17 replies to this topic

[ASeriesPower]

Hi all, 

I've got a 123/Tune+ distributor and would like to know a good starting point advance curve. My setup is:

 

1275 (+30 stamped pistons). - so i guess 1293 or 1310cc now?

Kent 266 cam

standard rocker assembly

hif44 carb with vacuum connection to distributor in place

lcb manifold/exhaust system 

 

Current I have only three points set for the centrifugal curve:

 

idle (1000rpm) 10 degrees 

2500rpm - 18 degrees 

3500rpm+ 30 degrees (max advance)

 

I have left the MAP curve alone and it's set at 0 through the range - is this correct? 

 

I figure with a few more points on the curve I could get better performance, but I don't really know where to start. Currently the car runs ok but feels a bit flat in the lower range, however it is pinking in 4th gear in the lower revs going uphill so I'm reluctant to advance the timing.

 

Obviously getting it to a rolling road would be best and I will when funds permit but for now I just want to set it up as best I can my myself. 

 

Any input greatly appreciated 🙏

[timmy850]

If you have the MAP sensor in the programmable unit then it should be used in place of the vacuum advance. It normally add something like 5-10 degrees under part throttle for improved performance and economy

What coil are you using? Is it running a ballast resistor?

Is the pinking issue new now you’ve changed the distributor- was it running ok before?

[ASeriesPower]

The 123 app has a centrifugal curve and a MAP curve, but the distributor comes with the option of vacuum connection or no vacuum connection. I bought with vacuum as I was told it improves part throttle running and drivability. I Don't know if these units actually have a mechanical advance caused by vacuum from the inlet, but my guess is not. I don't know. Pretty sure i've got a non ballast coil. It's been pinking since I've put the cam and distributor in and set the curve above as a starting point. May also be running a bit rich under wide open throttle...could this cause pinking? thanks for your input

If you have the MAP sensor in the programmable unit then it should be used in place of the vacuum advance. It normally add something like 5-10 degrees under part throttle for improved performance and economy

What coil are you using? Is it running a ballast resistor?

Is the pinking issue new now you’ve changed the distributor- was it running ok before?

[sonscar]

Not at all familiar with this system,can you program your own curves?If you can then program map curves.This way you can alter advance based on the engines load as well as RPM.Steve..

[ACDodd]

Have you verified the actual timing being delivered by checking with a strobe light?

What is your compression ratio?

When you installed your cam, what figure was it timed into?

Ac

[StefanMini]

I have simular specs and the 266 cam (just with an ported head), and also drive with an 123 ignition system. I have the basic one with 16 curves to choose. I currently drive with curve no. 1. That's 10 degrees @ idle, 16.7 degrees @2000 rpm, and 28 degrees @5000. Engine is running very well and pulls from idle till 6500 rpm like a beast! Part throttle also running great with this curve.

[timmy850]

The 123 app has a centrifugal curve and a MAP curve, but the distributor comes with the option of vacuum connection or no vacuum connection. I bought with vacuum as I was told it improves part throttle running and drivability. I Don't know if these units actually have a mechanical advance caused by vacuum from the inlet, but my guess is not. I don't know. Pretty sure i've got a non ballast coil. It's been pinking since I've put the cam and distributor in and set the curve above as a starting point. May also be running a bit rich under wide open throttle...could this cause pinking? thanks for your input

If you have the MAP sensor in the programmable unit then it should be used in place of the vacuum advance. It normally add something like 5-10 degrees under part throttle for improved performance and economy

What coil are you using? Is it running a ballast resistor?

Is the pinking issue new now you’ve changed the distributor- was it running ok before?

From reading the manual, if you have one with a vacuum connector then the port on the distributor is the MAP sensor. It won’t mechanically advance the timing under vacuum. You’ll need to add the vacuum via the MAP curve

It says the dwell setting is automatic, and it can run a >1.0ohm coil
https://123ignition....al_TUNEPLUS.pdf

If the engine was running fine before and it is pinking now then I’d guess it’d be timing related rather than the fuel mixture if everything else is the same. As AC mentioned, have you verified the timing with a timing lamp to make sure the numbers in the program match reality?

Edited by timmy850, 26 April 2023 - 09:26 PM.

[ASeriesPower]

Not at all familiar with this system,can you program your own curves?If you can then program map curves.This way you can alter advance based on the engines load as well as RPM.Steve..

Yes Steve you can program your own centrifugal and MAP curve with this system. Thanks

[ASeriesPower]

Have you verified the actual timing being delivered by checking with a strobe light?

What is your compression ratio?

When you installed your cam, what figure was it timed into?

Ac

I have not verified the timing with a strobe light recently so will do that in due course. 

Compression ration - not sure. Standard dish (i think) pistons in +30 bores with a stage 2 minisport head (assuming normal cc chambers as I didn't request a specific cc at the time)...so I don't know honestly exactly what the compression ratio is. 

I should mention its a midget 1275 engine (in a minor) in case that makes any difference with it not being an A+ engine. (sorry to crash the mini party!!)

I can't remember now exactly which figure I timed into, but i'm pretty sure I would have used the 24/56 61/29 figure as stated for the MD266 on the kent cams website. First time installing a cam but I checked it was in the correct position many times and finely adjusted with a vernier pulley from minisport. 

Thanks 

[ASeriesPower]

I have simular specs and the 266 cam (just with an ported head), and also drive with an 123 ignition system. I have the basic one with 16 curves to choose. I currently drive with curve no. 1. That's 10 degrees @ idle, 16.7 degrees @2000 rpm, and 28 degrees @5000. Engine is running very well and pulls from idle till 6500 rpm like a beast! Part throttle also running great with this curve.

Thanks for this, it may just be that my timing too advanced across the whole range with my current curve then. Will try yours an see what happens!

[ASeriesPower]

 

The 123 app has a centrifugal curve and a MAP curve, but the distributor comes with the option of vacuum connection or no vacuum connection. I bought with vacuum as I was told it improves part throttle running and drivability. I Don't know if these units actually have a mechanical advance caused by vacuum from the inlet, but my guess is not. I don't know. Pretty sure i've got a non ballast coil. It's been pinking since I've put the cam and distributor in and set the curve above as a starting point. May also be running a bit rich under wide open throttle...could this cause pinking? thanks for your input

If you have the MAP sensor in the programmable unit then it should be used in place of the vacuum advance. It normally add something like 5-10 degrees under part throttle for improved performance and economy

What coil are you using? Is it running a ballast resistor?

Is the pinking issue new now you’ve changed the distributor- was it running ok before?

From reading the manual, if you have one with a vacuum connector then the port on the distributor is the MAP sensor. It won’t mechanically advance the timing under vacuum. You’ll need to add the vacuum via the MAP curve

It says the dwell setting is automatic, and it can run a >1.0ohm coil
https://123ignition....al_TUNEPLUS.pdf

If the engine was running fine before and it is pinking now then I’d guess it’d be timing related rather than the fuel mixture if everything else is the same. As AC mentioned, have you verified the timing with a timing lamp to make sure the numbers in the program match reality?

 

Thanks for the info and the link, will have a read. Haven't yet verified the timing with a strobe but will get onto that. Looks like i need need to program in a MAP curve then to compensate for load. Will try to check the spec of my coil but it's been on the car since i bought it and worked on a standard 1098cc setup that I had back then so I guess it's fine? Thanks

[sonscar]

The golden rule which should never be broken is to verify the timing before any adjustments,how do you know what you are adding if you do not know your start point.I use standalone ECU on two of my non Mini cars and MAP based timing can give huge benefits.Steve..

[timmy850]

I wouldn’t bother doing any changes until you verify the timing

Is the idle 10 degrees like your program or zero? You might only be getting a total of 20 degrees

Or is the idle 20 degrees and you’re getting 40 degrees total?

[ASeriesPower]

Thanks steve I will verify the timing before changing anything. Good to know re. benefits of MAP curve

The golden rule which should never be broken is to verify the timing before any adjustments,how do you know what you are adding if you do not know your start point.I use standalone ECU on two of my non Mini cars and MAP based timing can give huge benefits.Steve..

[ASeriesPower]

I wouldn’t bother doing any changes until you verify the timing

Is the idle 10 degrees like your program or zero? You might only be getting a total of 20 degrees

Or is the idle 20 degrees and you’re getting 40 degrees total?

The setting on my centrifugal curve graph is 10 degrees at idle, so i guess that's total distributor advance. I'll have a reread of the manual to double check. It ticks over pretty comfortably so i'd be surprised if I was getting a total of 40