carbs to efi: which manifold?

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Originally Posted by PhilipA

No.
RV8s have a VERY conservative centrifugal advance curve and vacuum advance has nothing to do with high load.
I suggest
1 Your engine has a lot of carbon in it. OR
2 you have too much static advance OR
3 you are using petrol of insufficient octane
4 or you are asking too much of the engine and need to change your driving style.
OR all of the above.
I fthe timing is less than say 9 degrees BTDC then it will be one of the other things.
I don't know whether you have Low compression or high compression. This is stamped next to the engine number either 8.13:1 or 9.35:1.
High compression 9.35:1 needs 98 RON.
Regards Philip A

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I have a 9.35:1 high compression 3.9 running on 91 octane. Detonation appears under control using 12:1 at full load, but I think I could hear some at 12.5:1.
I don't yet have a timing number for this setup. But I hope to check it at some stage.
Vacuum and centrifugal advance are working fine.

another question is how the traditional cux13 or cux14 efis know the camshift position if they are fully sequentional? from the ignition system?

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Originally Posted by russotouristo

another question is how the traditional cux13 or cux14 efis know the camshift position if they are fully sequentional? from the ignition system?

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I don't beleive there is anything sequential in the 14CUX.

you mean to say it was continuous?
here's what I'm going to get.
https://www.aulro.com/afvb/images/im.../2014/06/8.jpg
https://www.aulro.com/afvb/images/im.../2014/06/9.jpg
https://www.aulro.com/afvb/images/im...2014/06/10.jpg

any ideas, what else do I need? idle valve? fuel pressure regulator? MAF?
one more thing: i looked for some wiring diagrams for v8, found one from some early morgan, and they used some power resistors in series with injectors - what for? Do I also need to use something in between the injector and the power switch (transistor)?

That is a manifold from a 14CUX automatic and has the idle valve which is the black thing at one end. It has a fuel rail with regulator which is good, and a Throttle position sensor. All you need are the wring ECU and MAF, assuming the IAC. TPS and the fuel temp sensors are OK.
It is an early AFAIK up to about 93 RRC manifold as the fuel temp sensor is at the front and the regulator at the RH rear.
Regards Philip A

thank you! i was going to use map instead of maf + i need to think about the filtering thing. plus probably i need an air temperatute sensor.
basically, now i am going to find the cux14 wiring diagram to see if there are any power resistors between the efi and injectors. thank you for so much info!

Sent from my JY-G4 using AULRO mobile app

The 14 CUX does not have the resistor bank, only the old "flapper" system has them. The 14 CUX injectors are high resistance.
Regards Philip A

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Originally Posted by russotouristo

another question is how the traditional cux14 efis know the camshift/crank position

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How does the 4CUX system know when to fire the injectors?

Thanks

Garry

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Originally Posted by garrycol

How does the 4CUX system know when to fire the injectors?

Thanks

Garry

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People keep thinking that there's something sophisticated about the 14cux.

There isn't.:p:p:p

It has one rotation signal input, the wire to the ignition coil negative. If there are ignition pulses present on this wire it will dump an approximate amount of fuel in each bank in turn. No error checking, no cam sensors, no fine control. And that's about it.:cool:

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Originally Posted by bee utey

People keep thinking that there's something sophisticated about the 14cux.

There isn't.:p:p:p

It has one rotation signal input, the wire to the ignition coil negative. If there are ignition pulses present on this wire it will dump an approximate amount of fuel in each bank in turn. No error checking, no cam sensors, no fine control. And that's about it.:cool:

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Ok - thanks - so if it dumps fuel on the ignition pulse for that cylinder it is clearly too late to be fired at that time so I guess the fuel sits in the intake manifold above the inlet valve waiting for the next firing.

Cheers

Garry