To jump in the 123 tune pool..do they come with a starter curve loaded or do you need to put one on the get going?... Sent from my SM-G973F using Tapatalk
I don't remember, but it's very easy to put one in. You'll see some of mine a page back including a stock 205P and measurements of my actual 205P.Good enough starting point.
Mine wasn’t the Bluetooth one. It was the preloaded curve model. For this you turn a mechanical, screw, dial for the best curve for your needs. I just did the standard zero one
The bluetooth one's don't come with any curve's in, or at least mine didn't when I got it 2 years ago
Not everyone. It does go to show that pretty much any car/engine needs the same advance though the fatter your pistons the more advance you need. Well, actually it's great. You can advance or retard the timing in 1 deg steps as you drive. I remember advancing mine at 40 mph and having to take my foot off the accelerator to stay in the speed limit. It's not until you can do these things that you find out how much effect they have.
Would have gone stock 123 but couldn't get one sharpish to get on road again so new toy is ready to go in when work is over...
There is another trick in the book .. if you plumb up the retard hose to the 123 vacuum advance you can set it for the USA emissions 5 degrees retard, then use the centrifugal curve to give an 009 like curve on top. May be something here for those trying to follow instructions for a pair of USA Solex PDSIT carbs.. Some other curve bending using one vacuum connection plus a speed related curve with retard at idle, might emulate a DVDA well enough to keep the carbs happy with 5 degrees retard at low idle, 7.5 degrees advance just off idle and then a combination of vacuum advance and speed related advance. https://www.thesamba.com/vw/forum/viewtopic.php?t=771786
Why on earth would you want to do that! Even the Yanks do away with the retard unless they're stuck in California. There's nothing special about the PDSIT carbs supplied to the US market, just the distributor.
With the preloaded curve type i found it useful that one or two of the curves had a 20 degrees advance differential between idle and 3500 + rpm. This ment I could set the idle advance at 10 deg btdc and the idle screws could be a bit further out on the idf’s so as not to uncover the progression holes. I have a decent 850rpm idle, which is correct for an automatic & a max advance of 30 btdc with vac disconnected.
Same set up on 2 litre T3s btw. Just an extra take off for vac hose and of course a retard on the van!
So.. just to double check.. i set the green loght to come on at 7.5 btdc just like the stock 123 amd then put in the curve like they say adding to the 7.5 maxing at 20 deg ish to get 28 max advance totat not setting light to TDC and adding a full curve.. just asking as it runs rubbish at first set up... the tin top runs great now on the donated stock 123!.. Using a starter curve of ...(ill drop the 25's to the 20 if i get the lower end going ok.) And MAP
Might be that rapid rise from 7.5 at 1100 to 22.5 at 1600. Try more like this. I'd only got to 17.5 at 1600. I set the vac curve for the advance of a 205p but to the max vac the 123 app measured. If yours measures different vacuum you'll have to adjust accordingly.
So the 7.5 btdc green light is correct starting point then?... I tried a gentler curve at first after reading this thread but it was even lumpier..got the numbers off the website for a one fits all curve. Ill make one to match that curve and play again on the light tomorrow. Idle is down to 600ish now on an engine that was about 1000ish on the old 123 I moved over to the other van with nothing but a distributor swap to cause it.. ...unless I knocked something....which is always possible when mr cackhands is in town!.. dont want to adjust revs back up on the carbs untill i run out of ideas . Sent from my SM-G973F using Tapatalk
Yes, but, have you checked with a timing light while it's running that this is what you actually have i.e. ticking over at 7.5. IIRC the green light thing was more like setting static timing and might not be super accurate, more like good enough to make it run. If the idle has slowed from 1,000 to 400, I suggest you're ticking over at about 3 or 4 degs, maybe even less and so when you try and pull away it's not going to be good.
