Belt Driven Supercharger

[blancojp]

Hello All!
I was looking through some of the stuff I have stored and came across the blueprints I made for a small belt driven supercharger. I believe it can be easily built using run of the mill items but I will verify this week.

My question would be directed to Rally Bob but can be beneficial to all so I am making a post instead of a PM. A standard Opel 1.9L engine, completely stock, electronic ignition and using a 32/36 webber carb.

If I add the belt drive blow through capability of developing 250cfm @ 6psi at a max 6000 rpms, what would be the theoretical increase in horse power for this engine?

I am planning to build one this week so the theory can be compared to the actual numbers when I dyno the engine.

[wrench459]

For what its worth I've tested late model cars with very advanced fuel management systems.
The blower cars was very low on the VE charts.
While the turbo cars rocked with VE around the 115 mark.

[RallyBob]

Roots type or centrifugal blower?

Do you know the lbs/min flow rating?

Depending on the actual boost level and the cfm rating (28" H2O??), I'd say 140-145 whp is possible on a stock engine. Until it heats up and efficiency drops...

Bob

[blancojp]

The unit is conparable to a turbo but it is belt driven with a dual compressor. So yes it is a centrifugal type but with compressor blades on both sides. The center intake can supply both sides or just one, depending on the size of the engine and the boost wanted. If a single port is used, you can use it as a blow through or you can mount the carb on the inlet to make a pass through system. If both ports are used, then it becomes a blow through system since you do not want fuel to pass by the bearings during use.

I am still looking for the rest of the spec's, just found CAD drawings on my old server so I will continuing this development. But using a single blade, running at 13,500rpm blower speed, it produces 250Cfm at around 6Psi or so. Using both blades will produce higher figures but I left the company before I had a chance to continue the development.

I will say this though, from what I see so far a kit can be made to mount just like an alternator on the passenger side of the engine, for less than $400. I will be firing up my lathe and mill this weekend to see what comes out.

[clemsongt]

So how much boost do you think the 1.9 can handle? You are thinking about putting about 6 psi of boost with the supercharger...how much more do you think you could do?

And what compression do the 1.9 typically run? I think I've read that having 130 avg across all cylinders is good...

[Gumby]

I've heard of a stock 1.9 engine taking 14psi without ill effect and I personally plan to run somewhere between 9 - 14psi with a turbo setup. I'm not sure I'd want to run that much boost without an EFI system but it has been done before with other engines.

[blancojp]

most turbo engines have a low compression ratio, like 7 or 8:1. The 1.9L has those figures so I would not expect a problem unless a high boost is expected.

This is a simple unit that was made for carburated cars. It has not been tried or designed for an FI system; but I believe it should work with some ECU tweeking.

I wonder how a fully blown 1.9L head with big valves and a 260/270H type cam would perform.

[wrench459]

Rough guessing here but it looks like Bob is right.
http://i250.photobucket.com/albums/g...nce/SCOpel.jpg

[wrench459]

I wonder how a fully blown 1.9L head with big valves and a 260/270H type cam would perform.

Depends on the LSA of the camshaft...I think you'll want one around the 110 mark or maybe even a little more. Good question for Bob.

[jeff denton]

Clemson, you've confused compression ratio with compression. Two whole different subjects.
I trust while we're radically increasing horsepower here we're considering how to keep it all in one piece, right? Ah, here I have a little experience, seeing how my Jimmy has been turbo-ed since the late seventies. There's been a whole lot of engines in that rig! Quite a few transmissions and transfer cases and axles, too. Still it's my favorite sleeper hot rod in my fleet.
The Biggest trick is proper ignition timing management. Now quite simple with modern electronics, there are all kinds of great, reliable, name brand components right there in the Jeg's catalog. (You all have heard me say "ditch that dinosaur distributor" before. With a turbo I say it even louder.)
Don't forget that extra power needs lots more cooling. Better have a good plan for flowing more coolant, especially into hot spots.
What were you going to transfer more combustion pressure to the crank with? Stock rods? Good luck. We know better than to do that with a Chev 350, I wouldn't dare it on a 1.9. How do you seal the heads? I learned a copper head gasket and o-ringed heads work great on a Chev, where do we get this for an Opel? The Opel crank I'm not worried about, it's good stuff, like the forged steel truck crank in my Jimmy, live and learn...
Have we got a good intercooling system all mapped out? That is crucial to high boost/lots of power/longevity of engine.
Eventually, at one point with the Jimmy I decided to get a little more realistic about what I wanted out of it. Just good fun power, not popping wheelies and nine second timeslips. That's when things got better, and less expensive. Nice heads, big valves, don't waste your time, it's absolutely not necessary under boost! Try a very mild RV cam, gets a quick startup and super mellow idle. Seven pounds of boost max and boy you really feel it from about 2500-4000 rpm. (It's run fine ever since, and will pass cars going uphill pulling the boat. Loves gas, but that's a given, right?)
So, I'm totally into it. Let's see it done!

[blancojp]

Let us not go overboard on this, the goal is to increase horsepower and not have to spend a fortune on the engine. I figure that if this unit installed on a stock Opel 1.9L increases 20-30HP, then we have somewhat of a winner.

I will be building this unit this weekend, should have my engine and car back very soon so I hope to test quickly.

[wrench459]

Let us not go overboard on this, the goal is to increase horsepower and not have to spend a fortune on the engine. I figure that if this unit installed on a stock Opel 1.9L increases 20-30HP, then we have somewhat of a winner.

I will be building this unit this weekend, should have my engine and car back very soon so I hope to test quickly.

Ok Ok lets get down to bare nuts and bolts then.
I'm no expert on blowers. But wont you lose somewhere around 15 ponys from the drag of the charger? That by my thinking your looking at 35-45 increase overall. You never did state if its a low compression engine. You also need to do some serious head work..major porting along with the bigger valves but I'm sure you already knowned that.

Oh the evil twin is taking over..

Lets put some good parts in the old girl and let her sing............dang gearheads

[blancojp]

Ok Ok lets get down to bare nuts and bolts then.
I'm no expert on blowers. But wont you lose somewhere around 15 ponys from the drag of the charger? That by my thinking your looking at 35-45 increase overall. You never did state if its a low compression engine. You also need to do some serious head work..major porting along with the bigger valves but I'm sure you already knowned that.

Oh the evil twin is taking over..

Lets put some good parts in the old girl and let her sing............dang gearheads

If you start with 70Hp per say, use 6-8Hp to generate enough boost to increase the output to say 115Hp without having to spend $2K on reworking head and cam, I say it is something to look at.

I have made arrangements with a local company to test the car with and without the supercharger installed. It turns out I have a Dyno 1 mile away and the guys are expert in blow through systems.

But my concern was if the engine could take 6Psi boost running stock and I believe the answer is "YES"

[baz]

what are you planning to do to the carb to make it a blow through one ?

are you going to box it in or are you having seals fitted to the spindles ?

do they need a higher pressure fuel pump to open the needle valve with 6 psi +ve pressure in the float chamber with a 4 pis pump ? i cant remember off hand


for a quick test bed job i believe a suck through is much easier to do as things on the carb can be stock in many respects

jmtcw

[wrench459]

But my concern was if the engine could take 6Psi boost running stock and I believe the answer is "YES"

I'm with you bro
look out for the stock dizzy it will cause detonation around the 2400 rpm mark.
Keep us in the loop with the dyno runs.

[Gumby]

You also need to do some serious head work..major porting along with the bigger valves but I'm sure you already knowned that.

Boost sort of negates the need for larger valves at lower rpms since you are pressurizing the intake that isn't to say bigger valves won't be beneficial but unlike N/A you can make power without them.

I am kind of curious how you intend to pressurize the carb. Pictures are needed!

[jeff denton]

You also need to do some serious head work..major porting along with the bigger valves .....dang gearheads

Huh-uh. Bigger valves not required, no porting needed. See the cool thing about boost is it forces air into the cylinder. Under pressure. Porting and big valves are good ways to slightly increase volumetric efficiency when you're naturally aspirated, without that great pressure. But the boost causes VE to go as high as you can afford to "contain" it. VE goes to levels way beyond your wildest naturally aspirated dreams...
That in a nutshell is why turbos and blowers make more power.

[RallyBob]

Let us not go overboard on this, the goal is to increase horsepower and not have to spend a fortune on the engine. I figure that if this unit installed on a stock Opel 1.9L increases 20-30HP, then we have somewhat of a winner.

I will be building this unit this weekend, should have my engine and car back very soon so I hope to test quickly.

Shouldn't be too tough depending on the efficiency of the blower. I used to have a root-type blower on my Toyota truck 20+ years ago, and it bumped the power from 108 hp to 135 hp @ 6 psi with everything else being bone stock (9.4:1 compression). When I added a bigger carburetor (more air in, so more boost @ 9 psi), a header and 2.5" exhaust, the power was closer to 150 hp, the torque approaching 180 ft lbs. It used to give all the 'hot cars' of the day fits....

[RallyBob]

I'm with you bro
look out for the stock dizzy it will cause detonation around the 2400 rpm mark.
Keep us in the loop with the dyno runs.

Best bet would be to use a 'late model' distributor (1973 works great) and restrict the mechanical advance slightly. Early dizzy's had way too much advance at part-throttle.

[RallyBob]

Huh-uh. Bigger valves not required, no porting needed. See the cool thing about boost is it forces air into the cylinder. Under pressure. Porting and big valves are good ways to slightly increase volumetric efficiency when you're naturally aspirated, without that great pressure. But the boost causes VE to go as high as you can afford to "contain" it. VE goes to levels way beyond your wildest naturally aspirated dreams...
That in a nutshell is why turbos and blowers make more power.

I agree that any crazy porting is not needed. But superchargers (root-type, screw-type, and centrifugal) all force additional air INTO the engine. However they do not help the exhaust side whatsoever. A turbo on the other hand, scavenges the exhaust quite nicely.

So with any supercharger, treat it like it's a nitrous engine. More exhaust port flow helps, bigger header, bigger exhaust system. And a cam with more exhaust duration and lift is a plus. Just keep the lobe separation wide, blowers don't care for overlap! Stock 1.9 cam is 110.5° LSA, so shoot for at least 112° LSA with a modest cam. If you're going with a 'hot' cam, then consider 114°.