Dellorto pump jet change - vertical to horizontal

[Si_130/5]

Our DHLA40 accelerator pump jets are vertical, the holes being at the bottom and so discharging fuel downwards in to the venturi to be drawn in to the bores by induction suck.
Has anyone tried using the horizontal jets found in the DHLA45 of the Elite/Eclat/Esprit which squirt the fuel forward in to the bores and is there an improvement?

Many thanks,

Si

[terryp]

Yes , better starting and slightly better progressive acceleration
I beleive the horizontal ones are just the later version. Matt at http://www.dellorto.com/ can help

All the best
Terry

[Si_130/5]

Thanks Terry,

Your car looks great, what's the weather like in the Charente Maritime?

I spoke to Dellorto and it seems a change to horizontal jets requires a reduction in jet size so here is the next question;

My two sets of DHLA40s, both from big valve engines, and those of a friend all have .045 cm vertical jets. The Lotus manual suggests .035 (presumably vertical too) as does the Miles Wilkins book. Has anyone found an ideal horizontal jet size for their twin cam, ie. no bogging down or flat spots and a keen acceleration?

Many thanks,

Si

[terryp]

I use .35's but I have used .45's with there is a little difference, mainly depending on atmospheric conditions!
elan-plus-f13/hesitation-again-acceleration-but-this-time-dellortos-t17462.html

Bon Courage!
Terry

[Si_130/5]

Thank you Terry,
In your thread you found 35 pump jets cured the hesitation problem experienced with the vertical 45s when running hot. On that basis I'll try the same.

Has anyone else experienced a difference changing to horizontally squirting pumps jets?

Thanks again,

Si