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New RX-8 Engine vs RX-7

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Old Mar 15, 2002 | 09:54 AM
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Question New RX-8 Engine vs RX-7

What's your verdict when we compare RX-8 new rotoray engine vs RX-7's 13B-REW ?

The new N/A Renesis engine is 15% lighter than 13B-REW, here are specs :

250 bhp@8500 rpm (without turbos it's quite good)
152.7 lb-ft@7500 rpm (that pretty small compared to 217 !)
Red Line : 10,000 rpm (wow!)

"The exhaust port has been moved from the periphery of the rotor housings to the side plates beside the intake port. This new disposition eliminates port overlapping and enhances fuel combustion efficiency, the intake port is also 30% larger. The opening timing of the intake and exhaust ports have been changed, the intake opens sooner and the exhaust later. There are 2 exhaust ports and 3 intake ports per rotor for high and low revolution, enhances compression efficiency".

"The rotors are 14% lighter than the 13B-REW ones"

"Engine runs on regular octane level fuel, it now burns 40% less fuel on idle"

* I don't want to compare cars, just engines *

Here's the link :
http://pages.infinit.net/ebedard/renesisspecs.htm

-Carl
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Old Mar 15, 2002 | 10:11 AM
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sounds more effecient....

I guess it is what you want from the engine. If this one is turbo-able (is that a word :p) and you can pump out the high end power that most want, then I say yes.

We will just have to see though.
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Old Mar 15, 2002 | 12:18 PM
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Re: New RX-8 Engine vs RX-7

[QUOTE]Originally posted by RX7 Rotary Rocket
[B][COLOR=white]
152.7 lb-ft@7500 rpm (that pretty small compared to 217 !)

--------------------------------

Well, isn't torque depends solely on the car's gearing? It wouldn't matter since your just comparing engines. I agree with ttpowerd that if this engine can be forced-inductioned and modded as much as the 7 can, it would be awesome.
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Old Mar 15, 2002 | 12:25 PM
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Torque is not dependent on gearing. The torque output of the engine, is a measurement of it's "twisiting" force. Just like opening a stuck lid on a jar. The force you are exerting is torque.
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Old Mar 15, 2002 | 12:39 PM
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I think the rotors are high compression, so boost maybe limited in turbo appl.
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Old Mar 15, 2002 | 01:41 PM
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I think it needs torque! It is gonna drive like a damn honda, with no bottom end. Carrol Shelby has been quoted for saying "horsepower sells cars, torque wins races." Besides, who wants to whine out the engine to get power. I like being able to flog it at any RPM (above 2000) and get strong power. However, the engine is definately cool, and the fuel consumption beats the hell out of our cars.
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Old Mar 15, 2002 | 01:50 PM
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Check out the latest Road & Track - with the latest specs. RPM is down (9000) and I believe tourque is up a bit, but I could be wrong.
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Old Mar 15, 2002 | 01:52 PM
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we just need to learn how to either turbo it and swap it into our rx7s or find out if any of its internals can directly be transplanted into the rew.
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Old Mar 15, 2002 | 01:59 PM
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In the new R&T article they quote torque at 162lb FT and 90% of it is available from 3500 rpms. This is SOME good news as far as driveability is concerned- The other advantage is that the rotors and the E-shaft are considerably lighter- which should make it more interesting and fun, as the motor will rev faster. It is really gonna suck though when you do have four adults in the car. I'm holding out for a true road test and evaluation with real world numbers before I cast final judgement- and even then it might take a test drive to convince me to get one.
One thing that is very promising is the chassis- its stiffer than an FD, don't know if that is saying much though for a car that is 10 yrs old, compared with todays sports cars/ sports sedans, but it should handle in a very respectable manner.
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Old Mar 15, 2002 | 02:00 PM
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Oh, and it qualifies as LEV. very good news.
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Old Mar 15, 2002 | 04:03 PM
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Originally posted by race1
Oh, and it qualifies as LEV. very good news.
A low emission rotary? that is very good news
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Old Mar 15, 2002 | 06:00 PM
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250 horses is just not enough. Because of the new positioning of the exhaust ports, this engine will be very difficult to turbo. If they make an aftermarket supercharger, you will only be able to get about 6lbs out of it. I guess you could put nitrous on it. The new computer contolled units are great, no more hitting a button.
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Old Mar 16, 2002 | 08:55 AM
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Originally posted by CPA
The new computer contolled units are great, no more hitting a button.
New as in anything made in the past 15 years?

seriously though... i see no reason why the side port exhaust engine can't be turbocharged, other than having too high of a compression ratio. the less "active" exhaust events would most likely mean we'd have to use turbos with a LOT smaller turbine housings to get the same spool-up... in other words it would behave more like a boinger than a rotary.

But on the plus side, since it's supposed to be a lot quieter (because of the new exhaust characteristics) the exhaust doesn't have to be so restrictive to keep the noise down to an acceptable level. So you can make more power with a street legal system.

Again on the minus side (sort-of), this means you can't gain an instant 25-50-more horsepower just by putting a better exhaust on anymore, because the factory won't be putting hugely restrictive exhausts on the car.

Even in stock form, it should be a lot of fun... one of the rotary's hallmarks is that they have extremely broad torque curves, and with revs like that you can just grab a lower gear if you want more thrust. Heck 2nd gear is probably good to about 90mph
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