Idle Jets size icrease

[iceblue]

I am noticing some backfire some firing issues in the 2200 / 2300 rpm range.
Above 3000 RMP all appears to be fine.

I was reading online http://dino246blog.blogspot.com/
The symptoms I am describing is due to low Octane gas vs back in the 70's
The remedy is to increase my Idle jets from .050 to .055

I am not sure what is on my car at the moment, probably .050? I will ask my mechanic on Monday.

Does anyone know what Idle jet size they are using?
Has anyone had to increase their Jet size from .050 to .055

Thanks
Olivier

[Stefan2000]

Here i wrote something about what i had to change and to what extend to get the carburettors in tune.
viewtopic.php?f=4&t=184&start=30

[alh]

Factory idle jets are.50 from what i remember, depending on the fuel quality you might want to go to either .55 or .60 for the idle jets.
My current setup is .60 idle jets for European Super fuel, which works quite nicely.

Also check the advance curve, you should see around 20º crankshaft advance at 2000 RPM.

[Stefan2000]

This is based on a 2000 with DCN carburettors. The Original setting is different from the later DCNF's and that might be one of the differences between the Original 50 and 55 idle jets.
At least on the dyno it was quite clear that i needed a size larger idle jets (and mains and correctors as well) so you could try 55's instead of the 50's first and might end up with 60's for best performance.
Best thing in my opinion would be to go for the 55's/60's for now, run the engine in for 1 or 2000km and than put it on a dyno to have your AFR right over the whole RPM band.