ignitor II, Pertronics fixes burnout problem? Options

[Jake Raby]

You can feel the differences in the better advance curve.... Very easily.
The differences in the idle and off idle performance is notable...

[lapuwali]

Advance curve, yes. But can you FEEL the difference between fresh points and a electronic trigger, assuming the advance curves are the same? That was the original question.

[anthony]

I can see and feel the difference between fresh points and a Pertronix in my stock 2L 914. The Pertronix smoothed out the idle and made the timing much easier to set because the timing mark was no longer jumping all over the place.

I've had good luck with the Pertronix but if I was doing it over I might buy the Compufire on the Captain's recommendation.

Someone asked about putting a Mallory on a D-Jet car - you can't do it. You need the stock distributor with the trigger points for D-Jet.

[Jake Raby]

And you can see the difference (on a CHT gauge) when you don't have to jack the hell out of the full advance to attain enough initial advance to wake the engine up at low RPM.

As piston speed and RPM increases the need for advance is lessened, some engines I build like less than 20 degrees full advance to make their best (most usable) power and yield their best MPG and head temps.

Tuning is everything, you can't tune with a crappy dizzy- period.

[swl]

Sorry guys. I have a bit of newbi-itis here. I've done a couple of searches and realize that the stock distributor is neither 009 or 050. I'm running the stock distributor with stock D-Jet. So that means the unilite distributor is out of the question without some fancy circuitry to replace the trigger points.

When you folks talk about the type of distributor is that a reference to the first 3 digits? As in 022 for the 1.7/1.8 and 039 for the 2L.

Does anyone know if the compufire fits in the stock distributor?

[alpha434]

what about the fireball??? that optical distributer cap. and there has to be a way to used a mallory with F.I.

I'll get some electrical engineers on it right away

[lapuwali]

There IS a way to use a Mallory with "FI", just use aftermarket FI or L-Jet. With D-Jet, the primary injector signal is from the trigger points in the distributor. You can simulate trigger points with other setups (Mueller did an optical setup once), but if you're going to that kind of trouble, then just get aftermarket EFI and be done with it.

swl, the distributor part number we're referencing is the last three digits. The stock distributor is a variety of the 205 series (there's more than one, just as there's more than one 009). I have no idea if Compufire, et al, will fit in the stock distributor. I know a Crane setup will.

[alpha434]

wow. I never thought that i'd be happy to have an L Jet. Everyone told me they were the worst you could have. HA!

So where does the L jet get the injection signal.

Sorry- i'm new to 914's. But i've been hip to the 911's and 356's for a while. Even worked on real RSR's

[lapuwali]

QUOTE (alpha434 @ Dec 28 2005, 04:34 PM)

wow. I never thought that i'd be happy to have an L Jet. Everyone told me they were the worst you could have. HA! So where does the L jet get the injection signal. Sorry- i'm new to 914's. But i've been hip to the 911's and 356's for a while. Even worked on real RSR's

The L-Jet system doesn't "get" an injection signal, really.

D-Jet attempted to be more or less sequential in its injection, and used two sets of trigger contacts to fire pairs of injectors once per crank rev. These signals are fed into the ECU, through the MPS, and on to the injectors to open and close them.

L-Jet drives the injectors very differently. It uses the tach pulse (same one the tach on the dash uses) to get engine speed, and processes that in the ECU using the signals from the airflow meter, and the ECU opens and closes the injectors to meter the fuel. There's no attempt to synchronize injection events to cylinder or valve events. It just makes sure enough fuel gets squirted in to match the amount of air being consumed by the engine.

[alpha434]

so the d-jet is better for performance unless you want to use a mallory or do something else different and exotic?

[lapuwali]

QUOTE (alpha434 @ Dec 28 2005, 05:45 PM)

so the d-jet is better for performance unless you want to use a mallory or do something else different and exotic?

No, D-Jet isn't "better". Indeed, D-Jet wasn't even used on all that many cars (914s, along with some VW, Mercedes, Volvos, even Jag V12s), and pretty much died out completely by the mid-70s. L-Jet, however, was a more modern system, and was used on a HUGE number of cars from the mid-70s into the 90s, including all later Porsches (DME was basically a modification of L-Jet).

Most of these OEM EFI systems aren't very good for modified engines, as they're not programmable. L-Jet has more wiggle room here, but it still has limitations. Nowadays, using programmable aftermarket EFI is a better bet.

[Gint]

alpha34, we need to get you on our local email list. Send me an email or PM. Did you recently buy that 75 914 that was on craigslist?

[Jake Raby]

L jet works fine with a Mallory....

[Air_Cooled_Nut]

I'm using the DIS-IX in my VW Squareback. A Mallory dizzy won't fit under the decklid.

The power difference IS noticeable. 5th gear up a hill I know would just keep me at a constant speed with a stock ignition system. Set up with the distributorless system (which, I agree, isn't accurate) I can easily accelerate up that same hill.

I've used the Compufire and the Pertronix electronic points without failures for years. Sounds like I'm one of the lucky ones. I would not hesitate to use such a unit in any of my cars. I'm not using one in my 914 right now because the dizzy needs a rebuild I believe. Can't get the damn thing to hold a steady timing (IMG:http://www.914world.com/bbs2/html/emoticons/mad.gif)

And there's nothing wrong with a magnetic sensor compared to an optical one.

My experienced $0.02.