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fliprio

Benifits Of Ignition Only Ecus Over Distributor Set-up

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fliprio

I am currently looking at some different map-able 3d ignition ecu’s to try and improve the dizzy set-up on my GTI-6 engine running on twin carbs.

I’m trying to weigh up the pros of a map-able ecu vs getting my dizzy curve modified, will the map-able ignition give better power output or is the main aim to improve driveability?

 

I have found one that accepts the 60-2 speed sensor, after seeing that megajolt only takes the 36-1. It also seems to remove the need for the ford edis unit used on the megajolt, although its a bit more expensive at £250.

 

http://www.canems.co.uk/pdf/ignition_manual.pdf

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Sandy

To be any real use, you need to know that it can be set up well by someone that knows what they are doing; therefore predominantly the most popular systems, DTA, OMEX, MBE etc. 3D brings the main benefits of part throttle mapping. When you set up a distributor, you're usually trying to achieve the impossible, especially on tuned engines, of a non linear, non-progressive ignition curve. Otherwise you have to often balance the risk of det lower down against the best power higher up. Good systems like also offer lots of useful features, such as rev limiter, shift light, fuel pump control etc.

 

Looking at the software in that link, it would appear to be a megajolt/megasquirt based system. Bear in mind that you are likely to be paying close to the price of a properly developed, tested and supported branded system (that will retain much of its new cost), for a system intended for DIY that has been built for profit instead. A secondhand brand system is likely to cost about the same, be better supported, have a better choice of people to set it up and generally cause less agro between buying and enjoying. I say this as clearly as I can, because my experiences of the professional branded systems is alot more positive and invariably what people who buy these MJ/MS based boxes save on the initial cost, they quickly end up outlaying on more setting up labour and lose again if they try to sell it later.

 

It's difficult to fully appreciate the broader pros and cons unless you work with engine management on a daily basis as I do.

Edited by Sandy

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pip470

Trying to get the dizzy to match the advance curve you want is a lot of trial and error. Also if you make any further modifications the dizzy could then be useless.

With the ignition only ecu you can adjust many many times accurately and easily. You can set the rev limit easily soft and hard. And if you get a tps you can have 3d ignition maps which will be great for part throttle driving with regards fuel economy and it will be much more drivable. Peak power shouldn't really change unless the advance curve of the dizzy was a compromise to start with.

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fliprio
To be any real use, you need to know that it can be set up well by someone that knows what they are doing; therefore predominantly the most popular systems, DTA, OMEX, MBE etc. 3D brings the main benefits of part throttle mapping. When you set up a distributor, you're usually trying to achieve the impossible, especially on tuned engines, of a non linear, non-progressive ignition curve. Otherwise you have to often balance the risk of det lower down against the best power higher up. Good systems like also offer lots of useful features, such as rev limiter, shift light, fuel pump control etc.

 

Looking at the software in that link, it would appear to be a megajolt/megasquirt based system. Bear in mind that you are likely to be paying close to the price of a properly developed, tested and supported branded system (that will retain much of its new cost), for a system intended for DIY that has been built for profit instead. A secondhand brand system is likely to cost about the same, be better supported, have a better choice of people to set it up and generally cause less agro between buying and enjoying. I say this as clearly as I can, because my experiences of the professional branded systems is alot more positive and invariably what people who buy these MJ/MS based boxes save on the initial cost, they quickly end up outlaying on more setting up labour and lose again if they try to sell it later.

 

It's difficult to fully appreciate the broader pros and cons unless you work with engine management on a daily basis as I do.

 

I know what you mean, I have looked around at the cost of some of them and if buying the main brand names new, its out of my budget. At the moment, I have a compromise between top end power and det lower down, the preveous owner had it even more advanced than it is now which seem to give it a few more BHP on the top end, but lots of det when under load below 3k, it now has a bit of det between 2 and 3k. Maybe its best I phone around a couple of the local recoemneded rolling roads and ask them if they have had experience of mapping megajolt, the reason I was looking at the one in the link was because its been used by some of the mini crowd (I have a classic tuned mini as well) and seemed to have a few good features like rev limiters, shift lights and the 60-2 trigger wheel facility so it meant I didnt have to rig up another 36-1 wheel off the crank pully.

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fliprio
Trying to get the dizzy to match the advance curve you want is a lot of trial and error. Also if you make any further modifications the dizzy could then be useless.

With the ignition only ecu you can adjust many many times accurately and easily. You can set the rev limit easily soft and hard. And if you get a tps you can have 3d ignition maps which will be great for part throttle driving with regards fuel economy and it will be much more drivable. Peak power shouldn't really change unless the advance curve of the dizzy was a compromise to start with.

 

I think the dizzy curve isnt exactly that well matched to the engine, being off the 1.9 gti I beleive. I was planning to get a TPS, seems fairly easy to get hold of for the Dorlettos

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locosaki

I went through the same thing a few months and settled with an H&H recurved dizzy.

 

I've also got carbs,I set the car myself with some help from knowledgeable on here and the use of a timing light and AFR gauge.

 

The car drives spot on,No hesitations or stuttering when you floor it from low down revs.

 

The car also made 140ish (142 I think) BHP at the wheels on the rollers.

 

This is on an 1900 MI I rebuilt myself.

 

I wasn't prepared to through money at the car just for the hell of it and I'm quite happy with the results.

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fliprio
To be any real use, you need to know that it can be set up well by someone that knows what they are doing; therefore predominantly the most popular systems, DTA, OMEX, MBE etc. 3D brings the main benefits of part throttle mapping. When you set up a distributor, you're usually trying to achieve the impossible, especially on tuned engines, of a non linear, non-progressive ignition curve. Otherwise you have to often balance the risk of det lower down against the best power higher up. Good systems like also offer lots of useful features, such as rev limiter, shift light, fuel pump control etc.

 

Looking at the software in that link, it would appear to be a megajolt/megasquirt based system. Bear in mind that you are likely to be paying close to the price of a properly developed, tested and supported branded system (that will retain much of its new cost), for a system intended for DIY that has been built for profit instead. A secondhand brand system is likely to cost about the same, be better supported, have a better choice of people to set it up and generally cause less agro between buying and enjoying. I say this as clearly as I can, because my experiences of the professional branded systems is alot more positive and invariably what people who buy these MJ/MS based boxes save on the initial cost, they quickly end up outlaying on more setting up labour and lose again if they try to sell it later.

 

It's difficult to fully appreciate the broader pros and cons unless you work with engine management on a daily basis as I do.

 

I might be able to get hold of a weber Alpha PI030 unit fairly cheaply, but people seem to be a bit negative on them because its dealer only software to map them

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sideways danny

Sandy, the Canems software is completely different to anything MS/MJ, although the tables have a visual similarity

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fliprio

Spoke to the guy at Mikeanics today who I usually get to do my Rolling road work and he had mapped a few of these Canems ignition ECUs and a few megajolts, he said they can be a bit more tricky to use, sometimes with comms dropping in and out, but thought it was an ok bit of kit.

 

advised me to steer clear of the re-curved dizzy, said you can get quite varied results and will still be a compromise

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shalmaneser

I'm no expert but at the end of the day a recurved dizzy is very old tech. May as well take the hit and do it properly to maximise your gains.

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Sandy

I'd avoid Weber Alpha.

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sideways danny
I'd avoid Weber Alpha.

 

 

i would too. Even places that have been dealers for years so have the software are dropping it now. Extremely out dated

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fliprio
Trying to get the dizzy to match the advance curve you want is a lot of trial and error. Also if you make any further modifications the dizzy could then be useless.

With the ignition only ecu you can adjust many many times accurately and easily. You can set the rev limit easily soft and hard. And if you get a tps you can have 3d ignition maps which will be great for part throttle driving with regards fuel economy and it will be much more drivable. Peak power shouldn't really change unless the advance curve of the dizzy was a compromise to start with.

 

sorry to bring this one back up again, if the dizzy curve is compromised, which most people seem to agree that it is, will the mapped ignition add much power, or just a few HP? The reason that I ask is that its running about standard power (169 BHP) on the carbs, and it would be much cheaper to just stick the standard induction and management on and sell the carbs.

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edbar

I have weber alpha, set up at aldons and it works for me. Added alot more flexability over the dizzy and we managed to smooth out the lower- mid range on the dyno session. My complete system only cost £150 second hand so bang for buck its done me proud.

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DrSarty
sorry to bring this one back up again, if the dizzy curve is compromised, which most people seem to agree that it is, will the mapped ignition add much power, or just a few HP? The reason that I ask is that its running about standard power (169 BHP) on the carbs, and it would be much cheaper to just stick the standard induction and management on and sell the carbs.

 

With respect, I think you're becoming too bogged down in peak figures. It's really not that important, in fact it's very much 'pub talk'.

 

What you really want/should aim for IMO, is a safe, reliable engine which delivers tractable power across the rev range.

 

Aim to be avoiding det (obviously), and also dips in the torque curve to make a much smoother engine which will last longer and give you more access to real world power in any gear.

 

I believe most people would sacrifice 5 or 10bhp peak for a higher average across the rev range. Driveability is key. :lol:

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fliprio
With respect, I think you're becoming too bogged down in peak figures. It's really not that important, in fact it's very much 'pub talk'.

 

What you really want/should aim for IMO, is a safe, reliable engine which delivers tractable power across the rev range.

 

Aim to be avoiding det (obviously), and also dips in the torque curve to make a much smoother engine which will last longer and give you more access to real world power in any gear.

 

I believe most people would sacrifice 5 or 10bhp peak for a higher average across the rev range. Driveability is key. ;)

 

thats what I was kind of trying to establish, I have two ways of making it more reliable/safe and improve diveability,which is my main aim. One would cost a fair bit (mapped ECU) and the other (standard injection) would cost virtualy nothing as I could sell the carbs, but what I didnt know is what kind of improvements the mapped ignition ECU would make, if its only 5 to 10 BHP, its a no brainer to go with the standard injection, but if someone said I could easily get 185 BHP and improve mid-range power, then it might be worth the extra cash.

 

Its main use is trackdays, but as you say, nice to have it running safely and staying in tune for a while

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DrSarty
I didnt know is what kind of improvements the mapped ignition ECU would make, if its only 5 to 10 BHP, its a no brainer

 

But that's what I'm (and perhaps others) saying.

 

The mappable ECU for ignition at least will deliver a better drive than the dizzy combination, returning the things I said. Even if it doesn't produce any more peak BHP, it'll be worth it, as that's what it does.

 

If you get 5 or 10BHP extra than perhaps that's just a bonus.

 

I'm saying it's not about doing it for peak power; it's about getting a better overall drive and power delivery due to it's accuracy and flexibility.

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fast_eddie

I reckon I must be the luckiest man ever to have transplanted an mi. I bolted a set of 45's on, I welded up a down pipe to fit the octopus into a 309 shell/tunnel with a magnex backbox, added a longman dizzy adapter, made my own set of ignition leads using mole grips and pliers and hey presto no issues with power, driveablity or pinking or fuel consumption.

Ok this was 17 years ago but what has changed?

 

There are SO many threads about this, I love a driveable car, I love to slide around in varying degrees of oversteer, I like to heal and toe, I manage sustained down changes, ALL on a Halfords dizzy cap, rotor arm and an 8v ecu with no mods whatsoever.

 

I even took maximum power at a RR shootout back in the day on the exact same set up...

 

Ok it is not or ever will be optimum but come on, it works, does not cause ANY reliability issues and costs NOTHING comparatively

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DrSarty

No-one's forcing him to buy anything; he asked the question.

 

I admire your post, ingenuity and gusto, but you must concede that fully mappable ignition timing (and fuelling too) simply has to be 'better' than mechnical methods.

 

By better I mean it can be tailored to suit the engine, fuel types and ignition. There are less moving parts to break and suits upgrades with minimal effort.

 

It's entirely up to the OP what he does, but he did ask and he's receiving advice. No-one is saying your method or any other method doesn't work, just that one is the modern progression, is available for a reason and has distinct advantages.

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fast_eddie

Yup agreed ;)

As ever, if I had had the money to make a different choice, it would have had a set of TB's and mappable ECU and that still stands true today

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fliprio
No-one's forcing him to buy anything; he asked the question.

 

I admire your post, ingenuity and gusto, but you must concede that fully mappable ignition timing (and fuelling too) simply has to be 'better' than mechnical methods.

 

By better I mean it can be tailored to suit the engine, fuel types and ignition. There are less moving parts to break and suits upgrades with minimal effort.

 

It's entirely up to the OP what he does, but he did ask and he's receiving advice. No-one is saying your method or any other method doesn't work, just that one is the modern progression, is available for a reason and has distinct advantages.

 

Cheers guys, thanks for all the advice, i dont doubt that on some set-ups people manage to get the dizzy working very well, but on my engine it just doesnt seem to suite it.

 

i think the answers have made me conclude that as its a standard engine, i am better off time/cost wise bolting on the orginal 306 gti-6 injection/ignition to get what i am after, and i can sell the carbs to offset most of the cost.

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Matt Holley

The best bit of advice I could give you is that if you do decide to go mapped ignition buy a full ignition and injection ecu, you won't lose much money in the long run if you do sell it and you may decide to go down the T/B route later on and you will already be half way there.

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