1. The MX-5 and RX-8, use the same platform and thus have the same engine location in the chassis. While the RX-8 has the advantage of the rotary engine that lowers the car's CG compared to a piston engine, the MX-5 hits back with very little weight above the belt line (roof, heavy rear glass, window frames for 4 doors, etc) which brings the car's CG down, despite not having a rotary. Also, it having the engine mounted so far back like the RX-8, but also having a much shorter wheelbase (ie. having the rear wheels much closer to the engine than the RX-8) causes the MX-5's engine to be much more centrally placed than in the RX-8.
Believe me, as good as the RX-8 handles, the MX-5 is even better because it takes the RX-8 chassis, lightens, shortens and sharpens it. The RX-8 cannot match that.
In fact many of us Mazda fans are dreaming of an MX-5 with a fixed roof, fitted with the RX-8 engine, that could be called the RX-7, or perhaps keep the open roof and call it an RX-5.....
2. on your quotes of engine specs, the performance results are in front of you. the MX-5 equals the RX-8 on tests that involve a wheel spinning, high rpm clutch drop start from a stand still, and it beats the RX-8 in tests that involve just getting on the throttle without wheel spin.
Despite the RX-8's peak HP and torque advantage, the MX-5 matches or beats it because its much lighter and has a more flexible engine. the MX-5 is fully 600lbs lighter than the RX-8. that is the weight of 4 passengers!
The RX-8 starts to show its power advantage at high speed. Its 0-100mph is 18 seconds, vs 18.7 seconds for the MX-5. Its not a substantial difference, but its there. this is because at high speed, power to drag ratio becomes very important, vs power to weight ratio, and low weight does not help to offset lack of power. You need hp to overcome drag at high speeds.
As for the narrow powerband, thats not unusual at all. Honda's 2.2L S2000's power band runs from 6000 to 8000rpm. The same is the case for the Civic with the 197hp vtec engine, it was also the case for the Integra Type R.
None of these cars are famed for their out and out speed because they don't have it. their engines don't have the broad based flexibility, even while they have excellent handling, etc.
Like I said, the RX-8 is for people who like its looks, need the extra seats, want a fixed hard roof. otherwise, the MX-5 is the choice.
Last edited by Harbir : 11th May 2008 at 18:26.
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