Plastic is Fantastic – Part 5, the Eagle Has Landed
In installment 4 of the Polystrand GT-Lite Project, we made our deadline and had the car ready for a couple of trade shows. Granted, we had some issues that we needed to take care of – we checked the rulebook, and it turns out the wheelbase was a bit too long – and the rear of the unibody was found to have been pushed over to the left about an inch from an on-track incident in the CRX’s storied past. In addition, since we made so many changes, the rear portion of the cage was no longer tied in to anything structural.
As with most amateur racing endeavors, life, work, and other projects inevitably took some priority, but, after locating some shop space and equipment, we were able to bring the car back from Detroit, and start digging in in earnest once again. Besides the structural work that needed to be done, we’ll be upgrading the driveline as well. The vintage mid-80’s 3-valve Honda EW motor, while still capable of being a strong contender because of the weight breaks allowed, is being replaced by an Acura B18 LS series motor for several reasons. First, and foremost, for reliability – because class rules require an intake restrictor, in this case a tiny 22.5 mm in diameter, the rpm ceiling is dramatically reduced. Calculations show that airflow will level off at about 6300 rpm, so power will start to fall off pretty rapidly at that point. At those rpm levels, wear and tear will be minimized, and many racers running restricted engines in the GT classes report racing two or three seasons between rebuilds, and seeing no appreciable wear when they finally do tear down. The second reason is simply that there’s a very strong aftermarket for these motors, and it will allow us to easily run a pretty sophisticated engine management system – the AEM Infinity – which is key to making good power above the choked flow rpm induced by the restrictor. Coupled with parts from Brian Crower and Action Clutch, we should have a driveline that makes good useable power with minimum fuss, and at a reasonable cost.
I’m a big fan of centralizing mass in a race car – keeping weight down low and centered in the vehicle makes a big difference in the handling and performance of most any vehicle, and our CRX is no exception. While not an advantage, the switch to B18 power requires us to add well over 200 lbs to the race weight of the vehicle. The bright side of this is we can put this extra weight where we can benefit from it the most.