There are many arguments on both sides of the fence for turbos vs supercahrgers and vice versa so you'll never get anywhere with that one. They each have their advantages and disadvantages.

You can't mill out the Renesis rotors because the castings are too thin. You can add boost and get comparable power at full throttle to a stock 20B quite easily. It's a part throttle and low/no boost situations that you can't match it though not to mention the fact that a boosted 2 rotor is stressed harder than a 3 rotor at the same power level. You can still get up to about 400 crank horsepower on a stock Renesis on pump gas. That's quite a bit and not weak by any means.

That's why I was talking about twincharging (to solve the part throttle and no boost situations).

Also, I know that the Renesis rotors are too thin but what about the 13b rotors?

The side seals will be an issue. I don't have any confidence in their longevity due to their shape. The rotors will physically fit but it's a big risk using them.

Yes I know. Maybe I wasn't clear enough, but I was talking about a twincharged low compression 13b (not Renesis) to obtain the same power-characteristics (including low end power) as a 20b.

Hi you all

I agree with armyofone

What some guys found here in SA is that the renesis do not like high boost even with lower compression, that is not the biggest problem, but a other problem start:
due to the exhaust now being on the side plates, the temps get higher there and when turbo the side seals (not the apex seals anymore) give trouble, they are the culprits now.
The renesis is made for NA or low boost.
otherwise, yes it will be a good idea to go with the rew housing to have the exhaust back on the peripheral instead of side, until a new development on the side seals come along.

If i change my 8 it will be to a 3 rotor (shorter than 20B, like one custom made in NZ wit hnormal intermidiate housing, making the length shorter) and all ceramic coated with a bridge port. that is it, then the power will be 300hp on wheels i guess, at least.
I will however use the renesis rotors etc, due to technology, weight, etc

see: www.powerkote.co.za for the ceramic coatings

my opinion only, use the renesis parts as much as possible due to the development and technology but for high power you need peripheral exhaust, reliable power i mean.

Chears

Philip

I'm surprised that no-one has tried the twincharging route on a rotary (at least based on what can be found online). Obviously a twincharging can have many advantages but its set-up can also be quite complex: http://www.greencarcongress.com/2005..._vws_new_.html

Twincharging does not necessarily have to complicated though and no by-pass system is needed as long as the blower is placed after the turbo. (If the Roots blower is placed first then blow through the turbo, the turbo will do nothing as it cannot draw in more air than the displacement of the blower.)
If the turbo is placed first, the blower can suck in air through the turbo before the turbo comes onto boost, and when it comes onto boost, the turbo can pressurize the air going into the blower. The blower will then compress it further and the turbocharged is controlled by the pressure after the blower. The entire system can handle a larger turbo, simply because the blower will pump more air than the engine alone.
Obviously if two superchargers are placed in series and both in constant operation, compression ratio needs to be lowered otherwise the engine simply won't handle the total boost (keep in mind pressure ratios are multiplied and not added).

Obviously with an electric supercharger, electrically assisted turbocharger or N2O the same goal (low end power with large turbo) could be reached but controlling such a system would be more complicated and N2O bottles need to be filled up.

Complexity and cost are exctly why no one has done one on a rotary. It's not to say that it can't work. Is it really worth it? If I wanted to do something like that I'd go with twin turbos of different sizes run in series rather than parallel but using a bypass valve. This would be far simpler. Opel has done this on a small diesel engine with great results.

You don't need a large bad lag turbo to give you 20B power levels. You can have a fairly small turbo give you those as you really only need about 300 hp. Too many people go too large on turbos. You design for your goal. Most people design with the intent of getting more from it later. That is less efficient now though. Unless you are searching for more than 400 hp, I see no reason to use a 13B. I don't really see any point in using a turbo and a supercharger either. The twin series turbo setup could give you great low end and fantastic high end though so it would ultimately be the best option if you want fast spool and high boost levels. I still wouldn't use a 13B though. It's an old motor. It's old technology. It's time has come and gone. The Renesis is the future. For a street car changing to a 13B is like changing from an LS1 to an L98. It doesn't make any sense.

Here's info on how Opel has done their twin turbo. It's so simple that I'm kicking myself for never having thought of it.

http://www.worldcarfans.com/news.cfm...ml/country/gcf

Actually I was thinking of a 450hp 13b (not because there is a need just to prove the point that a 13b can produce low end as well as high end power similar to a 20b).

It's true a sequential turbo would be even better as far as efficiency, power and compactness are concerned. The Porsche 959 might have been the first car with this system and ironically produced 450 hp from a relatively small 2.85l engine. http://en.wikipedia.org/wiki/Porsche_959
And this is a great OEM product for someone with a large R&D Budget.

However as far as complexity is concerned a twincharged turbo->blower->engine->turbo is simpler and a bunch of oneman-show-tuners have already implemented it.
I simply doubt that a single person is capable to control a relatively complex system such as this to a level that it will also have a smooth transition from HP to LP turbo:
http://www.turbos.bwauto.com/en/prod...s_schema_g.jpg
http://www.turbos.bwauto.com/en/products/r2s.asp

Cell phone pic of the BMW 535d with sequential turbochargers. (The 3.0l engine delivers 560Nm at 2000 rpm and 272 HP at 4400 rpm !).

NSU apparently manufactured high strength rotors without utilizing the sand core casting method (the rotors were partially die cast, soldered and pressed):
http://www.der-wankelmotor.de/Motore..._nsu_audi.html
scroll to the very bottom.

This patent explains part of its manufacturing method:
http://www.google.com/patents?vid=US...SU+manufacture

This means that the sides of the rotor could basically be milled and then soldered or welded to the flanks to form one hollow piece in order to produce a high strength low compression rotor (casting with a sand core would obviously be too expensive for a small series). Well - if one wanted to produce a high boost rotary engine with low compression rotors.

If you put a 13b in the 8 could you use the stock tranny without modification. Will it bolt right up or not? Or will you have to use the 7s tranny?

Bolts straight up .

https://www.rx8club.com/attachment.p...id=96531&stc=1

This is my latest addition :rock:

It is a collaboration effort between myself and a local rotor expert

Engine is a composition of series 4 , 5 , 6 , and rx8 componants

I think its a first ???

I have a run in tune at 6psi pumping 350 RWHP .....

In a week or so it will be in the 450-500 RWHP .

Not bad for a daily driver hey?

https://www.rx8club.com/attachment.p...id=96570&stc=1

Ciao

Dave

OoOoOoOoO

Nice. What parts go to each respective engine? Im just curious what all parts you used and where they are from. Sound like quite a frankenstein monster and it looks good too.

I thought the 13B-REW and the 13B Renesis had the same footprint? It just drops right in and bolts right up to the stock RX8 tranny and PPF.
The main thing is electronics that is confusing me. You have to use the PCM that came with the REW, because the 8's PCM obviously won't work. But then what about the ignition security chip in the key. I think that's controlled by the PCM, if so, it wouldn't matter.

Ciao- do all you're stock gauges and accesories work like AC (assuming you put AC in).

This is something I have been thinking about heavily for the past couple weeks. Just because I could pickup a Street Ported remanufactured 13B-REW for around $4800 minus turbo hardware, but with injectors, fuel rail, ignition, intake manifold, and just about everything else. Add on a big-ass GT35R dual ball bearing turbo, huge FMIC, Apexi Power FC piggyback PCM, intercooler pipes, turbo exhaust manifold, intake, battery relocation, a Koyo aluminum rad, and etc, everything to make the engine *work* to be powerful (like 400-rwhp) could be had for $12k. That's a little less than a Mazsport Type 3 turbo kit, not mention all the other little extras I would need for that, so it's about in the same price range, but the 13B-REW would be more powerful. I could wick the boost up and make over 500-rwhp. It would be interesting to see what OEM RX8 componet would break first at 500-rwhp- probably 2nd gear, a few syncros, or the rear axles.
Just a thought...

My exact setup is used in one of our race cars pulling 7's . His car has 750+ RWHP on methanol

The engine bolts straight in .A bit of mucking around .

Still running the engine in so its early days .The AC needs to be wired in still but i dont see any major issues .

I highly doubt 500 hp would be safely achievable with a GT35R .A TO4Z would be a more prefered option IMO.Still 500 hp is so easy to say .....harder to do

All the guages work But I got warning lights everywhere .Need some help there ,I think .

I have a nice tidy Guage pod that gives me more accurate readings

Can A moderator start a new thread or move these posts on this topic as I think a lot of people have an interest in this .RG ...You there mate ?

Ciao

dave

looking really good!!

i'm curious though, with some semi-high profile tires like 285/35/19, would i be able to put the power down okay w/ rx8? (550whp 'ish)

Ciao, you should start a new thread about your 13b-rew powered 8, please. Post up some more info and pics (If you already have done this can you please redirect me?)

Thanks


Dave

Ciao,

Very interesting build! I too would be interested in see more details of your build in another thread.