Super Stock/GT Fuel Injection Rules

Frechles71 · 12-05-2013, 06:20 PM

So I am hoping to pick some brains and gain some knowledge on Super Stock/GT fuel injection rules/regulations. I’m confused with what I have seen at the track compared to how I read the rules. I’m looking at maybe putting a FI combo together so any incite is appreciated! Sorry if this gets too long, hopefully you stay interested until the end haha.

OK, the way I interpret the rulebook with my lawyer hat on: Both Super Stock and GT sections of the rulebook are completely silent on anything dealing with fuel injection. The Intake Manifold segment under Super Stock (Section 11A) does say that any intake manifold can be used, however; it has to be of the same configuration as original for carburetor used. No mention of throttle body, plenum, runners, etc.

This falls back to the Super Stock Section 11A intro caveat that: Requirements and specifications for all Super Stock categories are the same as those for Stock Cars unless otherwise specified herein. This leads to the Fuel Injection segment under Stock (Section 10A) which requires: “Fuel injection must retain OEM throttle body(s), plenum and manifold.” There is no mention of modification restrictions for the throttle body(s), plenum and manifold in this section.

So to sum it up with my verbatim interpretation: A Super Stock/GT car running a fuel injected combo should be running the OEM throttle body, plenum and manifold for the year motor claimed, as directed by the Stock car rules since the Super Stock/GT rules are silent. The Super Stock/GT Intake Manifold segment is not applicable since fuel injection is not mentioned and only carburetors are specified. I do not see any aftermarket fuel injection manifold/throttle body stuff on the NHRA acceptable aftermarket parts/sizes page, but may have missed something, so used OEM is golden. Since the rules are silent on fuel injection OEM part modification, the throttle body, plenum and manifold can be massaged in any way imaginable.

Just curious how everyone else running FI on Super Stock/GT cars see the rules? I have noticed a few cars this past year running a Victor Jr style intake to a Wilson elbow to a factory type throttle body and I do not see how that is technically legal but was told it is acceptable. Am I wrong with the assumption that the throttle body can be massaged since the rules are silent on the matter? I know there are throttle bore size requirements on the Engine Spec pages but there is no specified +/-.

Thanks!

12-05-2013, 06:20 PM	#1
Frechles71 Junior Member Join Date: Sep 2011 Location: Ohio Posts: 14 Likes: 0 Liked 0 Times in 0 Posts	Super Stock/GT Fuel Injection Rules So I am hoping to pick some brains and gain some knowledge on Super Stock/GT fuel injection rules/regulations. I’m confused with what I have seen at the track compared to how I read the rules. I’m looking at maybe putting a FI combo together so any incite is appreciated! Sorry if this gets too long, hopefully you stay interested until the end haha. OK, the way I interpret the rulebook with my lawyer hat on: Both Super Stock and GT sections of the rulebook are completely silent on anything dealing with fuel injection. The Intake Manifold segment under Super Stock (Section 11A) does say that any intake manifold can be used, however; it has to be of the same configuration as original for carburetor used. No mention of throttle body, plenum, runners, etc. This falls back to the Super Stock Section 11A intro caveat that: Requirements and specifications for all Super Stock categories are the same as those for Stock Cars unless otherwise specified herein. This leads to the Fuel Injection segment under Stock (Section 10A) which requires: “Fuel injection must retain OEM throttle body(s), plenum and manifold.” There is no mention of modification restrictions for the throttle body(s), plenum and manifold in this section. So to sum it up with my verbatim interpretation: A Super Stock/GT car running a fuel injected combo should be running the OEM throttle body, plenum and manifold for the year motor claimed, as directed by the Stock car rules since the Super Stock/GT rules are silent. The Super Stock/GT Intake Manifold segment is not applicable since fuel injection is not mentioned and only carburetors are specified. I do not see any aftermarket fuel injection manifold/throttle body stuff on the NHRA acceptable aftermarket parts/sizes page, but may have missed something, so used OEM is golden. Since the rules are silent on fuel injection OEM part modification, the throttle body, plenum and manifold can be massaged in any way imaginable. Just curious how everyone else running FI on Super Stock/GT cars see the rules? I have noticed a few cars this past year running a Victor Jr style intake to a Wilson elbow to a factory type throttle body and I do not see how that is technically legal but was told it is acceptable. Am I wrong with the assumption that the throttle body can be massaged since the rules are silent on the matter? I know there are throttle bore size requirements on the Engine Spec pages but there is no specified +/-. Thanks!