{"product_id":"adopt-s1-s2-overbore-throttle","title":"ADOPT S1\/S2 overbore throttle","description":"\u003cp\u003eAs seen on NISMO S1\/S2 cars, and the R-tune development model. An OE throttle is bored out from 70 to 74.3mm, its barrel is re-shaped, and a larger butterfly assembly is installed.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDevelops 5-7whp above 5500RPM on cammed cars with higher mass flow demand\u003c\/strong\u003e; see AB testing dyno data in slides. Cars approaching 290+ whp will see definite improvement that scales with total air mass demand (ie, cam size or FI). \u003cbr\u003e\u003cbr\u003eEnables a larger throttle body while keeping the same 70mm intake tube size, so no need to re-tune. The smaller diameter preserves charge velocity and keeps response sharp, while still uncorking power.\u003cbr\u003e\u003cbr\u003eA 75mm throttle body will require changing the intake tube and MAF section, resulting in a 14.8% loss in charge velocity; or, a tapered fitting is required, which causes a rarefaction wave that disrupts the second-order harmonic wave scavenging between the runner and airbox, due to sudden change in diameter. This affects WOT power.\u003cbr\u003e\u003cbr\u003eRunning mass calculations for required throttle body size at 6500RPM yields an exact 70mm result, which is why it's the stock size. However, the butterfly valve shaft and throttle plate obscure about 15% of the throttle area, which we're accounting for with this modification.\u003cbr\u003e\u003cbr\u003e\u003cem\u003eProduct of Japan; a small shop in Osakayama, Osaka makes these. Any throttle, including those from other cars, can be over-bored on request.\u003c\/em\u003e\u003cbr\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"TRY-BOX","offers":[{"title":"Default Title","offer_id":43500519424206,"sku":null,"price":600.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0664\/5029\/2942\/files\/overborethrottle70to743.jpg?v=1777067551","url":"https:\/\/adopt-motorsports.com\/products\/adopt-s1-s2-overbore-throttle","provider":"ADOPT Motorsports","version":"1.0","type":"link"}