The V8 Owners Forum -

Is there some sort of module that will retard ign on boost that is a standalone item??

I've been tinkering with s blower for a mates skoda and he only has a dissy with electronic trigger.

I assume there is something out there that will retard prgressively as the boost comes up?

Topcat Tom!!

How did you control yours on the MX5 ??

A Mallory 685 with a MAP sensor can do it. Would also give him capacitive discharge ignition as well

MSD 6530 with a MAP sensor would work but they are not cheap!

Its a fully programmable ignition system.

mgbv8 wrote:Is there some sort of module that will retard ign on boost that is a standalone item??

I've been tinkering with s blower for a mates skoda and he only has a dissy with electronic trigger.

I assume there is something out there that will retard prgressively as the boost comes up?

Topcat Tom!!

How did you control yours on the MX5 ??

Turbo Technics used to do a vacuum advance unit for Sierras with an extra pipe on the opposite side of the diagram.
When the engine made boost it pushed the timing back mechanically.

Mark

mgbv8 wrote:Is there some sort of module that will retard ign on boost that is a standalone item??

I've been tinkering with s blower for a mates skoda and he only has a dissy with electronic trigger.

I assume there is something out there that will retard prgressively as the boost comes up?

Topcat Tom!!

How did you control yours on the MX5 ??

I've not seen anything which would be a simple fit between dizzy trigger and the stock coil driver. But you could use a variety of programmable ignition units and leave the mechanical advance as is, and just use the programmable side to modify that when and where you want. But if you went to the lengths of fitting one, why not go for a full map?

Cheapest is probably the Jaycar kit.

An older version of this product was used on the Swaymar Zakspeed Turbo Capri

http://www.newtronic.co.uk/new/main.php/turbos/

Hey Pel, an MSD BTM (Boost timing master) is the proper option for a stand-alone system, they do 2 types, one to go with their 6AL boxes and the other to go with standard dissy etc which is what I had.

HOWEVER- I connected my vacuum advance up (picked the right one as there are different types pulling more advance at different vacuums (you will know how much retard you need by what boost you run)) and that did the same job- under boost it looses suck and pushes the timing round to retard. Worked perfectly and I never had to use my BTM.

How much do these MSD boxes cost?

I think if it was me I would use megasquirt but just use it for the timing. Will read the dizzy signal then fire the coil where ever you want via the map.

If you can solder then I think its around £100 with the option to control the fuel if you want.

Tom.

Thanks for the replies chaps.
Some good stuff for me to investigate

More importantly, what sort of ignition system does the car use ? how many coils etc ?

SuperV8 wrote:How much do these MSD boxes cost?

I think if it was me I would use megasquirt but just use it for the timing. Will read the dizzy signal then fire the coil where ever you want via the map.

If you can solder then I think its around £100 with the option to control the fuel if you want.

Tom.

I don't think MegaJolt is available for DIY build any more due to using surface mount now, and costs rather more than £100. Before you get the EDIS etc bits. You can import a MS build yourself kit, but you're looking at about £250 including taxes. I don't know of a UK supplier.

The Jaycar unit can be built for under £100 complete if you use the original dizzy trigger and coil.

Hi Perry
Are you sure you need a boost retard, this is a drag car after all, all you are interested in is max power at full throttle , boost under those conditions is directly related to engine revs so you have a "one dimentional" ignition map. I dont think maximun fuel economy in the aproach lane is a concern and part throttle responce/ economy up on the return to the pits is really beside the point provided the engine will run. Just think that maybe this is a bit of over "egging the pud", get the distributor accuratly curved for the full throttle full power then if you are feeling fancy connect up a vac advance for when you shut off at the top end and want to rturn to the pits. lets face it a top fueler runs a magneto or two and to don't have any electronics with one of those. Yes I know I am setting mine up for MSQ ignition but that is really so I can use it to log the engine, (and I don't have any real provision for a distributor). I am seriously considering just going for a big fat maneto off the front belt along with the injection pump.
Best regards
Miike

There are various devices that can offer a boost retard, these are some of the most basic

http://www.newtronic.co.uk/new/main.php/turbos/

but TBH, it would be so easy to fit proper mapped ignition using the likes of Megajolt. it would seem silly not to. You could likely do it for the price of some of the retard modules.
And using the coilpack, you'll have a more powerful ignition system too.

I don't think MegaJolt is available for DIY build any more due to using surface mount now, and costs rather more than £100. Before you get the EDIS etc bits. You can import a MS build yourself kit, but you're looking at about £250 including taxes. I don't know of a UK supplier.

DIY megasquirt kit, $204 / £125ish plus vat/import, which isn't going to be +100% of the origanal value!

This will give you full mapped ignition and fuel thrown if needed.

Tom.

SuperV8 wrote:

I don't think MegaJolt is available for DIY build any more due to using surface mount now, and costs rather more than £100. Before you get the EDIS etc bits. You can import a MS build yourself kit, but you're looking at about £250 including taxes. I don't know of a UK supplier.

DIY megasquirt kit, $204 / £125ish plus vat/import, which isn't going to be +100% of the origanal value!

This will give you full mapped ignition and fuel thrown if needed.

Tom.

It will do, but best to go for an MSII V3. The extra cost is worth it.