48IDA problem with idlemixture -> progression circuit (transition) NOW SOLVED!!

[Rasser]

What A/F ratio are you getting and are you reading it at idle or partial throttle? Im curious.

I´m reading it at cruising speeds (partial throttle). WOT is all sorted out, and it gets the right A/F.

At steady cruising speeds (50-70mph) I am reading 11.5-12, and I am barely just touching the throttle. I would have liked to have it near 14.0 - but if I try to use smaller idle fuel jets or bigger idle air jets, then it doesn´t have good throttle response etc. - so right now it´s a compromise between running right and running fuel efficient (Guess this is why someone invented fuelinjection ;-) )

Anyone else have some A/F readings with IDA´s?

On the SCC bus (82x87mm 1950cc) we have 13-13,5 at full throttle from 2000-5500 and cruising mid 12´s.
48´s with 37 venturies, 60/155/210 jets. No extra progression holes.
Not in your league performace wise of course as it dynoed only 108hp last weekend, but I thought I´d share the numbers anyhow. 

2276 engine is on it´s way into my car this weekend, looking forward to tuning it!

13-13.5 at WOT? - isn´t that a bit lean?

Sure you don´t mean mid 12´s at WOT and 13-13.5 at steady cruising speeds ?

regarding the performance: I only get 136hp from my 1971ccm, but it is also only has a 280 degree camshaft. 
What´s the specs on your 1950 engine, and do you run with the A/F meter in the car on the street?

[BeetleBug]

Thank you for your advise, highly appreciated. Do you think changing the tube will throw my current jetting out the window?

I'm struggling with a slipping clutch and this is the reason why I have not been able to cruise as much as I was hoping this season. Found the reason and will fix it next week. I will post my findings as soon as I have some recorded data. But not WOT??? hmmm, that will be a hard one but I will try my best.

[JS]

13-13.5 at WOT? - isn´t that a bit lean?

Sure you don´t mean mid 12´s at WOT and 13-13.5 at steady cruising speeds ?

regarding the performance: I only get 136hp from my 1971ccm, but it is also only has a 280 degree camshaft. 
What´s the specs on your 1950 engine, and do you run with the A/F meter in the car on the street?
[/quote]

I was recommended 13,5 by some people who know much more about engine tuning than me. The engine feels very good and does not run hot even when you push it.

I´m pretty sure that was the readings, I have the log stored on another computer will check later.

The engine is built by BERGER a couple of years ago for his ghia. I think it´s 82x87,IDA, w100, og mexico heads with harder springs, og heat chambers, bugpack header, home made muffler.

We ran a LM-2 in the car when we drove it up and down the highway for jetting it, but usually no meter.

[Torben Alstrup]

12´s at cruise is RICH! and there is no need for so much fuel, unless there is another problem that needs to be masked by excessive fuel.
13 - 13,5 AFR is ok, as long as you dont go WOT for longer periods of time.
T

[Bobby Welker]

Hello,  I know this is probably a no-brainer, but here it goes.  Pretty much the same problem you are having with my ida,s  mixture screws, idle jet's, vent's, mains, idles, emulsion tubes the whole scenario. So being they were brand new i took it for granted and thought every thing else was ok but not.  I took the top off and to my amazement the needle and seat was unthreading almost completely out.  tightened it up and it was a whole new car.  Hope this helps dude.

[Diederick/DVK]

what is WOT? full throttle?
is there any other way to know or to get an indication of the AFR?

i'm hoping to finish and install my engine a week before EBI and I won't have an LM-2 at hand, still I intend to drive it to Chimay (600km round trip) and I don't want to do any harm to the engine...

thanks.

[Bruce]

what is WOT? full throttle?

Yes, Wide Open Throttle

[JS]

what is WOT? full throttle?
is there any other way to know or to get an indication of the AFR?

i'm hoping to finish and install my engine a week before EBI and I won't have an LM-2 at hand, still I intend to drive it to Chimay (600km round trip) and I don't want to do any harm to the engine...

thanks.

Diederick, do some sensible jetting of the carbs and maybe read spark plugs, of course it will not be 100% optimal but you should be just fine.

[Rasser]

Did some more driving today.

Drove on the highway with constant cruising speed to see what A/F readings i would get up through the rpm/speed range. I discovered that with certain throttle position changes the A/F would drop or raise. This was not speed or rpm dependant, but it was dictated by the throttle postion.
Funny to discover that you can actually see exactly when the progression holes kick in. 
I need to make the # 2 and 4 progression hole smaller, because right now it gets to much fuel when entering the 2. hole the 1. and 2. hole are VERY close to eachother, and then it leans a bit out (descent A/F readings)  and then finally richens again when reaching the 4. hole. You can clearly see the different progression holes kick in on the A/F!

Next up is trying to make the 2. and 4. hole smaller to make the transistion more even. We will see what the A/F meter shows. I will get back next  week when I have tried it.

Research is fun!