{"product_id":"holley-step-down-leg-booster-sizes-160-170-180","title":"Holley Step Down Leg Booster Sizes .160 .170 .180","description":"\u003ch3 class=\"heading has-breadcrumbs\" tabindex=\"-1\"\u003eHolley Step Down Leg Booster Sizes .160 .170 .180\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eHolley downleg step boosters are performance carburettor venturi boosters featuring a stepped or profiled underside.\u003c\/span\u003e They improve high-RPM airflow and signal strength in large-cfm carburettors (typically 830 CFM or bigger), helping fuel atomization for racing applications\u003c\/p\u003e\n\u003ch3\u003e Key Features \u003c!--TgQPHd|||[]--\u003e\n\u003c\/h3\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eDesign:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Machined with a step cut on the bottom side to manipulate the pressure drop (signal) and maximize air flow.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eOrifice Sizes:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Frequently found in sizes like 0.160\", 0.170\", or 0.180\" depending on the fuel delivery needs.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eApplication:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Ideal for high-performance and large-bore Holley 4150-style carburettors or custom billet main bodies.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eInstallation:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Considered an advanced component requiring specialist tools or professional carburettor builder setup to replace safely in the main body\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cspan\u003eHolley Step Down Leg Booster requires specific tooling to properly and securely install it. If you do not have the required installation tooling we can provide a fitting service\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eHolley Step downleg boosters \u003cstrong\u003e(also known as drop-leg or dogleg boosters)\u003c\/strong\u003e are\u003cspan style=\"color: rgb(0, 0, 0);\"\u003e venturi booster configurations designed to project the fuel discharge nozzle down into the main airflow path.\u003c\/span\u003e They offer a stronger low-end and mid-range signal than straight-leg boosters, providing superior throttle response for high-performance street and race applications\u003c\/span\u003e\u003c\/p\u003e\n\u003ch4 class=\"otQkpb\" role=\"heading\"\u003e\n\u003cspan style=\"text-decoration: underline;\"\u003eHow Step Downleg Boosters Work\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/h4\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eAirflow Signal:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e They sit inside the carburettor venturi ring, leveraging air velocity to draw fuel out of the main well.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003ePlacement:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e The nozzle bends downward (\"downleg\"), positioning the fuel exit point deeper in the throat for efficient atomization.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eComparison:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e They provide a stronger signal than basic straight-leg boosters, but a weaker signal than multi-hole annular boosters.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cul class=\"KsbFXc U6u95\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/ul\u003e\n\u003cdiv class=\"Fsg96\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003ch4 class=\"otQkpb\" role=\"heading\"\u003e\n\u003cspan style=\"text-decoration: underline;\"\u003ePerformance and Applications\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/h4\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eStreet\/Strip Balance:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Commonly found on performance models like Holley 4150 and HP-series carburettors.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eOrifice Sizing:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Available in varying inner diameters (such as .160\", .170\", or .180\") to tune air speed and signal strength for different engine displacements.\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\"\u003e\u003cspan class=\"iNqyIf\"\u003e\u003cstrong class=\"rQesXe MPyX\"\u003eTuning Adjustments:\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e Transitioning from straight-leg to downleg designs alters the booster signal, which may require re-calibrating idle circuits, air bleeds, or main jets.\u003c\/span\u003e\u003c\/div\u003e","brand":"Holley","offers":[{"title":".160","offer_id":46351387590753,"sku":"HP53SD-39","price":16.5,"currency_code":"AUD","in_stock":true},{"title":".170","offer_id":46351387623521,"sku":"HP53SD-53","price":17.5,"currency_code":"AUD","in_stock":false},{"title":".180","offer_id":46351387656289,"sku":"HP53SD-46","price":16.5,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0568\/2282\/5057\/files\/step1.png?v=1786187591","url":"https:\/\/carbparts.com.au\/products\/holley-step-down-leg-booster-sizes-160-170-180","provider":"Carb Parts","version":"1.0","type":"link"}