Fullauto Cylinder Head

Ken, I offered ...

Rohan said:

I respect your comments Ken, and all the comments here.

Click to expand...

Me too, Rohan. Lots of valuable experience and history in the posts here. And we manage to keep it civil too, at least most of the time.

But it sounds like you don't know a hp output either !!

Click to expand...

Quite true.

It is obviously marvellous that they are available at all, and not outrageously priced either.
But it is trifle odd that no-one has put one on a dyno ???

Click to expand...

Welll, at least one, and maybe more, race bikes with Fullauto heads have been put on the dyno, but no one has posted the results here. I don't think any of them were back-to-back comparisons of the same engine with a stock head and then a Fullauto head, so maybe the owners didn't think it meaningful enough to post.

Ken

Rohan said:

But it is trifle odd that no-one has put one on a dyno ???

Click to expand...

I don't find it odd at all. You can say that about most any single modification to a Commando; rarely does someone go in and change just one item. Exceptions might include adding a nitrous system to a stock Commando or adding a Drouin supercharger to a stock Commando. Go see what MegaCycle tells you about any specific cam they offer - just too many variables in my opinion.

You have to look at the whole picture. Intuition and logic should tell you that with the reported improved port flow with velocity (thanks to Jim Comstock and FullAuto) one will see improvements in performance. Again, rarely does someone plunk down money for a new improved head and not change other components along with the new head. Furthermore, are you asking about performance improvements for an 850 Commando, 750 Commando or a Combat?

As an after thought on this whole thread, it might be simpler to conduct a desktop dyno simulation to answer Rohan's question.

I don't know which systems out there can factor in port velocities; typically the lower costs desktop simulations will use port flow coefficients which do not necessarily factor in port velocity.

All gentlemen.
If you can wait until the last half of August, I will test my short stroke with Full Auto head. This is not out of the box head, because Jim Comstock has done some work on it. I will take this opportunity to thank Jim for all help and knowledge.
It has new 41 mm intake valves and new angle to maintain clearance between exhaust valve and intake valves. The diameter of the intake port is unchanged.

And yes, I've already had it on the dyno with orginal RH4 head. The exhaust system is not optimal yet, but leave it unchanged because of the comparison.



I have the Fullauto now on my bike and yes there is more power, a lot more. How much will we see in August. Wishing you all a good summer.

I have never fitted bigger valves to a motorcycle engine because I believe the extra mass lowers the usable rev limit for the motor. This is probably not an issue for a normal commando engine because above 7,000 RPM the bottom end of the motor usually gives up first. So I don't even lighten and polish the valve gear. If you are looking for more torque, bigger inlet ports are not the way to go. The bigger valves might help at certain parts of the rev range - probably more at the top end ?
With a short stroke motor, usually the complete power band needs to move upwards to get full benefit from the shorter stroke. Are you using titanium valves ?

I suggest that when you are using flow benches and dynos, you need to know that what you are measuring is what you need to measure, and that the precision of the measurement is adequate for the purposes of detecting an improvement. There have been improvements in performance reported when there has been a step in the inlet port, and also with the anti-reversion aspect of the Fullauto head. Personally, I would never have a step or a ridge in the inlet port, because I believe that what happens there is almost at sonic speeds, and the effects are unpredictable. In short what you see is not necessarily what you get and you don't know how a bike will perform until you use it in anger.
If you improve the top end of the powerband, it might help you defeat an opponent in a 'point and squirt' drag race, however that only accounts for a minor part of many race circuits. I would never take my Seeley 850 to a circuit such as Daytona.

Kvinnhering said:

All gentlemen.
If you can wait until the last half of August, I will test my short stroke with Full Auto head. This is not out of the box head, because Jim Comstock has done some work on it. I will take this opportunity to thank Jim for all help and knowledge.
<snip>
I have the Fullauto now on my bike and yes there is more power, a lot more. How much will we see in August. Wishing you all a good summer.

Click to expand...

Interesting, very interesting.
We will wait and see then ...

Not a road bike though, as you say, so not quite applicable to road bikes.

Dances with Shrapnel said:

As an after thought on this whole thread, it might be simpler to conduct a desktop dyno simulation to answer Rohan's question.

I don't know which systems out there can factor in port velocities; typically the lower costs desktop simulations will use port flow coefficients which do not necessarily factor in port velocity.

Click to expand...

Not quite a real world test though, is it ?

As folks used to say in the computer business - garbage in, garbage out.
'simulators' are only as good as the programmers....
???

acotrel said:

I suggest that when you are using flow benches and dynos, you need to know that what you are measuring is what you need to measure, and that the precision of the measurement is adequate for the purposes of detecting an improvement.

Click to expand...

What hasn't been discussed, anywhere, is how flow bench results and 'pulse tuning' results compare and coexist with each other ?

Its the harmonics and tuned lengths of the inlet tract and exhaust pipe and that pulse tuning effect that crams more into the cylinder than ordinarily would flow that enables things like the hypertuned manx nortons to get more than 100% (??) cylinder filling over a fair range of rpms. That torque curve rising as they go up the rpm scale* = racers nirvana !! = is what powers manx nortons to more race wins. (*within limits).

And Jim Schmidt recently showed that Norton twin mit 90 rwhp, and the l-o-n-g inlet tracts like a manx that seem to be the secret of this. Not that manxes were alone in this aspect - GoldStars and KTT Velos and 7R Ajays and G50s and Rudge 4Vs and Excelsior Manxmans etc etc etc all used this, this has been long known...
Its notable that Commandos, and indeed many roadgoing twins, are quite short in the inlet tract dept ??
As std road bikes anyway.
??

Rohan said:

Dances with Shrapnel said:

As an after thought on this whole thread, it might be simpler to conduct a desktop dyno simulation to answer Rohan's question.

I don't know which systems out there can factor in port velocities; typically the lower costs desktop simulations will use port flow coefficients which do not necessarily factor in port velocity.

Click to expand...

Not quite a real world test though, is it ?

As folks used to say in the computer business - garbage in, garbage out.
'simulators' are only as good as the programmers....
???

Click to expand...

A proper simulation will get you more answers faster than you can type questions. In fact this is an excellent example for use of a simulation. I am sure Jim C. has flow coefficients and if there's a simulation that accounts for port velocities then Bob is your uncle. The bench mark motor simulations are out there, one is really only looking for incremental improvements, not absolute numbers and this is a perfect application for simulation.

The garbage in, garbage out cliche is why they keep amateurs away from simulations Rohan.

Have YOU ever used any of these simulation packages ?
Did it give perfect results ???
Usually if you make the ports and valves bigger and bigger and bigger, they give more and more power !!!

But when they do such simulations on a real manx norton, s raced back in their heyday,
it couldn't possibly then have made that much power or won races.

On a flow bench its awful.
Its the pulse tuned intake and exhaust that makes the difference,
honed over many decades of careful trial and error !!

Its only amateurs that do such puter stuff, the real racers are out on the track - winning.
Look how much actual experimenting the F1 and MotoGP guys do....

There has been huge advances in engineering design through the use of simulation programs. To say that trial and error
is the way to go is simply out of date. For those of us who are civilians, sure, it can be a useful method but it isnt the best or
the fastest.

Dyno figures for a cylinder head will of no good to you at all.....

You produce dyno figures for an individual engine, with a given and matching set of components and ancilliaries, and still dyno figures will differ from build to build, and day to day and dyno to dyno.

Today, the Fullauto head is the best cylinder head you will buy for a Commando based engine...absolutey end of. Because for one, your other option will have been abused in some way in it's 40 plus years, and it wasn't as good as a Fullauto even when it came out of the factory. We all know this, the bitching is about wether it is worth it to you. Your decision.

You are free to fit it as it comes, or modify for your application. As it comes in the box, it will outperform your 40 year old head.

Dyno figures should not be part of your buying decision. Quality and life, versus a notion of originality if that is important to you, traded with cost and available budget should be your basis. But beware that putting new life in your old head may eat up more budget than you had imagined.

I just wish that those of you who haven't bought one would stop giving your opinion on something you are not qualified to comment on until you have installed and used one.

Every time Fullauto is mentioned we go down this rabbit hole. Please stop it, and lets support Ken in his endeavours and help him keep doing what he does, and maybe doing even more neat stuff.

One very satisfied customer.

Rohan said:

Have YOU ever used any of these simulation packages ?
Did it give perfect results ???

Click to expand...

Yes, and yes. Prof. Gordon Blair also conducted simulations for our 500 Norton which nailed the performance perfectly.

Rohan said:

Usually if you make the ports and valves bigger and bigger and bigger, they give more and more power !!!
But when they do such simulations on a real manx norton, s raced back in their heyday,
it couldn't possibly then have made that much power or won races.
On a flow bench its awful.
Its the pulse tuned intake and exhaust that makes the difference,
honed over many decades of careful trial and error !!

Click to expand...

This from your personal experience - I did not think so. This is why they keep amateurs away from the simulations since, as you say, garbage in, garbage out. One needs to know what they are doing. These views are dated.

Rohan said:

Its only amateurs that do such puter stuff, the real racers are out on the track - winning.
Look how much actual experimenting the F1 and MotoGP guys do....

Click to expand...

This assertion is at best naivete. Hell, in F1, more than ten years ago they were conducting Computational Fluid Dynamics (CFD) on impacts of intake scoops profile changes on overall vehicle aerodynamics.Your initial question was asked and apparently answered yet there are plenty of valid and in my opinion more useful ways to get the same answer as well as answers to many more what-if's.
I have a new Full Auto head in waiting for the next 500cc build. It is, amongst other things, the solid platform and quality I bought in to.

I have spent a career in simulation, not of engines but of aircraft.

Simulations have developed beyond most peoples wildest expectation in that time. They are used in the conceptual, specification, procurement and development phases of pretty much everything these days, particulary in aeropace and automotive. You want a lot of simulation evidence before you commit big budgets. (a big budget is anything you really cannot afford but are determined to do anyway....most of us have been there at some time!)

Simulation can represent all of the parameters of an engine including all anciliaries inlets exhausts etc. Don't under estimate what can be achieved or that they will continue to improve. The best use of simulation is to compare options, varying parameters. You will make decisions and select options to suit you. But a simulation is a much sounder basis for your choices prior to component selection and purchasing.

You will still want to test your build to see if it meets (simulated) expectations and can be improved, by carburation and ignition settings etc. and you will still need a competent rider to evaluate and make good use of it.

In aviation this work is done by test pilots who are highly experienced and trained in performance evaluation, and who work to a methodical plan. Most of us are not this skilled or experienced, and few of us have a really good plan....but somehow we seem to know best! :roll:

Re:

lcrken said:

Welll, at least one, and maybe more, race bikes with Fullauto heads have been put on the dyno, but no one has posted the results here. I don't think any of them were back-to-back comparisons of the same engine with a stock head and then a Fullauto head, so maybe the owners didn't think it meaningful enough to post.

Ken

Click to expand...

Exactly Ken, the numbers from my one dyno run on my Fullauto head at first engine build was fairly meaningless....it just allowed us to get the jetting closer before serious track runs, and to confirm it was in the expected ball park. I certainly had no previous figures to compare it with, and since I was just revving to 1500 below the revs I have now used, I have little evidence that I saw the full potential of it.

Unless you all have built a 750 short stroke race bike with the same compression, cam, pistons, rods, valves, carburation and ignition, its going to be completely meaningless to you too. And if you did, I ain't telling ya anyway! 8)

Do you think that if you buy all the fast bits and bolt them together, you would have a fast bike and the skill of the rider would be irrelevant ? In my experience, the development process has involved continual feed-back from the rider combined with changes to the set-up until optimisation is achieved. In many cases a near standard bike can be made to go very fast when subjected to the development process. I think the biggest mistake many guys make lies in enlarging the inlet ports - there is no easy way back. An important factor is also the way the rolling chassis handles. It is not much good having a torquey motor if you find yourself out on the ripple strips trying to out-drag superbikes, and the converse situation is even worse. A top end motor in a bike which tightens it's line in corners is dangerous.
With my old short stroked 500cc Triton, it would rev out forever and go extremely quickly. However if it dropped off the power band in corners and you tried to carefully slip the clutch, it would go instantly sideways. When it was fitted with four inch megaphones, it was a nightmare - all top end and it would scare you shitless. You might believe that if you rode it faster, you wouldn't have the problem - how fast is fast ? Personally I don't need that sort of anxiety. At the time I was racing the Triton, I also had a ride on a very good 500cc Manx. The Manx was about 5MPH slower down the straights but about 5 seconds a lap faster overall.

So, can anyone name an engine simulation package that would be applicable to my Norton,
AND give meaningful results. ??
And how would I get access to it - I'd presume it would cost millions of $$ ?

For those with an interest in F1, we will have noticed that Merc are somewhat dominant this season and last.
Does this mean they have the best computational engine simulation package, and all the others out there are sheet ? Or they just would have fed the numbers in, done some crunching and come out and whupped em on the track....

I certainly wouldn't deny simulation stuff has its place. A mate did his thesis on vibration analysis (of buildings), and just out of curiousity it was tried it on some bike frames. While it wasn't really tailored for this, it did show that longer unsupported tubes potentially could vibrate more. Someone with an experienced eye could have concluded about the same thing, but without any numbers ...

SteveA said:

I have spent a career in simulation, not of engines but of aircraft.

Simulations have developed beyond most peoples wildest expectation in that time. They are used in the conceptual, specification, procurement and development phases of pretty much everything these days, particulary in aeropace and automotive. You want a lot of simulation evidence before you commit big budgets. (a big budget is anything you really cannot afford but are determined to do anyway....most of us have been there at some time!)

Simulation can represent all of the parameters of an engine including all anciliaries inlets exhausts etc. Don't under estimate what can be achieved or that they will continue to improve. The best use of simulation is to compare options, varying parameters. You will make decisions and select options to suit you. But a simulation is a much sounder basis for your choices prior to component selection and purchasing.

You will still want to test your build to see if it meets (simulated) expectations and can be improved, by carburation and ignition settings etc. and you will still need a competent rider to evaluate and make good use of it.

In aviation this work is done by test pilots who are highly experienced and trained in performance evaluation, and who work to a methodical plan. Most of us are not this skilled or experienced, and few of us have a really good plan....but somehow we seem to know best! :roll:

Click to expand...

These 2 heads produce about the same power.
Punch them into these simulation packages and prove it...

https://s31.postimg.org/6h4kkx8kr/heads.jpg


We diverge from FA heads a little here....