Ignition controller when boosting ??

mgbv8 · Post by **mgbv8** » Wed Mar 23, 2011 8:23 pm

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

The car runs a Mallory AL6 CD ignition with MSD blaster coil fed from the magnetic trigger module in the dissy.

mgbv8 · Post by **mgbv8** » Wed Mar 23, 2011 8:25 pm

kiwicar wrote: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

Maybe thats the simple answer Mike??
Its track only so as long as it had enough advance to drive to the burnout area I guess I could just limit the dissy internally to advance to normal max -8 degree's for the 8 psi of boost??

stevieturbo · Post by **stevieturbo** » Wed Mar 23, 2011 8:30 pm

mgbv8 wrote:
Maybe thats the simple answer Mike??
Its track only so as long as it had enough advance to drive to the burnout area I guess I could just limit the dissy internally to advance to normal max -8 degree's for the 8 psi of boost??

If you are only using 8psi, and it is only a race car.....why not just chuck some methanol or race fuel in ?

Might not even need to retard timing at all. And 8deg for 8psi sounds like a hell of a lot.

mgbv8 · Post by **mgbv8** » Thu Mar 24, 2011 12:38 pm

stevieturbo wrote:
mgbv8 wrote:
Maybe thats the simple answer Mike??
Its track only so as long as it had enough advance to drive to the burnout area I guess I could just limit the dissy internally to advance to normal max -8 degree's for the 8 psi of boost??
If you are only using 8psi, and it is only a race car.....why not just chuck some methanol or race fuel in ?

Might not even need to retard timing at all. And 8deg for 8psi sounds like a hell of a lot.

Just going on what a blower guy said. 1 degree per pound of boost ??

not sure about the race fuel etc.. What would the effect be on the carb etc?? Would the system need to be flushed out when not in use. Would it be neat race fuel or mixed with petrol?

stevieturbo · Post by **stevieturbo** » Thu Mar 24, 2011 1:03 pm

Race fuel would pose no problem to the carb. Methanol used neat might.

But adding say 10-15% with the petrol would give a decent octane boost for not a lot of money.

And thinking 1deg per psi is really old old tech. The only real way to find out is by testing.

it sounds like this is a very old primitive setup ? When you say it has a dizzy...you mean an actual dizzy with advance weights etc ?

If so, cheapest way to stop advance is to weld stops into the advance mechanism. Or as others have said, just simply retard timing everywhere by rotating it.
Or by fitting a boost retard capsule in place of the vacuum advance

kiwicar · Post by **kiwicar** » Thu Mar 24, 2011 1:56 pm

Hi Perry
Mind me asking what compression ratio you are planning to use with the blower?
I really think a mild recurve on the distributor, or just wind it back a few degrees as Stevie suggests is really all it will need.
Best regards
Mike

JP. · Post by **JP.** » Thu Mar 24, 2011 5:05 pm

mgbv8 wrote: Just going on what a blower guy said. 1 degree per pound of boost ??

Yep thats true on a street engine cast iron block..
On an alloy block it could be less.

I drive our street alloy on that and it will do with less but its getting a bit temperamental with less and the misses won't likes that ( its hers anyway.)

Have it on 38' total all in at 4000 rpm. The MSD BTM sorts it out at 1'/1psi on our streetable engine (8psi).
Had it set on 34'( no BTM module) without issues other than very temperamental so to speek.

So strip only no need for a BTM module, just get it all in at aprox 4000 rpm.