XDi Ignition kits
05-12-2005, 01:10 AM
#1
Race Car
Thread Starter
XDi Ignition kits
Guys,
Any of you'll using this ignition from Clewett Engineering? Any good? Easy to fix? Which size pulley for my car?
XDi Ignition Kits
Replace your worn out distributor with an Electromotive XDi crank-fired, high-energy, high-resolution ignition and our adapter kit for Porsche. Kit includes: XDi ignition, wire harness, crank sensor, crank trigger adapter (pulley, trigger wheel, sensor mount, distributor hole plug), and instructions. Replace your worn out distributor with an Electromotive XDi crank-fired, high-energy, high-resolution ignition and our adapter kit for Porsche.
Kit includes:
XDi ignition
wire harness
crank sensor
crank trigger adapter (pulley, trigger wheel, sensor mount, distributor hole plug)
instructions
XDi Single Plug Ignition Kits Item # Racer Net
911 Kit with 116mm pulley # 9005-116 $1,169.00
911 Kit with 127mm pulley # 9005-127 $1,169.00
911 Kit with 131mm pulley # 9005-131 $1,169.00
Any of you'll using this ignition from Clewett Engineering? Any good? Easy to fix? Which size pulley for my car?
XDi Ignition Kits
Replace your worn out distributor with an Electromotive XDi crank-fired, high-energy, high-resolution ignition and our adapter kit for Porsche. Kit includes: XDi ignition, wire harness, crank sensor, crank trigger adapter (pulley, trigger wheel, sensor mount, distributor hole plug), and instructions. Replace your worn out distributor with an Electromotive XDi crank-fired, high-energy, high-resolution ignition and our adapter kit for Porsche.
Kit includes:
XDi ignition
wire harness
crank sensor
crank trigger adapter (pulley, trigger wheel, sensor mount, distributor hole plug)
instructions
XDi Single Plug Ignition Kits Item # Racer Net
911 Kit with 116mm pulley # 9005-116 $1,169.00
911 Kit with 127mm pulley # 9005-127 $1,169.00
911 Kit with 131mm pulley # 9005-131 $1,169.00
05-12-2005, 09:11 AM
#2
Nordschleife Master
Sameer,
These are just an evolution of the crank fired ignition Electromotive has been producing for many years. It is an inductive style ignition using coils from a mid 80s GM 6 cylinder engine (Chevy Celebrity for instance). If you go with EFI later, you'll end up replacing this system, unless you go with Electromotive TEC III which uses the crank fire coils and triggering mechanism.
These are just an evolution of the crank fired ignition Electromotive has been producing for many years. It is an inductive style ignition using coils from a mid 80s GM 6 cylinder engine (Chevy Celebrity for instance). If you go with EFI later, you'll end up replacing this system, unless you go with Electromotive TEC III which uses the crank fire coils and triggering mechanism.
05-12-2005, 10:10 AM
#4
Nordschleife Master
They would be an improvement over stock, but only because they have a fully mappable ignition table similar to what is found in and EFI system. However, these are still inductive ingitions, and poor ones at that so you'll end up being able to run only about .020"-.025" plug gap at 1 bar of boost. A CDI system will allow for .045"-.060" and will create a larger flame kernel.
You will need access to a dyno to properly map the ignition timing for maximum torque. Anything else is just a guess.
You will need access to a dyno to properly map the ignition timing for maximum torque. Anything else is just a guess.
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11-11-2005, 01:56 PM
#8
Cruisin'
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Geoffery,
You are correct about the XDi being part of Electromotive’s ignition evolution. Visit the Electromotive web site, this information is there. You are implying that 35 year old distributor and CD box technology is better than the new state of the art ignition systems. First of all do you see a distributor and CD box on new cars? They are all crank fired ignition with high resolution crank triggers. Porsche has been using high resolution crank triggers since 1989. High resolution crank triggers provide timing accuracy +/-.1 degrees (+/- 1/10ths of a degree). This is far more accurate than any distributor triggered system its best day. With a CD box , as engine RPM goes up, the coil charge time goes down. As charge time goes down, by about 3000 the spark starts getting weaker. Multiple coils on a 6 cylinder engine have 3 times as much charge time to the coils. This provides full spark energy to the coils to about 9000 RPM before any loss begins to occur. The typical spark duration from a CD box is about .2 milliseconds (2/10ths). The Electromotive systems spark duration is 2 milliseconds. That is 10 times as long, and can last over 90 degrees of crank rotation. The other advantages are that the advance curve is adjustable and a MAP controlled boost retard for turbos. There is also an upgrade path to Engine management. The coils may look like Chevrolet components but the system and components certainly are not.
You are correct about the XDi being part of Electromotive’s ignition evolution. Visit the Electromotive web site, this information is there. You are implying that 35 year old distributor and CD box technology is better than the new state of the art ignition systems. First of all do you see a distributor and CD box on new cars? They are all crank fired ignition with high resolution crank triggers. Porsche has been using high resolution crank triggers since 1989. High resolution crank triggers provide timing accuracy +/-.1 degrees (+/- 1/10ths of a degree). This is far more accurate than any distributor triggered system its best day. With a CD box , as engine RPM goes up, the coil charge time goes down. As charge time goes down, by about 3000 the spark starts getting weaker. Multiple coils on a 6 cylinder engine have 3 times as much charge time to the coils. This provides full spark energy to the coils to about 9000 RPM before any loss begins to occur. The typical spark duration from a CD box is about .2 milliseconds (2/10ths). The Electromotive systems spark duration is 2 milliseconds. That is 10 times as long, and can last over 90 degrees of crank rotation. The other advantages are that the advance curve is adjustable and a MAP controlled boost retard for turbos. There is also an upgrade path to Engine management. The coils may look like Chevrolet components but the system and components certainly are not.
11-11-2005, 03:02 PM
#9
Geoffrey,
He's just staing the "Party Line" here. I am not sure, so I will give him the benefit of my doubt, but he has stated some wrong statements.
For a bolt on system that gives adjustability, the Electromotive systems will provide. Unfortuntely, the accuracy is not so good. They do use a 58 tooth wheel, but the timing still shifts, making one to believe that many of those teeth are discarded in the software. This is common with multiple tooth wheels.
There are advantages in running Inductive over CDI, and each application should be choosen. The problem is that they give you no choice in Coil or Ingiter size. The Amp rating of their stuff is low and the Coils are pretty much as you say. If they offered a higher Amp rating for the Ingiter and a better coil, the stuff would be much better. I figure they never fully charge the Coils.
I was under the impression that with CDI there was no charge time or dwell. Dwell is only for Inductive systems as there is no way to store the energy. With CDI, once the Coil is charged the capacitor stores all ofthe extra energy.
I may be wrong here, but I'm interested in heraing your side.
To answer the first question, there are better option available.
He's just staing the "Party Line" here. I am not sure, so I will give him the benefit of my doubt, but he has stated some wrong statements.
For a bolt on system that gives adjustability, the Electromotive systems will provide. Unfortuntely, the accuracy is not so good. They do use a 58 tooth wheel, but the timing still shifts, making one to believe that many of those teeth are discarded in the software. This is common with multiple tooth wheels.
There are advantages in running Inductive over CDI, and each application should be choosen. The problem is that they give you no choice in Coil or Ingiter size. The Amp rating of their stuff is low and the Coils are pretty much as you say. If they offered a higher Amp rating for the Ingiter and a better coil, the stuff would be much better. I figure they never fully charge the Coils.
I was under the impression that with CDI there was no charge time or dwell. Dwell is only for Inductive systems as there is no way to store the energy. With CDI, once the Coil is charged the capacitor stores all ofthe extra energy.
I may be wrong here, but I'm interested in heraing your side.
To answer the first question, there are better option available.
11-11-2005, 03:30 PM
#10
Nordschleife Master
Hi Richard, welcome.
I'm actually not talking about 35 year old distributor sytems with vacuum advance and non crank triggered CDI systems. I'm talking about a fully digital CDI box and a modern distributor paired with a high quality ECU such as MoTeC. The purpose of the spark is to ignite the air/fuel mixture, nothing less, nothing more, and the degree to which an ignition system is able to effectively do that job is what determines its effect on performance. In a modern CDI setup with aftermarket ECU such as MoTeC, it will use whatever trigger system the ECU uses, in my case with the Porsche, it would be the factory 60-2, just like the Electromotive system's trigger requirements. With a CDI ignition system, the capacitor stores the energy, not the coil, so your description of coil charge time really applies to the inductive style igniton found in the Electromotive setup, not with the CDI since there is no coil dwell. In a CDI system, the coil's sole purpose is to step up the voltate. For the Electromotive system, the coils not only step up the voltage, but they also store it and require somewhere between 3.0 and 3.3ms of coil charge time as I've measured them with an oscilloscope. With the engine speeds we are talking about here, even 3.3ms is certainly within the range of time available when fired in wasted spark or CPP. In a distributor environment it would begin to have problems fully charging the coil above 6000rpm, however, since the capacitor in the CDI box charges in nanoseconds, capacitor charge time will not be a problem. Spark will not become weaker at the engine speeds we are working with.
A CDI system like we are talking about will provide a much hotter spark (albiet shorter) with more energy than an inductive ignition, somewhere on the order of 100mj compared to 63mj. This allows for a significantly larger flame kernl which is what we are after. The fact that an Electromotive ignition system is still lighting the spark plug "90 degrees ATDC" is not a benefit. After the flame kernl has been lit, the spark plug is no longer needed, and at 90 degrees ATDC, even the combustion process cannot keep up with the acceleration rate of the piston and maintian or increase the cylinder pressure. The larger the flame kernl, the faster the combusition process, and the less timing one can run and still acheive peak cylinder pressure 12-14 degrees ATDC. Why would you want LESS timing? Because the less timing, the less pressure against the piston on the way up, the more power the engine makes. I have seen gains from switching to a digital CDI system where we can increase the plug gap, reduce the timing, and make more power. On the order of 5-7% in some applications.
I'm actually not talking about 35 year old distributor sytems with vacuum advance and non crank triggered CDI systems. I'm talking about a fully digital CDI box and a modern distributor paired with a high quality ECU such as MoTeC. The purpose of the spark is to ignite the air/fuel mixture, nothing less, nothing more, and the degree to which an ignition system is able to effectively do that job is what determines its effect on performance. In a modern CDI setup with aftermarket ECU such as MoTeC, it will use whatever trigger system the ECU uses, in my case with the Porsche, it would be the factory 60-2, just like the Electromotive system's trigger requirements. With a CDI ignition system, the capacitor stores the energy, not the coil, so your description of coil charge time really applies to the inductive style igniton found in the Electromotive setup, not with the CDI since there is no coil dwell. In a CDI system, the coil's sole purpose is to step up the voltate. For the Electromotive system, the coils not only step up the voltage, but they also store it and require somewhere between 3.0 and 3.3ms of coil charge time as I've measured them with an oscilloscope. With the engine speeds we are talking about here, even 3.3ms is certainly within the range of time available when fired in wasted spark or CPP. In a distributor environment it would begin to have problems fully charging the coil above 6000rpm, however, since the capacitor in the CDI box charges in nanoseconds, capacitor charge time will not be a problem. Spark will not become weaker at the engine speeds we are working with.
A CDI system like we are talking about will provide a much hotter spark (albiet shorter) with more energy than an inductive ignition, somewhere on the order of 100mj compared to 63mj. This allows for a significantly larger flame kernl which is what we are after. The fact that an Electromotive ignition system is still lighting the spark plug "90 degrees ATDC" is not a benefit. After the flame kernl has been lit, the spark plug is no longer needed, and at 90 degrees ATDC, even the combustion process cannot keep up with the acceleration rate of the piston and maintian or increase the cylinder pressure. The larger the flame kernl, the faster the combusition process, and the less timing one can run and still acheive peak cylinder pressure 12-14 degrees ATDC. Why would you want LESS timing? Because the less timing, the less pressure against the piston on the way up, the more power the engine makes. I have seen gains from switching to a digital CDI system where we can increase the plug gap, reduce the timing, and make more power. On the order of 5-7% in some applications.
11-11-2005, 05:41 PM
#11
Burning Brakes
Thats very informative.I was looking at the XDi but as im going to goto EFi very soon I thought of getting my ECU to control the spark instead. I am now looking into replacing my stock broken ignition with EDIS and megasquirt to control it. What do you think of this Georffrey?, will it do me for the time being at least?- its very cost effective.... however it uses a 36-1 tooth wheel and I think you can only change by 1 degree, will this be enough? Also im interested in your Motec setup, what is the CDI you use and how do you get it to use the 60-2 wheel?
11-11-2005, 07:13 PM
#13
Nordschleife Master
Simon,
I guess you really need to define what "lean" is. I really haven't had an issue with CDI firing anything I've thrown at it. At cruise for instance, 15.5:1 is no problem, however, under full load on say a N/A engine, I'm backing out of it by the time it leans out to 13.8:1 so as not to cause heat related damage. So, in that respect, I've never probed the limit of CDI for fear of melting a piston. With inductive, I also don't have lean issues, however, as the engine gets richer, down towards 11.2:1, I find it begins to misfire where a CDI (good digital one) keeps ticking. Again, I have not probed the outer limits, so I'm not an expert on under what conditions would it misfire beyond what I'd consider to be normal. Another thing to keep in mind is that I consistently see the wasted spark coil packs wired so the coil fires both plug in one cylinder rather than true wasted spark as designed. Under these conditions, I see the ignition system misfiring as rich as 11.8:1. I'm not sure why OEMs use inductive ignition systems, but my guess has been one of cost, but again, I really don't know.
Miles,
The ignition systems I'm speaking of work in conjunction with an ECU that has ignition control. If I were to recommend a stand alone ignition system, the XDi would be on the top of my list due to convienence and lack of much else in the market. The triggering for an ECU is going to depend on what your ECU supports. For instance, Electromotive supports only 60-2 with the missing tooth 11 teeth after TDC, anything else or any other placement and it does not work properly. Autronic really likes a single tooth per cylinder, although it will do 60-2 with a chip change, but then it throws out some of the teeth. MoTeC for instance doesn't care, it will trigger anything, and if it doesn't, they will write it for you. In my case, I use the MoTeC ECUs and use either a MoTeC or other high quality digital ignition system with it and there are no issues.
I guess you really need to define what "lean" is. I really haven't had an issue with CDI firing anything I've thrown at it. At cruise for instance, 15.5:1 is no problem, however, under full load on say a N/A engine, I'm backing out of it by the time it leans out to 13.8:1 so as not to cause heat related damage. So, in that respect, I've never probed the limit of CDI for fear of melting a piston. With inductive, I also don't have lean issues, however, as the engine gets richer, down towards 11.2:1, I find it begins to misfire where a CDI (good digital one) keeps ticking. Again, I have not probed the outer limits, so I'm not an expert on under what conditions would it misfire beyond what I'd consider to be normal. Another thing to keep in mind is that I consistently see the wasted spark coil packs wired so the coil fires both plug in one cylinder rather than true wasted spark as designed. Under these conditions, I see the ignition system misfiring as rich as 11.8:1. I'm not sure why OEMs use inductive ignition systems, but my guess has been one of cost, but again, I really don't know.
Miles,
The ignition systems I'm speaking of work in conjunction with an ECU that has ignition control. If I were to recommend a stand alone ignition system, the XDi would be on the top of my list due to convienence and lack of much else in the market. The triggering for an ECU is going to depend on what your ECU supports. For instance, Electromotive supports only 60-2 with the missing tooth 11 teeth after TDC, anything else or any other placement and it does not work properly. Autronic really likes a single tooth per cylinder, although it will do 60-2 with a chip change, but then it throws out some of the teeth. MoTeC for instance doesn't care, it will trigger anything, and if it doesn't, they will write it for you. In my case, I use the MoTeC ECUs and use either a MoTeC or other high quality digital ignition system with it and there are no issues.
11-11-2005, 11:37 PM
#14
Burning Brakes
Join Date: May 2005
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Originally Posted by m42racer
Geoffrey,
He's just staing the "Party Line" here. I am not sure, so I will give him the benefit of my doubt, but he has stated some wrong statements.
[snip]
To answer the first question, there are better option available.
He's just staing the "Party Line" here. I am not sure, so I will give him the benefit of my doubt, but he has stated some wrong statements.
[snip]
To answer the first question, there are better option available.
And, what are the better options??
For the price, performance and simplicity, you can not beat the XDI. I also understand and agree with what Geoffrey is saying with CDI vs inductive, but for most of us the XDI will be completely adequate. I use the electromotive stuff and produce right at 500rwhp, so spending double or triple the money to get 5 - 7% more HP doesn't make much sense for mostly street use.
Sameer - the XDI is a hell of a step up from the stock system you have, since you can completely map the ignition. You will gain drivability as well as tune for torque as Geoffrey points out. Its not difficult to install and it won't break the bank either. Buying anything from Clewett is a plus too.
11-12-2005, 02:31 PM
#15
DonE,
I was trying to take the high road here, for a change and give him the benefit of my doubt.
His explanation of how the charge time goes down etc is quite wrong. The charge time goes down whatever type of Ignition you run. I have spoken to the Electromotive people at SEMA and at PRI and this is their standard answer. I guess its passed along to their dealers. It has every appearance that some of the dealers do not understand the electrical theories of either system. Maybe this is the case here, but I did not want to imply that, so I have given him the benefit of the doubt. I stated that this system is a good choice for many. For those wanting a bolt on system that give some adjustability, its a good choice.
I do come from a position of experience here. I have seen first hand the difference a good system can make. Forget about the HP you state, they mean little here. The throttle response is huge. I am not an expert in Ignition, thats for sure, but I have had it explained and shown to me by experts and have felt the difference by my "BUTT DYNO". The difference was huge.
You need to make up your own mind about what is correct here. That should be based upon facts not a sales pitch.
The Coils and Igniter unit included in these systems are very low grade. Take a look at the Inductive formula, and insert a larger AMP rating for the Igniter. Now see if the energy available is higher. These are simple systems all following a simple electrical theory. Most Inductive Igniters are current limiting at around 7AMPS. Increase this and you will have more Ignition energy. Measure the Electromotive and see what that is. Test them for yourself and see. Also test the Coil to see what the charge time should be. You will see that these Coils are never fully charged. With Inductive ignition you cannot over dwell the Coil and must start the charge time exactly at the point where the Coil will be fully charged when the Ignition is fired. You cannot store this energy. That is why the CDI system has no dwell in its system. The excess energy can be stored. So if the Inductive system is not controlled correctly, the Coils can be overcharged or undercharged. An undercharged Coil will show up in poor performance. For the same engine you could see a huge jump in performance. Now, with a fully charged decent coil, the Ignition point could be changed, typically with less advance, and a different Spark Plug end used where the spark can be projected out into the Chamber further if permitted, all providing way more performance.
As for the accuracy, this is an area all Ignition systems have a certain amount of issues with. The amount of trigger points definitely plays a big part here. From what I have been shown, many of these high trigger systems still have issues. That seems to imply that the software uses only some of them and discards the rest. The other issue here that is often overlooked is the use of reluctor sensors. If the software cannot compensate for the sensor shift, then the timing curve is based upon this factor as well.
If you doubt what I am saying, take a look at all of this with a scope. That will show you exactly what I am saying. The Electromotive system is a great choice for those who want a simple bolt on system, but to say its better than some CDI systems with a Distributor is a stretch. That would depend upon the accuracy of the Distributor. Some are really poor and some are good. I will go out on a limb here and say that a Porsche Flat six engine with CDI and a Distributor with adjustable timing will out perform any Inductive system, all things been equal.
I am not an expert here, just a convert to good Ignition.
I was trying to take the high road here, for a change and give him the benefit of my doubt.
His explanation of how the charge time goes down etc is quite wrong. The charge time goes down whatever type of Ignition you run. I have spoken to the Electromotive people at SEMA and at PRI and this is their standard answer. I guess its passed along to their dealers. It has every appearance that some of the dealers do not understand the electrical theories of either system. Maybe this is the case here, but I did not want to imply that, so I have given him the benefit of the doubt. I stated that this system is a good choice for many. For those wanting a bolt on system that give some adjustability, its a good choice.
I do come from a position of experience here. I have seen first hand the difference a good system can make. Forget about the HP you state, they mean little here. The throttle response is huge. I am not an expert in Ignition, thats for sure, but I have had it explained and shown to me by experts and have felt the difference by my "BUTT DYNO". The difference was huge.
You need to make up your own mind about what is correct here. That should be based upon facts not a sales pitch.
The Coils and Igniter unit included in these systems are very low grade. Take a look at the Inductive formula, and insert a larger AMP rating for the Igniter. Now see if the energy available is higher. These are simple systems all following a simple electrical theory. Most Inductive Igniters are current limiting at around 7AMPS. Increase this and you will have more Ignition energy. Measure the Electromotive and see what that is. Test them for yourself and see. Also test the Coil to see what the charge time should be. You will see that these Coils are never fully charged. With Inductive ignition you cannot over dwell the Coil and must start the charge time exactly at the point where the Coil will be fully charged when the Ignition is fired. You cannot store this energy. That is why the CDI system has no dwell in its system. The excess energy can be stored. So if the Inductive system is not controlled correctly, the Coils can be overcharged or undercharged. An undercharged Coil will show up in poor performance. For the same engine you could see a huge jump in performance. Now, with a fully charged decent coil, the Ignition point could be changed, typically with less advance, and a different Spark Plug end used where the spark can be projected out into the Chamber further if permitted, all providing way more performance.
As for the accuracy, this is an area all Ignition systems have a certain amount of issues with. The amount of trigger points definitely plays a big part here. From what I have been shown, many of these high trigger systems still have issues. That seems to imply that the software uses only some of them and discards the rest. The other issue here that is often overlooked is the use of reluctor sensors. If the software cannot compensate for the sensor shift, then the timing curve is based upon this factor as well.
If you doubt what I am saying, take a look at all of this with a scope. That will show you exactly what I am saying. The Electromotive system is a great choice for those who want a simple bolt on system, but to say its better than some CDI systems with a Distributor is a stretch. That would depend upon the accuracy of the Distributor. Some are really poor and some are good. I will go out on a limb here and say that a Porsche Flat six engine with CDI and a Distributor with adjustable timing will out perform any Inductive system, all things been equal.
I am not an expert here, just a convert to good Ignition.