Tachometer Adapter board

Post by **brentp** » Wed Aug 24, 2011 6:52 am

Here's something that neatly solves a nagging problem for nearly all Megajolt installations: interfacing existing Tachometers to multiple coil packs.

http://www.autosportlabs.org/blog/?p=1618

Available now in our online store: http://www.autosportlabs.com/tach-adapter-p-65.html

bossie · Post by **bossie** » Wed Aug 24, 2011 7:19 am

Looks good

(now it's time for some cheaper shipment options

)

Post by **brentp** » Wed Aug 24, 2011 8:32 am

Thanks!

Set up a group buy!

Broke4speed · Post by **Broke4speed** » Wed Aug 24, 2011 10:14 am

Just in time for my new project!
Thanks Brent!

molecular bob · Post by **molecular bob** » Sun Sep 11, 2011 11:15 am

just got mine and it looks good, i really underestimated just how small it would be.

2 questions:

1. Will the solder used for the components melt at the temperatures used to shrink heat-shrink tube?

2. What gauge of wire would be suitable for hook-up?

cheers

Ian B.

dr.occa · Post by **dr.occa** » Thu Sep 15, 2011 1:37 pm

Brent, will this resolve the 4AGE tach signal problem?

Post by **brentp** » Fri Sep 16, 2011 1:32 am

Ian,

The solder won't melt at the temperatures used to shrink heat shrink tubing.

Not a lot of current flows through here - small gauge wire is fine and makes it more convenient.

A similar circuit works for my AW11 tach, so it should work for the AE86 tach as well.

Note, this board is not a cure-all for *all* tachometers out there. it has the addition of 100K resistors across each diode which helps make certain tachometers compatible - such as the 914 tach we're using in our race car: that tachometer wouldn't work with just diodes.

toenee · Post by **toenee** » Fri Sep 16, 2011 10:43 am

If your tacho works, but has a hissy fit bouncing around at higher rpms.
Would this adapter help ?

Post by **brentp** » Fri Sep 16, 2011 3:05 pm

Toenee,

Can't say for sure. How is it wired now? More info would be helpful.

toenee · Post by **toenee** » Fri Sep 16, 2011 3:18 pm

Sorry yes more info needed, it's wired to the megajolt as per the diagram

Post by **brentp** » Tue Sep 20, 2011 3:33 pm

toenee, it would probably work- especially if the tach was connected to the (-) of the original single coil.

Ian,

Did you get the adapter board installed? How is it working?

toenee · Post by **toenee** » Tue Sep 20, 2011 5:43 pm

brentp wrote:toenee, it would probably work- especially if the tach was connected to the (-) of the original single coil.

Yep it's a RVC tacho from a MGB, just put my order in cheers.

molecular bob · Post by **molecular bob** » Thu Sep 22, 2011 11:04 am

Hi Brent

Feel a bit guilty 'cos it's not fitted to my megajolt. I am about 2 weeks away from start up on my Zetec Caterham 7 conversion and have fitted a DTA ecu as i want to go injection in the near future. The DTA has simillar issues driving Tacho's so i will let you know how i get on. I used raychem solder splices to join the wires near the ecu by baring a short section of the driver wire and then bonding a 18awg wire from here to the board. It's then all heat-shrinked into the loom.

Post by **brentp** » Wed Oct 12, 2011 4:15 pm

The first batch flew out the door- we now have plenty of the tach adapters in stock: http://www.autosportlabs.com/tach-adapter-p-65.html

Thank to those who've been patiently waiting!

73tii · Post by **73tii** » Wed Jan 11, 2012 5:43 am

My tach is not giving the correct readings at times. It's reading too low. Is this supposed to be a better option and replace the home made "diode circuit"?

Car is a BMW 2002 4cylinder M10 engine. Thank you

Autosport Labs