opcon autorotor twin screw blower

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v8alligator
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opcon autorotor twin screw blower

Post by v8alligator »

Hi All,

Today I have finally ticked something off my bucket list and after years of searching have bought a complete opcon autorotor supercharger kit with everything needed to rebuild onto my 3.9 / 3.5 4CU EFI HYBRID setup. I believe it has come from a Range Rover and it is a proper engineered piece of kit.

I have never played with superchargers so am after some advice on the best way to run this type of blower? I am planing on using the standard EFI system as it looks to be set up for it.

It is currently still bolted a inlet manifold and has a proper cast interface plate which replaces the trumpet base. Most of it is self explanatory but there is a few things I am not 100% sure about.

The front gear housing has 2 threaded ports is this for a remote oil reservoir? is it needed or can they be run as a sealed unit?

The front nose has a threaded pipe which looks like some sort of breather? not sure????

I plan to completely strip the whole thing and rebuild it with new bearings seals etc, any pointers, manuals etc out there. Unfortunately there are no model numbers on the blower so am struggling to identify what model it is.

[attachment=0]Supercharger.jpg[/attachment]

Any help appreciated.

Bryan
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Last edited by v8alligator on Tue Feb 12, 2019 10:22 am, edited 1 time in total.



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Re: opcon autorotor twin screw blower

Post by SuperV8 »

Interesting project, do you have any better photos?

Did it come with a re-programmed 14CU ECU?

What pulley did it come with and what boost should it deliver?
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Re: opcon autorotor twin screw blower

Post by v8alligator »

Here are some pics so far.

Its actually a 4CU EFI System and the only part missing is the ECU.... So not sure what to do there, someone must have a old 4CU Adjustable ECU laying about somewhere which I could purchase?????

Pulley wise... It has a 65mm pulley on the super charger. Not sure what sort of boost it will deliver but I am not really looking to go mad.

I have never played with superchargers / blowers before so its very much all a unknown.

Any help, guidance, tips or hints would be gratefully received
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Re: opcon autorotor twin screw blower

Post by DaveEFI »

My view is messing around with ancient analogue injection is a bit silly in this day and age. Much poorer choice of Lo-Z injectors than later Hi-Z ones. And any adjust ability is going to be very crude. The later hotwire at least allows you to programme it - although I dunno how easy this is, and how well it works with forced induction.
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Re: opcon autorotor twin screw blower

Post by SuperV8 »

Yes if it was me I would fit standalone easily map-able ecu (like megasquirt) controlling fuel and spark.

Do you have any info of the original install? like the size of engine it was fitted to and the boost which the 65mm pulley made in that case?
Failing that can you find out liters per rev of the twin screw supercharger - they you can use some online calculators to estimate boost/power level.
Which model Autorotor do you have? - interesting link:
https://books.google.ca/books?id=rF-fZN ... 50&f=false

http://www.hi-flow.com/HP002eSuper.html

What is your engine you are planning on bolting this to? What pulley system? serp or v belt?

Tom.
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Re: opcon autorotor twin screw blower

Post by v8alligator »

Have looked into all types of aftermarket / updating my current 4CU system and in having a long chat with Mark Adams I am going to stick with the 4CU system for now. Marks has offered to make a 4CU ECU which is matched to a JAG AFM which will run on my current set up.

I run a 3.9 V belt engine but the Supercharger will run of its own belt from the crank.

It looks like I have a Opcon Autorotor SR3 which according to the spec is:

1.16 Litres / Rev
14 Cubic Meter / Min (MAX)
13000 RPM (MAX)

Bases on the pulley being 65mm then it will do 2 revs per one turn of the crank.

It was originally installed on a 3.5 Range Rover. I am not sure what boost it will run but will do some calculations and see what I can come up with.

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Re: opcon autorotor twin screw blower

Post by v8alligator »

Has anyone calculated boost pressure before?

I have just done some sums and I think its about right.

Based on the following:
3.9 V8 = 239 CFM
Max RPM = 4750
Crank to Supercharger Pulley Ratio = 2.21
Super Charger is 1.16 LPR

____________________________________________________________________________________________________________

SC RPM = 4750x2.21 = 10497.5 RPM * 1.16 (LPR) = 12177 (LPM) = 429.97 CFM

3.9 V8 CFM = 239

EXCESS AIR = 429.97 (SCFM) - 239 (ECFM) = 190.97 CFM

BOOST = 190.97 (EA) / 429.97 (SCFM) = 0.444 CFM * 14.7 (ATMOS PRESSURE) = 6.52 PSI

This does not take into account any loss but does it sound right?

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Re: opcon autorotor twin screw blower

Post by SuperV8 »

Looking at that opcon spec sheet it quotes max flow 14m3/min which is 494cfm
Interestingly using the L/rev of 1.16 x max revs of 13000 = 532.55cfm
which is 92% efficiency? (seems a bit high!)
So going by the spec sheet you could say 490cfm max for the supercharger although it quotes max pressure ratio of only 1.4 (which is 6psi boost at sea level) which will limit the potential power.


playing about with the numbers here:
http://www.not2fast.com/turbo/glossary/ ... ycle=85#pr

assuming
VE 80%
Max RPM 4750
AFR 12:1
IAT 21 deg C
CFM 265
You get to 180hp (close enough to standard)

If you plug in 6psi that is 335cfm and 1.41 pressure ratio and 228hp and 258ft-lb
(I believe 6psi is generally considered safe for no intercooler and standard engine?)



What are you power goals?
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Re: opcon autorotor twin screw blower

Post by v8alligator »

I dont really have any power goals.

This is more of a can I put a Supercharger in my S2A Land Rover.... Its only because I stumbled on a complete kit that I thought why not.

Suppose its more of a technical challenge for me rather then a max HP.

Funny that the MAX flow and running the calc the other way of L/rev give different answers. Suppose it is to do with theoretical ver actual. I would guess the MAX flow takes into account loss

If I read your notes right are you saying a healthy standard 3.9 efi is 180hp and with the supercharger installed at 6psi it should be 228hp ????

Seams sensible and I dont think I would want to go much more then that in my series.

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Re: opcon autorotor twin screw blower

Post by SuperV8 »

If I read your notes right are you saying a healthy standard 3.9 efi is 180hp and with the supercharger installed at 6psi it should be 228hp ????
Yes, again this is based on lots estimated values so take it with a pinch of salt. When I first fitted my centrifugal supercharger I was only getting 3 psi but even this was a big difference, so I think if you can get 6psi it will make you smile! Definitely need a Polly v belt - tried using V belts a first but they just couldn't transmit enough power. I looked at fitting the later front end to my 3.5 but in the end found a 4.6 on ebay including serp front cover so had to be done!

Hope you're fitting disc brakes to your Series 2A :shock:
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Re: opcon autorotor twin screw blower

Post by v8alligator »

Thanks, I think the whine will make me smile :)

Supercharger is running poly V belt but am leaving the rest of my engine on std V belt.

My little S2A is allready heavily modified. LT95 HD Gearbox, Stage one V8 Axles and big brakes... Might need to upgrade to discs but will see.

This is my current set up.... Cant wait to get the supercharger finished and bolted on!

Thanks for the help
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Re: opcon autorotor twin screw blower

Post by SuperV8 »

Looks nice and tidy engine day.

One of my biggest headaches with my supercharger install was getting the belt system sorted.

How do your pulleys line up? I think I would have a measure up and see roughly where the supercharger pulley lines up - and if that interferes with your current V belt setup?

If your supercharger pulley is inline with your V belt you might have an issue?

Have you thought about fitting a serp timing cover and using one serp belt? don't know if that was the setup the previous engine used? (then maybe you can find a serp front cover which happens to have a 4.6 bolted to it :D )

Tom.
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Re: opcon autorotor twin screw blower

Post by v8alligator »

Original kit had a belt driving crank to waterpump to supercharger via a tensioner.

Done a bit of measuring up and I think??? The pulley will clear all the V belts Might have to machine up a spacer to stand the supercharger nose pulley a little.

Really don't want to swap the front cover as it will upset my hydraulic winch pump install as well.

Sure it will be fine :)

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Re: opcon autorotor twin screw blower

Post by v8alligator »

Hi All,

Finally got round to getting my blower kit installation underway


Got to wait for my new Radiator and to finish machining some custom pulleys but almost ready to start it for the first time :)

I have had a custom ECU and AFM done by Mark Adams of Tornado systems where he has put a basic map onto it so this should run straight out the box but where do people set there ignition timing to? Normally I would run at 8 deg BTDC but I think I might need to retard this a bit so open to some advice on that one.
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