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

 

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.

 

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

 

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

 

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 ...

 

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?
________
cheap condo in Pattaya

 

^^^ 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?