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  #81  
Old 01-03-2018, 02:03 PM
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Nice flathead!

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Old 01-03-2018, 03:44 PM
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Oh I know eh....
I really wish I could take credit for it.... But that's a google searched one...
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  #83  
Old 01-03-2018, 09:18 PM
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I might be able to up out. I am a newb to karts, but I recently finished a twin 76mm turbo charged fuel injected big block 540cid that sits in a 1971 chevelle.

One suggestions for tubing is radiator hose. For the short length you need, you might can walk behind the counter at a parts store and pick out what you want, maybe get lucky and find the bend/radius you need. Or maybe gasoline filler necks like this:
http://www.fillernecksupply.com/1-1-...SABEgLx9vD_BwE

I have not read this whole thread yet, will give it a read soon. I am a member over at Yellowbullet. Tough crowd over there, but I think your dimeaner will do just fine.

---------- Post added at 10:03 PM ---------- Previous post was at 09:48 PM ----------

Is this a blow through carb or will it pull through the carb? I will suggest pull through if that blower can handle getting wet with fuel inside. Blow through and you have to worry about pressurizing the fuel bowl and push air back into your fuel line. Blow through and you have to have an active fuel supply that can increase its own pressure relative to air intake boost.

I would not sweat the concept of recirculating the blow off air. Just use a blow off valve to regulate maximum intake psi. Just put that valve on a bung and install different springs for a desired boost. You can then work with the RPMs of the charger to make the right amount of boost versus wasting effort by purging air all day long. Like this but less psi:

https://www.zoro.com/control-devices...specifications


I also read that you want to clutch the charger to only spin at a given RPM and bove. When the charger is not spinning it is a huge restriction. So you will have to up your idle a lot. Do you have this thing yet? If so plumb it's feed side up to a runnig motor and see if it sufficates or stalls the motor.

Interesting project for sure.

---------- Post added at 10:18 PM ---------- Previous post was at 10:03 PM ----------

Home brew beer makers use something called a spundle valve. You just turn the handle to the psi you want. Not sure of the flow rate:

https://www.amazon.com/gp/product/B0...Q6I4IKSFEAO43T
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  #84  
Old 01-03-2018, 09:27 PM
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Maybe you need the mailbox Kelly bought.
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Old 01-04-2018, 12:03 AM
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Thanks for your help.
I'll try to summarize up to this point.

Draw (or suck) through system.

Whether the blower likes it or not, it is going to get wet.
I'm just going to ignore any damage the fuel will do to the bearings and any coating on the rotors. And I'll choose to only think about the cooling properties of the gas inside the blower.

I don't have it yet, but great idea on testing if it stalls the engine. I assume it will.

That is one of the reasons I was considering the recirculating bypass valve. I figured if the bypass valve is open at idle and the blower is not spinning - the air/fuel mix will get routed through the bypass plumbing (around the restrictive blower rotors).

One reason I was thinking about clutching the blower was the ignition system. Stock is around 24 degrees BTDC. So at around 2k RPM, the plug fires at 24 BTDC. But at 7000 RPM, it may be retarded to 18 BTDC. I was thinking I might have to back off timing and leave top end power on the table because I had to tune for boost at idle. But I suppose if the throttle is closed, even if the blower is spinning -then the manifold (between the blower output and the intake valve) is still going to be reading vacuum, not positive pressure. I think I was misunderstanding this before.

Still see it being an issue clutched or not (unless I don't want boost for half my powerband). If going WOT from idle, I might have full boost and max timing advance at 2000 RPM, then at 7000 RPM still have the same boost but less timing. Due to the nature of the ignition system, I might have to tune to prevent knock at low RPM WOT, which might prevent tuning for max HP at High RPM. Need a fuel circuit that gives extra gas at low RPM WOT and less at high RPM WOT to compensate for the timing. Or maybe if the blower leaks less as RPMs increase, then maybe this timing will work out ok. Not going to worry about this for now.

Another reason I wanted to clutch the blower was the cooling system.
The only thing cooling the engine while idling is the fins on the flywheel. While moving I'll have a 30 - 70mph wind helping me cool it, but while stopped, its just the flywheel fins. I prefer to build my toys as "daily drivers" as opposed to "track only" stuff because they never see any track time. lol


So in your opinion, IF the blower was clutched, COULD I use a Greddy Type S - blow off valve with hose coupler attachment as a recirculating valve??? It is adjustable. I think you can use the big spring, the little spring, or both springs. And you can fine adjust the preload by turning the nut at the top. Capable of holding 30 psi. My understanding is that it operates off of vacuum (downstream of the throttle).

It has two inlets. One on top - I assume this is to connect the vacuum line (from after the throttle but before the blower).
The one one the bottom can be left unconnected. It might be to operate the BOV off of max positive manifold pressure, instead of vacuum??

I'm partial to this type of bov because I already order one and it should be on its way. I suppose I could resell it if it doesn't do what I want or I don't need it.
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  #86  
Old 01-04-2018, 12:39 PM
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Go Directly to Go.
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Is this a new item?
It is new to me?

http://www.gopowersports.com/manifol...nes-predators/



I think I paid $40 for the NR Racing One.
http://www.nrracing.com/product-p/man-24-wp.htm


---------- Post added at 01:39 PM ---------- Previous post was at 01:35 PM ----------

Which reminds me that a pulse pump from the intake manifold probably does not work with this set up.
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Old 01-04-2018, 07:32 PM
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I Am too dumb to multi quote. yours is bold, mine is not...

One reason I was thinking about clutching the blower was the ignition system. Stock is around 24 degrees BTDC. So at around 2k RPM, the plug fires at 24 BTDC. But at 7000 RPM, it may be retarded to 18 BTDC. I was thinking I might have to back off timing and leave top end power on the table because I had to tune for boost at idle. But I suppose if the throttle is closed, even if the blower is spinning -then the manifold (between the blower output and the intake valve) is still going to be reading vacuum, not positive pressure. I think I was misunderstanding this before.


Timing depends on compression ratio. Do you know what that is? I am guessing it is low like 8:1 because these engines accept such crummy gas octane. I would ignore timing for now as those numbers sound conservative to me. Granted my V8 is totally different, but I run 36* at 3600RPM and no boost, but pull it down to 22* with 10psi of boost.

Correct that you should not make boost "at idle". Or even off idle. The centrifugal blowers need RPM to make positive pressure and they are usually geared for a specific RPM to produce a desired flow. If you are making boost at idle, then don't bother revving the engine because you'll be making too much boost at high RPM. The ramp is slow and linear like a 45* incline. Which is why people change the driven gear on them to effectively "scoot" that curve vertically, but the curve is still the same slope, just higher boost numbers across the curve. DO you have any data on the super charger, like a RPM vs flow chart vs back pressure?

Another reason I wanted to clutch the blower was the cooling system.
The only thing cooling the engine while idling is the fins on the flywheel. While moving I'll have a 30 - 70mph wind helping me cool it, but while stopped, its just the flywheel fins. I prefer to build my toys as "daily drivers" as opposed to "track only" stuff because they never see any track time. lol


I think you will not produce any boost at idle. I doubt that overheating will be an issue. Think of a pressure washer motor run full bore for hours and it sits put all day long. Your setup running even moderate boost at idle will not produce as much energy as that pressure washer. However, owning an infra red temp gun is a great thing. I think as long as you have an open air solution, you'll be fine. don't sweat this.

So in your opinion, IF the blower was clutched, COULD I use a Greddy Type S - blow off valve with hose coupler attachment as a recirculating valve??? It is adjustable. I think you can use the big spring, the little spring, or both springs. And you can fine adjust the preload by turning the nut at the top. Capable of holding 30 psi. My understanding is that it operates off of vacuum (downstream of the throttle).

It has two inlets. One on top - I assume this is to connect the vacuum line (from after the throttle but before the blower).
The one one the bottom can be left unconnected. It might be to operate the BOV off of max positive manifold pressure, instead of vacuum??


That will work for you. The top screw does preload the spring to allow you to adjust to a fixed "blow off psi" as seen at the mounting flange. The other two hose barb nipples act in the same regard as that screw to bias or alter the spring. You use them to create a dynamic boost. i.e. a "boost controller". The reason there is a top and a bottom is because you can bias the blow off valve to either increase psi or decrease it.

It is also used to help the blow off valve open when the throttle is slammed shut, to prevent bending the throttle blade. Your throttle blade is before he super charger, so no worries there. Just use it as a simple fixed # psi blow off valve with the nipples left open (do NOT plug or cap them).
Google "Greddy Type S - blow off valve diagram" and you see some good illustrations of how the insides of it work as well as some ghetto drawings of how each nipple effects psi.

And it has some nice bling to it! I am cheap and was thinking you wanted a $6 pop off valve. :lol:

EDIT, sorry. Important point, I skipped over the part about the blow off valve as a recirculator. ok, so I think the answer is, NO you cannot use it that way. You can discharge your unwanted boost back into the intake of the carb', but then you would be pressurizing that and that isn't good and you'd be feeding that boost back into a now closed system. So the unwanted boosted air never gets out, it just travels a longer distance and comes right back in. Contrary to that, if under a no boost situation, the only way for air to travel backwards into the blow off valve is if you could create a LARGE amount of suction on the upper nipple or a large amount of pressure on the bottom nipple to create a resultant force equivalent to 10psi on the bottom valve. Max you might have 10"Hg of vacum at idle. That wont budge that BOV spring. That valve face is about 1 square inch. So imagine 10psi is literally like lifting a 10 pound weight. your home vacuum cleaner could not do that.

Just vent the blow off valve to atmosphere and move on with the project. I do not think the super charger will be too much load on the engine and cause it to stall at idle. You'll just have to increase to a higher than normal idle. That maybe even be necessary to keep the air velocity up so that the fuel does not fall our of the A/F charge. Because your carb is now, what , like 12" from your intake valve as opposed to 3". Ever heard of a "tunnel ram" intake? Basically really long intake runners. Great for high RPM racing, but bad for idle and off idle performance due to lack of port velocity. Gasoline, even though it is a Air/fuel/mist thanks to the carb, it will still want to "fall".

I hope that helps some. I'm not expert on this kinda stuff. My big ol' setup makes 900 horse power and it's an under achiever compared to folks on YB will full out race cars. I built mine tame on purpose because it has A/C and no front mount I/C. I run 89 octane pump gas and have an option to inject ethanol (windex) to cool the air intake charge.

---------- Post added at 08:32 PM ---------- Previous post was at 07:44 PM ----------

Quote:
Originally Posted by bob58o View Post
Go Directly to Go.
Collect $20

Is this a new item?
It is new to me?

http://www.gopowersports.com/manifol...nes-predators/



I think I paid $40 for the NR Racing One.
http://www.nrracing.com/product-p/man-24-wp.htm


---------- Post added at 01:39 PM ---------- Previous post was at 01:35 PM ----------

Which reminds me that a pulse pump from the intake manifold probably does not work with this set up.
All the rage now in racing is gear driven pumps that run off of the crank shaft. Think of a dremel tool with a long flexible extension. Only the cut off wheel is a gear and dremel body is a fuel pump.
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  #88  
Old 01-05-2018, 01:43 AM
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Roots blower with a blow off valve, you two are brilliant! I am in awe of yur smartness.


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  #89  
Old 01-05-2018, 09:33 AM
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Quote:
Originally Posted by Denny View Post
Roots blower with a blow off valve, you two are brilliant! I am in awe of yur smartness.


Denny
I agree that a BOV has a built purpose to prevent backpressure on the turbo compressor when the throttle body closes. The application in this thread is to find some way to prevent OVER boosting because there is no prior data to know how much boost this contraption will make. I mean, it's as big as the crank case of the whole engine it will be boosting! I am not sure if he even plans to put a psi gauge on the bike. So for this instance it is simply a pop off valve with a rated spring. Much like a procharger would use.

Now, if this roots style blower does have an internal bypass valve like an Eaton, then he would not need to worry about the idle issue. But I do not see any mechanism on the body of the supercharger to actuate any kind of bypass valve. I think it is just a housing with two rotors and that's it.

It is tricky to safely monitor high boost when death is immanent. So I think the approach here is to safely prevent ~30 psi from breaking junk. And the screw on the top of this mass produced BOV will allow him to creep up on his goals safely.


Oh, and that reminds me. The intensity of your spark may need to increase so that the compression does not snuff it out. You should also tighten your plug gap. Just keep that in mind if at higher RPMs the setup starts to "break up" or cut out. It might not be a fuel delivery issue, but could be.
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Old 01-05-2018, 10:56 AM
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The engine in stock form is 8.5:1 according to the manual. After measuring a few of these, I got closer to 8.3:1 using an online calculator and the measured specs.

It is a roots blower - fixed displacement, not centrifugal.
The only data I have is 300cc per revolution.
The 4 stroke 212cc engine consumes 106cc per crank revolution IF VE is 100%.
For 10 lbs of boost, I would want....
((14.7 + 10) / 14.7) * 106cc = ~180cc blower output per crank revolution.
Something like 3" pulley on the blower and a 1.8" pulley on the crank "should" give 180cc blower output per crank revolution. The maximum boost I would see is ~10 psi if I am correct. I'm sure it would be less due to inefficiencies.
10 psi of boost on an 8.5 :1 engine would be like 14:1? I would use 110 Octane Race Gas.

It is my understanding that the output is "more or less" proportional to the rpm.
At low RPMs roots blowers will leak some, but low for me is 1800 RPM blower rpm (3000 RPM engine RPM, because it will be under-driven) - so not sure if that is still considered low?
At 6000 Engine RPM, the blower is only spinning 3,600 RPM. I might need to increase the crank pulley diameter since the blower is spinning relatively slow? - To make up for "low" RPM losses do to leaks around the rotors.

---------- Post added at 11:56 AM ---------- Previous post was at 11:09 AM ----------

Quote:
Originally Posted by Denny View Post
Roots blower with a blow off valve, you two are brilliant! I am in awe of yur smartness.

Denny
Vacuum operated bypass valve.

Look up Eaton blowers.
Positive Displacent blowers.
With recirculating bypass valves.
Throttle body > blower > intake valve.
http://www.3800supercharger.net/how.html


Eaton manufactures highly engineered, roots-type positive displacement superchargers. The Eaton supercharger increases torque across the entire operating range without compromising drivability or emissions. Increasing supercharger torque allows vehicle manufacturers the option of using smaller, more economical 4- and 6-cylinder engines, without perceived loss in power train performance. Additionally, the supercharger incorporates a bypass system to reduce air handling losses when boost is not required, resulting in better fuel economy. Typical applications are on engines with displacements of 1.8L to 5.3L.


Look up the cars that use them.
Like Mini Cooper S, before the turbo version.
Many cars with factory positive displacement blowers come from the factory with bypass valves.

Even if the only purpose is slight increase in fuel economy, some
ROOTS BLOWERS DO USE RECIRCULATING BYPASS VALVES.
Now whether or not people disable them is another story.

Bypass instead of venting to atmosphere is needed for these set ups on cars because of Air Flow Sensors, fuel injection, and fuel economy - I suppose. The air flow sensor is upstream of the blower, so the air gets dumped downstream of the sensor, but upstream of the blower.

I wanted to use one, along with a clutched blower, for increased engine and blower life.
It is winter. I have lots of time to plan. I already purchased the valve, so I will be able test with and without it.

I have no idea what type of vacuum these engines might see???
This page talks about tuning the valve for different applications.
https://www.evomoto.com/tech_article...h_article_id=7
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Old 01-05-2018, 01:02 PM
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This is a great idea. I think the supercharger came on 1968 Porsche. I Think it was used as a smog pump?
I haven't read all the post. I am tonight!
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Old 01-05-2018, 01:29 PM
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Quote:
Originally Posted by Frank ZX View Post
This is a great idea. I think the supercharger came on 1968 Porsche. I Think it was used as a smog pump?
I haven't read all the post. I am tonight!
Come back after you do.
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Old 01-05-2018, 02:08 PM
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Quote:
Originally Posted by Frank ZX View Post
This is a great idea. I think the supercharger came on 1968 Porsche. I Think it was used as a smog pump?
I haven't read all the post. I am tonight!
Yep, people use VW or Porsche smug pumps.
Which I guess are very similar.
http://www.elsberg-tuning.dk/supercharging.html
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Old 01-06-2018, 05:24 PM
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Ordered a Carburetor.
$21.24 shipped from China.

https://www.aliexpress.com/item/28-3...ceBeautifyAB=0

OKO 30mm Flat ("D-shaped") Slide with Power Jet.

Figured I might be able to use the Power Jet to help tune.
On the 24mm I am currently using, I have blocked off the Power Jet Circuit. Only using the idle and main jets. I might use the Power Jet, at least at first, to prevent a lean mix when first testing.

Supposedly, the power jet has more effect at WOT the the main Jet.
The issue is these jets are big and require a small main jet to prevent rich mix at WOT.
Nobody offers replacement power jets of different sizes (AFAIK).
The small main jet needed with the power jet makes the mix lean around 75% throttle.

Most people just put vacuum caps on the nipples for the Power Jet Circuit.
At the very least, using the power jet makes the carb hard to tune. Some say impossible on 4 strokes.
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Old 01-07-2018, 12:15 PM
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Here are some threads about using the AMR300 for draw-through carb set ups.

http://www.landracing.com/forum/index.php?topic=11775.0

http://speedtalk.com/forum/viewtopic.php?f=1&t=32315
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Old 01-08-2018, 09:20 PM
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SiliconeIntakes.com has shipped me the correct 48mm to 35mm reducer.

- The 30mm PWK carb with 35mm OD spigot has been ordered.

- I have a 35mm to 48mm Silicone Reducer to connect the output of the carb directly to intake of the blower.

- I have a 48mm to 32mm Silicone Reducer for the output of the blower.

- I have ordered a 32mm OD straight hose coupler inner-sleeve that will fit inside the Reducer. They say it shipped and got returned, so they are shipping it again.

- I have a 32mm ID hose that may or may not work. It will slip over the straight hose coupler inner sleeve. 1.25" ID, 1.75" OD braided PVC hose. I will probably end up replacing it with something else.

+ Still need to order the carb adapter / manifold which has a 32mm OD.
+ Still need to order the SC with 48mm intake and output.


Also, I need a drive pulley, a belt, and to decide exactly how I want to drive the SC pulley.

That will be most KISS way of doing the intake. No bypass. Denny and WhiteTrashRocker will approve, I think. But there is no "burst plate" like was mentioned.

I have ordered some of the parts for the bypass plumbing too. I can see the disappoint in your faces.

And now I have an engine to at least mock parts up on. It happens to be the hemi for the electric start/charging project. Not sure I want a flywheel with magnets used on the SC build. The blower build might end up spinning more RPMs than the flywheel can handle. Not sure how fast a Kohler charging flywheel can spin. The electric project will probably be a low RPM build. Under 6k RPM.

So I am saying I still need another engine.
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Old 01-08-2018, 09:51 PM
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I'm patiently waiting for carnage...
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Old 01-09-2018, 12:24 AM
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This valve TT540 suggested might work as is?
https://www.zoro.com/control-devices...specifications
The valve can be set for 25 psi. 80 cfm flow capacity.

If the 25 psi setting is 25 psi ABSOLUTE Pressure, Then it would be good for ... [25 psi absolute (total) pressure - 14.7 psi atmospheric pressure] = 10.3 PSI BOOST.
- Or am I wrong here?

10.3 lbs boost is around 180 cc Blower Output per Crank Revolution.

The 2.05" OD crank pulley would be perfect if actually getting 300cc output per SC revolution. If it is less efficient, I might need a bigger pulley on the crank and begin to worry about overboosting. If I stay with the 2.05" pulley I shouldn't ever produce more than ~10 lbs boost, which on a 8.5:1 engine brings it up to around 14.3:1 Effective Compression Ratio.

(180cc/ rev) * (6000 rev/min) = 1,080,000 cubic centimeters per minute.
1,080,000 cc's per minute = 38.14 cubic feet per min. Valve says good for 80 cfm.

Will this work to prevent overboosting? If the initial crank pulley is too small I need to up the blower speed to account for leakage/ inefficiencies.

Will this work to help prevent the blower from blowing up on a backfire?
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Old 01-09-2018, 06:20 AM
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I'm with WTR, there are significant explosive events in the future.
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Old 01-09-2018, 11:22 AM
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Where's all the HVAC people?
Where's Chancer?

I need to know if the set pressure on air safety valves is gauge pressure or absolute pressure.

Anybody?

Adjustable Relief Valve, MNPT Inlet 1/4 In, Flow Capacity 80 CFM, Pressure Range 25 to 200 PSI, Max Temp 250 F, Brass Body Material, Rubber Seal Material, Stainless Steel Spring Material, Hex 9/16 In, Length 1 9/16 In, Versatile Relief Valve Offers High Flow Rates and is Easily Adjusted to Suit Individual Applications, Not ASME Approved, Includes 4 Color Coded Springs
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