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Re: SU needle profiles

To: datsun-roadsters@autox.team.net
Subject: Re: SU needle profiles
From: bill/liz wessel <bwessel@itis.com>
Date: Sun, 21 Feb 1999 01:24:05 -0500
>hello all,
>
>     A while back someone posted the profiles of the various SU needles
>available. If someone has that handy could you please send me a copy. I
>finally got my oxygen sensor together and I am going to try out the various
>needles and see what they do. Also, I'll be bringing it to Shasta and would
>love to try it out on anything that will hold still long enough.
>
>                                     keith0alan@aol.com

Is this the one?

>Mime-Version: 1.0
>Date: Sun, 8 Feb 1998 01:22:19 -0500
>To: datsun-roadsters@autox.team.net
>From: bill/liz wessel <bwessel@itis.com>
>Subject: 411 SSS carbs/needle charts
>Sender: owner-datsun-roadsters@autox.team.net
>Precedence: bulk
>Reply-To: bill/liz wessel <bwessel@itis.com>
>
>>On the 1600 411's - they were all "SSS" badged. Not speed equipment,
>>but they replaced the 1300 engine with the R-16. All R-16's were
>>fitted with twin SU's (for USA market).
>>
>>The manifold was different, might have had a higher angle as the hood
>>would have been higher in the Sedan, than roadster.
>
>So, is there a performance advantage here or not? And will they fit under a
>roadster hood?
>
>>For the 1600 there was a chart of Needles in the "How to Modify your
>>NIssan/Datsun OHC engine" by Frank Honsowetz.
>
>Yep, you know, right after I posted this query, I went to my "library" and
>opened nearly to the exact page and saw the chart. I'll reproduce it here
>for those of you who don't have a copy of the (excellent) book. I got a
>copy through interlibrary loan and photocopied it (1986, ISBN
>0-89586-353-7).
>
>90-Series SU Carburetor Needles
>Diameters given are from shoulder to tip of needles
>0.00, 0.100, 0.400, 0.700, 1.00, 1.400 down
>
>SSS M-66 (16354-22011)
>0.089, 0.087, 0.081, 0.074, 0.0685, 0.064
>
>GX M-83 (16554-H2316)
>0.088, 0.0875, 0.0815, 0.0755, 0.070, 0.0625
>
>M-70 (16354-A7710)
>0.089, 0.088, 0.082, 0.074, 0.068, 0.060
>
>M-43 (16354-15810)
>0.091, 0.0875, 0.081, 0.075, 0.0695, 0.0665
>
>M-39 (16354-14610)
>0.090, 0.088, 0.082, 0.076, 0.071, 0.062
>
>There are other needles listed:
>M-76 (16354-A8710)
>0.088, 0.087, 0.081, 0.074, 0.069, 0.0635
>
>M-73 (16354-E3210)
>0.0885, 0.087, 0.081, 0.075, 0.070, 0.065
>
>M-87 (16354-H6000)
>0.0875, 0.086, 0.080, 0.0735, 0.0685, 0.063
>
>M-6 (16354-16710)
>0.0895, 0.0875, 0.082, 0.076, 0.073, 0.070
>
>M-26 (16354-10400)
>0.090, 0.088, 0.0825, 0.078, 0.072, 0.064
>
>M-15 (16354-12210)
>0.090, 0.088, 0.0825, 0.0775, 0.072, 0.0635
>
>Now, what do you make of all these numbers? Well, the smaller the needle
>diameter, the richer the mixture. The richer the mixture the better for
>racing?...not necessarily. The richest needle I see is the M-70; the part
>number indicates this was used (optionally?) on the late-model, smogged
>cars. The next richest, the M-39 was the early stock 1600 needle. I believe
>the M-43 was a "high altitude" needle option, hence it's one of the leanest
>(pack a set for Shasta).
>
>I don't know enough to say what is best for racing. Honsowetz mentions the
>SSS but does not discuss the merits of the needles. Neither does Bob Waar
>(How to Hotrod and Race your Datsun, 1984, ISBN 0-936834-41-2). The Sharp
>manual suggests going to .100 RH needles* and jets but never mentions the
>SSS.
>
>I'm looking for advice. SSS carbs and manifolds are available (two people
>have offered them for sale, recently). But in light of the above info (and
>the possibility the SSS may not fit under the hood), maybe its better to
>stick with the early stock carbs and the M-39 or M-70 needles? Do we have
>any SU tuners out there?
>
>* RH needle (from my Haynes SU book, if I'm reading it correctly)
>0.100, 0.095, 0.0878, 0.078, 0.069, 0.057

Bill Wessel
Madison, WI
68 1600, 69 2000,
67 GP roadsters



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