I have a real rich spot just about 2500rpm> to 4200rpm where the VVT kicks in.
Giving WOT chucks petrol out the carbs (the wrong way)
Question is, can I use the ign advance to dial this out?
I've dropped the needles down but AFR still goes down to 10 ish with a strong smell of fuel.
After 4200 its hunky dory with superb acceleration and 13 ish AFR.
Anyone know where I can learn about constructing an ignition map??
I have Megajolt with TPS on a ST170 engine running ZX9R carbs.
Ta,
Steve
Steve
Send me a U2U with your e-mail address, I will send you the map I have, it seems to work very well.
I have 1.8 Zetec, ZZR Carbs with TPS
Keith
I'd start with a 2d map first mate and then knob around introducing settings relating to tps.
I've stuck with my 2d, it works great on my pinto and can't see then benefit to be gained by arsing about.
Cheers
Rich
I don't think the ignition will make that much difference, it is more likely to be due to the valve timing with the larger overlap when the cam
advance operates.Have you tried disconnecting the VVT to see how it then behaves?
Ive thought about this on St 170 engines before and if I had one i would want a variable duty cycle system maybe operating on engine revs plus load
signal from the megajolt to allow the valve timing to adjust how it is designed to rather than just on or off.
Paul
Just been up to the rolling road for a power run. Last night had a fanny around changing the cut in rpm for the VVT.
With no VVT it drives real crap, woolly and rich in the midrange.
With the cut in set at 3K you can feel the change and off it goes..
So, 167bhp @ 6200rpm/111mph. Same as in the Focus but without Fords multimillion pound induction system.
So, on with the TB conversion to see if I can get more midrange torque as it drops off sharply after 5,500.
You can clearly see the 3k cut in on this graph
Rescued attachment P1000977.JPG
Nice graph there Steve!
And, as you say, with more to come!
Mike
post the same question on the robin hood site... there is a guy on there (gdc) that has been there and done it
he may have info for you
dave
quote:
Originally posted by paulf
Ive thought about this on St 170 engines before and if I had one i would want a variable duty cycle system maybe operating on engine revs plus load signal from the megajolt to allow the valve timing to adjust how it is designed to rather than just on or off.
Paul
quote:
Originally posted by MikeRJ
quote:
Originally posted by paulf
Ive thought about this on St 170 engines before and if I had one i would want a variable duty cycle system maybe operating on engine revs plus load signal from the megajolt to allow the valve timing to adjust how it is designed to rather than just on or off.
Paul
Everything I have read on the ST170 says it is not a continuously variable system in standard form, it's either full advanced or full retarded. FWIW this is works exactly the same way as the variators that Fiat/Alfa/Lancia use in some of their engines.
quote:
Originally posted by coozer
This allows oil into the front of the cam and as far as I can explain works bit like dizzy.. the oil advances the cam but as you back off oil pressure drops and makes for a continuously changing overlap based on oil pressure. Although its probably full on most of the time.
quote:
Originally posted by MikeRJ
quote:
Originally posted by coozer
This allows oil into the front of the cam and as far as I can explain works bit like dizzy.. the oil advances the cam but as you back off oil pressure drops and makes for a continuously changing overlap based on oil pressure. Although its probably full on most of the time.
I've heard this before and I'm really not convinced, but I'd like to know for sure.
Oil pressure doesn't just depend on RPM; it depends on temperature, wear of the engine, how old the oil is and what additives have been used by the oil manufacturer etc. I just don't think you could rely on the engines oil pressure to control something like valve timing accurately under all conditions.
