Hi All,

I'm helping a small race team here in Europe to launch a low cost Prototype race car powered by a HP Renesis engine.
To start with, they'll use a pretty standard engine configuration, using the OEM parts from the throttle body (not included, will be replaced by cable version) to the exhaust manifold (included). The engine will be managed by a low-cost EFI Technology (the Italian branch, not th US one) ECU.
So the objective is to use the original intake system (downstream of the T/B anyway) including the S-DAIS. I have however a few questions and issues :

1) APV : this valve is actuated by a stepper motor with a position sensor feeding the position back to the OEM PCM. Has anyone replaced the stepper motor with another kind of actuator, like a PWM actuated solenoid rotary actuator?

2) intake manifolds (metal and plastic) : are there on the market somewhere race parts to replace the complete OEM system, including S-DAIS.

3) Some rotary specialists told me it's OK to run same spark advance on leading and trailing spark. Comments, please.

4) Does anyone have info about what they do for the Star Race series in US regarding intake systems?

Some other questions might come out later.

Cheers,

Fabrice

The Star Pro Mazda cars use the OE intake less VFAD with a Motec M400 CAN-capable engine management controlling the SSV, APV, and VDI. I believe they do convert to a cable based throttle. I have some info I can send you that may be beneficial, PM me your email address.

IMO you'll be hard pressed to use a different APV controller strategy that will operate with the speed and control necessary to function properly.

Thanks TeamRX8?

I sent you a PM.

Re APV, I'm looking for solution to modify the actuation, because although the ECU I'll be using integrates a stepper motor controller, the software strategy is for idle control only. There is no software that will control it at higher RPM.
I might just leave it open at all times and loose a bit of torque below 6000 rpm then.

Cheers,

Fabrice

yeah, it's a conundrum for many stand-alones

email sent, not much but it provides some general basics

yeah, it's a conundrum for many stand-alones

email sent, not much but it provides some general basics
That was pretty quick. Thanks.
It gives some guidelines for the fuelling. Great.
And I just learned about the SSV opening anywhere between 4300 and 5500 rpm depending on TPS.

Cheers,

Fabrice

OK, some questions remain about the APV.

1) First, it seems the APV position sensor is a 0-5V potentiometer, and not just a switch. Indeed, the RX8 manual gives some info regarding this in the DTC code section. Can someone confirm?

2) Is there any mechanical stops in the movement of the APV, or is it just controlled in closed loop by the PCM?


Fabrice

APV issue solved. I'm going to use EFI Technology's Electronic Throttle Body controller to control the APV DC motor.

Fabrice

I'm curious why you are keeping the whole S-DAIS strategy. Won't you be running WOT throttle most of the time and defeating it's purpose? Or am I missing something?

You are missing something indeed as the S-DAIS activation is mostly engine speed-related and not load-related.

Fabrice

Yep - that's right. So, the Star Mazda cars run the S-DAIS also I guess. Maybe I'm thinking turbo - and with FI you don't need the intake runner tuning setup.

Yep - that's right. So, the Star Mazda cars run the S-DAIS also I guess. Maybe I'm thinking turbo - and with FI you don't need the intake runner tuning setup.
Yes the Star Mazda run the full S-DAIS also.
With FI, I would also assume you can get rid of most of the S-DAIS.

Fabrice

OK, we found a low mileage HP engine from a wrtite-off.
Next stage is to fit the engine in the chassis.
When it will all be ready, it wil be mapped on a dyno. Would anyone have base fuel and ignition maps for a Renesis that I could use as a starting point?

Cheers,

Fabrice

the only person I know of who might have that data is Alex with Astra Racing

well actually the Motec users would have it or their equivalent, the Star Mazda program is encrypted to keep them from playing with it, but SpeedSource and others use the non-encrypted version, not sure if they would just up and share the info though

I'm also looking for dwell time for the original coils.

Fabrice

I'm also looking for dwell time for the original coils.

Fabrice
Anyone please, we're dynoing in a couple of weeks...

Thanks,

Fabrice

there is none in the usual sense, unless you're referring to the trigger signal time period :dunno:

there is none in the usual sense, unless you're referring to the trigger signal time period :dunno:
The signal time duration defines the dwell to the logic coils. That's what I need.

Are you the only one hovering over this section, TeamRX8? :)

Cheers,

Fabrice

3.0 - 3.3 mS I believe

apparently so, I don't think some of the board technical specialists surf in this forum area ...

3.0 - 3.3 mS I believe

apparently so, I don't think some of the board technical specialists surf in this forum area ...
Thanks Team,

In the absence of info, I was going to start with no more than 3 to 4 ms anyway, or even less as I noticed Civic-R logic coils need 2 ms of dwell.

Cheers,

Fabrice

The Renesis engine's calibration was completed yesterday. We're very happy with the max power but the peak torque is a bit low due to do the APV open at all times.
We are starting testing on the track on Friday.

My thanks to TeamRX8 and Hymee+Phil, and some others for their valuable help.

Cheers,

Fabrice

great news, please keep us posted (publicly or privately :))

I posted a few pictures of the sport prototype with Renesis engine.

I went to Magny Cours in France where it participated its first race weekend.
The engine runs fine and seems very competitive but the car suffered from serious overheating problems all along the weekend.
The team changed the cooling and radiator set up so the two rather small radiators on each side of the car work in parallel in lieu of in series. It improved things a bit but not enough to finish the races. They are now evaluating the possibility to completely change to original set up and move to large radiators. Maybe OEM RX8 ones. They also need to make sure there is no issue with the water pump.
Any advise is welcome. Does anyone know what Star Mazda series use?

As far as I'm concerned, I'm very satisfied with my engine management set-up: 2 x EFI Technology Euro-1 ECUs working in parallel. It all runs fine and smooth, with a smooth idle at 1500 RPM despite all intake ports being opened. Performance is rather strong too.

It starts very easily too. I've read so many negative coments about how sensitive to fuelling this engine was for starting. No problem. The Renesis seems also extra strong. Last point, we encountered some starting issues initially (due to a wrong setting) and we cranked this engine for 2 days (not continually, no ;)). Guess what, the starter is amazingly extra-strong! Note it's the uprated version of the starter.

To be continued...

Fabrice

Oil coolers?
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^^^ Yes a large cooler is fitted. Are you suggesting the issue could come from a lack of oil cooling? I actually hadn't thought of that. Definitely worth investigating, especially if someone else concurs.
Which percentage of the total heat lost to coolant is dissipated by the oil coolers vs the water radiator?
I'll have a look at my Yamamoto's book.

Cheers,

Fabrice

Fabrice

Can you get a picture of the Oil and water cooler setup so I can see what you have?

Can you get a picture of the Oil and water cooler setup so I can see what you have?
Sorry, I don't have any, but will ask the owner for some, as he took loads during this race weekend.

Cheers,

Fabrice

Are you using the stock pulley on the engine? At sustained high rpms, the water in the pump can cavitate reducing the flow through the system. Have you tried underdrive pulleys.

I am sure you know this, but oil is used as a form of cooling the rotary internals, where coolant cant get to, its just as important as radiator. Look for the Courage C65 threads in the lounge and in the racing forum to check out RG's view on size/airflow of radiator and oil cooler
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I am sure you know this, but oil is used as a form of cooling the rotary internals, where coolant cant get to, its just as important as radiator.

..and probably the reason why many dedicated race setups (when the rules allow) employ auxiliary oil sumps as well, no? increase the total oil capacity and create a larger heat sink in the process.

I remember in my 911 SC, which of course has no water cooling, the oil capacity was huge; and there was a lot of external oil piping length designed into the car, to better introduce the oil to the ambient air temps.

First I'll reply to the few new posts :

The original pulley is used indeed. Although the use of an underdrive pulley is a good idea for a racing application, I don't think the original set-up can induce an overheating issue.

The oil cooling use a single cooler, larger than the original unit. It is not ideally located, as the engine is mid-mounted.

I had a proper look at some pictures of the Star Mazda car. They use a huge racing water radiator on the right side of the car. They use a second one, same size it seems, on the other side for oil cooling only. By its size, I guess it is oversized and allows a very large oil capacity (heat sink). Which match what GULAMAN just mentionned above.

Anyway guys, thanks for your interest and your help.

Fabrice

Can you get a picture of the Oil and water cooler setup so I can see what you have?
I found a picture of the car.

The 2 water radiators are rather small, and fitted at an angle. They already were on the proto when it was still running a peugeot V6 engine.

The oil radiator is the tiny cooler in front of the rear wheel. A small NACA air inlet insures it gets proper cooling.

Compared to the set-up in the original car, it seems sufficient. However, compared to the Star Mazda :uhh:...

Fabrice

What is your oil temperature looking like? This will tell the tale ...

^^ No gauge installed yet. So it's anywhere between ambient and deep frying...

One of the first rules of racing rotaries in chassis normaly used with piston powerplants is the need for larger radiators. Also the RX8 water pump is quite inefficient but luckily there are some fine folks coming out with an improved unit probably by year's end.

^^ No gauge installed yet. So it's anywhere between ambient and deep frying...


we need to send you back to race car building 101 :spank:

we need to send you back to race car building 101 :spank:I'm not a race car designer or builder. I'm not the designer of this Renesis engine proto either. I'm responsible for the engine management supply and calibration.

Fabrice

oopsie :o:

^^ Don't worry, I'll pass your message to the right person in the team...:naughty:

That said, I recognise my knowledge of rotaries is still pretty theoretical. That's the all point of this interesting project : getting practical experience on these beasts.

Cheers,

Fabrice

oil temp is paramout.......

it is just not a fluid it is life..

beers :beer:

For info, we have the cooling of the Renesis working fine now. We also got a podium (2nd place in our class) in August.

Some imporvements have been made to the car for the next races this coming weekend (7/8 - Oct) : the gearbox is now with racing gears and dogs (is that the right word? - the syncro were removed), better coolong air flows, better aero...
Engine hasn't been modified at all.

Next major step would be to build a second car in 2007. I have a engine (naked engine) and we plan to move from the original S-DAIS manifold and design a simpler one instead.

See here for the start of a discussion with RG on that topic :
http://www.rx8club.com/showthread.php?t=19553&page=2&pp=30

The technical requirements are :
- simpler, cheaper design
- minimum loss of perf compared to original part

I'm thinking about :
- getting rid of the SSV, that's for sure
- getting rid of the VDI, maybe
- move from a electric motor actuated APV to a solenoid / vaccum actuation

The design would be simple : think of a large plenum with 6 relatively short (around 450 mm) tubes going to the 6 ports. Throttle valves would open the Auxiliary ports at high engine speeds. And that's it!

If you have any comment on this, especially on some unknown (to me anyway) parameters like :
- is it a right decision to get rid of the VDI?
- how large should the plenum be? The airbox on the RX-8 is huge compared to the rest of the intake system.
- what about the lengths of the intake ducts (450 mm = around 18")?

Cheers,

Fabrice

For info, we have the cooling of the Renesis working fine now. We also got a podium (2nd place in our class) in August.

Some imporvements have been made to the car for the next races this coming weekend (7/8 - Oct) : the gearbox is now with racing gears and dogs (is that the right word? - the syncro were removed), better coolong air flows, better aero...
Engine hasn't been modified at all.

Next major step would be to build a second car in 2007. I have a engine (naked engine) and we plan to move from the original S-DAIS manifold and design a simpler one instead.

See here for the start of a discussion with RG on that topic :
http://www.rx8club.com/showthread.php?t=19553&page=2&pp=30

The technical requirements are :
- simpler, cheaper design
- minimum loss of perf compared to original part

I'm thinking about :
- getting rid of the SSV, that's for sure
- getting rid of the VDI, maybe
- move from a electric motor actuated APV to a solenoid / vaccum actuation

The design would be simple : think of a large plenum with 6 relatively short (around 450 mm) tubes going to the 6 ports. Throttle valves would open the Auxiliary ports at high engine speeds. And that's it!

If you have any comment on this, especially on some unknown (to me anyway) parameters like :
- is it a right decision to get rid of the VDI?
- how large should the plenum be? The airbox on the RX-8 is huge compared to the rest of the intake system.
- what about the lengths of the intake ducts (450 mm = around 18")?

Cheers,

Fabrice

Congrats on the 2nd place finish! :rock:

I don't know any of the answers to all of your questions but as far as the transmission gos dogs is the right term.

Where in Europe are you from anyways?


Oh and....


This thread is worthless without pics! Show us some pictures of your car!!!!

pictures on the 2nd page dood.

I meant of the car racing.

Sorry I didn't specify. :Freak_ani

Thanks Deamicls,

Here are some pics of the car.

I'm from Belgium. The car races in France.

Cheers,

Fabrice

Thanks Deamicls,

Here are some pics of the car.

I'm from Belgium. The car races in France.

Cheers,

Fabrice
HEY! I'm from Belgium too! I used to live in Rixensart at the Lac de Genval about a hundred meters away from the Castle. Where are you from?

Allez Les Diables!

Hi Fabrice- sorry i havent seen this thread before. it looks like an excellent runner now that you have the cooling sorted out. did you go with a Star Mazda-esque set-up with water on one side and oil on the other? ill put my intake thoughts in the other thread you linked to.

Zoom, no problem.
Re cooling, I suggested a Star-Mazda type of solution but the team manager went for another one with 2 smaller water coolers.
I'll have a look at the other thread too. Note that I moved away from that thread as it seemed more dedicated to an installtion on the RX-8, not to a full-racing custom manifold.

Deamicls,
I was born in Brussels and have lived in Overijse until 1995, not far from Rixensart and Genval which I often visited as I had a few friends in Rixensart. I know live in the Walloon part of the country, oustide the city of Huy. So I effectively lived in the 3 Regions of Belgium. My native language is French by the way.

Fabrice

Zoom, no problem.

Deamicls,
I was born in Brussels and have lived in Overijse until 1995, not far from Rixensart and Genval which I often visited as I had a few friends in Rixensart. I know live in the Walloon part of the country, oustide the city of Huy. So I effectively lived in the 3 Regions of Belgium. My native language is French by the way.

Fabrice

Thats really nice to hear. I am french speaking as well and overijse is great place. I'm sure you already know a really good restaurant called Istas. The the best steak ardennais. I come back every year since we still have our house at Genval and Istas is always the first restaurant I visit.

alright, back on topic. Sorry.

alright, back on topic. Sorry.Why?

Thats really nice to hear. I am french speaking as well and overijse is great place. I'm sure you already know a really good restaurant called Istas. The the best steak ardennais. I come back every year since we still have our house at Genval and Istas is always the first restaurant I visit. .Istas is very popular. But I only went there 2 or 3 times in 25 years. You might want to come and say hello on www.rx8france.com. Loads of Belgians there too, even moderators and comittee members!

Salut,

Fabrice

I'll have to say hellothen! At least it'll get me to write and read french again which I haven't done in 9 years. :hahano:


Je
Tu
Il

Nous
Vous
Ils

....brings back some bad memories. Gives me goose bumps.

OK,

So we raced last weekend. We did not win anything but the car was performing quite well. We had less reliability issues and only suffered gear box issues despite a partial replacement of the internals (gears, cogs,...) since last race weekend. On Saturday, the driver bent the 5th gear fork, which is an original Renault part made of brass! The mechanics repaired it for the races on Sunday.
First race was not bad with a good mid field finish. Second race was much better until the fork bent again! As the 5th gear was only used at the very end of the straight line (it's a very slow track) , the team decided to remove it (loosing the ability to engage 5th) and increase the REV limiter to compensate (the driver could stay in 4th longer). It costed us 3 sec per lap in the 3rd race and we did another confortable mid-field finish.

More important, some Mazda France managers were invited and they were pretty interested by our project. We might do a full race season next year...

On the technical side, with the new gearing, the engine speed often drops to no lower than 6400 RPM and rarely to 6000 rpm. Sounds like the APV might not be essential especially if we carry on increasing the REV limiter. I'll do some tests on the importance of the VDI at the next opprotunity.

The engine still pulls strongly, idle at a steady 1400 RPM, and starts very easily from cold. Amazing what that little buzzer can handle! I love the Renesis. So much so I bought a used one that is down on compression on one side of rotor #1 in order to rebuild it.

To be continued...

Fabrice

Video of the Renesis powered prototype : http://www.youtube.com/watch?v=Dedre-CTRp8

Pure rotary pleasure.

I'm the guy with the laptop...

Hello from Sweden Fabrice! Nice video good sounding car but can be better. I have been into Mazda rotaries for 25 years and i am a hardcore rotary engine builder for living (18 hours a day)! I must say that the Renesis engine do respond good to both bolt on and engine block preparing but you must think twice when it comes to a N/A engine. I have a 2004 RX-8 and have done some mods to it. The exhaust system made 10 hp with stock exhaust header. Of course i have developed prototype 1 header for the engine which we shall test next week on my RotoTest hub bench (very accurate). Then i have prototype 2 and 3...I am also in progress of developing both the cold air inlet air filter box and a new simple but high efficient intake manifold. To sum i8t up i have some pretty good experience when preparing rotary engines which is (almost) always dyno tested. Of course i have a rotary flow bench since 1997. What i try to say here is that i can develop parts on flow bench dyno test it and manufacture it here in Sweden. If this sounds interstesting you can Mail or PM me!

Best REgards: Lasse wankel Sweden.

Hey I am curious if it still makes power up top when you increased the rev limiter, I assume you're spinning it close to 10,000rpm?

btw, nice video, although it does not have the "burpy" idle of a PP 3 or 4-rotor, it sounds nice!, also were there any other rotaries running on the track when you recorded it? I thought I heard another rotary =D
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Hello from Sweden Fabrice! Nice video good sounding car but can be better. ...If this sounds interstesting you can Mail or PM me!

Best REgards: Lasse wankel Sweden.Hi There! Interesting. I'll e-mail you.

Hey I am curious if it still makes power up top when you increased the rev limiter, I assume you're spinning it close to 10,000rpm?

btw, nice video, although it does not have the "burpy" idle of a PP 3 or 4-rotor, it sounds nice!, also were there any other rotaries running on the track when you recorded it? I thought I heard another rotary =DNot quite 10000. 9500 RPM in fact was our new limit for the weekend.
There were no other rotary race cars. All psitons, but some sound good too. There were a few Civic Type-R engines too.

Fabrice

I have all the parts on Tuesday then we begin fabricate this week. Shall be really interesting to see the flow comparisions between stock inlet manifold and ML Wankeltrim custom one! I will post some flow numbers in the following weeks.

/Lasse

Here are some flow numbers at 10" of water: Stock fronthousing total flow of 4-port and 6-port: 142 cfm at maximum opening of both ports. Ported 4-port and 6-port (stage 0.5) 2 mm and radiused: 155 cfm, that,s an increasement of 9%.
Exhaust port stock: 73 cfm. Radiused only and cleaned up no porting: 82 cfm +12%! This weekend Mikael will flow the intermidiate housing stock and stage 0.5.

/Lasse

oooh i believe i have posted in the past that i believed there was at least 10% more left in the exhaust:D:

good work all!!

Ok. So now the Renesis stage 0.5 is ported. Intermidiate housing stock inlet port 51 cfm ported stage 0.5 63 cfm increase 23%! I have not the numbers for the intermidiate exhaust today but will post it tomorrow. Otherwise Mikael is busy building the fabbed sheet metal inlet manifold which we hope shall boost the cfm numbers.

/Lasse

We're planning to build a second sport proto next month, still powered by the excellent Renesis HP.
I'm rebuilding an engine right now and I'd like to know what can be done to it in term of modification of internals in order to achieve better durability (1 year between rebuilds) and higher max. RPM (10000 RPM min.).
This car would be used in sprint (20 min) and endurance (4 and 8 hrs) races.

Cheers,

Fabrice

wow, great news! now you gotta shoot us more videos=d...

ceramic seals, RB light weight rotors w/ snap ring (are they allowed?), but then durability and high rpm kinda go against one another... haha...
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Ceramic seals : do they require a change in the housing material ? Also, I'd need to check whether ceramic is allowed in the regulation.

RB light weight rotors : I just had a look at these on their website. I'm NOT paying $2000 for a 2,2% gain in weight .

Snap ring : don't know about those. Will do a search.

Lightened flywheels are limited to 10500 rpm.

We're planning to build a second sport proto next month, still powered by the excellent Renesis HP.
I'm rebuilding an engine right now and I'd like to know what can be done to it in term of modification of internals in order to achieve better durability (1 year between rebuilds) and higher max. RPM (10000 RPM min.).
This car would be used in sprint (20 min) and endurance (4 and 8 hrs) races.

Cheers,

Fabrice


I think you need to refer to time between rebuilds in hours not years. There are many items that can improve the life of these engines, however in a racing environment all bets are off. Better seals are a must,better lubrication,better bearings etc. etc.

The harder you stress the engine (RPM) the shorter the life span and it is NOT on a linear scale. While an engine with a max RPM of say 9800-10000 may last 30 hours between rebuilds one that sees 10500-11000 may last 3-6 hours.

Good luck with the cars they look like great fun!!

you need to start off with new housings for the ceramic seals, that's all

Thanks for the very helpful replies.

I intend to set a different rev limiter for Sprint and Endurance races. And I can do the same for Qualifying / Race.

For lubrification, I was thinking of using full synth for the internals and 2-stroke for the premix.
Or an adpater from Sohn that converts to a mechanical pump, but there is some space interference I need to work on. The car will be rented out to other teams sometimes, and you can defnitely trust them to forget to premix...

TeamRX8, I don't want to change housings that are perfectly fine. So ceramic will be for later.

What do you guys think of using 3 mm apex seals (require machining of the rotor grooves).

And what are the solutions in term of stronger bearings? Can they be found for the Renesis? Same as previous 13Bs?

Does someone know who is the engine builder for the Mazda Pro series?

Does someone know who is the engine builder for the Mazda Pro series?

i dont know the answer for that, but if you asked that ? i would talk to mazmart... knowledge is power...


beers :beer:

Does someone know who is the engine builder for the Mazda Pro series?So, nobody here knows?:sad:

Does someone know who is the engine builder for the Mazda Pro series?

it was discuse here in the forum , I just dont remember the name, ask paul from mazmart

OK, Swoope and Rotary Crazy, I'll ask Mazmart.

Does someone know who is the engine builder for the Mazda Pro series?

I think it is Drummond. Try 541-659-8634.

Thanks, but the mods mentionned above are not at the agenda any more. Due to new developments, we'll have to stay very close to production.

I will however have a look at what Drummond does, by curiosity.

I know jack shit... but I remember hearing that at higher rpms the e-shaft can flex and f stuff up. I was told to add a center bearing to decrease distortion.... not that i know if they make one for the 13b-rew though..

Drummond does the FM rebuilds, I'm not so sure about the FPM Renesis rebuilds ...

I know jack shit... but I remember hearing that at higher rpms the e-shaft can flex and f stuff up. I was told to add a center bearing to decrease distortion.... not that i know if they make one for the 13b-rew though..

Shaft flex is not a problem until revs exceed 11k especially on these motors. The problem occurs on nose of crank due to the mass of the counterweight. This has been reduced since the 3rd gen motors which carry a larger front spacer allowing more torque to be applied tightening the front bolt. This in turn adds rigidity to the nose. The 3 rotor (13G) was one of the first to apply this. Also the motors are better balanced these days and have lighter rotating assemblies. All this is to say you could get in trouble with a downshift by accident while attempting to upshift at high revs, otherwise there's not much problem or need to resort to the center bearing.

Paul.

Thanks for the interesting info,

Fabrice

I saw the needle swing past 10,000 on the tach for a very aggressive downshift the other day :uhh: the rear tires didn't lock up though ...

I saw the needle swing past 10,000 on the tach for a very aggressive downshift the other day :uhh: the rear tires didn't lock up though ...

were you braking really really hard?

beers :beer:

yes, heavy trailbraking no less, but the ABS is operational so who knows how hard the rear calipers were kicking in, I was a bit busy at the moment ;)

yes, heavy trailbraking no less, but the ABS is operational so who knows how hard the rear calipers were kicking in, I was a bit busy at the moment ;)

my thoughts were no weight no traction...

beers :beer:

I saw the needle swing past 10,000 on the tach for a very aggressive downshift the other day :uhh: the rear tires didn't lock up though ...That's one of the good points we use for marketing the Renesis : the fact you can do an over-optimistic downshift withtout the valves coming to kiss the pistons, unlike the more commonly used Civic-R engine...