JimV8

Ok, moving along in my ideas and thinking exhaust. Use the OEM down pipe shortened and elbowed up into a Vibrant 200 cell Cat then a couple of elbows to get it on top of the transaxle and into a Vibrant 1142 ultra resonator and finally to the racing beat REV30 muffler. Because of the space available those parts would be pretty well end to end.

I like Vibrant and used their stuff on the 968 project and they are local to me also. The Racing Beat REV30 is just sexy and would look killer on the back of the car and sounds wild too.

On-line I read that the Vibrant ultra quiet resonator is a quality piece but may not be suitable for a rotary. But then I can’t find any more reference to that comment and figure folks here might have an opinion.

Brettus

iTrader: (2)

If it's glass packed ...forget it ! You need stainless packing to survive rotary heat !

JimV8

Thanks, and I sent Vibrant email, asking if it will take the heat. FWIW, I did a forums search on REV30 and learned that in 2010 a guy built a Renesis powered Locost and used the muffler and a Racing Beat pre silencer and recorded it on YouTube and it sounded very nice. So I’ll wait to hear back from Vibrant, but thinking I might have an exhaust plan.

This muffler placed like this.

Fit like this.

This muffler, (obviously very little backpressure)

EDIT: good news, a review on Summit Racing says packing material in Vibrant ultra quiet resonator is STAINLESS STEEL. Whoo ho!

JimV8

I got an answer back from Vibrant and for the Ultra Quiet Resonator to have any life beyond a year it has to be placed well to the rear. In the case of my build that’s a much shorter distance than what the RX8 offers. I searched and found on the RX7 Forums the Ultra Quiet has a stainless steel over Cotton as absorptive material. Looking a bit further I found ceramic absorbing material that has a very high heat tolerance, up to 2000 F. https://shop.steelwooldirect.com/pro...24-x-60&page=2
i May try that on my Outlander 800 as its aftermarket exhaust is deafening with scouring pads I jammed into the chamber.

But there are other makers of resonators that tolerate high heat so all is not lost and the Rev30 muffler is certainly capable of taking heat.

The issues of high exhaust temps got me thinking of ways to cool the gases on the way to the CAT and back. So instead of going straight back with a log manifold and to a up positioned CAT I’m thinking of tubes coming straight out of the 3 ports curving sharply down and curling back coil like and merging into a single 3” and into the CAT. That should drop the temps into the CAT. Beyond that I figure that exhausting the radiator out flow air into a channel surrounding the whole of the exhaust system will sharply reduce under hood temperatures too.

Brettus

iTrader: (2)

Turbo

JimV8

That’ll be plan B.

CaymanRotary

The only issue you got is you want the exhaust to be as free flowing as possible. To make 270HP you would need to run the most free flowing exhaust you can fit. The exhaust porting on this engine is terrible and was done for emissions purposes. The 13b-REW had near perfect porting and lower compression rotors to allow for insane power. This engine was designed for a commuter car and Mazda left little room to extract more power than stock. It was always meant to be naturally aspirated.

This is why forced induction on the 13b-MSP gave so little gains. So much money for so little WHP...

JimV8

Great place for info here, just finished reading several pages of exhaust discussion by knowledgeable folks and I have a better understanding now of what has to happen and why. My next question is whether to wait for a series 2 to appear or go with a decent series 1. First I’m not in a rush so there’s that. But all the same an 06 is available with 2500 kms on the engine so I’m thinking not taking chances and if I go with that or similar to send it to a pro engine builder and get it checked out? Is it practical to upgrade a series 1 to series 2 oil delivery and do what ever other things to get it close to the series 2 spec which seems a much better engine? Bearing in mind that for all purposes I’m building a new car.

CaymanRotary

You could use a series 2 engine but I think the series 1 is just as good for your purposes. The main thing is to ensure good compression no matter which engine you choose. The extra oil port isn't a huge loss if you are premixing. Series 2 engines are rarer and more expensive so that is another consideration. All comes down to your budget and what you are looking for.

JimV8

That’s good news, and I’m noticing that 09s and later are as rare as hens teeth, at least in my area. Plenty of earlier one though.

I spent all day considering exhaust and had a eureka moment after sketching out several really pretty headers all in stainless steel. The solution was staring at me all along and solves a couple of challenges. The first one is the engine has to meet all emission standards and emissions devices must be in place. The 2nd challenge is heat and I learned the Renesis engine runs cooler than the earlier Wankel the exhaust is still really hot and even really good CATs don’t like to be beyond 1500f. And stainless steel is wonderful in retaining energy.

So my elegant solution is to use the OEM log manifold and the 1st step is just back of the 3rd port slice it in half and rotate the aft section 180 degrees so instead of curving downward it now does the opposite and goes up. 2nd step is another slice and completely remove the last transition curve to just before the O2 sensor. Now the exhaust pipe faces upward at about a 45degree angle and thats exactly where I need it and it’s cost almost nothing and the welding is doable too. Even the heat shielding is reusable and the engine mount brackets remain stock. Perfection.

The second part which I like is that cast iron is a great heat soak and just about the best way to lower exhaust temps. It might be necessary to add in an additional mild steel tube section, finned perhaps, to lose yet more heat, but with the CAT now angled upward the heat lost might extend its life. I read somewhere that CATs don’t die, they are murdered. Hopefully this will work.

Did I miss something?

JimV8

Oops, the exhaust tip is now too far back, so easy fix is to put the cat just after the upward curve in the exhaust pipe. Not much difference except now I’ll need a couple of heavy steel tube bends and some straight pieces and eliminate the OEM exhaust parts after the manifold . This buys about a foot reduction in overall exhaust length.

Next question relates to body design. The plan is a ground effect tunnel floor and that’ll need a very open front over a big splitter. It’s straying a bit from the original concept and my sketches have interesting space for lights and I’m thinking the RX8 headlights might be right. Question is how good are they?

CaymanRotary

The headlights are great functionally but I don’t know if they will look good on that car. That will be your decision to make.

The only thing you gotta worry about with body design is getting airflow to the radiator. The rotary engine causes a lot of heat and if the engine overheats, it can easily be ruined. Whatever you do, ensure that the cooling system can work to the best of its ability.

JimV8

Thanks. The headlights are among the first things noticed when looking at a car so looks are very important. Since the Type 33 was first designed and made the rules have probably changed but in North America head lights must be between 22 and 54 inches above the road surface and positioned as close to the sides of the car as possible, ( I looked it up).
I sketched the frontal area and it’s unlikely the RX8 lights will fit. The fenders will bulge over the front wheels then drop sharply across the front so there’s little room for lights as frontal area of the fenders is +/- 12”. Off the top of my head the Acura Integra lights circa 1997 might work as those are a pair of simple round lenses at each corner and DOT labelled too.

I thought a lot about cooling and it looked like a pair of custom rads will sit parallel or angled from the sides and just behind the axles and exhaust into the low pressure zone behind the car just over the diffusers. Rad intakes will probably be side pods but I’m not far enough into it yet to know for sure.

JimV8

Dang, I hate that. Just when I come up with a unique idea for a chassis I discover somebody else already did it. But it is killer good though. I’ll have to dig into how those lights are legal. Think rotary in that chassis.
Radical SportsCar - Rapture. I could give a link but don’t think that would be appropriate or in good taste.

Brettus

iTrader: (2)

Yep ...you did . The OEM manifold is like a jigsaw in construction .... it has an inner and outer shell . Too hard to modify IMO ....forget that idea.

JimV8

Thanks good to know. Probably better then to merge 3 short primaries into a 3” pipe with a 45 deg. elbow up to the CAT.

Brettus

iTrader: (2)

This was a copy of team's design ............Made from MS exhaust tube .....note the taper!

JimV8

Sweet, thanks

JimV8

Update. The real world of licensing and registration doesn’t make it easy recreate a vintage car. There just isn’t any leeway as I learned when I dug into the nitty gritty of regulations. Headlights shall be between 22” and 54” measured from the road surface and that makes perfect sense. Passenger vehicles shall have front and rear bumpers at least 3” wide minimum 14” from road surface extending to the out widths of tires. All vehicles shall have fenders. All vehicles shall have a motor hood.

Now just one gull durn minute what about Rat Rods and similar. So I looked at that and found the answer. They cheat and nobody seems to care. First of all the Rat Rod community guys look for sympathetic inspection shops and nobody seems to want anything but proper safety inspections but look for a bit of accepting of shades of grey. So in the case of Rods they all get fenders, hoods, exhausts, bumpers in order to meet the safety certification requirements. Then once they have their sticker they lose the fenders,hood and bumpers. And I suppose, because these cars get little actual street time they don’t draw undue attention either.

so I’m going to do the same. Build a chassis and bolt on the legal pieces and get a sticker, then pull the parts and fit the intended body work and drive a kick *** Alfa type 33 replica that revs to 10 grand.

As far as drawing attention I learned from the Porsche experience that Police hold people who drive performance vehicles to a higher standard. and they’re right they should. So as long as I’m not being stupid they won’t check me out except at Tim Hortons for donuts.

JimV8

Hi, I dropped in to say bye and thanks. I’ve decided to go another way on the motor and not that the Renesis was wrong either. The original Tipo 33 was powered by a high revving 2 litre V8 and that’s of course unobtainium and I didn’t want to go to an LS as that would over power the chassis and gearbox. But it still bothered me that going to all the trouble and many many hours of work that I was going to end up with Tigers heart in a Lions body by going with a rotary so I looked at the Alfa V6s. Very nice and the sizes are right but not very available on this side of the pond and then I read that the last Alfa 6 was a GM engine and apparently they build THE sixes on the planet right now. Sounds good but it needs the GM engine ECU (pcm) and that’s impossible. So and frankly I don’t recall exactly how I learned this but,,,,there’s another car company that built an amazing engine called SHO 3.4 all aluminum (with liners) DOHC. That’s Ford of course and the engine is a Cosworth design and heads are tuned by Yamaha. It powered the Taurus from 96-99 and was intended for another chassis that didn’t materialize so they stuck it in a Taurus having earlier experience with the crazy 3.0 six Taurus.. the V8-3.4 is rated at 235 hp @ 6100 and 230 ft/lb at 4800 and is limited to 7000 but easily revs to 9000, although that’s rather pointless. According to rumour when Yamaha delivered the prototype to ford it ran over 300 hp on the Dyno, Ford Brass thought that was going to steal action from the Mustang and there was also concern the auto box wouldn’t handle that power so it was derated. There’s an Achilles heel to the engine which is a camshaft sprocket failure, but if that’s dealt with it everybody says it’s a reliable engine. So I’ve found one with the fix in Pittsburg for all of $350.

An interesting by product of looking at the Renesis is I got check out the RX8, in particular the suspension. I’ve done a bit of work with a Porsche stuff and there’s no faulting it but it tends to be costly. the RX8 stuff on the other hand is very reasonably priced, very light weight, great A arms in front and semi trailing rear bars. So I ve decided to go drop in RX8 for the suspension mounted on a multi section carbon tub. BTW I found some really nice Willwood vented rotors at a nice price and only 6.5 lbs and good for street too.

So that it. Thanks again for putting up with me. BYE. I’ll check back from time to time.

RX0004

Just read your thread and was about to post that a Renesis power plant was going to be a dumb idea, IMO. I could go into the reasons why, but it's moot point now given you've changed direction anyways.

Best of luck with the build.