JoeMag

What are my options for twin plug setup with efi? ...thinking motec M4 ecu. ...what is most cost effective one?

shockm

Motec M48 Pro......wait ..."cost effective"? Nevermind.

Geoffrey

Joe, Are you talking about the ignition system selection or the ECU selection?

SoCal Mike

If your looking for Motec-like features take a look at Autronic's SM4. Probably not all the options that Motec has, but for most people's use, probably enough, and much cheaper. The SM4 ecu runs about $2250 and an ignition system for twelve plugs is around $1000 more. Autronic is owned by the engineer that was originally a partner in Motec and designed its products. Great user interface and one of the best fuel algorithms out there. I got to help tune an autronic equipped car during my efi university advanced class, very straight forward. One of the great autronic parlor tricks is starting and running a car with just one cell tuned Also , Stephen uses it in his efi conversion....that says alot.

ProtoCab

Do you really need all the fancy boost control, traction control, anti-lag and launch control features? If not, go with a bare bones Autronic SMC unit. MUCH cheaper and will do the job just fine.

JoeMag

Geoffrey -- Talking about ignition system selection.

SoCal Mike -- Would like to have boost control through ECU. ...but haven't looked at the Autronic's SM4 yet. Based on motec 06 catalog the M4 is $1,800, but would like to have data logging capability and wide band O2, so that adds another ~$1k.

Geoffrey

The Autronic SM4 has had some significant teething issues and was released prematurely before bugs have been released. In fact there are still triggering issues with the cam signal. 20 years ago the owner of Autronic was in partnership with the owner of MoTeC, but I'm not sure the relevance of that now since Autronic has not progressed out of the guy's basement where MoTeC has a large design and testing facility with many employees. As far as the fuel algorithm, that is a litlle simplified, you must have all of the supplimentary tables perfect before that will even work, and there are few who take the time to do that. Even then, it really doesn't have the flexibility of other systems for fuel control. None of the Autronic ECUs can do wide band lambda support directly and requires the purchase of a separate Autronic AFR meter which costs more than the entire SM4 ECU. All of MoTeC's ECUs can do native wide band support. The two are not really comparable, Autronic is really a simple system for beginners. As for the ignition system, I would never use the Autronic R500, there are much newer, better solutions out there for less money, in fact, MoTeC's CDI unit costs less than the Autronic.

Joe, You have lots of options here, all around the same price.

1) 964/993 twin distributor (need distributor gear on crank checked/changed to proper rotation for 964 distributor) using 2 MSD6A or 2 high quality CDI units like in my race car, or 2 inductive ignitors, and 2 appropriate coils (CDI coils for CDI and inductive coils for inductive)

2) 3 channel wasted spark inductive style. I like the Bosch setup, although there are options from Mitsubitui which I have used and Electromotive which I won't use.

3) 3 channel wasted spark CDI style. This would be some CDI specific double ended coils and a 4 channel (3 are used) CDI controller from MoTeC which works well, or MSD which I won't use.

4) Direct ignition using coil near plug. This would consist of 12 individual coils and options range from production type like the Denso 580s found on the LS1/6 Corvette, to the production coils found on any 996 engine to inductive or CDI specific race coils from Bosch, Magnetti Marelli, or some other manufacturer of high quality ignition components.

5) Some custom made 12 plug distributor. Never used one, cannot comment, but the option is there.

6) Secondary distributor driven off the camshaft. Performance Development has a setup. Never used one, cannot comment, but the option is there.

It will depend on how many ignition outputs your system has as to what type of system you can go with. A distributor requires 1 channel, wasted spark requires 3 channels, and direct ignition requires 6 channels. I prefer a distributor or direct ignition over wasted spark, although the Bosch setup will probably be your most cost effective solution.

JoeMag

Man, that's a lot of info... Thanks!! If I stay single plug with distr and MSD (just need to drop wheel in disr and get ignitor), what do I really loose? Is there issue that I could damage engine?

Geoffrey

If you are not using the distributor to provide a sync signal for full sequential ignition, then you don't need any trigger wheel in the distributor. An example is if you are running 60-2 on the crank pully from Clewett Engineering, and you are running multipoint or batch fired injectors then you don't need anything in the distributor. You can certainly run the engine on single plug, but the engine will want more ignition timing since the flame kernel is smaller (only 1) and so the effective flame propagation rate will be slower. However, the engine cannot support more ignition timing, so you will have to run better fuel or less timing, resulting in less power. You can certainly do it and have the engine run fine, but with less power than a twin plug setup. As with any engine setup, if you don't set the ignition timing properly then you will risk engine damange.

JoeMag

if i were to not twin plug then I would not run crank pulley encoder. already run 110. what do you think approx loss in power would be, maybe in %, over twin plug?

Geoffrey

Regardless, if you are going to use EFI, you will have a crank trigger of some type, whether in the distributor, on the crank pully, or on the flywheel (DME ring). You'd be able to run 100 octane unleaded and I typically see 420rwhp @ 1 bar on a single plug, SC cam, 930 manifold, typical turbo type engine compared to 450-480 for a twin plug engine. Obviously there are many variables in play here and I have not done back-to-back tests between identical engines, one single plug, one dual plug.

mclaren55

On my twin plug efi I run a disco TEC-1. Seems to be alright, but it is really old technology.

JoeMag

yea, realize I need to have some trigger signal... so you're saying around 8-15% less. actually I'm going to need to run low boost version to stay in same nasa class but could pump it up for pca. dyno after rebuild last winter was ~415rwhp 0.8 bar, ~450rwph 0.9 bar. ...just too lean to even think about running 0.9 bar.

marcvip

I hear AEM's EFI management systems are the best as far as support,cost and tuning. I don't beleive someone has attempted this setup on a Porsche however.

http://www.aempower.com/ViewCategory.aspx?CategoryID=80

Geoffrey

Chris at TurboKraft has an EFI kit for the 930 that utilizes an AEM ECU.