So the verdict is MSD Streetfire or 6AL?

[mfiazzo]

Car: 1978 911SC Targa

This will be one of my winter projects. Read everything on here in reference to MSD Ignition.

Only one question remains. Streetfire or 6AL.

I was thinking streetfire just because it seems to fit better and does not look big and clunky under the hood.

What are your thoughts?

Thanks

Mike

[ericbash]

I ripped out the big MSD 6AL and replaced it with a MSD Street Fire which fits nicely on the engine aluminum panel and behind the plastic panel cover. No need to relocate or alter the relays at the rear of the aluminum panel. The Street Fire has plenty of output for most of our engines. I added a Zims external electronic voltage regulator ($50) and Bob Ashlock's Tach-Adapt ($65) to finish the now much cleaner installation. I found the Tach-Adapt to be a better solution than the MSD 8910 tach adaptor. You might not need one depending on your year. My car is a 75 911. The Zims VR is small and if you mount it upside down you can get easy access to fine tune/change the voltage levels. Also changed the fuse block to the Classic Retrofit panel ($80) 911-FP3 available from Pelican. Used a MSD Blaster High Vibration 8222 black coil, which can be installed in any direction, head up, down or sideways. Do not install a ballast resistor with this set-up, and MSD says not to use solid core plug wires (I use Magnecor KV85). I am using a stock rev limiter rotor and points. Some people change to a rotor without the built-in resistor but I have never found one that fits my 75's distributor, no problems yet.

I ran all new wires in between the MSD cdi box, distributor and fuses etc. The "green" wire to the distributor is shielded to protect against electrical interference.
In my car the green distributor wire was grounded to the engine case, but I moved the ground to the electrical panel where it is easier to manage. I bought a few feet of green shielded wire off ebay and made my own.

http://www.ebay.com/itm/10-feet-20-AWG-Shielded-Silver-Plated-PTFE-Wire-Green-Twisted-Pair-w-Drain-/381852254308

I also ran a fat ground (welding) wire between the coil mounting base and one of the lugs on the rear engine mounts. The stud on the coil mounting base is threaded into the fan housing and is thus a direct metal to metal connection to the alternator housing. Your car won't run right (or at all) with bad/old wires and if you see problems at one end, then you likely have problems at the other end. You can never have too much ground on these cars. While you are in there, clean up all the grounds located near the fuel accumulator.

Voltage Regulator, 911 75-81

TACH-ADAPT

[Bob Kontak]

I would listen to Eric. I put a 6AL under my driver's seat. Lots of toil. Works great, but it is an elephant (skuz me - dinosaur?)

Less is more.

[ericbash]

Here is a better photo of the layout I used.

[merlinfe]

I used the MSD Street Fire with an MSD high vibration coil, Magnacor wires, and copper plugs. If you go this route look into a resistorless rotor for the distributor.

Overall it was a worthwhile upgrade over the aging Permatune setup I had before. And I know that short of changing everything out to go EFI, I'll never need to replace it. I could definitely tell a difference through out the rev range.

-Steve

[al lkosmal]

I've used the street fire a few times now and have one on my engine test stand...........works great.
regards,
al

[tirwin]

I've been running a Streetfire for a couple of years now with no issues. The pros are it's smaller and easier to install than the 6AL. Pretty sure it's cheaper too.

I'm using Clewett plug wires with NGK plugs gapped +.005 over normal factory recommendations. Resistorless rotor from NAPA and MSD Blaster 2 High Vibration coil. The MSD uses the +12V in the 6-pin harness as a trigger. You need to pull a new wire from the starter for the power and fuse it with a 15A fuse. Remember that the MSD wiring is different and the coil + and - need to be reversed from the Bosch CDI wiring. I think the wire colors are purple and green if I remember correctly.

[fred cook]

This is the MSD setup that I used before changing to an Electromotive twin plug system. The plastic cover fits nicely over the electrical panel.

[mfiazzo]

Thank you all for replying. Eric really nice job on the install.

Streetfire it is.

Eric I may be coming back to you when I start the project for some advice!

Thanks again!!

[Fred Winterburn]

The old Bosch and many more of the old CD ignitions used an oscillator type power supply to charge the discharge capacitor. If done right, that method can supply a high enough voltage at low battery supply voltage to start the engine with an almost flat battery. Not so for the MSD 6AL. It charges the discharge capacitor in one half cycle of the power supply. Two power transistors in parallel, supplied by a heavy wire directly from the battery, charge the discharge capacitor between each firing. The output is completely dependent upon battery voltage and the advertised voltage output (which is way too high anyway) is not actually reached until 18V is applied and that is beyond what the charging system gives. The real output is much lower than advertised.
I haven't tested a streetfire, but it most likely uses a different charging method than the MSD which is similar to the first production CDi (Tung Sol EI-4) and a real dinosaur in that regard. That method requires a much larger transformer and heavier, more robust components to accomplish the same thing as a CDI with an oscillator type power supply. (along with the voltage dependency mentioned).
I would bet the streetfire is a better CDi and for the give-away low Asian assembly price, you could keep a spare in the car without being too out-of-pocket. Fred

Originally Posted by mfiazzo

Car: 1978 911SC Targa

This will be one of my winter projects. Read everything on here in reference to MSD Ignition.

Only one question remains. Streetfire or 6AL.

I was thinking streetfire just because it seems to fit better and does not look big and clunky under the hood.

What are your thoughts?

Thanks

Mike

[Trackrash]

How do you manage a rev limiter with the streetfire? The 6AL has one built in right? What about the streetfire?

[mfiazzo]

Thanks Fred!

[merlinfe]

Originally Posted by Trackrash

How do you manage a rev limiter with the streetfire? The 6AL has one built in right? What about the streetfire?

The Street Fire has a built in rev limiter as well. Additionally, I didn't need a tac adapter, my '83 Tacho runs right off the unit. YMMV.

-Steve

[Jonny H]

Originally Posted by Fred Winterburn

The old Bosch and many more of the old CD ignitions used an oscillator type power supply to charge the discharge capacitor. If done right, that method can supply a high enough voltage at low battery supply voltage to start the engine with an almost flat battery. Not so for the MSD 6AL. It charges the discharge capacitor in one half cycle of the power supply. Two power transistors in parallel, supplied by a heavy wire directly from the battery, charge the discharge capacitor between each firing. The output is completely dependent upon battery voltage and the advertised voltage output (which is way too high anyway) is not actually reached until 18V is applied and that is beyond what the charging system gives. The real output is much lower than advertised.
I haven't tested a streetfire, but it most likely uses a different charging method than the MSD which is similar to the first production CDi (Tung Sol EI-4) and a real dinosaur in that regard. That method requires a much larger transformer and heavier, more robust components to accomplish the same thing as a CDI with an oscillator type power supply. (along with the voltage dependency mentioned).
I would bet the streetfire is a better CDi and for the give-away low Asian assembly price, you could keep a spare in the car without being too out-of-pocket. Fred

^ Yep, you get what you pay for. Both units are very cheap so do not expect too much from them. We decided to solve these issues once and for all...

Our CDI+ units produce a constant coil output voltage, irrespective of battery voltage even down to 5V. The voltage does not fluctuate with RPM either. Our boxes deliver twice the punch of MSD at high RPM yet fit in a standard Bosch size case and are plug and play to the standard harness. Alll boxes have programmable soft and hard rev limiters and full ignition mapping capability too. Designed, built, dynoed, raced and rallied by Porsche enthusiasts!

Search '911-CDI' on Pelican, or click this link:

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

Detailed install manual and dyno test report on our website too:

www.classicretrofit.com/products

[VFR750]

The 6AL-2 programmable is a nice fit. A lot more expensive than a streetfire



Fits nicely in the same location as the stock cdi box. Custom adapter cables using a 6-pin plug from timmy2. 100% backwards compatible, and 100% interchangeable with any msd 6al-2 programmable box.

[Jonny H]

Originally Posted by Fred Winterburn

And no variance whatsoever in voltage even down to 5V and absolutely no drop off with rpm? I'm sure there is some. And what is the component count to achieve that? The unit I make has some variance but is most probably ten or 20 times simpler than what you make. I don't make retrofits for Bosch units. Not that I couldn't as the parts will fit in easily.
I am pleased that you recognize the importance of voltage control. MSD and the other 'big boys' don't, or don't care as they wage their voltage wars.
How well do your units control current draw and do they limit current if the car's voltage regulator fails and drives the supply voltage excessively high? I don't mean fuses or zener diodes or up front modules to spill current away from the main circuit. I mean, is the current draw clamped if the battery voltage increases too far? It can be done using 100 year old technology (think magnetic amplifiers). I've used that old technology to both limit the voltage increase (that part is not published) and to limit the current draw (well established methods and used on the original Hyland CDi). I can't think in bits and bytes. Analogue rules! Fred

Our power supply section isn't complex, it uses an IC and a few support components. The IC takes care of the regulation. We have a close relationship with a company that has been designing power supplies for aerospace since 1954 so they pointed us in the right direction. Yes, the output voltage is rock steady, irrespective of battery voltage and RPM. I shall make a video when I have time.

Things are only over complicated if they serve no purpose.

Pictures of giant red boxes in Porsche engine bays hurt my eyes.

[VFR750]

Got the 7 year old laptop. So I'm good for another 13 years. 😀

Currently programmed with a 7,000 redline, and start reducing spark advance at 6800 to give me a warning. I am not using a locked out rotor. Just pulling timing at 6800 by adding a -3 in the table from 6800 on. Pretty easy.

Starting and idle has greatly improved with carbs vs old Cdi box.

[cnielsen]

We recently did a dyno run comparison between an MSD Streetfire versus a 6-AL....

Results were absolutely no difference.

The 6-AL does have a "soft redline" whereas the Streetfire has a "hard redline". The Streetfire does have a programmable redline.

The size of the Streefire is what I find appealing. It is only slightly larger than the stock Bosch units. Remove the factory black paint, wire brush some instant patina and add some period stickers...voila!

[75 911s]

Beautiful ^

The size and price! The street fire is $90 cheaper than the AL.

[al lkosmal]

Originally Posted by cnielsen

The size of the Streefire is what I find appealing. It is only slightly larger than the stock Bosch units. Remove the factory black paint, wire brush some instant patina and add some period stickers...voila!

I think that you can rely on Chris to come up with a simple, elegant solution......looks great with period correct hot rod vibe.

regards,
al