As wiring harness and components are ageing, I am considering
changing L-28 fuel injection motor to carbs. If doing this swap,
which carbs would be better, The dual weber downdraft carbs, or the
early SUs? The car is occasionally in autocross competion and more
often on street, bottom end is stock.

Has anyone ever run either of these set-ups with turbo?

Thanks

 

I am using the Duel DGV kit from red line with N36 manifolds on my L28, but my setup is radical, 268deg .474" cam, 10.5/1 comp., heavy porting, header-2 1/2 pipe. These are a little big for you stock engine, but could very easly be jetted down. I have done a lot of research on carbs for the Z and I will tell you what I have learned. Nissan did it's homework with the duel carb setup. The pulse pattern is as good its going to get, not including 4B converson yuck. This is the pattern with duel carbs, (101010101010101), three carbs,
(10010100101001). Triple DCOE's it have lots of fallbacks and are not that good on a stock motor, on a race motor watch out! So that leaves good old SU's, (very good carbs). If your L28 has a one hundered percent volumentric efficiency at 7000 RPM it would only need 340cfn. SU's flow 300cfn, Ztherapy can make them flow then needed 340cfn. So there it I just spit out everything I know. Hope it helped.

 

Davis:

Thanks for the reply. I have an option to buy either of these, set-ups, but SUs will need rebuilding. I plan to wait until I see what condition they're in before deciding.