when relating to vacuum advance distributors...

ive always wondered...

how can an electronic gizmo affect mechanical advance/retard?

 

bttt

 

it doesn't effect the mechanical advance as such, it electronically alters the coil output...

 

so it'll hold the spark off later then? that sounds clever

in which case how does it manage advance, sending a spark out before the signal has arrived?

 

TBH i don't know the exact details, but after looking at the EMS5 i had and readed the destructions that how it does it both advance and then retard. The EMS5 is a much better unit, the EMS6 only allows retard i think. The EMS5 can be used with an injector driver "PIC" it was on mine. You adjusted the RPM/advance/retard via a series of screws

 

ooh, i thought the 6 was the better model...

 

the EMS 6 is the one with the dial so your can quickly retard the ingnition (the EMS5 does have this) i believe its more gear toward n20.

the EMS5 is a more complete solution allowing you to advance the ignition as required and then retard it were you want, which is idealy only at peak torque which i'm 95% you can do with the EMS5. I doubt the TT dizzy module readvances the ignition past peak torque.

also the EMS5 is more expensive, i have a feeling the EMS6 works better with EFI, Cavs runs on on that DIY 2.8 twin turbo EFI 4i.

do you have one or are your getting one? i'd seriously look at the OMEX150 mapple ignition system this uses a phase sensor and MAP sensor. okay its more expensive but should be far supirior to the MD kit, couple that with an MF2 and you'll be cooking on gas. I bet karl or someone would be able to sort the OMEX gear out he certainly does the MF2 as you know.

 

cheers doh

no im not looking at getting one, i am just interested to know how they work

and no the TT (aka saab ) dizzy doesnt readvanc the ignition... it cant, as its "dumb" and doesnt even know what torque is let alone where peak torque is :P

 

Doh does the OMEX150 not require a crank sensor then?

 

depends chris a phase sensor can be used on the crank or a dizzy type sensor but i needs summink


technically jim the EMS5 doesn't know what torque is you have ot tell it were in the RPM range you want the retard to start and finish.

 

I am interested in getting something, I might talk to Mikeanics who are near me and are an emerald dealer I think. If I go low compression I deffinatly want a mappable ECU.

Jim are you still wanting to retard and advance your ignition or just interested in how the EMS boxes work. As Doh says they are just inline with the coil so delay or advance the spark after the mechnical stuff has dealt with it.

Isn't the vacume capsule adjustable or was it a different car that got the adjustable one?

 

vac capsule doesnt appear adjustable from what i remember... but i havent looked at it in a while

and no i'm not looking at actually doing this i'm just interested in the subject n thought it'd make good learning

 

Chris well i would go one of 2 ways. stick with eh MFI but return it to standard fueling i.e. no profile block and fit a standard but locked dizzy. Then use the omex box mentioned for mappable ignition and and MF2 (or similiar) for suppling the extra fuel required. this shoudl yield good cruising economy, well dialed in ignition and fuel requirements and would be cheap(er) and easy(ish) to fit.

the second would be go full on fully mapable, i would be looking at DTA tbh rather than MBE(my reasons being TVR based). This obviously would be the best all round solution giving maxium performace, economy and scalability(traction control/FTGC etc) but there the cost and the requirements for a complete map and also you would need to source the majority of the 2.8 EFI parts, not an easy task i tell ya.

you pays your money you takes your choice. i just don't feel the whole saab reg thing and tweeking the fuel dizzy is the way to be going. also scoob says there aboost limitation of the dizzy module 12psi IIRC

 

Yeah I don't want a bodge with this engine and that kind of boost pressure.

I have left a thread about it on your BB

I take it you can't stick a 2.9 inlet manifold on a 2.8?