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DIY supercharger option - with EFI!!!

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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, Nova Scotia, Canada   CAN
In reply to # 3608713 by Yankeedriver

As for the 'blow-through vs. draw-through' issue, I think what is confusing is that, in the Mini Cooper (and most modern cars), the fuel injectors are in the intake ports, not in the throttle body. So, the (modern) Mini Cooper is not a 'draw through' system in the conventional sense, like the Moss setup, old style V-8 drag racers, etc., vis-a-vis the fuel mixture; the supercharger merely compresses air that is much later on mixed with fuel.

Therefore, while it's true that the Mini's 'air only' throttle body is ahead of the blower, the function of the bypass valve is identical in the OEM application and my setup. That is, it allows air to go around the supercharger/intercooler circuit and directly into the intake track before fuel is introduced.

I wasn't confused about how the Mini Cooper works. It is a draw through setup the same as the Moss setup. Where the fuel is introduced doesn't matter. The Cooper has a "dry" blower and the Moss setup has a "wet" blower. You could introduce fuel after the Moss blower (instead of at the carb) and it would still be a draw through.

I was confused about what your setup was doing but I see now how it works. It will be easier to visualize once the blower is in place. thumbs up

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

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trevorwj Avatar
trevorwj Trevor Jessie
Louisville, KY, USA   USA
Joel,
When boost is being applied the bypass tube is under pressure. Correct?

My comment about the extra plumbing is because
a) it creates more variables to try to control and thereby complicates trouble shooting
b) creates more areas for potential leaks.
c) my Moss SC with the internal by-pass makes very little difference in mileage or performance (of course my carb is in front of the SC and I run a bit rich most of the time)



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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
Hey, Trevor.

I appreciate the feedback and relating your experience with the bypass valve on your Moss system. Here are my thoughts on your comments:

a) actually, the valve is simple in operation and easy to diagnose; the butterfly is either open at idle or there's a hole in the diaphragm. Also, unlike on the Mini, where it's buried in the bowels of the plumbing, on the Spridget you can visually check whether the unit is actuating, as it's got a little butterfly adjustment/stop screw the cam will lift off if it's working;

b) yes, you're right there are four more joints to police with a bypass circuit. But at 5~6 lbs. boost I don't think it'd leak badly even without the T-bolt clamps I got (cheap with free shipping). That 1.5" hose is really snug on the Caddy thermo housing and bypass valve, and the 1.5" aluminum joiner that reconnects the sectioned radiator hose has nice flares, too;

c) that is interesting. So, you've defeated your bypass and compared function and economy? I wonder if, as you say, it's because you run rich?

Anyway, I guess what I can do is check how well it works by simply disconnecting/plugging the vacuum line and see what difference the valve makes in drivability and economy. Please remind me to do that experiment if I forget once she's running. Easy to do and I'll be curious to see what happens. In the diagnostic video I think I posted earlier, if I remember right the symptoms were quite noticeable to the driver/customer.

Joel


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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, Nova Scotia, Canada   CAN
I found the same thing as Trevor regarding item c... No discernible (or measurable) difference with the bypass connected or disconnected. Of course we don't have a blow through system so your results will most likely vary. As I understand it the Peterson kits have no bypass. I won't bother with a bypass on my next one. I may even delete on my current one. It will be very interesting to see how your works.

You wouldn't know what page this video you mentioned is on?

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
Hi, Adrian.

Well, this will be an interesting experiment. Again, I'm baffled as to why Moss and Mini engineers (and Mercedes, etc.) would include a bypass circuit when it's essentially useless--but the absence of a bypass valve would make things tidier and the conversion ~ $150 cheaper. Anyway, we'll see!

I thought I'd put the repair video in post 291 but looks like I forgot. Here it is. The gentleman discusses running problems and an error code or two that he ultimately discovered were attributable to a bad bypass valve diaphragm--the codes obviously not a concern for folks running a carburetor:

Joel


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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, Nova Scotia, Canada   CAN
Joel,

Moss, Mini and Mercedes are using a bypass on their draw through setups. Doesn't really apply to your project. I think a bypass or blow off is more important to your setup... although I really don't know if it matters at the low boost we typically run. A topic to research for sure. Where you are only concerned with excess air I would personally just use an atmospheric vent. Cheap as chips and simple as dirt. Probably sounds cool too.

It's interesting(to me at least) that the engineers at Mini and Mercedes chose not to place the throttle after the blower.

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
In reply to # 3609242 by pinkyponk Joel,

Moss, Mini and Mercedes are using a bypass on their draw through setups. Doesn't really apply to your project. I think a bypass or blow off is more important to your setup... although I really don't know if it matters at the low boost we typically run. A topic to research for sure. Where you are only concerned with excess air I would personally just use an atmospheric vent. Cheap as chips and simple as dirt. Probably sounds cool too.

It's interesting(to me at least) that the engineers at Mini and Mercedes chose not to place the throttle after the blower.

Adrian

Hey, Adrian.

So, my setup is indeed like the 'blow through with bypass' schematic you provided above (thank you). As I've said, the only difference is I had to draw vacuum, not from the Mini's valve body but by extending the 1/8" hose to the Mini Spares manifold. Should work just fine--but, again, we'll see how things function with and without the valve connected.

One thing I note, and I'm not sure it matters, is that I inadvertently got the valve flipped the reverse of the direction of flow in the Mini. I may well swap the flanged adapters so the flow goes as intended--but it's just a butterfly now that I'm drawing vacuum remotely, so it shouldn't matter. The main thing for me is that its position is the least intrusive...

...yup. Looks like servicing the TPS and O2 sensor and the bypass valve will all be easier, and the vacuum hose routing tidier, if I swap the flange adapters. I'll do that mañana and post a picture. I will also show the new heater control setup I figured out. I never liked the old faucet-style one and needed a lower profile version. I found a high quality in-line valve for $4.00. Hope it fits!

Joel


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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
I wanted to turn wrenches today rather than do research after a long week planted in front of a computer, so called an old friend of the family, a retired Boeing engineer (don't know why I didn't think of this earlier). He agreed to consult after extracting a promise to bring the car out to the West Coast when it's done. Looks like I'm borrowing the neighbor's dualie and flat-bed...

At any rate, he was not surprised that you guys would sense only minor difference in driveability without a bypass because you're drawing through carbs--what he termed 'a very forgiving design' from an engineering standpoint.

However, he said a bypass is critical to a successful forced-induction, fuel-injected engine, and said that applies irrespective of whether it's draw-through or blow-through, because the problems it's intended to address are shared by both designs. I had a little trouble following the underlying theory, so that's not included for fear I'll butcher it, but the gist from a practical standpoint was this:

First - a bypass is necessary to avoid fluttering and surging when closing the throttle after accelerating on boost, and other kinds of erratic boost-generation situations that can cause a host of problems including backfiring. He said avoiding the latter is probably why it was designed into the Moss manifold. He said Turbos are more subject to some of those problems because the fan's RPM isn't linked as closely to engine RPM, but thought that leaving a bypass out of any forced-induction EFI setup would create as many problems as it would solve.

Second - in a number of low-demand and transitional throttle-position situations, he said a bypass allows engineers to use maps and ECU algorithms borrowed from N/A engines with minimal reworking. Reminds me of the bleach tank/squirt gun they slapped into the tail of the Navy Corsair II that the protagonist in my first novel describes, and which reduced the heavy smoke trail that got aviators shot down over Vietnam when the plane was first used in combat. He said that sort of engineering patch happens all the time to get machines into production under deadline, and told me some harrowing anecdotes about Boeing aircraft and one of the first Navy hydrofoils, which he reminded me I watched pull away from the dock perched on his shoulders when it was being tested in Puget Sound in the '60s. Indeed, when prompted, I remembered that thing rising up out of the water and shooting off across the Sound...

But I digress. As for higher-demand situations, and certainly WOT when the bypass valve is shut, he said a boost-monitoring fuel pressure regulator could possibly enable the Cavalier/Skyhawk's ECU to accommodate a blown 1275's needs, especially because the target horsepower approximates that of the N/A 1800cc Subaru. But there's no way to know for sure without a bunch of calculations I'm not competent to undertake.

But of course, that's the whole point of the DIY EFI project--to see if I can trick the ECU into servicing the smaller but more efficient 1275 without having Affordable Fuel Injection trim the maps. The additional layer of supercharging was something I intended to add on afterward--and indeed that is how I'll proceed: finish the mounting and plumbing details necessary for the M45 so I don't have to redo the wiring, etc. Then shift over to finish the EFI project, and finally attach a longer belt to actuate the blower and see what's what!

Joel


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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, Nova Scotia, Canada   CAN
"First - a bypass is necessary to avoid fluttering and surging when closing the throttle after accelerating on boost, and other kinds of erratic boost-generation situations that can cause a host of problems including backfiring. He said avoiding the latter is probably why it was designed into the Moss manifold." Doesn't happen. There is no "fluttering or surging" with or without the bypass. The only clue there is a supercharger installed is the increase in power. (There is also a slight whine under had acceleration.) Other than that it's more like you added 2 cylinders. Very smooth and seamless.

The only time I've experienced a backfire is during engine warm up when the engine "flames out" with a wet blower and then re-lights. This is consistent with what I have read from other users. The carb doesn't supply fuel under closed throttle situations... Nothing to back fire with. I suspect Moss used a bypass system because Eaton gave them a good deal on a blower that happened to have one. Mini etc. likely use one to squeeze a tiny bit more emission control so the EPA will let them sell their cars in North America.

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
In reply to # 3610376 by pinkyponk "First - a bypass is necessary to avoid fluttering and surging when closing the throttle after accelerating on boost, and other kinds of erratic boost-generation situations that can cause a host of problems including backfiring. He said avoiding the latter is probably why it was designed into the Moss manifold." Doesn't happen.
Adrian

Adrian,

A couple of things.

First, this family friend was designing aircraft propulsion systems (internal combustion and jet turbines) when I was in diapers, and a quick internet search confirms the purpose of a bypass valve is indeed avoiding a host of running problems, and improving economy, of course. Here's an example from AutoSpeed's website:

"It opens on throttle lifts, preventing a big pressure build-up between the supercharger and the throttle. (In this respect it’s like a turbo blow-off valve, but in the case of a positive displacement supercharger, the pressure build-up when the throttle is closed can be very high – in fact, high enough to stop the supercharger and slip it against its belt drive.)

"It is open at idle. This allows the supercharger to ‘freewheel’ – little work is being done by the blower as its outlet isn’t pushing into boost pressure. As a result, the supercharger is quieter and the idling fuel economy is better. Significantly, the outlet air temp is then also lower when the supercharger boost is actually needed."

Second, while you're welcome to your opinion, and I am thrilled you don't notice those symptoms, I'm not interested in this thread descending into a contest about who's right or wrong. Please feel free to offer suggestions and ask questions, but I'd appreciate it if you'd refrain from being argumentative. I consider that sort of thing to be a waste of time and posts.

Joel


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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
So, found time to redo the bypass circuit--which is indeed tidier and makes the valve much more accessible. Here are a few pics from different angles showing the ample bonnet clearance of the entire setup (did the silly puddy test and no contact).

I also was delighted to see that the Volvo expansion tank fits fine after simply moving it across the engine bay; didn't even have to touch the mount. There's ample room for the 2" snorkel to go through the hole where the heater intake used to go.

The piece of aluminum bar in the second photo of the cooling system shows the frontmost path of the belt will be well away from the tank. Just need to source a loop-like 3/8" hose to reconnect the left-hand radiator tank to the expansion tank, which I'm pretty sure I've seen before.

This also enabled moving the fuel pressure regulator up by the MAP sensor (second intake plumbing photo), where its output goes straight to a shortened OEM feed line, now serving return to swirl tank duty (sixth photo).

The last series of photos shows the $4.00 in-line brass (chrome plated) shut-off valve I've combined with a sectioned Dayco B87310 1/2" molded hose and Derale 98234 NPT to hose barb elbow to replace the old faucet-style valve. Pretty sweet.

Next weekend, I'll rebuild the M45 blower (I'll make an instructional video), mount the Smooth Flow modular pulley, and finalize the mounts. Por fin!

Joel



Edited 1 time(s). Last edit at 2017-10-15 07:11 PM by Yankeedriver.


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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, Nova Scotia, Canada   CAN
In reply to # 3610594 by Yankeedriver
In reply to # 3610376 by pinkyponk "First - a bypass is necessary to avoid fluttering and surging when closing the throttle after accelerating on boost, and other kinds of erratic boost-generation situations that can cause a host of problems including backfiring. He said avoiding the latter is probably why it was designed into the Moss manifold." Doesn't happen.
Adrian

Adrian,

A couple of things.

First, this family friend was designing aircraft propulsion systems (internal combustion and jet turbines) when I was in diapers, and a quick internet search confirms the purpose of a bypass valve is indeed avoiding a host of running problems, and improving economy, of course. Here's an example from AutoSpeed's website:

"It opens on throttle lifts, preventing a big pressure build-up between the supercharger and the throttle. (In this respect it’s like a turbo blow-off valve, but in the case of a positive displacement supercharger, the pressure build-up when the throttle is closed can be very high – in fact, high enough to stop the supercharger and slip it against its belt drive.)

"It is open at idle. This allows the supercharger to ‘freewheel’ – little work is being done by the blower as its outlet isn’t pushing into boost pressure. As a result, the supercharger is quieter and the idling fuel economy is better. Significantly, the outlet air temp is then also lower when the supercharger boost is actually needed."

Second, while you're welcome to your opinion, and I am thrilled you don't notice those symptoms, I'm not interested in this thread descending into a contest about who's right or wrong. Please feel free to offer suggestions and ask questions, but I'd appreciate it if you'd refrain from being argumentative. I consider that sort of thing to be a waste of time and posts.

Joel

First... check your PMs for a message I sent earlier.

Second I was addressing a draw through system on a Moss manifold... which is the same system I use.

Good luck on your project.thumbs up

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
Adrian - got your PM. Thanks for clearing up your intentions.

Joel


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Kerr Avatar
Kerr Platinum Member Norm Kerr
Ann Arbor, MI, USA   USA
WOW, 21 pages of hose routing and pulley choices. I just went back through it all (slogged back through it all) and just realized that I don't think that there is a single photo of the blower on this motor.

There's a couple of a blower, on a bench, but not where it goes in the engine compartment. Have I missed it?


N

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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, New Mexico, USA   USA
In reply to # 3610659 by Kerr WOW, 21 pages of hose routing and pulley choices. I just went back through it all (slogged back through it all) and just realized that I don't think that there is a single photo of the blower on this motor.

There's a couple of a blower, on a bench, but not where it goes in the engine compartment. Have I missed it?
N

Hey, Norm.

As for the M45's position in the engine bay, there are only two alternatives in light of the Spridget's sloping bonnet. First, on the intake/exhaust side, which mandates a draw-through like the Moss design, absent an elaborate casting like the Podifold discussed at the beginning of this thread--and which will not fit under the bonnet (and appears not to be in production anymore). Second, above/outboard of the alternator, which is where the M45 will reside in this setup.

As for the mounts, those pend for the reasons discussed earlier. I needed to figure out the pulleys, because using the OEM 2.8" pulley would've meant making a smaller crank pulley, not good for a number of reasons, and there were discussions on dual vs. single belts, etc.

Also, the modular pulley system I selected to give people a wide range of boost choices shifts the blower back quite a bit because the Smooth Flow pulley sits nearly flush with the end of the M45's shaft, whereas the OEM pulley is offset pretty dramatically. From an engineering design perspective, that repositioning affects: (i) the snorkel plumbing (now sorted), which, in turn, impacts (ii) the inlet/outlet plate design (now re-engineered), and (iii) locations of the coil and ignition module, wiring busses, etc.

So, next steps are to rebuild the M45 and mount the modular pulley, which lets me confirm the design for the mounts, which enables the final EFI wiring stuff above. Actually, I suppose I could just R&R the pulley rather than rebuilding the M45 right now, but was wanting to avoid repeated pressing/removal.

Joel


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