Hey are you two going to hijack my thread with all this mutual admiration? Haha!

Todd,

Promise not to hijack your thread. Like to think of it as mutual respect.

Which car we talking about here the track dog or the stocker. What mods does it already have. How is the car going to be used. What are you looking for.

Cole

Haha just giving you guys schitt
Tracdog It has 964 cams 27-7200 turbo 1 bar spring(,8 now) dwur MSD 6a
going to get a new intercooler,
using it sir Tracy days but keeping it street legal

Update just ordered the msd unit
Kieth are you gonna help me set up the ideal map for this baby??

Todd,

Hope you will like the new MSD unit. Couple things that might give you a heads up on.

You'll need to get a MAP sensor if you don't have one. I have PN# for MAPs and connectors if you need them.

Having a MSD 6A now will make the install a piece of cake. You might consider
leaving the distributor as is until you get things hooked up and functioning. Just set the defaults for the timing map and the retard map to "0" and it should run just like a stock 6AL. Then if you get your MAP sensor installed you can play with setting a boost map. I only suggest this because having a working boost map will help in determining your timing curve. Timing curves on turbos will make you head explode because there are 100 different opinions on what is needed. Hopefully you have good tried and true track dog timing experience to draw from.

This is cool you get to be the Chris Columbus of 6AL-2 on a Porsche Turbo
...... charting new territory ......

Cole

Thanks David,, I'll PM you with my email ,, IL'm sure I'll have LOT"S of questions
And yes please give me the MAP P/N as I'll need to order one soon

Lost another one to Geico.

Todd,

The MSD part# for the MAP connector is 8172

MAP sensor info:

GM

3Bar 12223861
2Bar 16040609
1Bar 16137939

MSD

3Bar MSD 2313
2Bar MSD 2312
1Bar MSD 2311



http://forums.pelicanparts.com/uploa...1272142921.jpg



http://forums.pelicanparts.com/uploa...1272143041.jpg


Cole

I would like to clear up some of the misinformation on this thread. While I agree that support is important with any purchase, it's also important to be able to acquire everything as a system rather than piecemeal.

Pricing in post #4 is overstated at $2200. A complete Electromotive top-of-the-line laptop programmable XDI-2 ignition dual plug system, including crank trigger and spark plug wires, ready to bolt-on and go is $1800. The standard XDi dual plug ignition is $1500. For single plug applications, subtract $300 from either of these kits. Take a look in the catalog under ignition and spark plug wires at CLEWETT ENGINEERING: Peformance and Innovation

Regarding the discussion in post #8, the spark duration on a CD and MSD coil is only about .2 milliseconds. The technology is simple, by charging a capacitor and then throwing everything at the coil to extract a hotter spark. With this they open the spark plug gap, increasing the spark voltage to make the spark as big as possible and insure combustion. This higher voltage stresses all the components of the ignition system. The MSD system provides multiple sparks at low RPM to insure ignition.

The distributorless ignitions, including Electromotive and most new car manufacturers, operate on a different principle. They use an inductive system, meaning that the ignition coils are charged rather than a using a capacitor. This includes most coil on plug systems. The spark produced from the properly charged coil of an Electromotive system is 2 milliseconds, or 10 times that of a CD spark. The long spark is used as a way to insure complete combustion, and on new cars to improve reliability, longevity and reduce emissions.

The comment in post #19 is typically from people who try to use the large spark plug gaps of a CD system with an inductive system or improper spark plugs for the application. The waste spark coils from Electromotive are one of the best available to produce a long hot spark.

Furthermore, another important factor in ignition is timing accuracy. Porsche/Bosch has been using a 60 minus 2 crank trigger for years. Now, almost all auto manufacturers use a high resolution system. The reason for this is accuracy. Most high resolution angle based systems are within .2 degrees under all driving conditions. Distributors and low resolution crank triggers are lucky to be within 5 degrees under all conditions.

These are all considerations which should be examined when purchasing an ignition system.

Hi Richard, nice to see you here.

That's my post...and I stand by my numbers. Looking at the invoice right now, total bill was $2146.53 including shipping. Yes, I rounded up to 2.2k...in my opinion 50 or 100 bucks is rounding error when dealing with these old P-cars;) With all due respect, I'm not seeing how you come up with $1,800 for a turn-key set up with plug wires.

What did I get?: XDI2 kit with rotary A/C pulley, 2 bar map sensor, 2 sets of plug wires and the rsr bottom plug wire retainers. Strike out the rsr retainers and go with a non-A/C pulley and you will save $90, but you're still over 2k.

That said, I am very happy with the system and the completeness of the package you offered which is why I responded to Todd's thread.

I stand corrected. With extra items, the MAP sensor and shipping it could come close to $2200.

So true and I've seen them with more than 5deg of timing drift especially when dealing with high mileage equipment.

Richard,

It is great to see you here (finally a real ignition expert) helping us learn more about ignitions. I learned two new things from you so far.

The length of spark duration on an inductive system and the timing drift info.

I still need to learn which is a better fit for a CIS single plug that probably has poor Air Fuel mixing and less than ideal / lean AFR's at low compression operation off idle. A spark that lasts 10 times longer or multiple sparks that last for x degrees of crank rotation.

The concept I have heard is you never know if you are going to have a proper mix with CIS at the spark gap that ignites properly with a to lean mix. This seems to come from the metering plates slow responsiveness (mass) and being isolated from what is going on at the intake valve but about 5 feet of plumbing, a turbo, an intercooler and the intake manifolds volume on a system that has not acceleration enrichment that is speced to run at about 14/1 AFR untill boost enrichment is achived at about 5psi. This is on top of the poor mixing that comes with an injector that has to spray fuel 100% of the time at low to high pressure maxing it possable that we might see somthing like 17/1 or 12/1 (a guess) at the spark plug gap.

What do you think is best or is there any improvement to be made?


The idea that timing might float as much as 5 deg scares me and might be another reason the stock 930's might be conservative in there timing values.

What are we to do to get better off idle response with the lean surge and poor air fuel mixing that comes with a very low compression 930 short of twin plugging?

Lastly, if you could help us with what we should be thinking a max safe timing advance number might be for a typical CIS build 930 runing street fuel, it would be highly appreciated!

Stock seems to be about -16/-19 to up to -23 on a C2 Turbo at .8 bar. We have one member here ruining -25 on street fuel at .75 bar boost. I am very confused as to what a reasonable expectation might be.

So please, what might a single plug and twin plug look for as a starting on boost advance timing limit for say .8 an 1 bar boost. CIS tends to run a bit fat at
TQ peak as you know and gets leaner at hight rpm.

Thank you in advance for your time and info if you can help.

The best.

[QUOTE=RClewett;5314612
Furthermore, another important factor in ignition is timing accuracy. Porsche/Bosch has been using a 60 minus 2 crank trigger for years. Now, almost all auto manufacturers use a high resolution system. The reason for this is accuracy. Most high resolution angle based systems are within .2 degrees under all driving conditions. QUOTE]

Question

What type sensor arrangment is used to obtain the high angle resolution?


Thanks

In my opinion the EFI system would come way before twin plugging. Since I have done the EFI swap with full timing control I can honestly say there is no comparision, drivability wise, to the CIS/dizzy. The car feels like an N/A car till the boost hits instead of the terrible off boost performance of the factory set-up.

I used MS2 with EDIS6. The built in boost controller is fun as well.

Carrera intake - $600 with rails and TB
MS2 / EDIS-6 = $850 includes sensors, trigger wheel, coil pack, plug wires, relay board, wire harness, operating software, boost controller, blinker fluid and muffler bearings
Misc items - $600 includes, fuel injectors, fuel hoses and fittings, fuel pressure regulator and misc.

The intake to cyl head adapters and intercooler mods would be additional. Those would be determined by who does the work and how crazy you get with fab work.

Sorry if the AFR plot is hard to see but it is an example of what I call "lean surge" that comes with CIS.

I belive this motor is reported to idle at almost 14/1 AFR and cruse at near 14.7/1, with acclereration the AFR goes to about 16/1 over the first apx 200rpm and it is not until 2500rpm that the AFR stabilizes back to 14/1.

Max TQ is closer to 13/1 AFR.

To a lesser degree this is what I saw on my C2Turbo when I used a Motec Wide Band monitor before my WUR mods.

I am a big believer in proper ignition settings but curring what I call the CIS 'lean surge' can also help throttle response and can give that extra kick that gets the turbo spinning quicker.

There are two ways to correct for this with CIS. One is to instantly lower Control Pressure with acceleration via the D-WUR's programing or a vac-sensing conversion to the WUR . It still takes a half a sec before the accl AFR's respond fully but they do respond well.

The other would be to trick the Lambda function. This would be more instant but would not reduce the restriction of the metering plate on the suction side of the turbo.

It would be interesting to put a vac gauge in the section between the metering assembly and turbo to see how significant said restriction is.


http://forums.pelicanparts.com/uploa...1266695422.jpg

911st,

The CIS system does/did a great job for what it was designed to do. It met emission standards and had reasonable performance. The CIS system does have its limits. The biggest problem is that after 20+ years mechanical parts wear out, and good 930 fuel distributors are hard to find. Good modified fuel distributors are even harder to find. With modified fuel distributors, low speed mixture control can be difficult to keep from fowling plugs. Warm up regulators are also a contributor to this problem. When you add the performance minded individual into the equation, the mixtures are adjusted richer than originally designed; and with no way to adjust the fuel range of fuel delivery, problems can arise.

For the rich idle condition at low speed, it's not so much how long is the spark or how many sparks you have. But do you have enough heat in the chamber to burn the fuel? When the mixture is too rich, there's not enough heat to burn the carbon off the spark plugs, and they foul. To maintain enough heat in the chamber, the mixture shouldn't be richer than about 13:1 AFR at idle, hot.

In my opinion, the fix for CIS is to go EFI. I admit, I'm spoiled. It brings the engine up to modern day ignition and fuel control technology. It is very easy to make changes and provides the means to use a wide variety of performance components. With EFI, much of the CIS and turbo lag can easily be tuned out, making the engine much crisper. By adding some slightly more aggressive cams, a 930 will wake up and start making some real power. That's why I'm spoiled with EFI.

Twin plugging might help the off idle response some. But the real fix is to have the correct mixture and timing.

With timing, the goal is to have peak cylinder pressure at 14 degrees ATDC. Earlier than 14 degrees develops excessive heat and beats up the top end of the engine. Later than 14 degrees leaves power on the table. The dyno is the best way to find the sweet spot. I typically recommend for a single plug 930, 20 degrees at .8 boost. On the dyno, I've been everywhere from 18-23 degrees, so I pick 20 as a happy medium and starting point.
The timing at .8 and 1 bar are about the same, maybe 1 degree less at 1 bar.

Twin plug is usually about 2 degrees less than a single plug timing. This number also depends on RPM. With EFI I'll add a couple of degrees @3000 and back timing down a couple degrees by 7000. There is certainly a power difference between single plug and dual plug engines.

I hope this helps,

Richard

Jimmcc,

The accuracy of a high resolution ignition system come from the number of points on the crank trigger. Most of the aftermarket systems available don't have the processing power for the high massive amounts of data generated by the 60 minus 2 input.

The high resolution angle based sensor arrangement typically uses a 60 minus 2 trigger wheel on the crank and a magnetic speed sensor. On the 964, 993 and later engines we use the 60 minus 2 on the flywheel from Porsche. Most of the new cars on the market use a high resolution system. The Electromotive ignition is true high resolution angle based system which updates crank position every 6 degrees of crank rotation. This data is processed & refined and the coil is fired at the precise crank angle. This type of system eliminates what is known as spark lag.

Low resolution or time based systems might use a 3 or 6 tooth (120 or 60 degree)trigger wheel or bedded magnets and a hall sensor for inputs. That data is then used calculate the time when the spark event should take place. This type of system has spark lag or latency which will affect timing accuracy during RPM changes, acceleration and deceleration.

I hope this answers your question.

Richard

Richard,

Excellent info in post 37! Thank you.

Great points.

Apx -20 on boost.

Apx -2 deg more advance with twin plugs.

Heat in the cylinder from ideal AFR helps ignition.


Can I beg you for recomendations as to timing for a more stock 930 from idle to 3000rpm if there were no boost?

The best.

Richard,

Excellent info in post 37! Thank you.

Great points.

Apx -20 on boost. One dyno -18 to -23 seems range.

Maybe one more deg for 1 bar.

Apx -2 deg more advance with twin plugs.

Heat in the cylinder from ideal AFR helps ignition.


Can I beg you for:

Recommendations as to timing for a more stock 930 from idle to 3000rpm 'if there were no boost'?

About how much more power are you seeing with twin plugs? I had heard about 3% on a NA motor from just the earlyer advance it runs.

The best.