Lotus Elan

123 Ignition Tune

PostPost by: simonknee » Wed Aug 29, 2012 9:57 pm

You measure MAP (manifold absolute pressure) and manifold vacuum at the same place on an engine. A MAP sensor is measuring absolute pressure, a vacuum gauge measures it relative to air pressure.

RPM tells you what speed you are at it does not tell you whether you are accelerating, cruising or decelerating. Or put another way whether you are wide open throttle (WOT), partial throttle or closed throttle.
Adding a MAP sensor into the equation allows this unit understand what is currently being asked of the system.
As Vernon(2) says this is what a vacuum dizzy did back in the day.

It may well be that taking a MAP reading from a single barrel causes issues. Not because this is inaccurate as all your barrels _should_ be doing the same thing. But as Vernon(2) says perhaps low rpm pulsing would be an issue. However since the unit obviously knows the RPM they should be able to apply a suitable filter (doesn't mean they have!). That said there are folks over on Keith's yahoo site having fun and success with mechanical vacuum advance units so my hunch is that you would be OK.

Vernon(2) is correct in that the points in the picture are specifically for testing airflow at each barrel not the actual adjusters.

As to what sums the 123tune might be doing we would have to look closer (I will be). In a mapped ignition system you would ideally be able to specify the advance on a table with RPM on one axis and MAP on the other. Then you could optimize all the points. Of course a really comprehensive system should be looking a trends in an attempt to predict what to do next, eek! Before we get too tweaky we are forgetting that we have no active control over the fuel. In an injected system (like what V2 has) the MAP is used to measure the air mass and instruct the system on how much fuel to deliver to achieve max power or max efficiency depending on the demand. So the 123Tune has to hope that the webers are providing a suitable mixture in the first place - hmm I wonder how to do this... :D

Still the idea of this unit appeals even if the MAP proves somewhat difficult to do. If I needed a new dizzy right now I would get one of these (assuming it fits). Of course I'm a sucker for this kind of stuff!

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PostPost by: vernon.taylor » Thu Aug 30, 2012 7:43 am

Salut

Merci pour vos r?ponses.

Bud: yes, this was one of my questions - is the distributor a weak link in that performance/timing is affected? Would it be possible to notice a difference between HT switched by the dizzy and HT transistor-switched through a coilpack?

If the 123 Tune is as versatile as it seems it appeals to me because 1) It would be easy to fit with no extra brackets, sensors, wiring, etc. 2) It would look reasonably stock uner the bonnet. Also now that Megajolt is no longer available as a kit, the total price is probably cheaper.

Simon: Brian(types26/36) in a reply about a headlight problem said he used to fit restrictors in the line to vacuum gauges to stop them pulsating at idle - could that be a solution (and what is a restrictor [I can guess from the name] and where can you buy them)?

Hebels replied that the height of the dizzy with clamp (I think) is 115mm - he didn't say if this was a right-angle cap. I tried to check on my engine with a ruler and it looked OK - could someone with a spare distributor check, please? He also said I could use both vacuum and mechanical advance.

@+

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PostPost by: Higs » Thu Aug 30, 2012 9:37 am

Vernon

There are various ways to smooth out the pulses but these all have drawbacks. So for example, you can put a set of baffles and a reservoir in the line (rather like an exhaust silencer/muffler) which will reduce the pressure peaks - but this will make the reading less accurate and, if the reservoir is large enough to damp out things, it will reduce the reaction time of the vacuum signal (i.e. the signal will lag behind what is actually happening in the inlet).

Some sites on the web suggest taking a take-off from each of the inlet tracts - this will give a better signa but will have horendous consequenses to the Webers (equavalent to having an air leak in each of them.

The only sensible solution is that 123 has understood this issue and uses software to record the peak values and to ignore the troughs in between. Only they know what their system does so I would think the best thing is for someone to contact them. After all, we are not the only car to run twin webers.

If 123 has sorted this, then a simple "T" off the headkight vacuum line would work (as long as the "T" is before the non-return valve). And the 123Ignition Tune would look very attractive.

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PostPost by: vernon.taylor » Thu Aug 30, 2012 10:41 am

Salut

123/Mr.Hebels has been very quick to reply to all my messages but his answers are very short and prompt further questions!

I asked about the vacuum pulsing and the answer was 'no problem', so I've asked again how the reading is taken - peak/averaging/or something else.

The Tune version is the same size as the other versions so it should fit OK - at least one lotuselan.net member has fitted one.
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PostPost by: quaybook » Thu Aug 30, 2012 11:23 am

Vernon

I hadn't realised that the MAP readings are applied electronically rather than mechanically on the 123 system. If they are applied electronically then, as Richard wisely suggests, hopefully they have written filters/damping into the system to cope with a pulsing signal. I notice that they do a Ducellier distrib which they recommend for Alfas, many of which have the same carb arrangement as the Lotus, which must point to it being ok.

I think Bud is correct in that a Megajolt style coil pack/ecu system is a better technical solution - certainly easier to map - but like you I want to stick to an original underbonnet look if possible, and the easy fit appeals. If you go Megajolt or similar you have coil packs, an EDIS unit and an ECU to locate somewhere, a trigger wheel to go on the crankshaft etc. which is quite a lot of hassle and won't look attractive on a period car. Also, in my case my Elan still on positive earth and Megajolt is neg earth only so another change would be needed.

Going 123 sounds pretty positive to me. Good luck with the decision :)

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PostPost by: cwsammut » Thu Aug 30, 2012 4:08 pm

I have had a 123 Tune fitted in my Twin Cam Europa for almost a year and a half now. It fits comfortably instead of the Lucas dizzy. It is easy to tune via the USB cable/laptop. The main reason why I had fitted it was because I had considerable spark scatter at low RPM which tended to improve as the RPM increased. Fitting the 123 did improve matters slightly but not as much as I had wished. So I changed the timing chain, tensioner and pad and everything stabilised nicely. I also used to have a sort of surging at 3500 - 4000 rpm which was very annoying. That has all gone now. I'm very happy with it, engine revs cleanly to 7000rpm and it is more flexible. I do not use the vacuum option at all. The built in rev limiter is also handy.

The LED is a bit of a pain to see when you are setting it up initially. I had spoken to the manufacturer and they were considering including an indicator on the 'dashboard'. But it is nothing a well placed mirror cannot solve.

They seem to be selling well because I ordered another one for another twincam engine that I have, and they are out of aluminium bodies at the moment. Should be back in stock in about 10 days. The original clamp used on the Lucas distributor will not fit the 123, but they supply a suitable clamp with the unit, so it is not a problem. This is because the diameter of the Lucas unit is different from the Motorcraft/Autolite one originally supplied by Ford and the 123 is the same size as the Ford dizzy.

The original Smiths tachometer works perfectly as well and is very accurate. I did replace some internal components, a couple of capacitors and possibly a transistor, with identical values as the original and it is like new again. It is easy to calibrate by twiddling the potentiometer at the back.

You can download the latest software to play around with:
http://www.123ignition.nl/downloads/sof ... v1.6.4.exe
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PostPost by: vernon.taylor » Fri Aug 31, 2012 8:27 am

Salut cwsammut

Thanks, that's very useful information. If I go 123 I'll definetly be asking you for your advance curve to get me going.

Still trying the definitive answer to the vacuum question - a 'veteran' on the 123 forum said vacuum from one carb is OK as the average MAP is used. I've asked him if he is sure and about pulsing.

@+

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PostPost by: vernon.taylor » Wed Sep 05, 2012 7:39 am

Salut

Got a reply from M. Hebels who said he called the factory:

The vacuum nipple on the 123 distibutor has a very small hole. This is to 'accumulate' and reduce pulsing at low revs.

nipple.jpg
nipple.jpg (12.7 KiB) Viewed 1707 times


So, a mechanical solution but no mention of a software solution - but it has been considered it seems. What do you think?

EDIT: According to Mr. Shmitz of 123 Sweden, the small hole in the vacuum nipple is not there for 'accumulating', but is just the part they use (but I suppose that could still be the reason). He said also that there is filtering in the software to allow for pulsing - though he did say one could still try putting a restrictor in-line.

@+

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PostPost by: quaybook » Wed Sep 05, 2012 7:04 pm

Hi Vernon

I doubt the small vacuum hole would have sufficient damping effect - if it were that easy, manufacturers using twin 40s back in the 1960s would have done that to allow the use of vacuum advance distributors I would have thought. So I think it is still down to the software. I guess if they produce 123 Tunes specifically for other twin 40 cars, eg Alfas, they must be confident that they have the problem licked? I don't want to sound too encouraging, because you are the guy potentially in the 'guineapig' position not me! I'm very interested, but go ahead just yet anyway.

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PostPost by: cwsammut » Mon Sep 10, 2012 9:55 pm

Hi Vernon

I have PM'ed you with the info you requested.

But I will repeat it here for general information.

For the Big Valve motor in standard tune, start with 5? increasing to 12? @ 1000rpm then straight to 26? @ 3500rpm. Check that you actually have 12? @ 1000 rpm with a strobe because the built in LED system is not very accurate. Set the rev limit to whatever you deem safe. That will get you going safely. Once on the road with a helper and a laptop hooked with USB cable, fine tune the max advance for best performance without pinking. You should feel the difference in performance and a cleanly revving engine.

If you have some special coil, check its resistance with an Ohm meter to confirm it is within limits.

For some reason my car emits a bang when I switch off after a hot run. Doesn't bother me, but startles passers by ;-)

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PostPost by: Pistacchio sprint 72 » Tue Sep 18, 2012 6:16 pm

Salut vernon, so you went 123 tune in the end? :mrgreen:
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PostPost by: vernon.taylor » Tue Sep 18, 2012 7:17 pm

Salut PSprint

Oui, I bought one - looks a nice bit of kit. I'll report back when it's fitted; but be patient!

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PostPost by: Pistacchio sprint 72 » Tue Nov 13, 2012 12:05 pm

I fitted one on my Caterham Xflow engine. I am happy with it. :wink:
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PostPost by: jrwiseman » Sat Dec 29, 2012 5:24 pm

vernon.taylor wrote:Salut PSprint

Oui, I bought one - looks a nice bit of kit. I'll report back when it's fitted; but be patient!

@+

Vernon


Vernon

Any update on your experience ? Also, which model did you order ?

thanks !
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PostPost by: quaybook » Thu Dec 05, 2013 10:03 pm

I've now bought and fitted a 123 Tune and thought it might be helpful to report.
I'm certainly pleased with it. As hoped it has made part throttle response much sharper. Just a whisker of throttle and there is instant response. The engine feels livelier and sweeter in normal road going part throttle use. Too early to say yet but I expect cruising fuel consumption will be much improved. At present I've only tried a basic set of curves, hopefully careful tuning of the curves will result in further improvement. When I get the chance I'll probably book a short rolling road session and tune the curves that way. Although a great improvement, the 123 Tune is not a full 3D system (you have a single load advance ramp, with full 3D you can alter the load advance ramping at different RPM). The full 3D I have on my Ford Kent engined Westfield is much more tuneable so results are better.

Installation. I inserted a tee in the vacuum take off for the headlights to provide the vacuum input to the 123. As this is fed by only one inlet tract there is a pulsing problem at low revs. The manufacturers advised that some damping in the form of a reservoir or restrictor would most probably be necessary. I experimented with a vacuum gauge and ended up with the following. A 5mm ID vacuum tube with a Dellorto DHLA idle jet (58) inserted as a restrictor just before it is teed into the headlight vacuum tube. (Two points to note here - 1 make sure the tee is too small for the restrictor to pass through so there is no chance of it being ingested by the engine - 2 the tee must be placed between the manifold and the headlight non return valve). To provide some additional damping I first tried a small fuel filter inserted in the 5mm vacuum tube line but this was ugly and cumbersome, so I tried cutting a length out of the 5mm vacuum tube and inserting a 120 mm length of 10mm ID tube - it fits nicely over the 5mm ID tube - so that the increased diameter provides a small damping reservoir. This works fine and looks really unobtrusive. The pulsing problem is further mitigated by the fact that the electronics enable you to set a minimum rpm level for the application of the load curve. I've set this at 1500 rpm, so any slight pulsing in the vacuum below these revs has no effect.

Hope this helps. If it would be of interest I could take some pics of the installation and try to upload them here. I also have the curve data I have used which might provide someone with at least a starting point.

My car is mostly original, but the joy with this mod is that I still have the original distributor etc, so all can easily be returned to original if desired, but in the meantime i can enjoy a sweeter, more responsive engine.

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