babylou

Nah, that's a normal underhood temp. Almost every car I have instrumented is within 10F of your measurement. Though 140F is at the limit for normal electronics all underhood electronics are uprated. My oil well drilling products use electronics rated for 347F.

olddragger

iTrader: (3)

Guys ,
thanks for the respones. Richard Paul I know you are proud of those kids! They sure sound creative and successful.
The rest of you thanks for the feedback on the heat also. I'm not an expert so I appreciate all the info. Glad to hear modern electronics can withstand this type of heat.
Another measurement I did today was interesting. I measured PRE-filtered air(temp sensor installed next to the actual air filter) temps after driving on business type roads etc for approx 15 miles, speed limits 45-55 ,outside air temp 92 degress and the pre filtered air for the cart was 112.8 F. Then I measured Pre-filtered air while driving down the interstate at 70-80 mph and it was 95.9F (still 92 degrees outside) Hmmmm 17 degress differance, Probaly doesnt mean anything but it does futher suggest to me that this car doesnt have a lot of airflow going on under the hood. WHich also probaly may not mean anything . Anyway food for thought! Keep up the good work Richard.
olddragger

Richard Paul

iTrader: (5)

Babylou, those temps all sound about right. Are you telling me then that underhood electronics in modern cars are uprated to the numbers like your oil equipment stuff?? Also how does one know? It would be nice to know there is a saftey margin on your car.

Olddragger, that all makes sense. What is happening is that at low speeds you are not evacuating the air fast enough, so it picks up heat. To another effect the ram air is not as active. I know people don't think they have ram air if there is no scoop. That's not really true. There is always a high pressure area in front of the car. The faster you go the more pressure there is. You can't help but get the pressure.

In fact it may hurt some trans am guys out there but a scoop ala old mustangs and transam are in a low pressure area. Notice NASCAR guys never use that sort of scoop even if it were stock. They take air in at the base of the windsheild.

Anyway I just came home for lunch after assembling the new blower. I'm going back to finish up and take some pictures. I'll post them when I get them back on disc.

babylou

No, the automotive underhood electronics are rated to a lower spec than my oil field stuff. I believe that underhood automotive electronics should be rated to 212 F. To be sure I will ask a few buddies in the biz next week.

How does one know what temp rating your electronics are rated to? Without getting the information from the manufacturer it would be tough. Sometimes the same chips can be rated for two different temps but the difference is the QC testing.

bureau13

Maybe I'm missing something. How does a computer handle boost if it can't adjust fuel and timing based on pressure?

jds

Richard Paul

iTrader: (5)

All the efi systems have a MAP sensor, right? So therefore they are always monitoring pressure. The speed density type use just those inputs plus preset maps. The air density type may get away without it but I think most still use the imput. Air flow type must know density. I guess they could get it from baro pressure, temp, and humidity. But still manifold pressure and temp are so easy to use it seems silly not to.

There have to be some experts out there reading this thread, pitch in. I have built three EFI system using componants from all over and they were very good. I was not having to CARB them though.

Here is a picture of a unit I built for myself. I made all the special parts and bought the controler from Haltec. It was a 16 nozzle system. I used a GM map sensor. Two corvette 2 btl throtle bodies. I modified a Holley intake and hand made the fuel rails.

Richard Paul

iTrader: (5)

atachment didn't stick. try again

IKnowNot'ing

To actually measure the quantity of air going into the engine , OEM ECUs usually relies on two different principles :

- Mass Air Flow measurments using a MAF sensor (hot wire / hot film) that converts the required heating of a hot wire into an air mass and therefore air charge, or engine load.

- Speed Density based upon a T-MAP sensor (Manifold Air Temp + Manifold Air Pressure), based on the principle that air charge (or engine load) is directly proportional to manifold pressure.

The RX8 EMS is of the MAFS type and, based on the service manual, has no MAP sensor. It's not the best system to manage a supercharged engine with significant boost.

Aftermarket ECUs usually don't evaluate or calculate the amount of air going to the engine as it requires very accurate and elaborate simulation models. They usually just use the sensor measurements as direct inputs for the base fuel, spark advance and all the other tables. These sensor inputs can be, on the best systems, of three types :
- Throttle position based on a TPS
- Speed density : based on MAP with an air temp corretion
- Mass air flow based on MAFS

Some also provide a 3D tables MAP vs TPS vs RPM that are difficult to calibrate (map) and usually used for highly restricted turbocharged engines (like WRCs or GTs).

The super/turbo-charging of an engine require the following features concerning the engine management :

- In order to keep a sensible level of spark advance in the case of significant boost pressure, the compression ratio needs to be lowered. Failure to do so, will require a very high level of spark retard (due to detonation) leading to very hot exhaust gases, low efficiency a,d probably some toubles with the exhaust manifold. For very light boost pressures, one can rely on the knock control level of autorithy to keep detonation to an acceptable level. This option can be further stretched by using high octane fuel. My rule of thumb tells me :
> 1 RON corresponds to approx. 0.2 CR
> 1 RON corresponds to approx. 1°CA spark advance

- I think that for fast road application, one MUST keep the original ECU in order to manage all the emission, diagnostic, confort and safety functionalities of the OEM system. It would also allow the system to work close to standard until significant level of boost is required by the driver. That would leave you with three options to supply more fuel under boost :
1) Rising rate fuel pressure regulator : cheap and nasty but works for medium levels of boost
2) Auxiliary ECU driving extra injectors. Their injection phase must be referenced against TDC.
3) Auxiliary ECU intercepting and modifying the original injection pulse signals under boost. I believe that's what the Canzoomer piggy-back does already.
4) Modifying the calibration of the OEM ECU : you must either sleep with a Mazda calibration engineer or be one.

- The increase of air flow du to the supercharger WILL trigger a diagnostic error due to MAFS readings going beyond its calibrated max level. Some electronic gadgetry (basic signal processing) needs to be placed between the MAFS and the ECU to prevent this.

- If boost levels are significant, I guess one could get rid of the complex acousticly tuned intake system. In either case, I wonder how an axial S/C will behave when its outlet side will be 'hit' by a returning pressure wave. Will it instantly stall or will it behave like a windscreen hit by a fly?

zoom44

doesn't the RX-8 pcm have a baro? i believe i have read that in one of the many canzoomer posts. then it could derive the pressure from baro,humidity and temp as richard states above

IKnowNot'ing

The baro pressure sensor is either integrated within the ECU or at a remote location in the engine bay. It gives info about the ambiant conditions, not what's going on in the manifold.

babylou

BR Performance makes Eaton supercharger kits for the newest Miatae that use two small little piggy back computers. One for fuel and the other for spark. The computers have their own pressure sensors. The setup is supposedly limited to 8 psi boost and the piggies are a Jackson Racing product.

I can attest that the solution works flawlessly. In fact, I have never driven any full aftermarket ECU cars that peformed so well in the real world. We are talking about idle, throttle response, etc. all are the same as when the car left Hiroshima.

Why did I say all of the above? Because I think this talk of highly sophisticated aftermarket engine management schemes will lead to more blow-ups, longer development time and reduced driveability for the first few years. Down the road when there is a large base of experience built then of course there will be a legitimate need for the fancy ECU's so the fringe can build their 450hp monsters.

RoTaryStYleZ

All i want is some damn boosT, haha, Will this engine need to be ported? and Compression Lowerd for some boost? this car runs almost an 11 compression rate, guys who work on my car tell me to get any significant boost , that needs to be done

zoom44

paul yaw will be/is using a motec for his supecharger.

TybeeRX-8

Last week I attended a car show where Brumos Motorcars had several different new Mercedes-Benzes displayed including a new E55. Now the E55 is supercharged and produces approx. 469hp. I was told that this car (the ECU) had been sent to Renntech in Miami where the ECU had been reprogrammed and the estimated hp was now about 520 and the speed limiter had been bumped to 176 from 155. The cost for this was, if my memory serves me, about $1500, maybe a little more. All this did NOT void the warranty.
So, here's the thought. If Renntech can get 50 hp out of reprogramming the ECU, why can't someone in Rotary world do something similar. I'd gladly pay $1500 for 50hp while keeping the warranty intact. Maybe this only works for super/turbocharged engines??? That likely is the answer, but it seems that something should be able to be wrung out of the 8 without having to add on all sorts of piggybacks, etc.:D

Velocity-8

FI vs NA is a big difference when it come to tuning.

olddragger

iTrader: (3)

Richard,
Iknow nothing sure sounds like he knows a lot! (not flaming ya man) He makes some good points BUT dont get discouraged. Build the dang thing and I KNOW it will be workable. I understand Canzoomer is almost ready to ship his programable unit which I believe has been said to be an opion when a boost system is available. Also someone(i forget who) on this forum has managed to apply a Geddy system to his 8. Hell people like me and you (that have been around a while!), know that perserverance is much more effective than intelligence! Like I know nothing says "imagine"!
Go Richard,Go Richard, Go Richard!
Remember the simple life with the muscle cars?!
oldragger

Richard Paul

iTrader: (5)

Olddragger, True, true, Oh if only there were a 409 with 2 AFB's.
Then again, nothing was fast enough for me, so mine had a Paxton on it.

Then there was the factory number 4 Studebaker Hawk with 2 AFB's. Then when the factory part of that deal was over I put a Paxton on it too.

I must love problems.
RAP

rotarygod

What kind of other pictures or info do you have on that V-8 that is pictured? What type/size was it. How much boost did you run and how much power did it put out? It looks pretty damn cool!

Ajax

Here's some more pics from richard:
1. 5 stage comp sec, one together, 1 apart.


2. 5 stage comp sec with shaft


3. 5 stage rotor sections

bureau13

Well, I'm not sure if the sudden outbreak of EFI discussion was due to my question or not, but all I really meant was that it was my IMPRESSION that a number of piggy-back and stand-alone ECU solutions could modify fuel and timing based on pressure. No, the RX-8 doesn't have a MAP sensor, but adding one should not be problematic. So, I didn't understand what sounded like gloom and doom over the fact that the current stock ECU didn't already do this. Now, the comment that few stand-alones do this confuses me, and made me wonder what I was missing.

Anyway, any FI solution requiring a Motec is NOT going to be anything close to a mainstream solution. I'm pretty sure Paul Yaw's supercharged motor is aimed at racing, right? The ECU in the 8 is just way too entwined with all of the other stuff going on that people are not going to want to sacrifice. However, I still don't see anything that would prevent a piggy-back ECU solution from providing what is needed for FI.

As for the compression issues, they've been beaten to death in numerous other threads, from what I've read there it doesn't look like 10.5:1 or whatever it is is necessarily the death-knell for an FI Renesis.

jds

Richard Paul

iTrader: (5)

First off Ajax will be posting some new pictures of the Mazda compressor just assembled. That is as soon as he finds them on his e mail.

Next Rotorygod, You mean you have an interest in piston engines also??

That engine is my personal small block Chevy that was intended for my El Camino. It never got there due to a divorce. Anyway it was 396 cu in. I know it's a small block. I;m not confussed. Bore=4.030 stroke=3.875. 396".
Billet Crower crank and rods, JE pistons. chamber shaped dish. Crower solid roller cam. Special grind. Double roller t chain. two peice front cover. Crane springs and rev kit and pushrods.Fisher dampner. Aviaid pan. Mannly pump blueprinted and welded pick up.

Brodex heads ported in my shop. 2.02 intake 1.65 exhaust. Isky roller rockers on ARP studs. ARP studs throughout. .000 deck with .038 gasket. 8 to 1 comp ratio. I used a EFI distributor gutted everything but the mag sensor. Then hooked to an MSD 7a

Holley single plane manifold machined to acceept nozzle bosses. Nozzzles held down with fuel rails. bosche 55 lbs nozzzles. bosche pump. Haltec controler.

The supercharger was a one off all billet 7 stage designed for 1250 cfm at 14 psi. but was never run full speed. ran it at 11 psi and 1080 cfm. at 7300 rpm on my dyno it made over 740 hp.

This engine sadly wound up doing mule work on the dyno for a few months. Not used at full power just checking stuff out. Work that could have been done by a mild 350.

It then sat in storage bolted to the superflow until I sold the dyno. Then it sat in my Mothers garage until I sold the blower to one guy the efi to another then the engine to another. Who ironicly put in an El Camino. I think he put a street roots blower on it. Still an awfull lot of bullet proof parts for a street machine. probably at best pumping 600 hp.

The real interesting thing is the blower. It is going on a cost no object '56 studebaker Hawk. With a Packard no less. The owner is a very smart guy with so much knowlage of things automotive and old someone should upload it.

I don't recall there being any other pictures of it but maybe. If I come across them I'll send them to you. If there are any details you want to know I;m sure I still remember or there is a file on it someplace. There are pictures of the supercharger.

Wait I'm wrong. The pictures are of the 1800 CFM 18 psi Reverse flow blower I built for a Ryan Falconer V12 600 inch engine for a 3/4 scale P-51 Mustang. Notice the rear inlet, axial style. The standard automotive is Radial inlet in the front and radial rear defuser. You can see the standard type of setup on the engine. Also notice the add on planetary searset. That was stolen from a Ford transmisson.

When the supercharger pics get posted I'll coment on them.

RAP

Richard Paul

iTrader: (5)

OK the pictures are obvious. They are of the first 5 stage assembled. Notice there is one not assembled. Does this mean there is more than one??
Yes, we bought matirials for 25 and machined 7.
The next pictures you will get will be of the unit on the test bench. I hope I'm not boring you with all this but I was a little sensitive of people yelling vaporware.

I'm keeping you up to date so you know I;m working ***** out on the thing. You'll just have to grin and bare it. It was you guys that talked me into putting the honda aside abd doing the mazda.

RAp

04RX8DRIVER

I can't even beging to express how excited I am about this project. I just read the entire thread in about two hours! I have to admit that the numbers are a little overwhelming for people like myself with little engine experience. However Mr. Paul, you have done an excellent job explaining you design and how it works. I'm ready for this to be in my 8. I'm 18, this is my first true car, and I have major respect for all other RX-8 drivers. Our car is a unique design, and only deserves unique parts. This design is perfect for the 8. Mr. Paul, GOOD LUCK... MAKE IT HAPPEN CAPTAIN!

04RX8DRIVER

oh yea, screw the check... I'll drive to Cali and I'll bring the CASH!!! :D

Ajax

Richard, if I had the time (which I don't right now), I'd put together a website for you. Maybe when I get back from all my business trips (Phoenix this weekend and then chicago for a week and a half) I'll put something together.
It's easier to actually run a site than just linking all of this from one of my boxes.
That way I can also just set you up w/some upload scripts and you can upload pictures and comments to one of my databases.

Something I'll have to work on.. I'm still not done w/the ROAD-Club website either, lol. But then, when you work 70+ hours a week, you dont have time for anything. Thankfully, I'm an insomniac so I dont need to sleep :b