Norton F1 - more power please

[Norton]

'Interesting' (for some) discussion on the Norton Rotary forum today (unusual!!)...
Thought i'd share it with you...

1. Hi, my name is Mark I have recently bought an F1 sport and would like to do some tuning to make more power. I have had the bike dyno'd and have 85 bhp at rear wheel. I would like to get 100bhp+. Does anyone know where I can get performance parts from and what power increases I will get. I don't really want the ejector exhaust system as they are probably too loud to use on track or road. I would be grateful for any advice. Thanks.

2. Hi Mark. An F1 Sport !! you lucky man !! As i understand it you cannot get much more power due to the high air intake temperature. For more power you need cold air feed into the carbs. The only proven way to do this so far is by using the noisy ejector exhaust. If you do find another way to get more power please let me know.

3. Hi Mark, Well I think it is fair to say there are no performance parts for the F1, with only around 200 being made there isn't much of a market really. They can be ported in much the same way as a 2 stroke, someone on here might have one of the templates they used to open up the ports. Apart from that the ejector exhaust is really the only way to get big increases in power. The problem is that they breath hot air and that isn't conducive to making power.

4. You could do worse than to talk with Richard at Norton, Rugeley; mention the 'curly wurly' exhaust system.... he reports a power increase with this.

5. I imagine that the Norton Motors 'curly wurly' exhaust system is less restrictive than the standard system. Rotaries seem to respond quite well to a free flowing exhaust, the first mod' Mazda rotary owners always go for is a 'de-cat' pipe (replaces the Catalytic converter section). I’m convinced that the loud exhaust on my Interpol has increased the power a bit.
Having said that ive either heard or read somewhere that no matter what else you do, without lowering the intake temperature you hit a power ceiling at around the 100bhp mark. Ah! ive remembered where it was...i quote John Robinson (Performance Bikes magazine, August 1990) -
'More power could be available but not with the present system of rotor cooling. At about 100bhp, this becomes the restricting factor. Intake air is taken through the eccentric shaft; oil is injected into it and centrifuged out through the shaft bearings to lubricate the rotor seals. The air is then fed into a plenum chamber before going to the downdraught Mikuni (F1) carburettors. This preheats the air to between 70 and 150 degrees C, and pressurizes it to some 20 inches of water. The extra pressure is good for power, but the increasing temperature isn't and around 100bhp is where the temperature has more influence than the pressure. The 'exhaust ejector' method of forcing air through the shaft (as on the racer) is too noisy for use on a road bike. One possible way to get more power would be to use a separate fan to cool the shaft and rotors, and let the intakes breathe fresh air'. (end quote).
The claimed power output for your bike is something like 90-95bhp which ties in with your dyno rear wheel figures. If the above info is true then i fear that the best you can hope for by tuning is a gain of 5-10bhp. Sorry!

6. ‘One possible way to get more power would be to use a separate fan to cool the shaft and rotors, and let the intakes breathe fresh air'. Hasn't this been done already? Somewhere in the darker back regions of my mind something says that Crighton or whoever tried this once just before the last Rotaries where build. Shouldn't be too difficult as the rotation of the fan could be used for some kind of centrifuge or the oil mist might be routed through a cyclone separator.

7. I believe you may be right, i have heard rumours that Brian Crighton was experimenting with fan cooling when Norton went under. All we need now is for someone to finish off the work Brian started.
If only Norton had survived maybe we would now be riding highly developed 150bhp rotary road bikes.... maybe.

8. At least the engines have survived, somehow. The Diamond Air-rotaries (used to be Mid-West) still feature the same displacement numbers, however they are similar in performance figures, 105Hp for the FI'ed 588 twin rotor.

9. Also UAV at Shenstone still make the 588cc Norton engine. They quote 120bhp using fuel injection. I believe they use the exhaust ejector system though.

10. Hi Mark, I have recently bought a Norton Commander (in bits and no fairing) with the express object of achieving your aim - to increase the power without using the ejector exhaust (which is ok for racing but not really acceptable for road use). What I am planning to do is to use an electric fan and an oil-air separator to suck cooling air through the engine, and to allow the carbs to breathe cool air in the normal fashion. Unfortunately I haven't even put my bike back together yet. I have a couple of things to get out of the way before I can start playing with the Norton so I don't think I will get round to this for a few months.
Another option would be to convert the engine to oil cooling, and use an electric scavenge pump to suck the oil out. However as the engine was designed as air cooled I am not sure how practical this would be as it would certainly need internal engine changes to prevent any problems with puddling and the oil may change the effective mass of the rotors which could have other effects. Also the bearings may need to be changed, but it may be worth investigating. I will keep the group informed as and when I make any progress.

WATCH THIS SPACE !! as they say.

Any suggestions? / bright ideas?

[MikeLMR]

is the frame big enought to fit a single rotor 10a or 12a in it :)

[Norton]

Sigh... well i did ask for 'bright ideas' i suppose :Hammer

:Tongue1 :Tongue1 :Tongue1

[Norton]

Ive found a bit more info in Kris Perkins book 'Norton Rotaries'...

Despite the mechanical simplicity of construction in the charge-cooled rotor engine there are several draw-backs to this system. Firstly, the incoming charge is heated as it passes through the rotor which results in a low maximum BMEP (Brake Mean Effective power, a measure of engine efficiency). Secondly, the long inlet path through the rotor restricts engine breathing at high speeds.
Various designs were tried using a partial bypass system in which only a proportion of the induction air was drawn though the rotor, the rest passing directly to the working chamber. The resulting marginal power increase was offset by the reduction in rotor cooling in a system where the Fichtel and Sachs KM9l4 engine had already shown signs of being close to the limit.
Attention then focused on alternative means of induction. In one BSA experiment the heated mixture emerging from the rotor was ducted through an air-to-water intercooler before passing into the induction chamber. Work was carried out on the openings in the housing end plates. The original half-lemon shape opening was eventually expanded to a full lemon shape. With this system there was less restriction on the incoming charge.
The unsatisfactory intercooler was replaced with a plenum chamber of five-litre capacity, allowing expansion and subsequent cooling of the incoming charge. A major breakthrough in increasing power output came from repositioning the carburettor between the plenum chamber and the induction chamber so that only air and oil passed through the rotor and not the fuel mixture. Using this system with a single rotor engine gave an amazing 85% more power when compared to the original KM914 engine output.
So by the spring of 1971 a solution to the cooling problem had been found. It was decided that by careful positioning of very deep fins around the housing, no fan would be needed. Obviously a twin rotor housing would provide a greater surface area for the location of cooling fins.
The essential breakthrough had been the drawing of air/oil only through the rotors and not the air-fuel mixture as in the original engine. This allowed the temperature of the fuel charge mixture to be lowered from 100 degrees C to 50 degrees C before entering the combustion chamber. The total temperature drop was party achieved by passing the air through the plenum chamber, a large volumetric chamber allowing expansion and therefore cooling of the air. The temperature dropped from 100 to 75 degrees C in the chamber, and the further 25 degrees reduction was obtained by the evaporation of the fuel in the carburettor. The charge density was subsequently increased, which therefore created a greater power output.

For those of us who don’t understand what 75 degrees Celsius is, when we ride our Rotary Nortons its like riding a ‘normal’ bike in 167 Fahrenheit weather (the highest recorded temperature on earth is 136 Fahrenheit - Libya Sept 1922). :flamed

[shaunwil]

Just out of crazy interest what would the potenttial of running a small water injection setup to try and pull the air temp down once its passed through the carb. Would have thought it would only need a very small setup and jet to get some help. Just a crazy thought.

Shaun

[Norton]

what would the potential of running a small water injection setup to try and pull the air temp down once its passed through the carb. Would have thought it would only need a very small setup and jet. Shaun
Not so crazy, youre not the first person to have mentioned it. This is something im not familiar with... what is the normal purpose of water injection ? do you normally inject the water into the fuel / air mix ? if you reduce the air temperature AFTER the carb, how does this get more air in ? how effective is it ? what sort of water consumption / water tank capacity would be needed ? (would it be practical on a bike?). ???????
:3Confused

[shaunwil]

just been having a read here :

http://www.aquamist.co.uk/rescr/rescr.html

Looks like it only works on turbo cars from the jist of the faq page, but i may be wrong.

Shaun

[banned advertiser]

As far as I am aware, its only ever been done on forced injection, on a bike I would have thought NOS would have been a easier option for cooling

[Carl]

Water/Methanol injection is not limited to forced induction.
It has been proven to be succseful in naturally arpirated applications too.
I have tried it and it works.
Regards
Carl

[Norton]

just been having a read here :
http://www.aquamist.co.uk/rescr/rescr.html
Looks like it only works on turbo cars from the jist of the faq page, but i may be wrong. Shaun
Thanks, interesting reading... answers a few questions. If i read it correctly you inject the water after the intercooler but before the point of fuel mixture.
When they say it wont benefit an N/A engine i think that they are assuming that a normally aspirated engine breaths at ambient temperature (reasonable assumption), of course, the Nortons carbs dont breath ambient temperature, they breath at mild supercharged temperatures. They do say - 'in countries where the ambient temperature is very high, injecting water will lower the inlet charge temperature and produces power increase'. My carbs are breathing air that is heated to around 75 degrees C.
I imagine that the biggest problem would be finding room for it on a bike.

[Norton]

on a bike I would have thought NOS would have been a easier option for cooling
Oh eck :2Confused not ANOTHER option to consider :D
NOS has a cooling effect ??? really? how does that work then?
Downside, obviously only good for 1/4 mile at a time (mind you, thats all i want - to be as quick as Geoff with his extractor/ejector exhaust... 11.99 yes please :Thumbs-up ). I could go down the ejector exhaust route but that means taking the engine apart and modifying it to reverse the oil/air flow and it means pre-mixing oil into the fuel everytime you fill up. Im looking for something simple and cheap (not asking for much am i?). Also looking for some suitable ideas for Mark and his F1 who started all this off in the first place.
Oh dear! what am i getting myself into here? :Typing :Hammer :confused:
Edit: erm, NOS, its not going to be cheap is it?

[banned advertiser]

If you have a small water tank made for under seat it wont last either, on a bike there wont be a easy solution and probably best to resign yourself to something that is only suitable for odd track or 1/4 mile.
If you wanted track or to make water or NOS last longer you would need an ecu that will allow nos to be programmed in EXPENSIVE.

Nos will cost from £200 to £400 approx.
Will have NOS kits coming in soon and will have a refill service to.

[Norton]

One concern re: water injection... It appears that it would have to be injected into the plenum chamber which is located within the steel frame of the bike. The thing that worries me is that the air is laden with oil mist and the inside of the plenum will be coated in oil. The conventional wisdom is that oil and water should not be put together... im wondering if it would result in a sludgey mess??

[MikeLMR]

how does the ejector exhaust work ? I presume it's using the exhaust gasses to somehow pull cool air through the eccentric shaft ?

and does it need to be noisy to work ?

[Norton]

how does the ejector exhaust work ? I presume it's using the exhaust gasses to somehow pull cool air through the eccentric shaft ?
and does it need to be noisy to work ?
You are correct, i think its called the venturi effect, and Yes, it is gloriously noisy :D Thats what the 'vacuum' pipe coming off the top of the exhaust is all about.

[Norton]

some diagrams...

[Norton]

Nos will cost from £200 to £400 approx.
Snigger, it would be sooo cool to have NOS but my credit card really cant afford it. Ive had a look on a website called 'Wizards of NOS' and their bike kits are around £500.
Its tempting to buy an empty NOS bottle and mount it on the bike... it would be worth it just to see the look on my drag strip rivals face (Geoff) when i roll into Rotorstock :evillaugh

[MikeLMR]

how do the uav engine people cool the rotors nowadays ? they still air cool them (got to have a look at a rotor) I suspect they use the ejector exhaust too

[MikeLMR]

OR ... how about fitting a turbocharger to soley blow air through the rotors ? would be nice and quiet and similiar to the ejector exhaust sytem setup ?

[Norton]

how do the uav engine people cool the rotors nowadays ? they still air cool them (got to have a look at a rotor) I suspect they use the ejector exhaust too... OR ... how about fitting a turbocharger to soley blow air through the rotors ? would be nice and quiet and similiar to the ejector exhaust sytem setup ?

Yes, UAV use the ejector exhaust system.
I think ive finally figured out how to use the ejector exhaust without taking the engine apart. Its so simple and obvious that i dont know why i didnt think of it before, ive tended to just take everyones word for it that you have to do it the same way as they did the works racers. I think we, in the 'Norton rotary community' have become blinkered and unable to think beyond the established way of doing it.
Im already halfway there having had the replica race exhaust put on a few years ago, i just need to get a few bits ive drawn made up and hopefully i will have it done before RSIII.

[Norton]

All Norton Rotary engines (both the air cooled and the water cooled engines) use air-cooling to cool the centre of the rotors, the eccentric shaft and the main bearings. The centres of the rotors have air-cooling fins incorporated into the castings. Oil is ‘injected’ into the airflow by a metering pump that varies the flow according to engine revs (effectively a ‘dry sump’ system). On the air cooled engine, air is pulled in through a channel in the centre plate, oil mist is then injected at the centre plate and is drawn outwards to the left and right sides towards the end plates where it is then ‘sucked’ back out from the engine through two ports. For the race bikes the direction of the air flow was reversed with the oil being injected at the main bearings near both the end plates and being drawn in towards the centre plate and then extracted from the engine at one central point (by the ‘extractor’ or ‘ejector’ exhaust) where the air would normally enter the engine. This ‘reverse’ direction of flow was later used as standard for the water-cooled engines. For road use, both the air and the water-cooled engines use the suction of the combustion process, or the suction of the carbs if you prefer, to draw the cooling air through the centre of the engine.
All the (three) owners of air-cooled road bikes that now use an extractor/ejector exhaust have closely followed the example of the factory race team. The thing that has put me off connecting the ejector previously is the cost involved having the engine stripped, the route of the oil pipes modified (which involves drilling through castings etc), the cost of an expensive pair of amal carbs or similar and the relocation of the carbs. I was thinking about it and started to question why it has to be done the same way as the race team did it. Why must the ejector pull the air out from the centre plate? (it works well enough with the combustion process sucking the air out from the two 'ports' at the sides)... and what’s wrong with keeping the SU carbs situated right where they are?
On the standard air cooled bike, the shiny alloy air transfer ports on top of both sides of the engine take the hot air out of the engine and feed it into the plenum chamber in the frame. This seems to me to be the ideal point at which to split the processes of the internal engine cooling and the carb intake. One small complication is that the air transfer ports also double as engine mountings, attaching the engine to the frame.
My idea is to replace the air transfer ports with basic stainless steel engine mountings complete with openings through to the engine and the plenum chamber. The openings from the engine will have twin flexible pipes connected going to the ejector exhaust venturi vacuum pipe to draw the hot air out from the centre of the engine. This cooling air will still enter the engine through the standard air filter and the oil-metering pump will still inject oil mist into it at the centre plate.
The openings into the plenum chamber in the frame will have air filters fitted (the K&Ns in the diagram) to filter the incoming air for the carbs and subsequently the combustion chambers. The plenum chamber will now act as an air box. 50:1 ‘Pre-mix’ lubrication for the rotor tips will now have to be added manually to the petrol tank (groan).
The carbs will have to be adjusted to flow more fuel (to cope with the denser cold air). I’m hoping this will be sufficient on its own without having to change to differently profiled needles.
So, there you have it! All I need to do is have the required bits made (I have no welding skills) in time for Rotorstock 3. With luck I will be able to chase my track rival down into the eleven-second bracket, hopefully without wrecking the rotor motor in the process.

[Norton]

All I need to do is have the required bits made in time for Rotorstock 3. With luck I will be able to chase my track rival down into the eleven-second bracket
Unfortunately Geoff has been too snowed under with work to make the bits for me yet, looks like my bike will still be standard for RSIII.

[DHeart197]

Hey Norton, what kind of trans would you use with a UAV engine for a bike.

[Norton]

If you could afford a UAV engine then you could probably afford something like a Quaife gearbox as well.
A cheaper option might be to find a modernish production bike that uses a seperate gearbox...erm...dunno, is the...no...or...erm... cant think of one right now!

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P.S. Re: My 'Masterplan' (a couple of posts previous), ive been advised by three of the top Norton Rotary experts that it would be very 'risky'. It seems the oil supply to the mains bearings on the air cooled bikes is only just adequate and an increase in power output could show up its weaknesses. They all advise that it is strongly recommended that the oil feed is 'reversed'... Oh Well, back to the drawing board :Hammer