Hi im running a single 45dcoe on my l18.
Its running high comp head, wade 72cam stockish rebuilt bottom end ekec dizzy and extractors through a 2inch exhaust

im running the following in my carb
32mm chokes
160 air corrector
f2 tube
130 main jet
50 idle and the other says 50f2

have been advisded to try 150 air corrector to fatten up top end as it chokes and detonates at about 6k
was running 95 octane fuel but will use 98 from now.
with the ported head work and rest should be good for 7-7.5k by my under standing.

Any advice for jets etc? Got offered to try some 38mm chokes but seem too big from my reading

Not exactly what your after but this info i stumbled accross today was interesting regarding jetting

http://cmy510.tripod.com/tech.html

Thats for duals not single dcoe. Cheers for link.

im thinking of dropping air corrector to 150 or 140 even

pulls hard to 6k then detonates as to lean up top.
larger chokes. 32 too small so 34 or 36. But will loose low down

Go up in choke size, possibly the 72 deg cam and the overlap/duration is causing a little reversion at higher rpm.
Dropping to 150 Airs will reduce lean out.

The stock hitachi down draft runs 2x32 ? chokes, common upgrade was a Weber 32/36, the 36 was the mechanical secondary, to give a bit more total airflow, but these would get a bit wheezy above 6500

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Yep, i race a Datsun, and I drive a truck, sometimes I get confused, and then the truck goes fast, and the Datsun gets a lot of boxes shoved into it. AWW GEE

Cheers jase. So up to a 34 or 36 choke? Wont I need new mains etc and start from scratch with air correctors etv.

Jetting will depend on the type of manifold.
If its a cross over then it will need to be on the rich side
as these manifolds suffer badly from reversion.

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A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

F2 emulsion tubes will cause a rich flat spot.
They are a Methanol tube.
Lots of them around as a fair percentage of new webers were sold jetted for cooper S'.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

non cross over baz

At least you are half way there with that manifold.
I would start with the idle jets & emulsion tubes.
If these are not right then it makes all the rest of the jetting difficult.
Like building a house & doing the foundations last.

That said, I am not a fan of single DCOEs. on L series.

Street use with 72 cam, max 34mm chokes. Single or twin.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Its not purely street baz. Mainly trying set up for hillclimb and slower trackdays. Also some spirited cruises.

Its no daily but dont want a total pig if stuck in traffic.

If you have been offered 38 mm chokes I would try these as the SSS su carbs are both 38 mm throats so you should be letting the same ammount of air thru the carbys.
I'm running 32 chokes with my l18 on 45's and these seam great on the street and they pull like a tractor however the engine dosnt want too rev past 6 but I suspect the cam is causing that(25/65) if you want I'll remove the jets tomorrow and let you know exactly what I'm running.

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Chris Thomas

1971 1600, mild L18, 5 speed

All I want is less to do, more time to do it and higher pay for not getting it done.

Thanks chris. Sounds like you have similar power delivery to mine. Would be appreciated

Hey mate, I just checked my jetting, keep in mind I'm running twins so I'm not sure how much different that will make things.
Idle, 50-f9
Emulsion tubes, f11
Main jet 125
Air correctors , 200
32 mm chokes
4.5 aux venturie.
That is on a long rod L18 running L16 con rods, flat top pistons, ported a87 head and datrally manifold with a 25/65 cam. I do feel it floods a little bit every now and then but overall I am happy with how it runs considering I have done all the tuning myself. It's an awesome street engine, pulls hard from 2000 to 6000 rpm.
Hope this helps

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Chris Thomas

1971 1600, mild L18, 5 speed

All I want is less to do, more time to do it and higher pay for not getting it done.