07-17-2007, 06:31 PM
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Registered User
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Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 760
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 Quote:
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It seems from comments that the key to driveability is the 3d mapped ingition set up, is this the case ???? I my opinion that is a big part of it as the dizzy does not have much scope for modification (Nothing compared to 3d mapping as I had on my evo6, but that was fuel as well) so my current plan is to use a megasquirt with throttle bodies (Actaully modify a set of dellortos so it looks period correct) and put a crank sensor on ( Machine teeth into the pulley on the front of the engine and use a standard induction sensor) so the dizzy can be totally removed (Of course airflow sensor and throttle position sensor etc would need to be added)
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Geofd:
You have asked a question I'm curious about, too. I don't have a good answer but, since there are quite a few people here who do know about this, perhaps we can stimulate some additional discussion. Generally speaking, we have three different technologies to consider. First, of course, is the traditional dizzy w/points and coil. Second, is the traditional dizzy augmented by electronics: brakerless, CD boxes, etc. Third, is modern engine management technology which eliminates the dizzy uses the crank or front pulley as its timing reference.
My old Alfetta sedan used a Marelliplex/MSD6A combination which was the cats meow two decades ago. The difference between it and the old points/coil ign. was dramatic. The addition of the MSD6A was equally a quantum leap (and rather surprisingly so) in that it thoroughly cured a pesky detonation problem.
Having read Max Bank's comments on his killer TS motor, it appears that a mapped ignition is yet another dramatic step past what I was getting with my Marelliplex/MSD6A combo.
But, here's my question. Just as there are some practical considerations involved in deciding to use a modified nord motor or a TS, so are there some regarding my Marelliplex/MSD combination. I willing to accept that a mapped ignition has definite advantages, but I'm also wondering just how much of a difference there is between using a good dizzy/MSD or other multifiring ignition and a fully mapped ignition. Max sells a mapped ignition that is Alfa specific. MSD and other companies also sell boxes which map the ignition.
But wait, there's more. Megasquirt, Gotech, MSD, and other companies now sell aftermarket FI engine management boxes that are crankfired and can do away with the dizzy entirely. Max is getting a healthy 198hp from his Webered TS and 178hp from a Webered 2L Nord motor. That's impressive, but with Megasquirt engine management there's probably a bit more avaliable with the same street drivability.
So (finally) here's my question for those on the forum who actually know something about this stuff.
We have two injected Alfas both of which have identical full-tilt modified Nord/TS motors. One retains it's dizzy but uses a mapped ignition. The other uses full engine management, no dizzy and is crank fired. If we take the two cars out and drive them will we immediately be able to tell a significant difference between the cars, or will the differences be more subtle?
Basically, a dizzy is a mechanical reference. Granted it is less accurate than using the crankshaft or the front pulley, but, in terms of driving dynamics, how important is that difference?
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Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
Last edited by 180OUT; 07-17-2007 at 08:25 PM.
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