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MG MGB Technical - 123 best curve?

I have now started some work on this engine which I will specifically surpercharge. I am still gathering 'intelligence', so that I don't make a fool of myself when it is finished. I run a 123 at present on a standard GT, and I am very pleased. Does anyone know what would be the best curve to use? The instructions say that two of their alternate ones are for modified engines, but no other details. I suppose I could just experiment. ( I have no contact for 123 themeselves in Holland, their site say contact local supplier for queries? ) but that initial start up with a new engine will be very scary, I would want it to start and be able to run for the specific 25 or so minutes at 2000 revs to 'break in'. Any thoughts? Mike
J.M. Doust

Hi Mike

Assuming you have an MGA/MGB specific 123? Set the 123 to 6. set the static timing as it says with the instructions. start the car and have a cup of tea while the engine beds at +2000 rpm for 15-20 mins to bed the cam and followers. Then set the max advance to say 30 degrees at 4000 rpm with no vac. This is a starting point. A N Other curve might suit better. Road/Rolling road testing will tell you. To be honest the 123Tune would be better for you.

P Burgess

Hi Mike,

As Peter says, an 123 Tune may best suit you.
123 has a forum that you can join, which is almost as good as this forum.

I run an 123 GB 4 RV, the generic unit, on my stock B, using curve "C". Read this article, even though its for an MGC, the OEM curves are the same as for the B.

Herb Adler

Hi Herb

Curve C is just right for mildly tuned non SC Bs to use the extra high rpm advance to enhance power. It may be a little too much advance for the SC. Curve 6 is shorter and will give more low rpm advance which might suit Mikes engine. As you say the 123Tune is just right and easy to use.

Better go off and get to work before I get sacked :)

P Burgess

Suck it and see, it all depends on your engine and the fuel you use now. Even originally there were about 20 curves for the MGB, although most of those were fighting the continual battle with changing American emissions regs.
PaulH Solihull

Thanks very much gentlemen, I have logged all the info. Peter, I thought you were the Boss, they cannot sack you!. regards Mike
J.M. Doust

I will have to be less tough on myself Mike :)

P Burgess

This thread was discussed between 16/02/2011 and 18/02/2011

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