75 Twin Spark after market tacho

Started by alanm, March 29, 2012, 02:14:30 PM

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alanm

Hi all

I would like to install a (discreet) aftermarket tacho in my 75 Twin Spark and I was wondering if the installation is complicated by the fact that the car has 2 coils and 2 distributors?

Does it matter which of the 2 coils you connect to?

I gather that the two sparks on the 8V TS engines do not fire at exactly the same time, but they presumably fire at the same speed?

Any information much appreciated!

Cheers
Alan
Present
1987 75 TS Rosso
2001 GTV V6 Nero
2001 156 V6 Monza Rosso
Past
1986 GTV6 Grand Prix
1988 33

festy

Just pick up the tacho signal from one of the ignition modules, I don't think it matters which one.
The ECU provides the same advance and dwell to both modules and they appear to be both fired at the same time, because the two ignition pins are joined together inside the ECU.



Paul Gulliver

Thanks Festy, Now back to that important work your doing with the Motronic tuning over on Alfa BB.

http://www.alfabb.com/bb/forums/engine-management/190352-what-stock-75-ts-motronic-can-cannot-do.html

Bump: For anybody with a twin spark motronic this is very exciting news worth reading the whole thread & the work Festy is doing
Paul Gulliver
Present
2017 Silver Giulia Veloce
1979 Silver Alfa 116 GTV Twin Spark
1973 Red Alfa 105 2.0 GTV

Past
2013 Giulietta QV
2006 Black 159 2.2 J
1970 Dutch Blue Series 2 1750
1975 Blue Alfetta Sedan 1.8
1981 Piper Yellow Alfetta GTV 2000
1985 Red Alfetta GTV2.0
1989 White Alfa 164
2000 156

alfagtv58

Quote from: Paul Gulliver on March 30, 2012, 11:46:06 AM
Thanks Festy, Now back to that important work your doing with the Motronic tuning over on Alfa BB.

http://www.alfabb.com/bb/forums/engine-management/190352-what-stock-75-ts-motronic-can-cannot-do.html

Bump: For anybody with a twin spark motronic this is very exciting news worth reading the whole thread & the work Festy is doing

WOW!  Thanks for the heads up Gully!  It's all above my IQ level, but I will go back and try to read it later on when I can actually concentrate on it.
1967 Giulia Sprint GT Veloce - (WIP) Strada
1977 Alfetta GTV Group S - Corsa - For Sale (http://www.alfaclubvic.org.au/forum/index.php/topic,9600.0.html)
2009 159 JTS Ti

Paul Gulliver

QuoteIt's all above my IQ level, but I will go back and try to read it later on when I can actually concentrate on it

Phil,

I'm only just hanging on with  that thread. Your kids are probably a bit young but teenagers should be able to help.
Paul Gulliver
Present
2017 Silver Giulia Veloce
1979 Silver Alfa 116 GTV Twin Spark
1973 Red Alfa 105 2.0 GTV

Past
2013 Giulietta QV
2006 Black 159 2.2 J
1970 Dutch Blue Series 2 1750
1975 Blue Alfetta Sedan 1.8
1981 Piper Yellow Alfetta GTV 2000
1985 Red Alfetta GTV2.0
1989 White Alfa 164
2000 156

BradGTV

im a teenager.. some bits are still comfusing  ;D
79 gtv sr20, 83 gtv, 83 gtv6 3.0, 75 ts x 3, 85 gtv, 76 gt, 91 164, Subey L Series, S13 silvia, Bmw e30 318i, VT SS 6spd

Henry Goodman

I'm waiting for the summary in plain english.

Oops I off topic on this thread - sorry.

alanm

Hi all,

Completed the install over the long weekend, thought I would share some learnings...

Photo 1 shows the rear of the fuse box with accessory power terminal circled (fuse 10).

Photo 2 shows the white wire which connects to the negative terminal on the coil.
Alfa/Bosch conveniently supply this with a male connector. Your choice of coil, on my car the factory tacho (brown/white wire) is connected to the coil on the left of the shot.

Photo 3 shows a row of male connectors earthing to the front of the car right behind the headlight, once again Alfa conveniently supplies 2 spares (lower row)

Photo 4 shows the installation of the Speco tacho to the windscreen frame (no holes in dashboard!).

I only needed to drill 1 x 7.5mm hole in firewall right behind the fuse box to pass wires into the engine compartment, this was finished with a rubber grommet.

Cheers
Alan
Present
1987 75 TS Rosso
2001 GTV V6 Nero
2001 156 V6 Monza Rosso
Past
1986 GTV6 Grand Prix
1988 33

alanm

A SMALL  BUT IMPORTANT ADDITION TO THIS POST.
I got an erratic tacho reading until I installed a 1N4004 diode between the coil and the tacho (make sure you install the diode facing the right direction, band facing the tacho).
Al
Present
1987 75 TS Rosso
2001 GTV V6 Nero
2001 156 V6 Monza Rosso
Past
1986 GTV6 Grand Prix
1988 33

Colin Edwards

Present
2023 Tonale Veloce
2018 Abarth 124 Spider
1987 75 3.0

Past
2020 Giulietta Veloce
2015 Giulietta QV
2009 159 3.2 Ti Q4
2012 Giulietta TCT Veloce
2006 147 Ti 2 door Selespeed
1979 Alfasud Ti 1.5

GTVeloce

Alan, your engine bay looks far too clean and tidy! You need to drive the car more!!