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Title: baseline jetting for 40 DCNF's Post by: Glauco on April 21, 2023, 11:36:55 am Hello,
I'm looking for a good baseline to start my jetting to go from IDF's to DCNF's on my 1641. engine specs are: mahle P&C scat cw crank scat connecting rods Scat 170mm pulley and lightened flywheel stock heads with the "how to hodrod a vw" port job and SS valves. oteva springs and titanium retainers. Engle FK65 with 1.4 rockers (rather 1.5, lift measured out at 12.95mm) MSD 6AL ignition S&S 1 1/2 header with S&S DQP running good on the IDF's, rev limiter is set on 6300 and I have the feeling the engine likes to go there, even with the fk65. But I have a killer set of 40 DCNF-12's on DDS manifolds and linkage I'm dying to use. they received a full overhall and I did the berg mods, including the snorkel for the float bowl. what would be a good baseline? I was thinking to go with 28mm vents, possibly 26/30 or 28/32 Berg style venturies 200 Air corrections - 125 mains - 50 idles I was thinking to use the 50 Idles because of the very large pump jet cam that is in it now. not sure on the pump jet size. I have a set of 26mm and a set of 32mm vents as well, 26 would be to small I presume, might try the 32's later in the tuning stage as well// Title: Re: baseline jetting for 40 DCNF's Post by: Lightning on June 30, 2023, 22:43:02 pm Hei,
have an engine spec. fairly close: stock 1585cc mahle P&C stock crank stock connecting rods CB serpentine pulley stock lightened flywheel machined for ignition pickup stock heads with my own port job, app 9:1, SS valves, stock springs and retainers. Stock cam with 1.25 rockers MegaJolt ignition Memminger Sebring replica exhaust 40 DCNF's in original state expect cold start system blocked 28 vents 145 main jets F24 emulsion tubes 210 air correction jets 052 idle jets port matched Scat manifolds Runs pretty well with a slight flat spot mid range. Easily scares unsuspecting BMW's when lights turn green :D [attachment=1] Title: Re: baseline jetting for 40 DCNF's Post by: Glauco on July 05, 2023, 11:07:22 am thank you for your input, I might try that combo.
I installed an AFR-meter just to make sure I wasn't doing anyting wrong and I had to bump up to 55 idle to get it right. also changed the 200 air for a 180, but now it's a little too rich, so might change back to 190 or 200 just to doubble check or I install the 220's I have and try a bigger main jet, also a possibility Glauco |