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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 1:39 pm 
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Paul.. this is not the end of the thought though.

You could absolutely utilize this via long tract intake runners, or overcome the mass loss with forced induction. with no body panels for restrictions, you could probably fit some 12" velocity stacks with a large ish plenum that would be pretty beneficial. You could still meter the air at the mouth of the intake, and use one throttle body, though you may suffer a little bit of throttle input lag at the expense of smoother, larger power..

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 3:12 pm 
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I think the main problem with my idea is that higher velocity = less mass = less combustible air. Therefore even if the air flows faster into the engine it will be less dense so any gain would be negated. Still a great exercise in critical thinking and as always thank you all for your wealth of knowledge. I guess I am back to trying to keep intake air temperature cooler. Now where did I leave my ice.


You do want high velocity and you do get more air that way. There are different things happening here for different reasons. The size and shape of the cylinder head intake and the intake manifold do make big differences in the power.

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air flows faster into the engine it will be less dense


I don't know how we got here from the tubes hanging from the cup. Jack did a good job explaining that two tubes have more surface area and friction.

Air flowing faster into an engine is what allows the intake to be tuned. Look at your motor and all the modern ones with long folded runners on the intake. Trying to make use of momentum and pressure waves in the gas flow. You don't need an intake manifold with direct injection engines, but they are still there.

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 3:58 pm 
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wrightcomputing wrote:
I think the main problem with my idea is that higher velocity = less mass = less combustible air. Therefore even if the air flows faster into the engine it will be less dense so any gain would be negated. Still a great exercise in critical thinking and as always thank you all for your wealth of knowledge. I guess I am back to trying to keep intake air temperature cooler. Now where did I leave my ice.


BUT . . . what if you did enough smaller pipes to gain back your volume and then you get to keep up your higher velocity.

As I've learned recently fountains use many soda straws in a pipe to gain a laminar flow stream of water. (discrete flow vs. garden hose type of spraying)

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 5:15 pm 
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Well my whole thought processes came from the idea of making a custom manifold to install and Eaton TVS 1320 supercharger. Unfortunate there are no kits available as there is not enough room on the s2k, however I have plenty of room. There are kits for k20 and k24 which do very well.
I like this type of blower as it is a reliable form of boost and should outlast the engine in my car. I think it would be capable of around 400whp but I would start lower and run the blower on the cooler size of the RPM range.

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 6:24 pm 
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For the manifold design I an thinking about slightly larger and longer than runners (is runners the right name) on the stock manifold. The plenum would then be about the same area as the total area of the four runners.

The eaton supercharger opens on the size which would go directly into the center of the plenum by the 2nd and 3rd cylinders.
Attachment:
blower.jpeg
blower.jpeg [ 5.79 KiB | Viewed 828 times ]

I would then place the MAP sensor somewhere on the bottom of the plenum with the IAC. Then add a few vacuum ports for brake booster and crankcase. The throttle body is then on the back of the engine directly into the supercharger.

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 7:51 pm 
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I don't know what a TVS Eaton is (maybe a Lysolm type blower) but I put an Eaton M-90 ( a 90 cubic inch per revolution Roots style) blower on my 3.2 liter Yamaha V-6 that came out of the old Ford Taurus SHO's. I kept the original intake (bundle of snakes) and sucked through a Ford Lightning 90mm MAF sensor, through the throttle body, into the blower, and then out to an Air-to-Air intercooler before entering the stock intake. Worked VERY well but the SHO motor outran the M-90 by 5,000 rpm. This arrangement basically gave me a [plenum where I could store a little pressure waiting for intake valves to open.

https://www.youtube.com/watch?v=sG16m2e4O6I

Beat up many a V-8 powered buggy with that arrangement. I eventually converted to a turbo (these motors absolutely love boost) but don't like waiting for the grunt to arrive. I will probably go back to a positive displacement blower in the future but will do a Lysolm style and up the displacement to 112-122 cubic inche version.

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 Post subject: Re: Fluid flow?
PostPosted: March 29, 2016, 11:07 pm 
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Wow your buggy is very cool.
The Eaton Twin Vortices Series (TVS) Supercharger is their 6th Generation Supercharger. The 1320 is displacement in Cubic Centimeters or 1.3 liters. They added a 4th lobe to the rotors an more twist (160 degrees). Basically it is smaller, cooler, and can spin faster providing more boost. Unfortunately you cannot find them used so you are looking at over $2000 just for the unit.
http://www.eatoncorp.com.au/Oceania/Pro ... PCT_378413
The only thing stopping me getting one is the cost. I figure just over $2K for the unit then I need injectors, new throttle body, some form of cooler and I have to make the manifold. So $3K+ minimum which is a lot to justify at the moment.

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 9:15 am 
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I love blowers..
Attachment:
legacy blower.jpg
legacy blower.jpg [ 96.3 KiB | Viewed 801 times ]


that's an eaton m62 gen 3 blower mounted remotely on a 2.0L wrx motor, intercooled.

I went with a slight different approach.. pull through MAF, fully recirculated charge control and a "throttle slammer" intake routing. the idle control was done through speed density, and all boost values were calculated through a combination of speed density and the MAF.

This set up made 3lbs of boost at idle, full boost by 3200 rpm and carried it till 6700 rpm, where it tapered from 9lbs at the SC outlet to 7. even with the long front mount intercooler piping, it barely lost throttle response by utilizing the supercharger in front of the throttle plate as the whole intake tract was pressurized and recirculated to the throttle body.

Contrary to what you're saying.. as you are planning a fixed drive supercharger ( IE one not controlled with a clutch..) your plenum size will potentially hamper performance. With a roots style blower, you actually do not have a compressor. Centrifugal and twin screw lysholm type blowers create positive pressure, roots blowers are just air pumps, and are the least efficient of the three.. as well as creating the most amount of turbulence in the intake tract.

I would be more concerned with Helmholtz resonance and smoothing the pulses from the blower than plenum size. as a rule of thumb, plenum volume on NA fuel injected cars is to be 1.5 x the volume of the intake runner, including head pathing. You can get away with less on a supercharged car because of the potential for constant, immediate boost. superchargers share a linear relation to engine RPM, where as turbos are exponential.

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 10:20 am 
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Where I tucked the M-90 on the side of the Yamaha block. At about the 4 o'clock position.

Image

And a side view

Image

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 10:30 am 
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Tucker,

I thought that the pulses were pretty much smoothed out with angling of the lobes and the twisting of them. I though we only had to worry about the pulses with the old straight cut lobes.

I loved that instant torque of the Roots.

Tom

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 10:41 am 
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I'm new to Superchargers and just learning but I thought the TVS was very efficient and a much better option then a centrifugal. Here is an interesting comparison to the root style.http://www.musclecarmodfather.com/forum ... efficiency This states that the TVS is more efficient up to about 15lbs of boost (more than my target of 10psi).

Could you expand more. I am looking to learn as much as I can at the moment. I know ones person installed the TVS 1300 on the hot side over the exhaust and ran it in though the stock S2000 manifold. He ran his car in XP and apparently it ran very well.

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 11:24 am 
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Off Road SHO wrote:
Tucker,

I thought that the pulses were pretty much smoothed out with angling of the lobes and the twisting of them. I though we only had to worry about the pulses with the old straight cut lobes.

I loved that instant torque of the Roots.

Tom



In doing my research (and unfortunately I'm most intimately familiar with the gen 3/4 eaton roots blowers).. what it basically boiled down to was more lobes + more twist = less turbulence. Without a screw type or centrifugal though, it is impossible to eliminate the pulsing effect of a lobed rotor, as there will always be some absence in air movement in the cycle - as opposed to a centrifugal or screw type which have a constant mesh or turbine speed.

this can easily be mostly eliminated by intake design, and in particular what the supercharger mounts to plenum wise. pulses are dwindled by longer, smoother runners - more severe pulses can cause cavitation and premature failure of rubber/silicone couplers and intake components.

I originally had a plenum mount under my SC on the m60/legacy. I had really weird power delivery issues and funky MAF readings. I switched over to a single 3.5" cylindrical collector, tapered down to the 2.5" size of the IC piping. by my math, I gained about 18% efficiency and had a much smoother power curve.

the new roots blowers are pretty nuts - operating at 70% efficiency. for comparison, the m90 on the SC3800 GM motor operates between 45-50% efficiency. My m62 at its peak was about 50% efficiency at a 2:1 pressure ratio.

screw type and centrifugal routinely operate between 70-90%, depending on the application and compressor of course.

the best way I could describe driving a roots powered car..

It was like driving a car with a bigger motor. did not feel like forced induction, but there was certainly more oomph under the pedal.

That and the noise.. my god.. the noise.. not the belt squeal.. but the whine - so addicting.

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 11:38 am 
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wrightcomputing wrote:
I'm new to Superchargers and just learning but I thought the TVS was very efficient and a much better option then a centrifugal. Here is an interesting comparison to the root style.http://www.musclecarmodfather.com/forum ... efficiency This states that the TVS is more efficient up to about 15lbs of boost (more than my target of 10psi).

Could you expand more. I am looking to learn as much as I can at the moment. I know ones person installed the TVS 1300 on the hot side over the exhaust and ran it in though the stock S2000 manifold. He ran his car in XP and apparently it ran very well.



I first found my boost addiction in superchargers. I think the easiest way to explain the difference between the roots and the twin screw/ CS is thusly:

The roots is geared towards driveable, usable power. low end torque - something that feels like you've got some extra displacement under the hood for a decent price (roots blowers are histrocially much less than others..)

Where as twin screw/CS are geared for high boost high horsepower high peak power applications.

roots blowers simply can not keep up with the others once you cross the 2:1 pressure ratio threshold - and that's inherent in their design. they are air pumps, not compressors. its not that they're faulted, its what they're designed to do - lol.

after reading more about this newfangled eaton unit you've got your eyeball on .. it looks like a roots that took some lessons from a twin screw. more rotors, greater twist means smoother, more efficient. That looks about as close to a screw type compressor as you can get.

I cant find any info about what the seals are coated in? In a roots type blower, the rotors do not actually touch - there is a miniscule amount of distance between the two rotors. Most are Teflon coated.

If you do buy one used, and have the chance to check it out in person - Bring a standard piece of A4 printer paper with you. Flip the blower over and twist the snout pulley to slightly pull the paper into the rotors. If you can get a 1" or so of paper into the rotors and tug and the paper does not come out - you have a good seal. if it slips right out, the rotors will probably need to be coated again.. which sucks.

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 1:21 pm 
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Well it certainly seems like you guys have a good amount of knowledge on Superchargers. For my power goals I think the TVS is a good option because I want the instant predictable power for Autocross Anything more than 400WHP (Currently approx 210WHP NA) would become traction limited anyway I expect. I am not however married to the idea or Supercharger type. If you were going to add a Supercharger to my F22C engine how would you do it.

Here are a couple of options.
1. As discussed custom manifold with the supercharger directly into the intake tubes and into the engine
2. Mounted under the intake Manifold similar to Off Road SHO where my AC compressor used to be then use tubing (with or without an intercooler) into where the current throttle body is.
3. Over the exhaust and run in front of the engine similar to option 2.
4. Something else.

I do not plan to run at the upper end of the Blower so do I need to have an intercooler, if so what and where?

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 Post subject: Re: Fluid flow?
PostPosted: March 30, 2016, 2:05 pm 
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wrightcomputing wrote:
Well it certainly seems like you guys have a good amount of knowledge on Superchargers. For my power goals I think the TVS is a good option because I want the instant predictable power for Autocross Anything more than 400WHP (Currently approx 210WHP NA) would become traction limited anyway I expect. I am not however married to the idea or Supercharger type. If you were going to add a Supercharger to my F22C engine how would you do it.

Here are a couple of options.
1. As discussed custom manifold with the supercharger directly into the intake tubes and into the engine
2. Mounted under the intake Manifold similar to Off Road SHO where my AC compressor used to be then use tubing (with or without an intercooler) into where the current throttle body is.
3. Over the exhaust and run in front of the engine similar to option 2.
4. Something else.

I do not plan to run at the upper end of the Blower so do I need to have an intercooler, if so what and where?


Depending on the thermal efficiency, cooling power and construction of the blower - you can see intake heat soak around the same temperature as a turbo may yield. A Centrif SC yields the lowest heat soak by virtue of how they work. the good ones are oil/water cooled though.

My advice to you is to pick a location where the SC will see adequate airflow. On that legacy, you notice I mounted it straight through the hood. I had a cover for it, and when the cover was mounted to the hood - I would see intake temps at the TB rise ~15° or so.. a noticeable difference just from it being exposed to airflow.

If I had my druthers, I would use an air to water intercooler in the intake/ right beneath the blower on a custom manifold set up. Since you are auto crossing/ tracking, you want the least amount of throttle input lag. designing a custom manifold will also allow you to get the proper intake runner length for the RPM range that you want to reach max efficiency / peak power band.

I wouldn't mount it above the exhaust, not unless you can really guarantee that you can preclude it from being exposed to the high exhaust manifold temps of prolonged runs. Blowers, like everything else, have wear components and oil in them. large amount of external heat will excessively degrade the bearings/ oil in the unit.

Also, the closer to the crank pulley, the better. The longer the belt, the more chance of slip you'll have. If you're spinning yours as fast as I was mine (14k rpm).. you will get belt slip. You also want to have as close to 180°, if not more of belt wrap on the pulley. so keep that in mind when locating your SC

whatever you choose to do, I would run the throttle body before the SC in the intake tract. It would be much better suited for your intended application, and is a lot easier to tune.

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