> >> Is there much of an advantage to fitting the earlier carbs though? >> Power wise I mean? >Bob, >I don't have any data. The guys in Nissan Datsun Sports Owners >Club (NDSOC) who were considered to be the experts when I first >joined in 1990 told me not to waste my time trying to tune the later >carbs. If your engine is modified over standard, there is more >tunability with the earlier carbies! >If you get hold of David Vizards book on tuning Mini engines, he >devotes a couple of chapters to tuning SUs ie modifications that >include things like thinning the spindles, modifying the slides and >increasing the flow rate of the carby quite substantially. I don't think >the later Hitachi SU lends itself to any of this, but others may >disagree? >Steve, what do you think?
Years ago, I ran a set of the flat-tops for awhile after doing a carb rebuild and on a standard L26 they were fine. It is the minimal adjustability that is the problem as Chris says - which includes needles that are'nt easily interchanged with anything else. There is no doubt that for any performance apps the 'round top' 240Z carbs are the way to go. The biggest problem with those carbs is that they use plain bearings for the throttle spindle which inevitably wears leading to air leaks, erratic idle and adjustment difficulties. Interestingly according to the factory manual for the 240Z/260Z carbs the flat-tops actually have a slightly larger throat and so could at least theoretically flow more air, but with limited adjustability any 'advantage' is negated. BTW Chris, if you read this tonight I'll be dropping around one of your VG30 heads in the morning, if your not there I'll leave it in the 'usual place'. The other one I'll get off on the weekend. --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
