3.2 conversion cars, Public service announcement Options

[Marv's3.6six]

Interesting... wow.

I had a weird tach issue that was the opposite of this problem. My 3.2 tach would only "kind of" work with my 3.6 engine, the tach needle was slow and lazy, would lag behind the engine by about one second... fricken drove me nuts.

Blowing up ECU's, thats bad. (IMG:style_emoticons/default/wacko.gif)

[mb911]

So the question I have is what are people I swing to convert the stock 4cyl tachs to 6cyl pre 3.2s?

[0396]

Interesting... wow.

I had a weird tach issue that was the opposite of this problem. My 3.2 tach would only "kind of" work with my 3.6 engine, the tach needle was slow and lazy, would lag behind the engine by about one second... fricken drove me nuts.

Blowing up ECU's, thats bad. (IMG:style_emoticons/default/wacko.gif)

My understanding is with a 3.6, sometimes a 3.2 will work. Best is to source a 3.6 tach and or take it to North Hollywood Speedo for a conversion.. That's what I did...with a OEM RSR tach to convert to accommodate the new electronic. I'm sure there's other options like simply plug in a 3.6 tach- but it will not look vintage. To each its own.

[porschetub]

Isn't one tach electronic (3.2) and all the older ones electric ?
SC 3.0 tachs are an exception as they are low voltage output and the early are high voltage output,but they operate in a similar way.
Surely an Ashlocktech tach-adapt would sort this issue,I have been working with Bob directly and find him super helpful,he has basically given all the specs for a great ignition set-up.
Mark I would be happy to contact him and run it past him,his unit is very versatile and has a great rep for reliability unlike the MSD unit.

[Marv's3.6six]

My understanding is with a 3.6, sometimes a 3.2 will work. Best is to source a 3.6 tach and or take it to North Hollywood Speedo for a conversion.. That's what I did...with a OEM RSR tach to convert to accommodate the new electronic. I'm sure there's other options like simply plug in a 3.6 tach- but it will not look vintage. To each its own.

That was my understanding also, and to be fair the tach did work, but very slow to react. However my 3.6 has a light flywheel and revs up very quick. The tach pictured was built for me by NHSpeedo and required a 964 movement.... an expensive proposition. This conversion took significant time and energy as NHSpeedo had to do what they call the "Singer" modification.

[914dave]

Mark
Thanks for the heads up. Just drug out my dash and checked the part # on the tach i bought for my conversion. Turns out, I got lucky and bought a 3.2 tach. one less worry.
Dave

[larryM]

WOW - thanks!

curiously - Steve never raised the issue when i b'ot the chip a couple months ago - and he knew it was going in a 914-6

has anyone yet checked to see if NHS or PAS can put new 3.2 guts in our older tachs? - at what price?

last nite i b'ot the only used 3.2 tach on ebay from msroadrace -
expensive but half the price of replacing my 28-pin 082 DME with Wong chip in it - - call it insurance


fwiw - currently running oem 911/914-6 tach that is orig'l to car; it's been fine with the 3.2 for 3 yrs, but not many miles, nor sustained high rpm like we'd do on track-

i have 2 good spare 3.2 DME's as well - looks i can let one go now!

, (and dump the spare SC tach as well - sounds like it is useless with the 3.2 DME)


wiring diagram for 3.2 tach here
http://forums.pelicanparts.com/porsche-911...tml#post3972081


p.s. - here is a good link from one of our colleagues http://forums.pelicanparts.com/porsche-911...lity-chart.html

to wit:

"5. 1978-1983 Tachs. These are driven from the "TD" tachometer drive output from the six-pin CDI box because the points were eliminated in favor of a magnetic reluctor. According to the following thread, the SC tach signal is the same as the later Motronic:SC Thread

6. 1984-1989 Tachs. These are driven from the Motronic box. Chris Bennett posted the Motronic signal here: Motronic Thread"