The lastest edition of C&D came today. On page 34, "The Dirt Road", it is reported that Mazda will produce an RX-8 in '05 with an electric powered turbo!!!! No hp figures cited, but maybe this will answer all the speed needs some have. Aftermarket availablity will be a real plus...Mazdaspeed Turbo RX-8...one can hope...:D :D :D :D :D

 

But will they be able to sell it as an add-on for the 2004's?

 

The electric assisted turbo was first shown on the hydrogen concept RX-8. The electric side comes into play as it only helps the turb initially get spinning to minimize any lag. After it gets moving the speed of the exhaust gasses makes it work like every other turbo. Just consider it an anti-lag feature. It is not just an electric turbo. I am a sceptic because of the extreme high heat of a turbo. How long can an electric motor live under those conditions?

 

If it was a true electric motor driven full-time FI system then I think they better name would be supercharger.

The fact that CD called it a turbo system implies exactly what rotarygod is referring to.

I don't know how they would come up with a system either that would take that kind of heat, but if it is coming from factory you always have the warranty to fall back on.

-Mr. Wigggles

 

Unless they are switching to 48 volt electric i doubt its full time.

 

Mr. Wiggles is on target.
"Mazda is working on a more powerful RX-8 that will boast a newly-developed electrically assisted turbocharger. The electrical turbo was chosen over a soley exhaust-driven turbo because the electricial unit is able to meet increasingly stringent emissions regulations. Mazda plans to unveil the turbo RX-8 at the biennial Toyko show in 2005."

 

sounds like a good enough idea i think mazda should put it throught

 

I'm not clear on how the electrical assistance aids in emissions, unless perhaps they've done something funky with placement, like put a cat first? That would be weird, but the only thing I can think of that would effect emissions.

jds

 

If the turbo is spooling earlier then the cats can heat up quicker and catalyse all that bad stuff that comes out of the engine quicker.

 

Yes, C&D also said the problem with Mazda putting on a normal turbo was the exhaust would be too cold to be effectively catalytically converted. This would solve that problem. I am hoping the system is basically positive displacement so that it would be on full time and give that needed boost down-low. I suspected Mazda would try something innovative in their new engine design because they did the innovative twin turbo system on the RX7.

 

So are they producing it in '05 or unveiling it at Tokyo? Seems to me if they're unveiling it in '05, it won't see production til '06. But I guess they've been working on the design with the H2 powered car so they might be able to fast track it. Kinda sweet either way :D . I've planned on trading in '06 anyway when the sequential 6spd is released, more power would be even better.

 

its just a belt driven turbo, kinda like the one shown in another thread, runs of a belt like the alternator, so its kinda similar to a supercharger

 

Have you been reading the whole thread??? It is not just a "belt driven turbo," which is a whole lot more than "kinda similar to" a supercharger.

jds

 

The turbo is electronically assisted to decrease turbo lag at low RPM's.

Turbos increase heat, not decrease heat since it is forcing hot pressurized air into the intake manifold. The emissions problems have to deal with increasing the fuel per air ratio to decrease the temperatures so the engine does not detonate.

A belt driven turbo charger is exactly what a centrifigual supercharger is, not the best idea on a rotary since it combines worse efficiency than a turbo with boost not building until the higher RPM's ranges.

 

I personally feel that Mazda should re-engineer the sequential concept of the 3rd gen Rx7 for the 8. Here's my idea:


Mazda could use an electrical turbo charger to "assist" a larger single turbo. You would have two turbos(electrical primary & exhaust driven secondary) instead of just one. Think about it......the electrical turbo(primary) would run (depending on load) in the lower rpm's while the larger single is getting spooled up by the exhaust as normal and eventually joins in at full boost. Plumbing should be easy because only the compressor side of the electrical turbo would be plumbed into the piping of the exhaust driven turbo. In the end you would have the advantages of the stock seq system while being far less complicated(no rats nest), with reduced heat and making more hp. I like the Mazda idea but like RG, I too feel that the heat will eventually kill the electric motor. My idea would elliminate the heat issue because the electric turbo would be in a completly differant location. What do you guys think?

 

Actually I believe the heat issues as they relate to emissions have to do with the cat. The excess energy put to good use by the turbo is no longer available to heat up the cat. The turbo does create heat as you say, but in the intake, so it isn't do so in a way that will help the cat get up to temp.

jds

 

My question is why not just use electric motors to assist the rotary by themselves like the Honda DN-X concept shown a few years ago? it would seem more simple, no?

 

Trust me, if it was easy, they would have done it along time ago.

 

Interesting thread, and good possible news. Sure hope Mazda comes out with a retrofit kit! Of course, once they do it'll most likely be in late '05 or sometime in '06, and by then my factory warranty will be so close to run out that I won't care anymore. And also by then, there will be a ton of other (aftermarket) turbo kits available. So...

MAZDA, we know you're listening. PLEASE release this kit in 2004 or early 2005, and make it available as a non-warranty voiding accessory!!!!! If you build it, we will come! :D Here's an opportunity for you to make some money - and if you wait, the money MANY of us would be willing to spend on forced induction will go to other companies.

Too bad they'll never reply. But the proof is in the puddin... perhaps they'll release a "kit" sooner rather than later. We can only hope.

 

Wrong issue - any device that compresses air creates heat, it's simple thermodynamics - heat of compression. Generally, turbos actually create less heat in the compressed intake air than superchargers because they are more efficient. HOWEVER - exhaust temperature is important to turbos because the hotter exhaust contains more energy to drive the turbine. Moving the turbocharger further downstream results in a cooler exhaust gas temperature, which has less energy, and thus spins up the turbo less quickly (more lag)

Quote:

The emissions problems have to deal with increasing the fuel per air ratio to decrease the temperatures so the engine does not detonate.

No, completely wrong. The emissions problems with turbos is that the emissions regulations require catalytic converters to reach functioning temperature within a certain time period, a minute or two. With a turbocharger located between the engine and the first cat, it is quite difficult these days to 'light off' a catalytic converter quickly enough to meet that requirement. For example, this is a major reason why Audi moved away from the 2.7T twin-turbo engine for the S4 to the V8 - to eliminate the turbos and simplify the future emissions compliance work.

So - what Mazda may be doing is locating a pre-cat before the electically-assisted turbocharger to meet the startup emissions requirement, and because the turbo is thus located farther downstream and getting less energy from the cooler exhaust stream, using the electric assist to eliminate the increased lag that would result.

Regards,
Gordon

 

Yep, that's a better way to say what I was feebly trying to get at a few posts back. It didn't make sense to me that electrically making the thing spin up faster would heat a downstream cat significantly quicker.

That could make for a fairly tortuous intake path though...

jds

 

I saw a company called Thomas Knight (www.boosthead.com) which makes a fully electric supercharger. I'd imagine this could be a good alternative to nitrous injection, as you would activate several pounds of boost via a button (a la fast n furious) or via throttle position switch. It looks like it goes somewhere between the intake manifold and the air cleaner, which reduces the chance of heated intake charge due to exhaust gas proximity.

 

HUGE battery pack needed which increases weight and throws out 50/50 balance. Mazda doesn't want that!!