regaining power in automatic
 

Is the HP loss in the automatic controlled by the ECU? That is, has the factory intentionally lowered the HP or is it a function of something else?

I'm going to have to purchase the auto, even though I hate to (city driving). I'm hoping I can recover the lost HP without adding a ton of mods.

Then, of course, I'll add a ton of mods :p

--Rip

The power is really not that bad for a daily driver.. If you put in in "tiptronic" --paddle mode you will be able to gain some lost sprts feel. I am not a dragster, so for me the power is fine for my needs.

You're probably not going to pick up as much power as the 6-speed has. The auto engine has one less intake port and one less injector per rotor housing, among other things. Try doing a search for auxilliary (or tertiary, thanks Wakeech) ports.

Also, the auto engine can't spin as fast, probably limited mainly by the breathing, and the torque converter's design.

the horsepower is quite simply a number, and the 12-13 hp loss isn't a big deal. your best bet is go test drive the car, fall in love, then buy it. i too didn't want to buy an automatic, but now after 400 miles of city driving (i've been busy and haven't been able to drive enough) i'm very happy i decided to listen to my brain and get the auto. the power is great, and i believe its not the ecu but the transmission that causes the hp loss. someone told me but i don't know if i shoudl trust them or not, the engine in both auto and 6 speed are the same just the transmission is built in a wierd way or something. just also to give you a fair warning, i made a post explaining my story of my problems with the 8 and warranty, search the forums for CAN management. before you buy the car go to a couple dealers and ask them if i put this this and that mod will it void my warranty. good luck and don't worry at all about the numbers, the automatic is still amazing.

I thin this was the actual reason for the lower power version, the torque converter can't handle over about 7500 rpm, so that automatically chops off the peak power band. Because of this, they were able to do away with the tertiary ports, since they don't open up until 6000 something, anyways. As most RX-7 owners will tell you, the easiest way to make more power in a rotary, is to spin it faster, so the torque converter's limit is really the problem here.

On a side note however, there are companies working on different torque converter designs, using different fluids, and fluids under pressure, to allow them to operate at higher RPM's, but like most things, only time will tell.

ya, the auto does seem faster in paddle mode

Thanks for the info, everyone. Will do some more searching with it.

Rotary engines are a complete mystery to me. Well, I learned more about supercharging that I ever needed a few years ago. Now it's time for rotary engines.

--Rip

this is my first rotary and I'm learning and loving it

I have read on a car magazine review (forgot which one) that the reason the A/T RX-8 has lesser power is because of it's torque converter not being able to handle higher rpms. So it is limited and since the Renesis' peak power is at higher rpms, the A/T cannot reach that. The limitation is also set at the ECU. Changing that could compromise the health of your torque converter. Maybe removing the limitation and installing a racing torque converter (?) would enable the A/T to reach the peak potential of the Renesis engine.

But hey, cheer up coz that article (as I remember) mentioned that the A/T configuration has higher low-end torque than the M/T configuration. And that this is due to the 4-port configuration that it has compared to the 6-port M/T. Buying an A/T RX-8 for city driving might have be the best decision you've made as far as buying an RX-8.

... just my .02 cents ;)

Interesting.

Then, in theory, I could upgrade the torque converter and tweak the ECU and I'm in business.

I assume it runs an ECU IV, ala Ford. Any good info on the ECU someone can point me to (can't search on 3 letters)?

--Rip

No, not really. I don't know the performance torque converter market at all, but do you think there are that many torque converters out there that can take 9000 rpm? The only other engines that can turn close to that are the Honda S2000 (no auto tranny at all), the BMW M3 (no auto tranny at all), Ferrari 360 (no auto tranny at all), and the Acura NSX (engine is detuned for auto version). I suspect you will have no luck finding a torque converter that can handle that rpm.

Re tweaking the ECU - that won't make much difference at all, the current ECU can provide all the fuel and spark that the low-power engine can make up to 7500 rpm. The problem is that the low power engine isn't physically equipped to rev higher, since it's missing the extra ports, extra injectors, and extra inlet manifold path that the high power engine has. Just changine the ECU to raise the rev limit does nothing to address the fact that the low power engine isn't capable of breathing at higher rpms, so can't make more power at higher rpms.

Sorry.

Regards,
Gordon

whoa there...with those kinds of mods, my don't you just get a 6 speed??? that is to say if you haven't gotten the automatic already...

The simplest way to upgrade your power is to do what a rotary engine wants most.

Freedom

Get yourself a sports exhaust with the proper extractors & that should bring the 141 kW 4-port engine up to almost 160 kW without excessive noise.

Add a performance (currently in development) ECU to suit the auto version & you should find another 10-15kW easy in there.

By the time the (slightly) weak torque convertor starts to slip, there should be performance versions of those available too.

REgards

Learn to drive the manual, or wait for the auto/manual bix in 2005/6.

The Auto(lo-power) wont rev as high, although mods and FI will help.

I don't have a problem driving the auto at all. It's just this vehicle is going to do some traffic time, so the auto just made more sense.

In any event, thanks for the information. Really, it's just a theoretical question so I can learn a little more about the vehicle itself. I'm just trying to understand why there is a limitation on the auto.

So, to surmise, the issue is really the engine's limitation in inlet ports, injection ports, etc. (Assuming I could even find a torque converter that would handle the RPMs).

OK. I think I get it. Thanks everyone for the replies.

--Rip

The limitation - on RPM is the torque convertor. No point adding RPM when the convertor cant handle it.

Power isnt the issue. You can have more power, just not more RPM.

The man's got a point there. Listen to him. I guess you are stuck.

How about a Turbo?
 

Can the automatic handle a turbo?

why not

In Toronto we do traffic as well, forget the auto and get the 6spd GT. When you start in 1st and rev it up to the redline @9,000RPM you'll be doing 40MPH, plenty fast for Austin. If you need more speed to keep up with those TX Suburbans shift to 2nd and you should hit 70MPH. All this and you can still smoke, drink coffee and talk on your cell phone. If you want performance you really owe it to yourself to get the MT.

well if traffic is gonna be a problem then maybe a sports car isn't right for you...seriously, the auto shouldn't even be considered a sports car anymore, maybe just a "sporty" car in the looks department...if you really must drive an auto sporty car, then i suggest a G35c...they're much faster than an auto RX8...faster than even a 6speed RX-8 stock...sorry to tell you that but that's the truth

Toyota has a torque converter that will handle at least 8000rpms on their Celicas, but I doubt you would be able to use it in the RX-8. I'm sure that there are aftermarket torque converters that can handle the revs like that, but it will take some looking and patience in order to find it b/c your car is still pretty much brand new.

I got the A/T already. I wanted the M/T, but I'm not going to be the primary driver. I still love the car and am looking forward to maximizing it's potential.

The main reason for the A/T is the traffic. I didn't consider that I would be at 40 mph before shifting out of first (man, that's really weird...gotta lot to get used to), but I do feel that the clutch would have been ridden a bit much (North Austin to downtown everyday).

As far as the sports cars can't be A/T comment, I completely disagree. It's certainly not the same feel (again, the M/T would be a preference), but it doesn't take away from the 'feel'. However, if I had the space, this car definitely would be even better as a manual. Oh well. You gotta go with what works.

BTW, while some wouldn't consider it a sports car, I do own a 2001 Lightning at 400 rwhp. While it doesn't handle as well as the RX-8, trust me, it makes up for it in straight line speed (consistent 12 sec quarters).

--Rip