We never developed E30 ITS cars but I do have a lot of experience with the E30 chassis. I think the main disadvantages of the E30 325 are suspension, aerodynamics, and engine design. The rear suspension is fairly hard to adjust because it is a trailing arm design, each side is mounted with two bolts. We have eccentrics to adjust camber and toe, but you cannot adjust the two independantly so proper alignment at the track is very difficult. The E36 has a multilink rear and we can adjust toe or camber (stock adjustment ability), both independantly, both can be marked easily to return to a base setting. We adjust camber at the track based on tire temps, takes about 5 minutes to do on an E36. Once an E30 is set, I leave it alone. Aerodynamics are an issue if you are not running with traffic - definitely more drag on the E30 body.
Finally engine design. The E30 engine has rocker arms that like to break. Spend a few hours polishing them and you may not have problems, but I have seen a lot of these break on track weekends. It also has a timing belt - easy to replace and not a problem if you stay on top of maintenance, but I think it is a weak part of the engine. Also, the engine will not make as much power as the M50 Vanos engine in the 93+ cars (direct ignition, dual overhead cam, variable valve timing, ...). Granted there is 100 pounds less in an E30, but I don't think this makes up for all the differences.
Ed York has one of the best developed E30s I have seen. However, when he raced at the ARRC at the point when the E36 cars had started to come out and RX-7/240 development had gotten very advanced, it did not do as well. The E36 is at the beginning of its competitive life and it should be one of the best cars to have for the next 5 years or so until newer cars are allowed and it begins to fall off the pace. The track records keep dropping because the cars are continuously getting faster. All the E30 tricks have been figured out and I think York's car is a good example of a car that used most of them. Our E36 lap times are faster and we are still figuring things out with engine and suspension development - our 28 car is a second faster than it was at the end of last year and we just figured out how to get 10 more Hp from the engine last week.
$8200 is a smoking deal for a racecar - if you have the skill to build it yourself you can definitely save some $$$. But the costs on the go fast parts are almost exactly the same - suspension, cage, 5-point harness, kirkey seat. Wheels, tires and headers are a little more (10%?), diffs have to be built for the right ratio, but most E30 guys rebuild for better LS properties also. We ran most of last year with a stock 130k mile engine - they are so bulletproof that I don't think a rebuild is necessary at first. Initial car cost is about $6k for a nice one if you dig hard - you will recoup the difference if you sell it - a winning E36 is going for $40k or more at this point. I don't think that I would be going too far out on a limb if I said that the cars that win consistently in the SE, whether they are BMW, Mazda, Honda, etc, all have easily $20k or more in parts and development time in them - we have more in ours in parts alone, not considering labor or the initial cost. ITS is getting closer to World Challenge as far a prep goes for some people - I priced out building a GA Cup car last week and it is about $5k+ less than we have in our ITS car!
I do not think you have to have an E36 to have fun and I don't think you have to have one to win everywhere you race. But I don't think an E30 will win the ARRC at this point and I think SCCA has allowed enough cars in that have more potential that E30s will fall further off the pace in the next few years. The cars are not equal, but the price isn't either...
I think that there are some situations where renting a car is perfect - to decide if you want to buy a particular type of car or start racing at all, or if you don't have the patience, knowledge, spares, tools, equipment, etc to support the car yourself. I can think of several times I would have paid a handsome amount of money to not have to deal with the issue du jour. But I also agree that if you have done your research, know what you want to build, and are saving the money for the car, I would probably save the rental money to apply toward the car - that is enough to upgrade to DA shocks or build a diff.
Just my opinions.
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James Clay
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