gazita123

Straight from the tech guy at the Mazda Rev it Up event in SF. He said that Mazdaspeed for the US is building a hydraulic supercharger unit. This eliminates the issue of low end boost with a traditional pulley driven unit that is tuned for the high RPM. No info on the target HP or anything.

The same guy also said that Racing Beat has an RX-8 that they are working with, and that they tried some different configurations for the intake, but have found the original design to be the best. They are now doing a cat-back design for exaust and we'll have to see what they finally find to improve the performance.

He also said that the current exaust manifold is pretty specific to help the emmisions.

rxtreme

iTrader: (1)

I tried to research the hydraulic supercharger to some extent before I posted to make sure I'm not beating an already talked about subject. It seems like there isn't too much known about this type of supercharger. I remember reading about it in SCC some time ago, but I can't remember all the details. If I remember it correctly, it's supposed to be a "best of both worlds" type of forced induction system, being able to offer good boost at low and high RPM's and offer good thermal efficiency. In addition, it's supposed to be more compact and offer greater versitility in it's location/mounting in the engine bay. The last I had heard it was still in the development phase so it would be extremely interesting to see if Mazda R and D'd it for the RX-8.

If anyone else knows the specifics of this "hydra-charger" I am very interested.

Sputnik

It seems like there might be a couple of different designs out there, if not some misconceptions.

The "hydracharger" that I've heard of in depth starts out as a turbo setup. Instead of the turbine and compressor being directly connected with a shaft, there is hydraulic fluid that is pumped by the turbine which spins the compressor. It offers alot of flexibility in mounting options. This isn't a matter of convenience or cost, but the ability to install more efficient exhaust manifolds, and shorter, more efficient intake piping.

I don't see how that setup will be able to change boost onset characteristics or anything. So it sounds like there is some other design that is being confused with the "hydracharger".

---jps

Cruising Rolla

It will interesting for folks that yearn for reliable upgrade.... However, I seems unable to find anything on this anywhere..... Got any more details on it?

gazita123

I didn't get any more specfics. It seemed like the guy was talking about something different than the turbo setup that is listed above. He seemed to basically be describing using a hydraulic pump as the input from the motor which would then turn the supercharger. The speed could be regulated electronically via valves, getting around the whole issue of gearing with direct pulley drive.

babylou

This concept of a hydraulically driven compressor would give the ability to tune the torque characteristics of an engine (like a turbo) and possibly have low lag (like a Roots blower). The problem I see are there are so many energy conversions taking place that the system will be very inefficient. Lets look at the known systems:

A turbocharger has the following losses: 1. Turbine losses (exhaust pumping losses); 2. Compressor losses.

Roots blower : 1. Belt drive to blower; 2. Compressor losses.

Electric Supercharger : 1. Alternator losses (including generating inefficiency, belt drive losses and current transmission losses); 2. Compressor losses.

Belt Driven Hydraulic Supercharger : 1. Belt drive to hydraulic pump; 2. Pump inefficiency losses (including transmission to blower); 3. Turbine drive or PD hydraulic drive motor losses at blower; 4. Blower losses.

While the last option would have very low boost lag and boost could be varied throughout the rev range I see fuel efficiency being measured in gallons/mile.

If more power is wanted I say screw all this and just make a larger displacement Renesis. This is the cheapest, lightest and most reliable option. My preference, though, would be to make the car lighter!

lefuton

good sir, i beg to differ

MrWigggles

This is the aftermarket part of the forum. I think everyone (or just about everyone) would love a larger displacement Renesis, but most of us are interested in increasing the power of the 1.3L engines we will be getting this summer.

There is also the issue that Mazda is already very close to the 277HP quasi-legal limit for Japan so I'm not sure if they will pursue a larger (i.e. 1.8L or so) Renesis because they wouldn't be able to even sell it in Japan.

I think forced induction will be the only way to get more horsepower out of the car in the near future.

-Mr. Wigggles

babylou

I thought this part of the forum also covered Mazdaspeed versions of the RX-8, in addition to the aftermarket? Maybe, only aftermarket Mazdaspeed pieces? If so, my bad.


If we are talking aftermarket then hell yes a blower is lower cost. If we are talking about factory built then a displacement increase is very low cost.

MrWigggles

If Mazdaspeed has the economic means to create a larger displacement rotor engine than so be it. But it isn't a simple stroker kit like the piston guys do. I seriously doubt Mazdaspeed has that type of scratch laying around for such an engineering project, but I could be wrong.

If and when a larger 1.3L design comes out, I think the first larger than 1.3L design will be in the next Mazda RX-7.

-Mr. Wigggles

babylou

Hey Wigggs,

As I understand it MazdaSpeed is simply a group within Mazda and therefore should have access to the same muscle. I also heard rumblings of a Renesis with 90 mm wide rotors instead of the 80 mm wide rotors. How true is this? I dunno. Maybe Mazda uses this engine only in its' "MazdaSpeed" RX-8?

Farsyde

Well this is the limit for manufactures to "say" the power of the car is. Look at the Skyline or Supra, or half the cars there. They all say 277hp but if you dyno them they are way underestimated.

Oh and about making a bigger renesis???? There is no way this is cheaper than any option, in fact this is probably the most expensive route to take. Lets look at Aftermarket. How many People would you trust to stroke (if you could) your rotary?? There are only a few and i guarantee they would charge out the ***. Just think how much piston work costs and the fact that everyone does piston work and now limit the market to < 1% rotary work. Now the factory end. Do you know how much money prolly went into the development and testing of the Renesis??? Millions to say the least. Now asking them to mass produce a larger displacement renesis, tune and perfect the engine, and sell it below $30k is a mountain of a task.

babylou

By my count Mazda would need to redesign 14 part numbers / 27 parts to add 10 mm to the rotor width. I am not including any changes to the wiring harness, vacuum lines or plastic covers under the hood. This is not a large task. In fact Mazda has done this twice in the past.

wakeech

yeah Farsyde, i think you've got the wrong idea with the displacement increase: they're only gonna make the rotors wider, not scale the whole engine bigger...

lefuton

um, how are you going to fit wider rotors into a motor that's not scaled bigger?

it's not just a matter of machining a rotor that's 10mm wider and a housing 10mm wider and stretching the manifolds to fit. little things like the way air flows in at different rpms, eshaft gets heavier and is balanced different, wider/heavier rotors put more stress on the stationary gears etc etc etc, the list goes on.

there is just flat out no way increasing displacement is cheaper than tuning a blower for it. unless perhaps you are inventing a cold fusion powered forced induction system.

wakeech

...that's how it's been done before... of course, ancillary systems like the oil injection, "optimal" coolant passages, and things of the like change with time as manufacturing processes advance, materials get better, and thinking changes, but this is the gist of it.


yes, the eshaft will get longer, and be less resistant to flex... no, the internal dynamics of the combustion chamber will not change all that much, and because of the nature of the mechanism, you haven't the opportunity to really mess with it all that much anyways: it's just gonna happen the way it's gonna happen, there is not much room for special contouring, vaning, or guiding of the air... it gets where it needs to go, that's all that counts.

but the rotors themselves will not gain very much mass, far less than a pound, and the stationary gears have the opportunity to get larger right along with the rotors... and remember too that the current outer gears aren't on their tolerance maximums either, they could probably handily cope with heavier rotors anyways.

...i'd like to see how long that list is, as it's not as long as you think.

using a forced induction system is not a way to increase the static volumetric displacement of an engine, and that second comment is just silly.

like it or not, i've official word from A FEW sources that this is what is going to happen, like it or not.

zoom44

it's not that silly. i know a guy who says his girlfriend's cousin who lives in arizona has a neighbor who's son knows about a guy in california who has been running his house air conditioning on one for years.

lefuton

well that was meant to be silly =)

ok i'm not saying that a bigger displacement motor isn't going to happen, just said that the costs involved exceed that of putting a blower on. at any rate, i surrender...you guys have worn me down. have it anyway you like, im gonna take delivery of my 1.3L/2.6L/3.9L renesis or whatever it "actually" is and go happily putz about to and fro from work.

Cylo

Me too! I can't wait to putz.

Cruising Rolla

Hmmmm, a larger engine? Dun think any car manufacturers will dump in more R&D monies closing to launching date. We probably will know more once the car launch end April (as projected) in Japan.

In the meantime, I do wish that Mazda-Speed or RE will set up producing after-market parts for owners like us.

rx7tt95

I had a conversation last year after the Sebring 12 hours with the editor of RX7 Magazine (Japan). In his words, the RX8 was being HIGHLY anticipated by the aftermarket tuners in Japan and was being received very well. Rumor has it that RE-A had been playing with various updates of the Renesis going back over two years. There will be no shortage of aftermarket performance parts for the RX8.

My best bet is that there will be some form of supercharger kit for the 8 but as many before me have mentioned, the "new" 7 will have a larger displacement engine. I can't fathom the cost of development going over well with Ford, who is in a financial crisis. Not to mention that sales wise, the RX8 hasn't proven itself yet.

Pick up the latest SCC, there's another mention of the Garrett hydra charger or whatever it's called...along with a twin compressor turbocharger (on one shaft, one turbine).

Damn the bean counters, full steam ahead I say. Any hp increase (and potential increase) is good in my book. :D

All the Japanese manufacturers are violating the "gentlemen's hp agreement". The U.S. is the largest market they have, hence a special Scooby STi with a unique to this market 2.5L engine. Just one example...The Supra has been making 320hp here since the introduction of the MKIV back in what, late 1993?

vipeRX7

And that leaves the door wide open for Mazda ...

rx7tt95

But if Mazda is "smart", they'll let all the aftermarket companies (that doesn't include Mazdaspeed) do the work. Why? Less warranty claims. Mazda won't be at fault when that aftermarket unobtanium flux capacitor blows an oil control ring inside the motor. You'll be SOL and Mazda won't loose a dime.

Talk to the Scooby guys...they're having tons of problems, and rightfully so, getting Subaru to pay for broken parts, especially transmissions.

Sputnik

Seems to work with the Miata.

---jps