Power to weight

pr2jon · 07-15-2002, 05:42 AM

New to this Forum but interested in the experienced views.

Question is the all important power to weight ratio and a comparison RX7 Twin Turbo vs RX8 estimates.

I am lucky enough to own 2000 model RX7 Type RB (from new - a Japanese import) which is (stock) 265 bhp and weighs approx 2800 lb (1270kg)

From the RX8 I see 250 bhp at almost 3000lb (2970)

Soooo...... about 6% less power and 6% more weight (I think the math is about OK?)

Any thoughts on what impact will this have on performance / acceleration / drivability of the RX8?

Any thoughts also on a similar comparison with my other car - which is (of course) an RX7 Twin Turbo Convertible?

Personally they are both great cars to drive and the performance of the TT is awesome and the handling razor sharp, but in may ways the T2 is a 'more pleasant' car to drive - its just that bit more relaxed and you dont always have to keep that caged tiger at bay.

I guess I am just spoiled for choice! all I need now is an RX8 to compare them with - if only ....

The $64k question is - should I even consider a trade of my Twin Turbo for an RX8?

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Strider · 07-15-2002, 07:33 AM

Maybe it might clear some things up for other readers as well... but which RX7 are you thinking about trading? the convertible or the 2000 RB (as a slobber on myself with jealousy)?

pr2jon · 07-15-2002, 09:50 AM

Simple - I would keep the convertible :- since its 12 years old its hardly worth anything secondhand, costs me very little on insurance and is a hoot to drive on those rare English summer days. I would be interested to know if the RX8 would be any quicker - hence the pwr / weight comparison question.

The new twin turbo costs a lot to insure, is depreciating like crazy, and costs a fortune to fuel up and use every day. However it would take something very special to make me want to trade - question is - is the RX8 going to be special enough?

Would be also interested if other have the same view - or would they keep the twin turbo and get rid of the convertible? I really cant have three RX's - that truly is being greedy!

The other point to ask is about fuel consumption - more of an issue in the UK at about $10 / US gal - but the Twin Turbo is thirsty. I havn't seen any figures but Mazda keep talking about how much more efficient the new engine is but any clues how much? mpg???

Styjan · 07-15-2002, 10:29 AM

Here is a snip from the March 02 Road & Track article.

Quote:

The Renesis engine has been tuned to produce 250 bhp at 8500 rpm and 162 lb.-ft. of torque at 7500, the highest output ever from a naturally-aspirated 2-rotor Wankel. While the rotor housings are similar to those of the 13B RX-7 engine's, a new 3-stage, 6-port induction system gives the Renesis improved breathing, eliminating the need for turbochargers. Also, it's more economical than the RX-7's 13B, getting up to 30 percent better fuel economy in certain driving situations.

I would keep the convertable and sell the 2000. I think the RX-8 will be a blast to drive. It wont be as fast in a straight line, but I think it will hold it's own on a track. Plus, you'll be able to take 3 of your friends.

Pork Chop · 07-15-2002, 11:50 AM

Based on those numbers alone, I doubt the RX-8 will be faster than the RB. Furthermore, the 106" wheelbase probably won't make it any nimbler than the RB (95.5"). Not to say the RX-8 will be a total dud (I think it should be able to hold its own compared to other cars in its class), but it's really not meant to be the RX-7 replacement.

From a practical standpoint, it probably makes more sense for you to get rid of your RB (costs more to maintain, uses more gas, costs more to insure) and keep the convertible. That way you can have a "practical" everyday car (the RX-8) and a fun occasional-use car (the convertible). On the other hand, if you kept the RB and relegated it to "non-daily driver" status, you'd probably put a lot less miles on it, thus cutting back on your operating expenses. Maybe you should keep the RB.

Sorry, I'm not helping here...

As for the weight, from what I've read in an interview with one of the Mazda production managers, he claimed that the target weight was 1260 kg (2778 lb) !!!!!! I would be thrilled if they managed to pull that off. It's doubtful that they can, but I think I'll be content if they manage to keep it in the 2900 lb range.

Rich · 07-15-2002, 08:11 PM

Here's the key:

Quote:

Originally posted by Pork Chop
it's really not meant to be the RX-7 replacement.

I don't think the performance of the RX-8 will come all that close to your RX-7. If you want a 2-seat pure sports car, I think the RX-8 will really disappoint you. If you're getting sick of the "caged tiger", high gas and mainenance, etc, then the RX-8 should fix those problems without being too boring. I'd expect the 8 to be much more relaxed on the road, have a softer suspension, and just be more user friendly than the 7. It also probably won't have the punch in the back that you can get when you floor a 7.

That's not to say it'll be soft or slow! But we're comparing it to a real, all-out sports car.

Would you like an apple, or an orange?