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 seagull
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| posted on September 7th, 2004 at 08:54 PM |
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8 spark pugs & two dizzys
who has a photo please
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HotRodMatt
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| posted on September 7th, 2004 at 09:00 PM |
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Only good for aeroplanes...
Get an MSD and get 3 fatter sparks for performance.
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56astro
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| posted on September 7th, 2004 at 09:03 PM |
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Sorry Seagull, no photo but I have seen several sets.
And Matt, no they are not only good for aeroplanes. What makes you think that? Twin plugs provide a far more efficient fuel burn than one plug,
especially when placed in the head correctly!! And other advantages that flow on from that.
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56astro
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| posted on September 7th, 2004 at 09:08 PM |
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Oh, and if you want a set, ring Stan Pobjoy. He knows all about it!!
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Craig Torrens
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| posted on September 7th, 2004 at 09:10 PM |
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2nd that astro ! it has already been proven the advantages of two plugs...................performance bikes and cars have been using this form of
technology for a while.
Its not only a fatter spark that you want (MSD etc), but also an even burn across the combustion chamber.
Its worth about 10-15% more power in the bottom and mid rev range.
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Craig Torrens
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| posted on September 7th, 2004 at 09:14 PM |
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Stan's kit is a single Dizzy (that's right 8 leads), and he machines your heads to suit the extra plug per cyclinder.
Several cars and trikes at Nambucca had them fitted, all owners have loved the extra power and better fuel economy.
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HotRodMatt
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| posted on September 8th, 2004 at 08:49 AM |
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Twin spark plugs DO NOT create more power. They have only the effect of curing rough running at low rpm. And we know that the engines that these
systems are being used in DO just that under 3 grand. The reason for this is the massive overlap in the cam for the engine to acheive power at high
revs.
Aeroplanes use them not for low rpm stability but for safety - if one plug fails there's still spark in that pot.
MSD and the like give mutiple sparks at variable times to create an even better flame front throughout the rev range and unlike dual sparks continue
to work throughout the entire rev range.
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Craig Torrens
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| posted on September 8th, 2004 at 10:26 AM |
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twin plugs, more bottom end and mid range power. Does not increase peak/max power.
Already proven Matt.....................oh and we are not talking about massive overlap cam engines either...................its already a known fact
in the aircraft industry about the power/torque gained by the twin plugs.
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HotRodMatt
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| posted on September 8th, 2004 at 10:31 AM |
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It doesn't increase the power merely compensates for the poor engine combination design at the low end.
Alfa who do a lot of twin spark themselves admit that variable cam technologies would be a better option than twin spark.
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56astro
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| posted on September 8th, 2004 at 10:46 AM |
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| Quote: | Originally
posted by HotRodMatt
Twin spark plugs DO NOT create more power. They have only the effect of curing rough running at low rpm.
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So if the engine runs better at low RPM, and as a result makes more torque, then doesn't that mean that power is increased at low/mid RPM??
And that was one of the flow-on benefits I touched on.
| Quote: | Originally
posted by HotRodMatt
Aeroplanes use them not for low rpm stability but for safety - if one plug fails there's still spark in that pot.
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Matt, you've been following the wrong sheep if ya think that is the only reason. Time for a change of flock, or even a new shepherd!
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56astro
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| posted on September 8th, 2004 at 10:56 AM |
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Another flow-on advantage could be the ability to increase the CR of the engine without the risk of pinging!
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HotRodMatt
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| posted on September 8th, 2004 at 10:56 AM |
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Don't need a shepherd...
Better combination of cam will produce the same thing.
Difference between a sheep and me is I look at a whole solution rather than a compensation for bad combinations.
Working with old solutions is not revolutionary or advancement - if the same energy was devoted to looking at a better head design and truly
revolutionary valvetrain design we would end up with much better engines. Instead we get a band aid for combinations that aren't effective at low
rpm.
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56astro
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| posted on September 8th, 2004 at 11:20 AM |
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| Quote: | Originally
posted by HotRodMatt
Better combination of cam will produce the same thing.
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What, the same max power as seen in Troy's dyno chart but with a fatter and flatter torque curve. Lets see it then ..........
| Quote: | Originally
posted by HotRodMatt
Working with old solutions is not revolutionary or advancement - if the same energy was devoted to looking at a better head design and truly
revolutionary valvetrain design we would end up with much better engines. Instead we get a band aid for combinations that aren't effective at low
rpm.
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This is probably the best single cheapest performance gain apart from dual carbs. Sure, some combos might give better max output but at what cost and
loss of drivability?
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Craig Torrens
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| posted on September 8th, 2004 at 03:34 PM |
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Oh Matt, don't get so hung up on what you think you know about cam grinds and engine combo's..
Look at the facts Matt.
The twin spark plugs will have a benefit on any engine combo that has a bore size of 90mm or more.
Anyone in the Aircraft industry appreciates the extra power the twin plugs creates and they are around the 2500 3000rpm range ! Not exactly high RPM
cams.
Go fly a light aircraft and switch off 1 ignition and feel the power difference.
This is not about cams ,but about more even combustion
The benefits are there for any cam/engine combo.
The benefits a performance motor will gain is the fact that you can use a "Hot" cam that has High RPM HP as well as having the benefits of a
"mild" cam for low and Mid range.
I would love to see your cam combo Matt that will give you this without the plugs...........because its not possible.
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Craig Torrens
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| posted on September 8th, 2004 at 03:42 PM |
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| Quote: | Originally
posted by HotRodMatt
It doesn't increase the power merely compensates for the poor engine combination design at the low end.
Alfa who do a lot of twin spark themselves admit that variable cam technologies would be a better option than twin spark.
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So where can I buy variable valve gear for my VW engine?
Maybe a better "big picture" option.........................but not available!
Lets just enjoy the benefits of what's available today, and all work on something better for tomorrow.
[Edited on 8-9-2004 by Craig Torrens]
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HotRodMatt
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| posted on September 8th, 2004 at 04:33 PM |
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3 sparks even better and a much better flame front from one plug as mentioned above. But never mind that - Stan's 2 plug has got to be promoted...
This is just another 94 thread now...
By the way I have seen two great streetable and very racable motors that pull better HP from 2000 to 6000+ and better torque to boot. But they are
both from strokers so it mustn't be true... Both have only one plug and only one had MSD!
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BiX
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| posted on September 8th, 2004 at 04:53 PM |
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ok now settle down boys, each to his own. Persoanlly i would never get a engine from stan, not my thing, much prefer a stroker by my engine builder.
But i can see the logic behind the twin spark and yes it may work better with 3, but it comes down to how much room you can get in the cylinder head
for valves, plugs etc.I also understand the logic behind MSD. To me they are both trying to attack the same problem but using different ideas- to
getter a cleaner and more efficent burn of the fuel and therefore make more hp/nm per combustion cycle. Now what would happen if we combine both
ideas. Using twin plugs to get a better flame front, while using a MSD system to get a fatter spark?.
SO keep it non personal and lets talk facts about both ideas that seem to be able to give our little vw engines more power!!!
[Edited on 8-9-2004 by BiX]
I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!
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HotRodMatt
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| posted on September 8th, 2004 at 05:11 PM |
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MSD isn't just a better spark it's multiple sparks from one plug - usually at around 20 degrees of rotation...
Quite simply - a properly conceived combination does not require either MSD nor twin plugs to operate effeciently under 3000rpm while still producing
hp at high revs.
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Craig Torrens
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| posted on September 8th, 2004 at 05:19 PM |
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Firstly, Stan builds strokers.... and a lot of them.
Craig Pattons stroker is currently being built by Stan and Peter Richards...........also with twin plugs.
Secondly,Matt this is about promoting a new option for anyone's engine that has not yet been utilised by any other VW builder, don't worry about the
fact that Stan developed it.
Thirdly,nothing wrong with the MSD, its just one plug does not cover the same area as the two plugs can.
Matt, if you think its not needed then that's fine............your loss.
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BiX
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| posted on September 8th, 2004 at 05:31 PM |
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yes i understand what MSD stands for , but with the multiple sparks (MSD) the aim is to get a better spark and therefore better combustion. Sorry
craig , it was meant in the sense that iam not a stan fan, or avid supporter, but i can still see why its a good idea.
I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!
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 Peter Leonard
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| posted on September 8th, 2004 at 06:33 PM |
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let's see who gets it.
I've used a msd cdi kit, and I've used (am using) the twin spark setup now.
if you can imagine, the major difference is the LOCATION, and speed of the flame front propagation.
A more efficient head design would have a central spark plug (which makes the expanding flame front hit the crown of the piston dead centre, and
travels with radial symmetry as it ignites. hard to do with two valves and an offset sparkplug like, say, a VW. MSD cannot change the direction, or
speed of the flame front. The first spark sets it all off, and later sparks are just fudging a kind of increased duration, because the spark thrown by
a cdi is bloody hot, but incredibly short lived.
How do you get around it? have two sparks ignite simultaneously from opposite sides of the combustion chamber, effectively fixing the offset,
but more importantly starting the flame front from TWO places.... quicker and more complete burn... are we getting it yet? The dissy that powers the
setup is a solid state unit, with great duration, hence no need for for MSD.
anyone with half a brain should understand what THAT'S worth. People like Ducati (ever heard of the 1000DS... but that's an old 2002 model) know the
advantages, and they're not building engines in sandpits wearing funny hats.
In 2003 upon release of the 'Multistrada' reviewers said "The engine has been bored to 94mm for 992cc and updated with new cylinder heads with
twin spark plugs and Marelli fuel-injection with twin 45mm throttle bodies.."
look it up. yes, they're 94's. so shoot me. But why does Ducati keep banging its head aginst the wall with these crazy twin ignition ideas...
possibly for the same reason Porsche did it.. or BMW... or Harley, or Moto Guzzi... or Nissan... Or Toyota
Why is it not MORE prevalent? four valves per cylinder makes it kinda hard. Lucky for us we got 2.
why do more VW's not have them? It's a bloody dangerous job that's incredibly easy to screw up. To cover the cost of a a macining slip up you can
pay up to 3000 bucks to have your single zapper heads converted to double bangers. Have a surf on the net. I did for four months before i decided it
was a serious bet.
now get with it..
let sleeping dubs lie
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56astro
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| posted on September 8th, 2004 at 06:47 PM |
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always a pleasure, Pete
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Craig Torrens
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| posted on September 8th, 2004 at 10:40 PM |
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but Pete, surely they are just covering for poor CAM choice !:thumb
..................maybe I will ring Ducati tomorrow and let them know that they are wrong with their latest model having twin plugs :jesus
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Kai.A.
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| posted on September 8th, 2004 at 10:51 PM |
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just out of interest, does anyone have any piccies of stan's twin-spark heads?
kai
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Alex Holzl
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| posted on September 8th, 2004 at 11:00 PM |
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hahahha i have 8 plugs!! 4 in the glove box and 4 in the motor!!! 4 wheels, 4 cylinders, 4 gears, 4 spark plugs, 4 goodness sake stop it!!! Whats the
whole kit worth?
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seagull
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| posted on September 8th, 2004 at 11:50 PM |
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um I just asked for a photo ( please ) hee hee
very good reading , I think I told craig one of my customers has this donk in a plane over here .I left the dig at home that day bummer !
very interesting to see ( I just wanted to pull it apart there and then one the back of the ute .I call and see when it gets stripped next and take
some shots .
Now my 1.8 turbo toyota has two per pot , and that is very fast .( for Me )
Looking for that special lady : PM me for coffee & cake
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Peter Leonard
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| posted on September 9th, 2004 at 01:09 AM |
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oh yes. the cam.
| Quote: | Originally
posted by Alex Holzl
hahahha i have 8 plugs!! 4 in the glove box and 4 in the motor!!! 4 wheels, 4 cylinders, 4 gears, 4 spark plugs, 4 goodness sake stop it!!! Whats the
whole kit worth?
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Guess you'll never know, Alex
Stick to four, it's way easier.
and craig, sure.. ducati has never been able to design a cam. some 60 years of R&D and they still can't get it right.. somehow i don't think so.
unless they're waiting for a rounder number to have a go at the cam. and to think how many world superbike titles these shitty cams have won.
but you wouldn't know anything about winning, craig. bags the first ride in the next killer btw. as long as you lose the shitty cam. :kiss
seagull, bet that turbo toyota has a shitty cam in it why can't HUGE
manufacturers just get it RIGHT?
[Edited on 8-9-2004 by Peter Leonard]
let sleeping dubs lie
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lugnuts
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| posted on September 9th, 2004 at 02:44 AM |
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Please someone kill this thread,a few too many unscripted infomercials from Jones and LAWS.:kiss |
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 barls
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| posted on September 9th, 2004 at 07:02 AM |
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all i have to ask is does this get more power out of the little mouse on the wheel :duh will this make him run faster :blush
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HotRodMatt
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| posted on September 9th, 2004 at 09:24 AM |
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OK. Here we go again…
A little lesson in economics. Manufacturers look for the cheapest solution to their problems. Quite simply auto components are as standardised and
interchangeable as possible. Majors are forced to go twin plug for a limited number of engines because it is much simpler and cheaper to tool for head
work than it is to change entire combinations. They too are forced to use a less than optimal solution to the problems of incomplete burn. Have you
noticed that it is only in engine combinations designed for high power at high revs?
Same situation here. A band aid is being applied to cure the rough running at low to mid rpm in a combination designed for high end power. Quite
simple. None of the responses have addressed this – the engine where the majority of these systems will be fitted simply are not close to optimally
performing at the lower end.
Why does the problem exist? There are a few reasons. Firstly the cams used for high end high rpm power have too much overlap for the fuel to burn
efficiently at low revs – that is a fact Craig! It is not just spark shape, direction, duration or timing that will cure this problem but also the
shape of the combustion chamber (a good head shape is not just about flow but also controlling the spark and flame front from ANY given direction),
the velocity of the piston during combustion and the ratio between bore and stroke. Piston velocity is naturally greater with a longer stroke but a
smaller piston on a shorter stroke will give a higher relationship.
The velocity of the piston is determined by the rpm of the crank but the important factor at low to medium revs is the relationship between the piston
velocity and the bore/stroke ratio. The optimum static ratio for a clean burn combination is believed to be around 1.18. The efficiency is less
crucial at higher rpm.
So what is a whole solution? Something that takes more than changing only one of the elements. A twin spark or a multiple discharge system will help
but it is not the cure – it is a stop gap. Getting an efficient velocity relative to bore/stroke, using a suitable cam or even better variable valve
timing, a better shaped combustion chamber and even direct fuel injection will get you much closer.
As you will see below the strokers often have an inherent advantage in their natural ability to have an efficient burn.
Some bore/stroke ratios (best static ratio 1.18):
85.5/69 = 1.24 (stock 1600 is pretty good!)
94/69 = 1.36
94/78 = 1.21
94/82 = 1.15
Now I’m not blowing anyone’s horn here – I don’t believe there are any engine builders in Oz (regarding VWs anyway) that are addressing the
whole issue. Most are too busy building the engines their customers want – and that is always a compromise. The only people who appear to be looking
at the whole picture are people who are prepared to fabricate and investigate. I’m not talking about looking at what other people are saying for a
whole 4 months I’m talking about some of the people for whom I gather data for (my training is in information and research) – one of which has
been researching clean and lean burn technology for several years full-time who has pulled down and modified and improved hundreds of engines
including aircooled flat fours (even some by “renowned” engine builders) and has thousands of hours of empirical evidence that quite simply they
are not getting it all the way right.
In the end I will say this with complete conviction – forget twin spark plugs do some critical thinking and find better combinations and whole
system solutions.
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