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Author Topic: Supercharging a Bagheera  (Read 66097 times)
andyowl
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« Reply #90 on: June 12, 2010, 09:59:55 pm »

Thanks for putting the video on the 'net! I thought it was a "First" for me and Baggy Joe but I see that Titus also has some video of Baggy Joe (including me visiting the gravel trap at Prescott!) Thanks to him too!

I cannot tell which run it was at Prescott as I visited the gravel on every trip up the hill. But I think it may be the first practice run as that was a "two wheel visit" as was the second competitive run! The others I think were only one wheel at a time!

Brilliant, thank you chaps!

Andy
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suffolkpete
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« Reply #91 on: June 12, 2010, 10:58:39 pm »

Loved the noise it makes Cheesy
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Spyros
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« Reply #92 on: June 13, 2010, 12:29:09 am »

Loved the noise it makes Cheesy
I even find it better in reality  Wink
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Spyros
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« Reply #93 on: June 16, 2010, 12:56:58 pm »

Andy,

Today, I posted the video of BaggyJoe on the Bagheera-café forum. I think you wouldn't mind.

I'm a bit surprised of the relative lack of interest since I only see the usual folks following your project.
To me, with relativelly low investments, you created a wonderful car.
- At low to middle revs, it is quite as civilized as a standard one.
- It doesn't appears more temperemental than a standard Bagheera.
- It's quick, nervous and has a terrible sound
- The roadholding is much better

I must say that I'm only wondering when I might decide to follow your path, or who will do it first  Wink
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andyowl
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New exhaust "straight through" - good sound!


« Reply #94 on: June 16, 2010, 02:53:39 pm »

Spyros wrote..  - The roadholding is much better..

That is an interesting comment. I do think the roadholding is better but I find it hard to compare objectively the righthand drive Bagheeras with the lefthand Baggy Joe.

Lowering the suspension has removed much of the rolling that is part of the traditional french feel but I find it hard to analyse the other features.

The "sticky" tyres must help too. I had the Yokohama A048 tyres on when you were in the car last week.

Andy
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Spyros
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« Reply #95 on: June 16, 2010, 04:59:15 pm »

I had the Yokohama A048 tyres on when you were in the car last week.

Andy
I noticed them.
When you take a runabout at an impressive speed, your smile is going from one ear to the other  Cheesy

You might also have seen my legs being thrown on the side by the centrifugal force.
I advise to add a purposefull seat rest, like the one I show you

Spyros
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andyowl
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New exhaust "straight through" - good sound!


« Reply #96 on: June 17, 2010, 10:11:43 am »

Spyros wrote..  when I might decide to follow your path, or who will do it first ..

Well I do have another supercharger that you could use. It is a "Roots" type blower manufactured by Wade. I was told that it is big enough to supercharge a 3.5 Litre Rover/Buick  V8 but its output can be reduced by simply changing the diameter of the drive pulleys.

Like in Baggy Joe I planned to mount the blower on the rear bulkhead using a separate drive shaft with two universal joints to allow for the movement of the engine. The carb(s) would be in the luggage compartment away from the engine heat and this would allow the normal engine cover to be retained. It would also be much easier to work on than Baggy Joe.

If anyone would like to give it a try I can provide a list of the key parts.

Anyone up for a challenge?

Andy
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Spyros
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« Reply #97 on: June 17, 2010, 12:33:38 pm »

I like your idea of UJ for allowing the engine movement.
But for what I'd like to do, I don't have space for a blower fixed to the rear bulkhead.
You might remember that I spoke about engines with a VW 16 valves head.
It's reaching slowly completion and I have actually 2 version of the engine.
I've built 2 version of the engine head.
One based on a KR head and another one based on a PL head. There are subtle differences in the casting which made me decide to do so.
Then one is supposed to be using a Kjetronic (or other) injection and the other 2 big horizontal delortos (Delortos because they cost only 10 % of the price of the weber DCOE equivalent while having about 95 to 98% of the power capabilities and some of the design are much better )

Now the big issue with these heads is the compression ratio.
I'm close to 8 to 1 if I don't surface the top of the block and the head.
One of the engines (the carbuator one) is already surfaced but this also meant lowering the seat of the valves and of course changing the valves followers (done)

Thinking about it, a 8:1 ratio is what you need with a turbo or a compressor.
I'm actually thinking about a M45 Eaton, matched to the Kjetronic injection.
But not as you with a custom built overpressure valve.
More by using a big external wastegate. Something standard that can be bought without problem.
And also a king of air cooling devices. In France, I met a guy building a turbo in his Murena and he convinced me about the ideal device to cool the charge.
Ideas only because of the little available space

The 16V engine with injection or carb is fitting the Bagheera engine compartment. I'm not sure that adding the blower will still be possible
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andyowl
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New exhaust "straight through" - good sound!


« Reply #98 on: June 17, 2010, 11:15:21 pm »

Spyros wrote... I'm actually thinking about a M45 Eaton, matched to the Kjetronic injection....

Have you an idea about the power this may produce and which Bagheera engine size are you using?

Is there really space for an intercooler? Water injection maybe an alternative?

Andy
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Spyros
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« Reply #99 on: June 18, 2010, 08:52:05 am »

The engines I started with is actualy the 6J2 because you need evenly spaced bores.
I think these heads can also be adapted to the other uneven Simca engines but I didn't try. If yes I'd try with the shortest stroke.
I have to admit having 5 of these 1590 cc engines versus only 4 1440, one 1290, and one 1200 cc.

In order to rebore a worn 1590 engine, you need to be either very lucky  Grin and have a set of large overbore pistons, to use pistons comming from another make of engines or rob your bank and go for custom built forged pistons.
This will mean an engine of about 1700 cc.
Given that the original VW of 1800 cc was producing about 140 BHP (din), an easy calculation would leave something close to 130 BHP for an engine having the same type of injection.
Replace the injection by 2 horizontal carbs and ... I can only expect at least a similar number
Replace the cams by a schrick and it's said to produce 25 extra bhp, so about 155
Add a compressor ... I don't know
But I've seen such an engine, based on the 1290 cc, without blower, delivering 160 bhp, like nothing.

Actually, I would first be happy that it'd work ...

I'm not speaking about an intercooler but a charge cooler which may need less room in the engine bay but will mean other issues for the cold water supply ...
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andyowl
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New exhaust "straight through" - good sound!


« Reply #100 on: October 20, 2010, 06:45:32 pm »

Spyros wrote..I spoke about engines with a VW 16 valves head

Thinking about upgrades over the winter I wondered if you had made any progress with your 16V VW heads on a 1592 Bagheera engine?

I have concluded that I am not likely to get much more power from my "original" 1592cc engine even If raise the blower pressure further and gas flow the inlet path. The inlet valves are just too small.

Update please??

Andy
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Spyros
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« Reply #101 on: October 20, 2010, 07:25:25 pm »

Well, after months of waiting, last Friday I came back from my machine shop with a key piece.

It's a Simca-Talbot camshaft, that was totaly worn on which on end was cut. The end were you bolt the chain drive. On this side, a second piece of metal was put. This allow to prevent the camshaft to move back and forward, allow to put a basket to prevent the oil to go on the cam belt and to mount the cambelt drive.

The fact is that I didn't want to go to an external oil pump/dry sump. So I needed to keep the Matra camshaft for this purpose. (Like in the Lotus-Ford engines)

I already have 1 engine monted but only with 1 piston which is hold by an axe that was just machined down to allow not to be fixed forever to the rod.
Next weekend will be spent fitting the cambelt and turning the engine by hand with plasticin between the top of the piston and the valves.
Then I will be able to see if new valves recesses will have to be machined in the pistons.

Then calculation on the compression ratio to see how much I'll have to machine down the top of the piston.

Then exhaust collector ...

Then final assembly and start, first as a carburated version (2 Delortos DHLA 40) and checking the evolution to the KJetronic injected (potential to be blown)

I have pictures of a similar engine with dry sump : 160 - 180 BHP on Weber DCOE 45
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andyowl
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New exhaust "straight through" - good sound!


« Reply #102 on: November 24, 2010, 12:11:43 am »

Andy wrote..I have concluded that I am not likely to get much more power from my "original" 1592cc engine even If raise the blower pressure further and gas flow the inlet path. The inlet valves are just too small.

If I cannot easily increase the valve size (and unless Spyros goes into production with his VW heads that seems unlilkely!) increasing the blower output pressure seems the obvious way.

But the Shorrock Blower is already running at the maximum recommended RPM with a 1:1 drive pulley ratio. Gas flowing the inlet system would improve the quantity of fuel/air mixture getting into the engine but the improvement may not be great say 10-15% perhaps.

But I do have another "Wade" Blower. It is a twin rotor compressor recommended as suitable for 1300-3500 cc engines. I have not done any serious research into this machine but I assume the flow rate will be adjusted by changing the size of the driven pulley. Normally one thinks of supercharging pressures as around 0.5 to 1.0 barg at the inlet manifold with any higher pressure likely to lead to overheating and detonation. But with the small Bagheera inlet valves a higher pressure may simply get more fuel/air mixture entering the cylinder. It is the pressure in the cylinder that matters, not necessarily the pressure in the manifold.

The combustion pressure creates the pressure that pushes the piston downwards. In a slow reving engine (e.g. a ship's reciprocating steam engine or a stationary gas powered engines) one can measure the "BMEP" (Brake Mean Effective Pressure) and calculate the horse power produced. I suppose this may be possible with a petrol engine with a fast acting pressure transducer. Does anyone have experience of this technique?

Food for thought over the winter?

Andy

PS Charlie is now back home after four trips to hospital in 6 weeks! Maybe I can keep her out this time! Thanks for your good wishes.

AMO
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andyowl
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New exhaust "straight through" - good sound!


« Reply #103 on: January 02, 2011, 09:04:28 pm »

Happy New Year to you all! Charlie is still home, nearly four weeks. This is progress!

We are working on making an adaptor box to connect the Wade Twin Rotor Blower, Type R020, to the Bagheera inlet manifold. Photographs will follow shortly. It will be located directly on the manifold above the engine. Think of a Drag Racer layout and you will get the idea!

Planning ahead however I was thinking about the carburettor to use. A standard Bagheera DCNF would seem to be ideal. But how many to we need? Let me try this theory on you...

On a twin carb Bagheera, there is one "choke" for each cylinder. That choke only admits fuel/air mixture when that inlet valve is open, and that is only once for every two revolutions of the engine, i.e. it is only working for 25% of the time. I had not thought of the "stop/start" action of the air flow until now. If that one choke was flowing all the time e.g. fitted to the inlet of a blower running continuously, feeding fuel/air mixture to all four cylinders, it is working 4 x 25% of the time i.e. 100%. By adding the second choke on the same carburettor we should have the capacity to fuel at twice the rate needed by the standard engine and capable of producing, potentialy, twice the engine power!

Conclusion...We only need to use a single DCNF carb! That will simplify lots of things not least tuning it! Nothing to balance other than the air flow through both chokes (easy). Main jets are fixed and we can use one or both idle jets.

Is this too simple or am I missing somthing?

Your opinions are very welcome!

Andy
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andyowl
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New exhaust "straight through" - good sound!


« Reply #104 on: January 03, 2011, 12:39:53 pm »

Making templates for the Wade Blower..

The pictures show the general concept - you see the similarity with an American Drag Racer?

We have a choice of orientation in that the blower needs to rotate in the same direction as the engine and road wheels.

- The "Drive End" may be on the gearbox side of the engine (as shown in the picture) which would be simplest to do at present since we already have the Shorrock drive shaft at that side too. The downside is that we will also have the friction and power loss associated with the bearings and universal joints. Another problem is that the Wade Blower, unlike the Shorrock Blower, will move with the engine and we need to allow for that movement e.g. by having the Blower drive belt bearings fixed to the engine somewhere.

- Alternatively the "Drive End" could be on the right side of the engine above the crankshaft pulley which is the conventional USA way of doing things. The problem is that the engine mounting rubber block is exactly where the drive belt would go! An idea that we could make a different engine mounting system is being thought about! It might allow the drive belt directly off the crankshaft pulley minimising the friction and power losses. There would still need to be a tensioning device but it might be a better engineered design.

It would be fun to have the blower directly on the end of the crankshaft, "Bentley style", but that would require the right side rear wheel to be at least 500mm further out!

These blowers on Drag Racers always seem to have a toothed belt rather that "Vee" belts as used by Shorrock blowers. More research needed. Probably something to do with the power needed to drive the blower input shaft. This was stated for the Shorrock as 8hp but I have not found an equivalent figure for the Wade. I used 8hp at 6500rpm when sizing the drive shaft diameter.

Finally, I said earlier that the Wade Type R020 was intended for up to 1600 engines. This is not correct. I now know that it is intended for 2000-3000cc engines! It is said that one revolution of the blower will pump 2000cc of fuel air mixture. The 1600cc Bagheera engine only requires 800cc of mixture per revolution! That will be interesting!

More info at  http://www.bcsc.co.uk/info/allard.html

Keep those ideas and comments coming! This is the "R" part of "R&D" !

Andy
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