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Author Topic: More jetting, looking forward to rolling road session  (Read 1548 times)
Anders Dinsen
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« on: April 02, 2009, 08:26:45 am »

I have a moment to make some jottings before leaving for Provence in the Grand Espace.

The pump has really been running well - glad to have that sorted!

So I've been playing with jets again, and decided to try the 45F8 in the idle. Other idle's I've tried are: 50F9 and 55F8, both of which I think are a little too rich. The results are promising, but the change obviously did cause some other challenges a bit higher up in the range, where a flatspot occurs in the transition to the main circuit. This could be compensated by going richer in the main jet, but it doesn't appear to produce full power higher up then, and it hasn't cured the flatspot completely.

My conclusion so far is that while a 45F8 may actually work well, it may take some other changes to get it perfect, and this time I'm thinking of the choke tubes. The chokes that came with the carbs are rather large for a 40DCOE: 36 mm. Murena S was shipped with 34's in the 40 mm Solex carbs, and this is probably a suitable solution for a road car.

Here's the link to my jetting chart:
http://tmp.dinsen.net/murena/jetting.html

On the other hand: I know it can be tuned to run reasonably well (though probably a bit on the rich side) with a 50F9 in the idle and the 36 mm chokes and the universal F16 emulsion tubes, and the 36 mm chokes will certainly favour the top end, so why not go all the way: Forget fuel consumption in city driving, and go for a low end driveable, but high performing top end?

April 27th is scheduled for a rolling road tuning session at a Swedish tuning company: http://www.ft-tuning.se/
I'm going to take advantage of the advantageous DKK/SEK exchange rate, and I'm really looking forward to the trip to Skċne, which will also mean a chance to meet Helge, the owner of the white 530 that participated in last summer meeting (which I couldn't make).

Cheers to all,
Anders Cool

Here's a photo of my new engine wiring loom:

« Last Edit: April 02, 2009, 08:29:02 am by Anders Dinsen » Logged

'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
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