dcfc3s

Spoken like someone who hasn't driven a turbo rotary...

Rotaries and turbos get along together like peas and carrots. Part of the reason is rotaries have VERY powerful exhaust energy - I've read it's actually equivalent to a 12-cylinder engine! You can run a much bigger hotside and get far better flow characteristics with a rotary.

Put a T04-series turbo on a rotary, and it's a case of how much power you'd like to make. 300hp is easy. Just keep throwing fuel at it .

Many turbine housings are divided, giving two exhaust paths around the turbine wheel to spin the turbine up. Run a divided manifold so each rotor has it's own path through the turbine, and you can run a much higher AR turbine with less lag and more flow.

Dale

bureau13

Very true with the older rotaries. SUPPOSEDLY the Renesis doesn't have quite the exhaust energy of the previous models. I don't know how significant that is (or even if its really true, although given the added efficiency of the Renesis it makes sense).

jds

AbusiveWombat

the reason I say supercharger is because with 10:1 compression you're already looking at ~5 PSI or around 50-60 hp. So for such a low boost application why burden your car with the added heat, intercooler, turbo, and all the piping rather than a simple belt and supercharger. It's less complex and thus more realiable.

JeRKy 8 Owner

I dont know much about turbochargers. I know they will void the warranty if you get one. I want to know if you get a turbocharger on the Rx8 will the gas mileage that isalready bad right now get even worse or stay the same?

Crazyfool

It really depends on how you drive it. Under boost youll be eating gas like crazy, but while cruising or under light acceleration, you'll see about that same mileage.

mikeb

from what I've since on this form the dealer must prove that the aftermarket piece you put on your car directly affecting what is not working to make the warranty void. For example if you lower it and then it starts leaking oil they still must fix that because you lowering it didn't cause the problem

Rotary Soul

a couple of months ago i kept on hearing about how renesis could "easily" put out 280 hp NA. now everyone is talking about FI, and talks of improving NA engine performance has gone down the drain. anyone know about any NA tuning they've been working on?

Efini 8

boosting N/A performance via the engine would maybe one would consider a 20B or 3 rotor rotary if you want to go with N/A and port that sucker. But if you are doing that why not go turbo cuz like others said, they work great together!

Also one point about supercharging vs. turbocharging is that supercharging is limited but with turbocharging the boost increase and rebuilding of the engine and fuel/timing adds sooo many more possibilities to high performance gain figures

Noxlupus

How about taking the Twin-Turbo setup from the 7 and use it on the 8? That should work shouldn't it? Or would the 10 to 1 compression be a problem? I wouldn't think it would be, but I'm not in the know when it comes to this things - yet.

wakeech

i don't know who "they" you're thinking of, but since the 70's you can take a 13B block engine and make more than 300hp on it EASILY, zero turbos: it's called the Perhipheral Port (and ~10k RPM redline).
now that emissions and fuel consumption are high on the priority list, efficiency is traded for ability to make power at high rates of consumption.

to re-tune the engine to 100% top-end comprimise could see this motor to 280hp or more (at the crank), but in its factory guise it's (obviously) far more subdued, emissions friendly, and less thirsty (don't even start, it depends on how you drive it: ask Elara).

"put a bigger engine in it"... typically American answer
seriously though, tuning the engine as-is will result in pretty siginificant gains, especially as tuners test the (rumoured to be quite conservative) redline, and push porting further and further as a SCIENCE (and not the "make it as absolutely huge as possible" approach so favoured on forums like nopistons :p), and art.

when people get sick of whining about their lost 9hp and realize that 250 isn't all that much to brag about either (relative to many other cars on American roads today), and are ready to take the plunge, we (i'm hoping) will see the NA motors eclipse some previous RX-7 twin-rotor records.

as far as supercharging vs. turbo charging, PLEASE KEEP IT OUT OF THIS THREAD. there are already about a million on this server already. i'm pro-turbo, and have voiced my opinions on many technical concerns about both. search, read, revive and post. please.

the sequential twins setup on the 13B-REW was a seriously over-engineered peice of equipment for the series 7 RX-7's that made it to north America, and is the source of much of the wankel-phobia present in today's car market.

as a system, it's alright, but is completely unecessary as a system to try and develop a quick-spool, flat boosting system, possibly even at the time of its inception: twin-turbos in the late 80's and early 90's were almost completely a marketing tool. a slightly larger single turbo would have slightly (maybe even undecernably) longer spool-up time (turbo "lag" is determined by many things, and spool-up isn't the greatest factor either), but would remain far more efficient over a wider range of flow volumes and boost pressures. basically, if Mazda or MazdaSpeed is going to develop a supercharging system (by either belt or exhaust driven compressors), it'll be certainly using only a single, simple compressor setup.

JeRKy 8 Owner

Are you guys saying that it would be better to turbocharge the four speedsautomatic Rx8 instead of the six speed stickshift Rx8?? Are you just talking about something else?

wakeech

no, we're specifically addressing only the engine side of the equation. North America is the only continent that gets automatic 4 port motors, whereas in Europe and Asia you can get a 5 speed with it.

i forget where the auto is scavanged from (pretty sure it's a Mazda unit...??), but should still be good to take the extra torque of a turbo.

M-ster

In Asia we would be able to get the 5speed manual, I guess this would be the best engine to put a turbo in. Manual trans, 4 port engine.

rx-8club.co.uk

Australia has the 4 port Auto also. I THINK? the UK is getting the 4 port engine (low power as it is known as) with the 5 speed manual, and the 6 port (high power) with the 6 speed manual. I don't believe that they are getting an auto version.

I will be close to doing either a turbo or a supercharged set-up myself in a few months time.

I know one thing for sure - there is a lot more room around the inlet manifold on the 4 port engine. So it would probably make supercharging easier - as for the turbo set-up the battery will have to go to the boot and the exhaust manifold would have to be quite long to bring it up and away from the oil metering pump etc. as there is no room along side the engine.

If I go down the supercharging route I would look at a mechanical type that provides boost at low rpm - still a little way of the decision yet.

.ps Next thing is - how strong is the Auto box?

Shadygt2000

Hey, new to the scene here...I'm debating picking up an 8...Been reading the forums, watching the problematic areas and resolves of the threads...although I havn't really seen much chatter about any means of future suppliers of forced induction for the 8's. I realize that some will say...you need to get an rx7 in that case...could be, but I was never a fan of the seven. Not really a fan of import anyway, but I have been following the progress of the 8 from the beginning and it is really an ingenious and technically sound project. I really like it... and am ...eer want to pick one up..but I was wondering if any of you know of any companies that are investing in a turbo kit for it?

I have had several boosted cars and it's a rush that doesn't go away once its there....from a 87 GNX, 67 gt350, turbo 302 mustang, and now a 00' Lightning...I just haven't really seen any threads for it and wanted to get an opinion from everyone here.....

BTW nice forum...format is simple and the color scheme is A+++

Thanks Guys
Steve

SuperRex

Welcome to the Forum! Although this car is very new, a lot of R&D is going on right now. I think that there are at least about 3 turbos in development. The ones that come to mind are greddy, SSR engineering, and Trust. I think that Apex may be developing one also, but this is just speculation. They just recently picked up they're guinea pig rx-8, so ive heard. There has also been many rumors about a mazdaspeed supercharger, made by eaton. Speculated #s are a boost of 20-30hp but a whopping 100+ lb/ft torque increase. Either way, any forced induction will be running 5-6 psi at the max so you wont be feeling that kick in the pants very much. All the kits should be running fairly small turbos which results in a very quick spool up in combination with the wonderful rotary engine. :D

emailists

any guess as to the effect of having a turbo in the 8? requiring shifting mroe quickly, not using the upper RPM's as much? I've never owned a FI car. Just trying to get a sense what it would be like.

I could definitely use extra torque, doing alot of stop and go, as I do in the city, but I really do enjoy driving in the upper RMP range of the 8 (of course when I'm not granny driving testing the MPG- which is often) I just wouldnt want to do anything to ruin that wonderful 7000 rpm and up feeling.

SuperRex

Emailist- it sounds like a supercharger would much better suit your situation. eaton superchargers are very fuel efficient and would provide loads more low end torque but a turbo produces a stronger mid- high end.

lefuton

color me impressed =) that car/motor is on my list of things to eventually tinker with

wakeech

*can't believe what he's reading*

c'mon guys, read up on what your'e talking about before you start spouting bullcrap.

SuperRex

http://www.rx8forum.com/showthread.p...r&pagenumber=1

http://www.rx8forum.com/showthread.php?s=&threadid=9500

http://www.rx8forum.com/showthread.php?s=&threadid=9603

i did state that the numbers were rumor/speculation... and i do believe all the info i stated has been posted in the past

Zio

Its nice to know performance items are being made. So far i've seen a couple air intakes that are in development :D

wakeech

those threads... haha... oh boy. i tried to find the actually good (and technical) mouldy oldie "turbo vs. supercharger", but couldn't find it... i hope it didn't get lost/deleted.

but those numbers (like thinking 6 psi is gonna hit another 100lbft of force at any rpm) are just a bunch of baloney, and aren't worthy of mention. if Mazdaspeed came out with any kit that ups low range horsepower trading off potential top end, i'd be disappointed (that said, i doubt that's what they'll do... Japanese hate blowers, and love turbos... for good reason).

finally, most of the stuff on this board is whining, repeated questions answered repeatedly, and speculation. sometimes, a few of the bright guys from the early days would get together an answer a few big questions, but now it seems to be the same old thing... over and over and over. just 'cause it was posted here before doesn't mean it was true, and sometimes not even worth mentioning again.

SuperRex

I stand corrected!:D I've known that 6 psi out of turbo would never produce those #s anywhere but I don't know much about blowers and have heard of massive torque increases from them in the past so i just assumed it was possible. I apologize for posting old rumors and will refrain from doing it again.

PS here are a couple old turbo vs super threads
http://www.rx8forum.com/showthread.p...o+supercharger

http://www.rx8forum.com/showthread.php?s=&threadid=3707

wakeech

...yeah, i was searching before i even first posted here... i still can't find the (actually good) one i was looking for.
those aren't bad, but there WAS another... can't friggin' remember... anyways, it was pretty good, layed it all down about how the 4 port motors are better for FI, and turbos are better than superchargers (while the supercharging guys put their hands over their ears singing "la la la").