My overly complicated ignition setup
Turbo Mini Forums

Hi everyone,

I figure this might be useful for someone out who's curious. I've been doing a series of ignition upgrades in the interest of achieving better performance out of the 1275 metro turbo motor. So far I've installed a Mallory Hyfire 6EZL unit, and this past weekend I have also installed a MSD BTM (boost timing master). Nothing has caught on fire just yet. It is a bit of a rats nest:

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The Mallory unit is basically fires each spark plug multiple times and amplifies the overall spark voltage allowing me to run larger plug gaps without breaking up (running at .042" gap right now). The Mallory unit also has a built in rev limiter. I installed the BTM in order to better manage off boost and boost transition timing. The BTM lets me retard the timing x degrees per pound of boost (I run about 8psi). Currently running 20 degrees at idle, 32 degrees total timing when not boosting and 28 degrees (as standard) at full boost. The timing map, as you would imagine, is a bit complicated.

Without access to a dyno (and a lot of tuning time) it is difficult to see the real world gains, but in theory (yes, could easily get me in trouble), the car off boost and up to transition should produce more power due to the advanced timing (improved around town driveability), and should create the same power when boosting. I also have the added benefit of having an in-cabin boost timing retard knob which adjusts the degrees/psi ratio on the fly (if I run race gas tomorrow, I can run less retard for more power, or if I only have access to 87 octane, I can run more retard to prevent detonation).

The tuning process can be considered complicated, involving an adjustable timing light, spare boost gauge, bicycle pump and an assistant. Everything is based on the magical number of 28 degrees BTDC at full boost (known to be safe). The very abridged version of the process (I did a lot more back and forth, fact finding, check and rechecking):
1) Attach bicycle pump to BTM unit (it has a boost sensing port)
2) Tee in the spare boost gauge between pump and BTM
3) Detach vacuum advance from distributor
4) Rev engine up to 4000 RPM to engage full distributor advance (28 degrees)
5) Assistant pumps and holds 8psi
6) Set boost retard knob to retard 1degree/psi. At 4000 RPM and 8psi, the timing light should now read 20 degrees
7) At 4000 RPM and 8psi, Advance timing to 28 degrees by turning the distributor.
8) Take a break
9) Go back to check the work. Run the motor to 4000RPM, Pump 8psi, make sure the timing shows 28 degrees.
10) Shakedown, listen for detonation, do a plug chop.

The car feels peppier, the plug chop (run full boost up to 6000rpm, turn off the car immediately, and pull the plugs out to see what they look like) looked clean.

Today while driving, I decided to turn up the fun knob just a LITTLE bit without a timing light on hand. The car was a little bit more responsive, no audible detonation, however, checking the plugs revealed a small amount of detonation (pinking). The boost retard knob will now be returned back to the original setting.

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I can see more gains by advancing the base timing even more, then changing the boost retard to take 1.5 degrees out per psi, but will likely need a dyno/RR to verify this. The only annoying thing right now is that the inductive tachometer no longer works, i'll likely have to pick up a RVI unit. Thoughts, questions, concerns always welcome :)

Edited by lenn on 29th Jun, 2009.

Sounds like you have spent a lot of time and a good chunk of wanga trying to achive DIS Maped ignition with a Dizy :-$

Fair play though looks like you got simlar results :)

I have to say the same as Paul - a lot of time/effort/expense compared to MegaJolt (or similar) and presumably (from the photo) the HT is still being distrubuted by mechanical means (rotor arm and dizzy cap) rather than electrically from a coilpack or COPs.

But if it suits you, fine - I don't think anyone here has gone down that route.

Schrödinger's cat - so which one am I ???

Actually, the current setup had cost me about $100USD as they are used components ($30 for the BTM, $70 for the Mallory, all about 60GPB), the time...well you guys got me there, lol.

I was curious to know if anyone else has tried a similar setup on a RR to see if there are any measurable gains (like the off-boost and boost transition).

Any opinions regarding my base timing? I was going to try maybe 22 degrees base timing, 35 degree total off boost timing, and keep the 28 degree at 8psi timing.

Actually, what would an agressive n/a timing figure be for a regular 1275 motor? I'll match that on my off-boost setting, and retard it to 28 degrees when I'm in boost.

Thanks!

Edited by lenn on 29th Jun, 2009.

Can't remember my idle advance, but on my n/a 1380, 300deg cam at 11.5:1 compression. My max advanve is 28 deg.

I can run more without det, but it gives no measureable gain in power.

buut,on the plus side ,youv got a stonking multi spark output ,and dashboard adjustable timing ..

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Hi,
As the "top line" timing hasn't changed you won't see much gain on the rollers.
However the extra advance off boost should give you more torque, improved economy and earlier spooling of the turbo :)
Cheers,
Gavin :)

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