THE NEW GT-LITE RULES SUCK!!!! So much so, that I abandoned my GT-4 project.
For the 2005 season, the 32mm restrictors kill the Opel. Keep in mind that "former GT5" cars have no such restriction. "Former GT5" cars are also given a 5% weight reduction in addition to the 2.5% weight reduction they were given last year. So, we went from 45mm side-draft FI throttle bodies to 32 mm restrictors, and they lost 7.5 % of their weight. (By the way, the F-Production Opel is required 32mm chokes in the side-draft carbs, but is allowed to weigh 100 pounds less than the GT-Lite Opel.)
SCCA said that they will make competition adjustments to GT-Lite as necessary throughout the 2005 season. Yea... right! What that means is that those who "sand-bag"... or curry favor within SCCA will be given allowances.
One thing for sure... SCCA did not take into account the relative impact of the restrictor on various power plants... they just said "everything with 2 valves per cylinder gets a 32mm restrictor. Do not expect any "adjustments" for the Opel to correct this "blanket blunder". Despite numerous requests, SCCA has provided no adjustments to the GT-4 Opel for over 10 years... there's no reason to expect fair treatment now.
For the future, all GT-Lite (all GT cars for that matter) will be required to have a single "airbox" with a restrictor plate for the inlet. What Rally-Bob says is true... an air box will be better than the 32mm restrictors... except that it is likely that the restrictor for the "airbox" will be far too small for the Opel. In any event, the "air-box" won't fit in between the side-drafts and the fender well.
The inlet air-box requirement forces any one considering going to GT-Lite to have at least a full-tube-frame front end. This means that there will be no realistic way to "migrate" from other classes. (Almost all "tub" cars will have the same problem... not just the Opel.) So, in the end there will be fewer cars going into GT... and I am predicting that GT-Lite will loose "national eligability" due to low participation. (SCCA requires minimum participation numbers or a class is downgraded from "National" to "regional" status.) So I'm going to call this air box the "SCCA Blunder Box"
To me, it's clear that the SCCA has the pooch "firmly by the hind quarters".
Do I sound bitter? Your damned right.
I spent 2 years doing engine/ induction development... and last fall I spent over $20K buying new stuff for a GT-4. Only to discover that dispite what the membership wanted... (I know of no GT-4 or GT-5 driver I have competed with in the So-Pac division or surrounding divisions who wanted this change)... dispite no clear way to equate GT-4 & GT-5 cars... dispite sound recommendations to improve GT-4 & GT-5 class participation... despite anything contrary to this bad idea... someone at SCCA made this bad idea happen.