EGR and performance

how much does a vehicle's exhaust gas recirculation system generally effect peak horsepower?

I'm asking because there's a competition my university takes part in that some of you have probably heard of, formula sae, where you build a racecar from scratch. the cars are tested in a number of different areas, one of them being fuel economy. since egr can reduce throttling losses at part throttle, i was wondering if it could help increase fuel economy in a racing situation without reducing power at WOT significantly.

Zero, zip, nada. A properly functioning EGR is fully closed at anything past about 3/4 throttle. Its strictly a cruise thing. Big benefits to MPG and emissions without any performance drawbacks.

how difficult would it be to design an egr system for an engine that doesn't have one?

do motorcycle engines (600cc or under) have egr valves?

Look here (http://en.wikipedia.org/wiki/EGR_valve) for more EGR info.
EGR valve controls must be quite sophisticated to use them to their best advantage. It would be difficult to design a truly efficient system from scratch on an engine.

When EGR valves first were used back in the 1970's, they used very simple vacuum operated mechanical controls. Such controls could be easily duplicated on an engine which never had one, although you would need to fabricate some parts.
However, performance and mileage often suffered in the past with these simple control systems, and, as things progressed, electronic controls became more prevalent. These modern controls would be more difficult to adapt since they obviously are integrated with fuel management and ignition systems.

do motorcycle engines (600cc or under) have egr valves?
far as I know, no motorcycle has an EGR system (600cc or otherwise)

air injection is popular, EVAP is popular. Cat's are starting to be seen on more models. Thats about it as far as emissions equipment. Even closed loop systems aren't very common....yet

so does anyone think a properly designed system would help fuel economy appreciably in a racing situation? the tracks are generally pretty small, the cars don't see over 100mph, if that.

assuming you spend any time at partial throttle, which it sounds like you wouldn't with that application, it also keeps the combustion temps lower.....but like I said, you are probably only seeing partial throttle at corner apex

Any type of egr system would be a waste of time in a small car like this. Besides if your egr system isn't working properly... it can lead to problems like increased engine temperature (I know this from exprience) and other problems that would hinder your efforts. If you're looking to increase economy have you considered using o2 sensors to make sure you have the correct air/fuel mixture? What about a mass air flow sensor?