Mazda Family

So it's been said that the ecu pulls timing and richens the mixture when it senses the front tires arn't turning. Now before you say this isn't true, like some people think, remember that you can't dyno anMm3 for the same reason but in BMWs cause it more noticable because the engine actually stops reving at a certain rpm.

Okay so the sensor reading comes from a speed senor on the wheel (or hub) No why can't you unplug the front sensors and wires the rear sensor to both the sensor inputs on the ecu. Basically have the driver side rear feed the computer as both the front and rear speed sensors, and the same on the passanger side. Those the ecu thinks that all 4 tire are turning and they are doing so at the same speed, no diffrent than driving down the road.

Anyone else been thinking of ways to get around this little problem?

ZoomZoomH

iTrader: (1)

my question is, why are people so obsessed about dyno numbers to the point of actually considering altering CORRECT sensor wirings and setups just so they can see a few more horsies on a dyno????

I thought cars are suppose to be driven ON ROADS?????

boarder

Why ? Aftermarket. If someone says they get 10HP on the high end for a mod off a dyno, don't you want to know its not just fixing a problem the ecu/dyno created ? Dynos are relatively easy ways to test changes to the car and that your car is performing up to spec. Not so easy in the RX-8 case it seems.

ZoomZoomH

iTrader: (1)

I'd figure track testing (drag strip or road course, depending on modded parts) would be a more accurate measurement of what the new parts have done to improve the performance of the car...

klegg

Actually, I do not consider an engine saftey system a "problem", and I do not fancy a 2,000 repair job replacing a fragged cat. Car is not ment for stoplight racing, it is a GT.

If you really want to tune a 30,000 plus car, be my guest. I hope you have a whole lot of disposable income.

DijabutiA

anyone plan on running a dyno? pull your fuses on your dsc AND abs systems; to make sure their off

syntrix

You will still get a pulse from the abs sensors.

What I would try (if you so choose to hack), is to put the leads from the rear abs sensors in parallel with the fronts. At the same time, turn off aka cut the front sensor wires or wire in some electronics to make sure the front doesn't pulse into the ecu/harness.

Sure, you might have an airbag go off and break your arm and bruise your face, but at least it's thinking outside the box.

YMMV, proceed at your own risk, I'm not liable for the suggestion above.

Either way, wideband electronics and reader are on the way, just gotta get a k type thermocouple to add to the electronics, and that will tell a bit more about egt's and how rich the car is running. Serial output (computer logs) is very possible with the path I'm going down.

Basically, we must understand what the car is doing before we attempt any mods.

Hymee

iTrader: (1)

I can definately say from what I witnessed yesterday, the wideband O2 sensor showed a noticible increase in richness accompanied by a corresponding drop in power, in the top 1/4 of the run.

A dyno is a tool for comparing changes to the performance of the powertrain of a vehicle - in fact it measures the exact amount of tractive effort at the driving wheels across the whole RPM. It is in fact a road. A rolling one. It takes out lots of other variables that you would normally see on the road to allow (as much as possible) apples to be compared with apples. But is it just one tool. The track is another tool. A G-Tech is another.

But I don't want to get into dyno wars

Cheers,
Hymee.

bobclevenger

Hymee, That avatar is fair dinkum, mate! Hypnotic too.

Hymee

iTrader: (1)

Thanks! And it is a renesis as well! (see the side exhaust ports)

I was wondering how they go on an engine dyno - no wheels turning... I had a brain wave that if we disconnect the rear sensors, then the computer might think the front and the back were doing the same speed. But I tried the experiment, and the computer throws an ABS light (the same as it does on the dyno).

Oh well - ya gotta try.

Anyone else with something to offer. I guess we need to do the // thing like has been sugested, or some sort of pulse generator or resistor or something.

Cheers,
Hymee.

Omicron

This limp-mode thing may well affect more than just dyno results. It seems that if you do a 3-4 second burn out (such as when you're trying to get the best 0 to 60 or 1/4 mile acceleration) the car goes into limp mode then too. If so, the retarded power of the limp mode would seriously affect the performance of the car, and lower than possible times would be the result. So you see, this really may be relevant to the streets/tracks too.

Anyway, Canzoomer has somehow worked out slaving the front sensors to the rear ones, so that the ECU thinks both pairs of wheels are turning at the same rate. Sounds like he's working out some sort of a dynamically switchable setup. Anyway, he's working on just this issue now, and I'm sure we'll be seeing results soon.

djmano

this is exactly why we want all the ponies possible squeezed out of our car. by the wording of your previous statements you are implying that a 30k is a bit too much to be spending money on. well for your 30k wouldn't you want all the horsepower that you paid for? or would you prefer to sit there and 'grand tour' everywhere?

OURRX8S

HERE IS A TIP I THINK
WHEN TURNING OFF YOUR DSC. TRY KEEPING IT PRESSED FOR A FEW MORE SECONDS TILL YOU HERE A BEEP. THIS WILL HOPEFULLY DISENGAGE THE WHOLE DSC AND STOP THE CAR FROM GOING INTO LIMP MODE.
NOW TRY TO SPIN YOUR WHEELS!!!
HOPE THIS WORKS
:D

Omicron

Nice thought, but not the magic bullet. Car will still go into limp mode as this doesn't really disable TCS. Check out this thread for a complete explanation... it burried somewhere in this 29 page read: https://www.rx8club.com/showthread.p...threadid=11614