:18 am

I have a homebrew small foundry and have been using a 3d printer to do patterns for castings... I'm trying to work up to doing "engineering" grade stuff rather than just decorative, with water cooled heads being an eventual target. But I figure it'll be a heck of a lot easier to try to do a working air cooled single cylinder first.

Everyone needs a hobby, right?

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Re: Single Cylinder Engines

Post by Bow » Thu Mar 15, 2018 11:28 am

mekilljoydammit wrote:
Thu Mar 15, 2018 9:18 am
I have a homebrew small foundry and have been using a 3d printer to do patterns for castings... I'm trying to work up to doing "engineering" grade stuff rather than just decorative, with water cooled heads being an eventual target. But I figure it'll be a heck of a lot easier to try to do a working air cooled single cylinder first.

Everyone needs a hobby, right?
Oh wow... you win! That is a hell of a hobby indeed.

Casting your own head would be great, but I wonder how big of a valve you can stuff into the stock 212 head...

looking at this photo:
Image

The 27mm Intake looks like it won't fit much bigger, and the 25mm exhaust, in its current position, looks like it cant grow much, if any, at all

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Re: Single Cylinder Engines

Post by mekilljoydammit » Thu Mar 15, 2018 11:51 am

Not with the stock valve guide location. If you look at it though, with some cutting and probably welding you could move both valves closer to the edge of the combustion chamber.

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Re: Single Cylinder Engines

Post by Bow » Thu Mar 15, 2018 5:23 pm

pcnsd wrote:
Tue Mar 13, 2018 10:22 pm

EnginePro suggest the bottom end might spin up to 15krpm in the short term, so I believe that others may be getting to 10k, but it ain't gonna happen with the stock head. My number crunching suggest the intake port and valve will fall flat somewhere in the 6-6.5k range. Look at the Valve to Bore ratios. The intake valve is very small for a Hemi. The exhaust valve is just smallish in comparison.
Paul,

how did you get Engine Pro to take the Valve Sizes?

it won't let me put in actual size, saying its too small...

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Re: Single Cylinder Engines

Post by pcnsd » Thu Mar 15, 2018 6:06 pm

That is correct. If it doesn't accept reality, it will replace it with its own. It is why I did not post the output from EnginePro. That said, I was reasonably successful applying a work around, which was to tell it airflow at lift was 53cfm@28" I tried to upload the files I built for both EnginePro and Pipemax, but they are invisible to the dialog box.
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Re: Single Cylinder Engines

Post by pcnsd » Thu Mar 15, 2018 6:13 pm

Here is what I set up in EnginePro. The flow data is what my spreadsheet suggest is a best case scenario.
EngPro Predator 212.png
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