jmanolov

Speed Racer, can you pls click on the "HP & TQ vs RPM" tab and make a screenshot of it too?

KyngNothing

Canzoomer: Is that the same sensor that is used for ABS? I find it hard to believe that turning off the DSC would turn off all ABS functions as well, which must also use some type of wheel-speed sensor...

Speed Racer

They were posted on a previous thread. You can check out the graph and comments here.

canzoomer

On the front wheels there is one sensor.
On the rear there are two, but in one package.
There are two output circuits on the rear, and one on the front.

Makes sense, as front wheel are not powered, so slip reduces wheel speed.
On the rear, you can have slip, and you can have wheelspin from power.
Two differing conditions.

The main reason people are turning off DSC for dynos is so that the inevitable wheel spin does not trigger DSC, which reduces power selectively to counter skids.

The other effect is that the DSC monitors front wheels for skid, and will aslo reduce power to counter.
Disabling DSC puts the wheels in static response mode.

Disbabling DSC does not reduce performance.
Try driving with it off and you quickly realize you get a lot more response and power with it off.

zojas

did you measure the voltage after merely pressing the DSC OFF button quickly, rather than holding it down for more than 5 seconds? The owner's manual indicates that holding down the button makes the computer thinks there is a problem with the switch, and that merely pressing the button quickly is enough to turn off the DSC and TCS. I'd try it myself, but I don't have my rx-8 yet! thanks.

canzoomer

Pressing the button down turns off active DSC control. There is still power to the sensors, and pulse from them when wheel turned.

Pressing and holding results in 3 pulses to the sensors, then power shuts off to them.

zojas

thanks for the info.

Good Duck

Here's what I see from looking at the GTech rpm graph. The 2nd run at 6k drop and the 3rd run at 8k drop should produced the same time and result. The difference between them is the shifts time. The 1-2 shift is almost exactly at the same point but the 2nd run shift take more than half a second longer than the 3rd run. This translated to a half second difference at the 1/4 mile.

canzoomer

First off, maybe I am out to lunch on this, as I do not own a GTEch, and have never used one.
I DO notice one thing, however.

Look at the timeline on the bottom of the graphs sheet.

The time is indexed to start at -1 seconds, not 0. The car started moving, and from that point to the end (1/4 mile) the times on the graph are one second higher than on the printed numbers.

If I read this correctly all the run times are offset by 1 second.
In other words the 1/4 mile runs are actually 15.704, 15.575 and 15.037 seconds.

Please correct me if I am wrong, but also please explain that to me..

Another thing I am curious is how the GTEch data gets the points for distance?
It does not measure where the car is, only the rpm and the G's, so how is it told when you pass a distance like 1/8 and 1/4 mile??

Any info on that?

Good Duck

It doesn't actually start at -1 sec, but at -.58, -.38, and -.38 sec respectively. Look at the "Rollout" line. This is done to simulate a dragstrip. At the strip, timing doesn't start until the wheel clear the staging light. This can be as much as the width of the wheel at the height of the staging light. In this case, it's about 12 in.

canzoomer

Thanks, that makes sense.

Now for the second question:
How is the distance input to the GTech?
If it is done manually does this not also potentially skew the numbers quite a bit?

If a person has a variation in response of half a second in this case ( such as in the 1st to 2nd gear shift times) then would there not also be the potential for a similar inaccuracy in the distance points?

I sure wish we could see some private runs done on a real drag strip, preferably a nice one with trap lights at various distances..

I can see why few would want to be doing this.
I personally would not want to hammer my car that hard, especially at low mileage, but then the same could be said for GTech testing..

A few of us forum members, who are not professional drag racers would sure make a nice sample of real world data..

Maybe we could talk Mazda into lending us some cars, fresh off the dealer showroom?

Nah, I guess I am dreaming!

zojas

hey speed racer, can you run about 3 tanks of 87 octane through your car, then try your 1/4 mile run again on 87 octane? there are reports of increased fuel economy on 87, and I'm intensley curious about the power output at 87 octane.

check out this thread about 87 octane:

http://www.rx8forum.com/showthread.p...5&pagenumber=1

Speed Racer

Hey Zojas,
The thought of experimenting with 87 octane has crossed my mind a few times but the thought of knocking under a heavy load (i.e. speed tests) scares me a bit. From what I understand knocking is one of the reasons why the apex seals may fail and I don't want to be the first guy to announce that he has blown his motor. So I think I'll pass on the 87 octane at the moment.

zojas

good point, I hadn't thought about that!

Rays8

Hi Guys

Just wanted to contact other rx-8 owners in metro.

Got my red 6m gt last friday!

Love it but already need the converter replaced.

Dealing with City Mazda.
Trying to get the M flash done also but they don't seem to know what that is.

Anyway I would like to know who you guys deal with for service.

Have any of you had the M flash done?

Thanks

bgparsons3

Hmmm, those of us who took delivery of our 8's last year dealt with Steele. They were very knowledgable and kept a membership active on this forum - not sure if City and Steele have a good relationship or not but that might be one way to move the information around.

Also, do a search for "TSB" and you'll find all the technical info you need to get any update/recall work done. Typically the info is released to MNAO months before the dealers in Canada get it. Go to the TSB link, print it and take it to City with you.

The "M" reflash is great, haven't noticed improvement in fuel efficiency but definite power improvement. Just waiting on my CZ Stage 1 now ... The City guys may understand the "30.8 PCM recal" as opposed to the "M reflash".

Redshift

iTrader: (2)

I wouldn't let City Mazda breath in the direction of my car, never mind work on it.

Long story short: Bodyshop stalled my 8 and it flooded.. they called City looking for how to get it started and were told by the City service department to "Tow it up to speed in 2nd gear and dump the clutch..."
Thankfully the guys at the bodyshop were MUCH smarter then that... especially since there is actually a section in the owners manual on how to handle it.

Also, when I went in to talk to the manager at City when I was setting up the Dyno day, not only did he totally dismiss me, shoot me down, tell me "none of our customer have any issues" and basically try to get me out of the dealership as fast as possible, but I had to spend a couple of minutes explaining to him what I was talking about.

So far, I have had good results with Steele. They have taken care of my car as expected and effeciently.
But, if I had major work to do, or didn't mind a bit of a road trip every time I needed an oil change, I would take my car to Will at Mills Mazda in Truro.

Will used to be with Mills in Dartmouth before he sold it to Steele, and then moved with him to Truro.
Will just came in Top-2 in the Candian Mazda Tech competition a few months ago and finished Top-12 in North America. He is VERY good.... did the Supercharger install on a friend of mines Miata 10AE...

Redshift

iTrader: (2)

Oh, and welcome to the Metro RX-8 owner family!
Hopefully we'll see you around.
In fact, if I get some initiative, I may have to put together some kind of a meet in the near future.

Rays8

Hi

Just thought it would be nice to set up a meet for RX-7, RX-8 owners some time soon.

Point Pleasent Park, Parking area seems to be the inplace for other clubs.

Any takers?

Rays8

Jasper_the_2nd

It would depend on the date, time and weather, since it's about and hour and a half drive from here.

Gord96BRG

You might want to start a new thread with an appropriate subject line! An old thread titled 'Dyno day' might not get too many people's attention...

Regards,
Gordon