Interesting. With EDIS, they are connected to the same 'coil' in as much it has just the one feed to it. But the two plug outputs aren't simply in parallel - there is a reading of 12K ohms between them, so I'd guess the coil has twin secondaries. Since it is likely an auto transformer, I suppose it could look like the outputs are in anti-phase. But the spark isn't a simple DC arc anyway, and I've never heard of one of the plugs from a pair wearing faster than the other, and it hasn't happened here even when using the original plugs designed for conventional ignition.
I'll see if I can find a schematic of the EDIS coil.
Yes, from a speedo which was over-reading by probably between 5 and
8% I'm not the only one to use that as a reference, the 20 to 80 time gains are still significant despite the error. The error was certainly minimised by using as much tyre pressure as was safe and I doubt the error was in excess of 4%.
In practice the from the showroom times were more like 10.5 to 11 seconds for 0-60 as tyres with lower rolling resistance were fitted after the tests were made.
That's because the dissipated energy is smaller so the effect isn't noticable by looking at the plugs, hence they "last forever". The smaller energy dissipation is noticable in how fast the flame front develops, the hotter and fatter the spark the faster the flame moves and the greater the available torque. I suppose one could use a lower energy output when torque demands are lower and at lower speed this may be beneficial in assisting a quiet running engine for creeping about town under the cover of darkness.
Just pulse it with a button cell and check for direction of needle deflection.
Ha ha, I think I'd notice if the valves were bouncing at 33kph. Oh yes, the optimal tappet clearance was around 11 or 12 thous, not 14 as stated. That was a seriously good cam and every one I've met who kept a Maestro for some years has done so with finding this performance tweak. And a check with oil pressure after filling with the 30weight synthetic as even then the oil pressure can be high and needs reducing to spec to develop full acceleration. After sorting "everything out" I found that the baffle plates in the sump to be inadequate for my road use as I was developing high G on open corners. I never did fit a horizontal plate to prevent a dry pump, it was a good reminder how hard I should be cornering.
The same techniques are used on every other model on the racetrack. For a normally-aspirated small capacity engine with siamesed ports on a single choke, yes it was probably the finest. Never saw a Ford Fiesta with the same arangement anywhere near it.
Nice one, just reading his notes and came across a point about tyre pressure and how it affects dyno readings and road performance. Well, BL specced the tyre pressure at 28 all around and I had the fronts at around 36psi. That possibly gives 10% more torque at the wheels in third gear. he also states that manufacring tolerances will typically have engines producing 5% more or less than manufacturers spec.
The torque is entirely a function of engine torque times overall gear reduction ratio.
Tyre pressures affect many things, but not torque at the wheels.
Do you realise what a fool you are making of yourself?
he also states that manufacring tolerances will
Considerably more than that with a 'blueprinted' engine. Well they CLAIMED it was only 'blue printed' ..as long as the scrutineers didn't spot the bored out to the max oversized pistons fitted skimmed to the min head that ran on 110 octane fuel ONLY.....and the carefully smoothed ports with the edge of spec large valves and the scrubbed clean air intakes...an the dymamically balanced crank and matched pistons that would redline a whole 750rpm beyond the normal and the delicately corroded and reskimmed flywheel ..and the slightly 'adjusted' camshaft with the absolutely to the micron adjusted valves and teh somewhat stiffer springs that fell off the back of..well we never did know where they came from.
Let say that one in a billion engines might *just* accidentally have come off the production line like that...
On Jan 27, 11:53=A0pm, "Dave Plowman (News)" wrote:
The vehicles they used were on regular oil at least a grade thicker in both the gearbox(which was overfilled) and the engine. The vehicles they used would not have had the rings bedded in well after a significant wear-in period. The vehicles they used, if fully to spec would have had engine oil in the carb piston damper which did restrict breathing. The vehicles they used if to spec would have had the tyres under pressure (and of a higher rolling resistance, economy tyres were later fitted between brochure publication and actual manufacture). The tappet clearance on a specification vehicle is too big. the spark plugs on a spec vehicle would not have been non-resistive, small gapped and cut back. The specification that they were legally obliged to follow within manufacturing error still would always result in a slower vehicle. These were base model vehicles expected to attract a minimum insurance premium. They would have lost sales based on expected insurance premiums if they had released a specification resulting in a quicker vehicle. 68bhp IIRC was sufficient at that time in an 850kg car meant principally for around town and tight back lanes outside town. Using the greater capacity I had extracted at the wheels was rarely fully possible in these environments. The ignition mods I made allowed the timing to be 4 deg later to produce maximum aaccelleration IIRC. Every change I made outside specification made an on the road timeable improvement in acceleration. The use of upper cylinder lubricant was also not to specification, it was a NO-NO according to BL. Just because I wasn't throwing money at the cylinder head (there was nothing wrong with it except the constraint of the siamese port to valve timings) and fitting aftermarket carbs (BL got it right with the SU), blah blah blah, doesnt mean that significant gains over a specification vehicle cannot be made with what on the surface, to the uneducated, are insignificant procedures. Every change resulted in timed improvements, they all added up. Adding
10.bhp to specification without any modification was normal, taking to
85.bhp was considered rare. I don't know the bhp figures, I felt it a waste of money making such a test, the vehicle complied fully to the insurance policy as it was not modified (meaning a signifant variation in the powertrain or chassis components) and the acceleration optimisation was what mattered to me.
It surprised me, but that's were the "static timing" ended up. I test drove the vehicle for two weeks with the distributer vacuum connection plugged so as to ensure things were not getting mucked up and I pushed it forward, I pulled it back. The stated timing was too early once the ignition was working fully due to the exposed spak plugs' centre electrode casing a faster initiation of ignition. I researched the subject thoroughly on the available literature at the time. That extra 4 deg time is required with enclosed plugs because they sheild the fuel mix from the spark and quench the initial flame. There is an unnecessary delay in developing the flame front which results in sluggish acceleration.
It will have an effect on the acceleration. And the torque as measured on a rolling road. Under inflated tyres get hot when transmitting a lot of power - and that heat has to come from somewhere
You're suggesting the performance figures were taken with a vehicle straight off the production line. This wasn't the case. Of course they used a fully run in one and any other minor alterations they could get away with to produce the very best possible figures - exactly as is done these days to produce 'official' MPG figures.
I had an Escort Mk1 van like that. Went like shit off a shovel and on further enquiry, found it had been fitted with a 1300GT spec lump as a replacement - turned out the dealer in Belfast replaced the engine under warranty and Ford sent that engine (perhaps by warehouse mistake, perhaps that all that was to hand at the time). Even on the standard carb and manifolds it was quite good; and the van gearing gave it an edge at the traffic light GP.
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