MSD Ignition Again Who Has Tried It

[Lotus-e-Clan]

They also do Tech Edge Wide band kits.

I've got a TechEdge 2J2 WBO2 ((their budget unit) with an LA1 A/F gauge permanently installed in my Clan....now if you really what to get a full picture of your combustion efficiency don't forget to add this to your shopping list. You can tune accurately your carbs AND ignition using A/F ratios as a guide.

[fitz]

I saw that too peter!, if I go crazy i'm thinking of doing that too, I'm also intruiged about using a o2 sensor to adjust timing - or would it be best to stick with the combination of vacuum advance from the MAP and engine coolant temp to retard, or is there an advantage to having a lambda / o2 sensor, if i was to say, put a sports CAT in the system, would the placement of the sensor pre / post cat have any benefits, from what i've read, as this wouldn't be a full oem ecu solution with the emissions safeguards, it would not be necessary to site the o2 sensor post CAT??

[Lotus-e-Clan]

CATs!

Fitz, I know nothing about CATs and I don't know why you'd want to fit a sports version as they didn't come as std AFAIK, and certainly not on my model year 89SE. They're not required unless you have it on you conscience that the Excel is contributing unduly to pollution and you want to do the right thing?

The WIDEBAND (not to be confused with OEM narrowband lambda sensors) O2 sensor needs to be fitted within about 30 inches of the exhaust valve/port so a hole has to be drilled on the manifold down pipe and the sensor boss welded on...a simple job for your local custom exhaust fitter.

If you had full EFI (1500-2000 Quid mind you) then you could use the wideband interactively to set the correct fueling, otherwise for us carb owners you use it to set the right jetting...which isn't necessary on a std mill as Lotus has already done that for you.

To set the ignition advance curve it's a bit more laborious in that you select a rpm target and adjust the advance (on the computer) to achieve the most optimal AF ratio for the particular load on the engine....if its a WOT (wide open throttle) load then you aim as near to 12.8-13.2 as possible...if its part throttle cruise then you aim a bit higher for economy, say 13.8 to 14.5 or even a tad higher if you're tight with money.

Takes a while to do a full map this way but you only need to check key points and extrapolate.

After optimising the ignition map to the best achievable AF ratio for a given rpm/load you can then identify any less than optimal AF ratios that ignition mapping won't correct because then they will most likely be attributable to a faulty carb / induction set-up (ie air leaks, jet blockages, fine balance problems etc) and you can get stuck-in to that job next. ie the rule of thumb is to always optimise the ignition before tackling fueling on the carb/induction front ...and AF ratios allow you to do that without stabbing in the dark.

[fitz]

many thanks for that excellent explanation, it seems clearer to me now, the CAT would be purely for my conscious but as discussed with Andyc today, on further thought the amount of time the car is used, especially when the cat would be hot enough to be fully active, is not that great, and chances are the first thing a future owner would do would rip it out...

RE mapped ignition, i and my wallet have a lot to thing about! maybe in a couple of months i'll give it a go if i'm still having some hesitation issues + for the fun of it!

[JimmyC379]

One think I cant work out is how you mount the TPS to the Lotus twin carbs in the Megajolt or Canems. Does anyone know?

[fitz]

Jimmy, you can get a TPS for the DHLA carbs, it attaches to the throttle linkage to measure position

one of these

http://qedmotorsport.co.uk/qed-shop/vau ... dcoe-carbs



also seems they do a neat 36-1 pulley for a 'lotus twin cam' whether it is suitable for the 912 i'm not sure..

http://qedmotorsport.co.uk/qed-shop/lot ... y-36-teeth

[Lotus-e-Clan]

DHLA neeed a different bracket etc as above...I have this DHLA kit from EuroCarb not cheap though at 50 -60 quid.

[Lotus-e-Clan]

Update on the Canems mapped ignition fitted to my Clan. Wiring was quite simple to do...only a coil pack, crank sensor and TPS to connect up to the ECU. The main issue for the Excel would be finding a suitable crank pulley / trigger wheel.

Actually ran it today. It started first time!

Given that I was pretty pleased with my DIY comp 25D dizzy and just wanted to spoil myself with something new to play with, the difference with the Canems is well worth the effort and expense!

The engine is a competition specked 1040 with a Ben Boult BVHead, 11.5:1 comp ratio, GB72 (George Bevan) high lift, long duration, large overlap camshaft. Strengthened, lightened and balanced bottom end with a knife-edged crank. Twin DHLA 40s.

Instantly I've noticed with the Canems.....

1) The tick over is rock steady.
2) The engine sound is now turbine-smooth when revved.
3) My tech Edge AFR meter shows both a raw and damped/filtered lambda display. The raw value would normally bounce around and the damped value would follow it with a small delay. Now the raw and damped display coincide most of the time because the combustion is more consistent/stable with the Canems. Brilliant.
4) Zero load throttle repsonse is crisper.
5) So easy to remove hesitation from the supplied base map by dialing-in a bit more advance at the low speed / midrange load sites. amazing.

BTW, the Canems tacho output is successfully driving:
1) A 10k rpm Elliot tacho
2) the tech edge digital display
3) a sequential shift light display

I might even lash up the Canems shift light output too at some stage but maybe use it as a gear shift BUZZER via a relay as I already have sequential shift lights.

Meanwhile, I'll be spending the next few days or so out on the road developing the map...can't wait!

[Lotus-e-Clan]

WOW!

I can't afford to add Canems mapped ignition to the Excel as well as the Clan at the moment, but if ever I believe that the Excel dizzy is worn, or the electronic ignition plays-up, I'll be fitting Canems mapped ignition for sure.

It's brilliant! As expected, the gains are in low-mid range tractability rather than peak power over the dizzy and it effectively removes any suspicion or doubt about the effectiveness of DHLAs...the Clan was flying this afternoon once I'd tweaked the map adding a little more advance to yesterdays' conservative base map!

[fitz]

darn it peter! you're making me really want this even though finding and preventing a vacuum leak to the TIV has transformed my excel into running fabulously, there is still a vague stuttering on idle pickup at junctions, but once going it...well goes!...perhaps a treat for the summer!

[JimmyC379]

I have still done little to change my ignition setup but thought I would through another option in to the mix. 123 Ignitions are a digital distributor that do not require the electric ignition amplifier, they seem to have good results and are similar in price to the other option and a lot easier to fit. Here is there link: www.123ignition.nl/

Also here is a you tube example: www.youtube.com/watch?v=F1PFb46gKlc

Cheers,

Jimmy

[tonypoll]

I've recently had fitted a DTA S40 for ignition only, and kept the carbs. This kept the cost down and meant I did not have to worry about a new, high pressure fuel supply.
Plus mapping only the ignition, rather than fuel and ignition, is somewhat easier.
The difference to the original distributor ignition is amazing - just really good low down torque, eager to rev, steady idle. The previous mid-range hesitation has totally gone. I can now accelerate at any revs without wondering if the engine will bog down.
(I previously had the original distributor based system on a rolling road by someone who knew what he was doing, so the carbs and ignition were set up correctly).
I'd strongly suggested getting it mapped on a rolling road, as low revs and partial throttle can produce great gains when the advance is set correctly.
The idle jets were increased from 56 to 58, which removed a mild mid-range (2,500 - 3,500) hesitation.
The ECU also replaces the rev limiter and controls the fans (replacing the Otter switch), removing two other problematic areas of the Excel.
This was on an otherwise standard 1992 Excel SE.
The car really is SO much better in every day driving.
I wanted to find out if carbs and mapped ignition was a sensible choice, and I'm very happy with the result.
I used LotusBits to fit the system as they have a lot of experience with DTA, plus mounting the toothed crackshaft wheel and sensor requires a bit of engineering, and I wanted a professional installation. The ECU is the easy bit; getting reliable electrical connections and loom should result is a robust solution

[AndyLotus]

That sounds great! I'm planning to go down the megajolt route once I fixed the head gasket, rebuilt the suspension, respray.............the normal stuff.

[Lotus-e-Clan]

I've recently had fitted a DTA S40 for ignition only, and kept the carbs. This kept the cost down and meant I did not have to worry about a new, high pressure fuel supply.
Plus mapping only the ignition, rather than fuel and ignition, is somewhat easier.
The difference to the original distributor ignition is amazing - just really good low down torque, eager to rev, steady idle. The previous mid-range hesitation has totally gone. I can now accelerate at any revs without wondering if the engine will bog down.
(I previously had the original distributor based system on a rolling road by someone who knew what he was doing, so the carbs and ignition were set up correctly).
I'd strongly suggested getting it mapped on a rolling road, as low revs and partial throttle can produce great gains when the advance is set correctly.
The idle jets were increased from 56 to 58, which removed a mild mid-range (2,500 - 3,500) hesitation.
The ECU also replaces the rev limiter and controls the fans (replacing the Otter switch), removing two other problematic areas of the Excel.
This was on an otherwise standard 1992 Excel SE.
The car really is SO much better in every day driving.
I wanted to find out if carbs and mapped ignition was a sensible choice, and I'm very happy with the result.
I used LotusBits to fit the system as they have a lot of experience with DTA, plus mounting the toothed crackshaft wheel and sensor requires a bit of engineering, and I wanted a professional installation. The ECU is the easy bit; getting reliable electrical connections and loom should result is a robust solution

I found a similar improvement when I fitted the Canems ign only to my Clan that had twin 40 DHLAs. The only reason to go to full EFI is to get ECU adjustment for air temperature and barometric pressure ..that is the icing on the cake.

I did a track day in the Clan during the recent hot weather and I logged AFR, RPM and TPS. Power was woefully down in the hot weather, and my WOT AFRs were much lower (richer) than during extreme low winter temps on the same DHLA jets when AFRs were too lean...it's the air temperature difference that counts here.

Similarly, air pressure and elevation affects AFR and this in turn affects power. With EFI all is accounted for and adjusted on the Fly.

In the good old days when winters were once again winters and summers were summers, engine tuners developed the air intake to have winter and summer settings. Then during the eighties and nineties summers merged into winters and the intake adjustment trick to correct AFRs was forgotten about and abandoned and anyway, ECU / EFI eventually took over.

But for sure, having said all that, mapped ignition alone with DHLAs is definitely worthwhile.

And it's worthwhile managing air intake temperature too..hence the cold air box and thermostatic air intake valve developed by Lotus. K&N filter users take note...you are losing power with no air temperature management especially @ extreme ambient air temps.

And ambient air temperature is important when going for a rolling road rejet too..if you rejet in hot weather then you could run dangerously lean (and lose power) in winter...if you rejet in very cold weather then you will be too rich in summer, lose power and wast fuel!

[tonypoll]

Andy,

I initially got interested in mapped ignition from a Jensen Healey (which uses an earlier version of the Lotus 907 engine) forum, where someone had fitted an ignition only ECU and spoke very highly of the results.
MegaJolt was the first system I looked at extensively. I liked a lot of what I saw and read on the Megajolt and MegaSquirt forums.
However, my Excel was at LotusBits for some suspension work and I got talking with Mike Taylor. (Mike has extensive experience of car electronics from his previous life).
He had some interesting views on the MegaJolt system, which (if I remember correctly) he said had fine digital electronics and software, but the robustness of the electrical wiring in a hostile engine environment, especially the interfaces to the ECU, were below what he'd expect in a professional system.
That's not to say there are many successful MegaJolt installations, as witnessed on their forum.
Mike knows the DTA system very well, having installed it on a number of Excels, which bode well for an installation where any 'learning' issues have been resolved previously. Plus DTA could provide a professional loom, robust sensor, connectors and coil, all of which are know to work together without problems.
If you want a toothed wheel and crank sensor mount LotusBits may be able to provide.
For me DTA was priced competitively, and I knew Mike would be able to install it and configure the software.
There are many others ECUs: Emerald, OMEX etc. A case of choose your poison .

My mapping was done in August - so I've yet to see what cold weather will be like.