nochrome Posted January 12, 2012 Report Share Posted January 12, 2012 Does anybody have any experience/knowledge with boosting SU carbs? Type 3s on nismo itake, l20b, long tube header, lightened flywheel, dual points. I'm wanting to run a small junkyard turbo, maybe 10lbs. If anybody can help, it would be appreciated. Quote Link to comment
Boaty Posted January 12, 2012 Report Share Posted January 12, 2012 If I remember correctly, SU's can't be used on a blow-through setup, but can be used as a pull-through setup. At least that's how it was explained to me one time, since the SU carb's run off of vacuum. (negative pressure = raised piston, etc). I remember seeing somebodies build thread (might not have been on Ratsun) using a single SU carb on a draw-through turbo set up with an old school RayJay kit. Quote Link to comment
ggzilla Posted January 12, 2012 Report Share Posted January 12, 2012 Any carb can be used with a blow-thru system. Just put them in a box. And replace the hollow floats. Quote Link to comment
nochrome Posted January 12, 2012 Author Report Share Posted January 12, 2012 Any carb can be used with a blow-thru system. Just put them in a box. And replace the hollow floats. the carbs don't run on "vacuum", they respond to pressure diferentials. so theoretically, if the piston sees 8psi under it and 7psi over it, it should lift Quote Link to comment
nochrome Posted January 12, 2012 Author Report Share Posted January 12, 2012 I've thought about the box, but mounting the carbs is already difficult. with a box, almost impossible Quote Link to comment
ggzilla Posted January 12, 2012 Report Share Posted January 12, 2012 Impossible? Tell that to the dozens of guys already done it. Even twin SUs have been done blow-threw but that is a bit cumbersome. Most guys use a single carb -- which will flow almost as much as twins if you use a large plenum. And you can boost them outside a box too. If you are talking Datsun Hitachis, make sure the throttle shafts are tight, and use solid floats. If you are talking actual S.U.s, there are other special changes you can make. Quote Link to comment
Guest kamakazi620 Posted January 12, 2012 Report Share Posted January 12, 2012 Heres an SU pull threw system http://www.motormavens.com/2009/10/center-stage-garage-autohero-datsun-510/ Quote Link to comment
erichwaslike Posted January 12, 2012 Report Share Posted January 12, 2012 this has already been covered... i know cause i started a thread on it b4 that went a few pages... http://community.ratsun.net/topic/29800-turbo-setup-with-stock-su-carbs/page__p__444442__fromsearch__1#entry444442 Quote Link to comment
nochrome Posted January 12, 2012 Author Report Share Posted January 12, 2012 didn't see that thread earlier, thanks for the link Quote Link to comment
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