Tire Pressure Sensors Gotta GO!
 

Hi Everyone,

Picked up my new base package 6spd RX8 yesterday (yeah, S-Plan!!). Read the manual cover to cover last night and I wish the base package did NOT include the stupid gimmick tire pressure warning setup. According to the manual it does not work for sudden loss of pressure...the only purpose I would think it could serve since the manual also says the system does NOT alleviate the need for you to manually check your tire pressure anyway! And then I see the mile long strip of balance weights on each factory rim needed to balance the wheels because of this purposely inserted rock, er., "sensor," and I want these things gone! Going to install lighter wider rims anyway.

I also don't want the dash light on. I read the older thread about cutting the wire to the dash light, etc., but that seems an inartful way of doing it. Perhaps an ECu reflash that includes a delete of that function? It also seems that making a small battery operated transmitter that sits in the glove box and mimics the signal from the sensors would be easy to make. Or perhaps once the sensors are removed they could be modified for this purpose and then left in the glove box? Other ideas?

Brian Goodwin
Good-Win Racing

Perhaps a wiring diagram for the Canadian RX-8 might be useful in determining how to disable the system - we don't get the TPMS system at all!

(Sure makes buying winter wheels easy, no worries about transmitters or idiot lights!) BTW, Brian, I ended up going with a 17x7" Konig Holes wheel, ~17 lbs. The OEM 18" wheel with RE-040, no TPMS transmitter ;) , weighed 41.2 lbs, the 17" Konig wheel with Toyo Garit HT 215/55-17 tire weighed 35.2 lbs! There is a LOT of weight to be saved over the OEM wheels. Wait, if you got the base, do you have the sport suspension, big brakes, and 18" wheels? If you have the 16" wheels and smaller brakes, then you will have a LOT more choices in wheels/tires.

Regards,
Gordon

I suspect Brian here would go with a big brake system if he had the smaller brakes. :) Actually, in the US the manual comes with all those goodies.

Brian, definitely keep us updated on your mods. I haven't bought an 8 yet, and you've already convinced me to ditch the tire sensors, so who knows what else you'll convince me of. What kind of rims are you getting? I was thinking that SSR Comps in 17x8.5 would be the way to go for me, if they fit over the larger brakes. It would have a lot more tire options, like Kumho Ecsta MXs or Yokohama AVS Sports.

Also, you must go to the solo2 events at the Q. If so, you mind if I ogle your 8 if you take it there? :)

Re: Tire Pressure Sensors Gotta GO!
 

Bear in mind that any non-MNAO ECU reflash will theoretically bump you out of stock.

Talk to the service guy at your dealer, the ECU has programable settings for the tire pressure range, and odds are, one of the standard boxes is an empty box with no limits. This would be the most likely way mazda would implement the non-tpms version cars. That way the ECU ROM is still the same, just the smaller configurations settings are different. The dealer can adjust these settings through the CAN interface from their computer.

On a side note, I remember seeing somewhere that the TPMS reciever module is remote to the ECU, and since the ECU will work with different pressure ranges, odds are the remote TPMS reciever sends tire pressure signals to the ECU. My ultimate goal would not be to remove the TPMS system, but to intercept these signals (probably just a serial connection, since the SuperH micorcomputer in the ECU has a butt ton of serial connections integrated into it) and design a display that would actually show the individual tire's pressures. Just this morning coming home from work, my light came on (it was damn cold this morning) so i figured that is what it was, but i still did not know for sure if a tire was just a little low, or damn near flat. An actualy indication of the pressures here would be a serious boon, and would take little extra hardware mods.

Hi Guys,

Thanks Gordon for the data on the wheels, will indeed be looking to save some weight on the wheels off those factory numbers. Yep, got the big brakes, the base package 6spd here includes all the go-fast goodies like limited slip, 18 inch wheels, and anti-lock brakes. In fact, I think the Sport package is a misnomer here, should be "convenience package" or something because all it adds are goodies I don't need like fog lights, Xenon headlights, DSC, etc.

rabinabo, those SSRs were indeed my first thought since I have four sets for my Miatas that I have been very happy with over the years and we are a tirerack dealer so that makes it easy. But, I analyze everything to death first so I going to do a little research into the options...since the SEMA show is this week the timing is great....going to do some shopping!

eccles, yep, flashing the ECU will kill stock hopes but I would likely race this in another class anyway, we have a local class called IS2 that would permit me to do all the mods that I want to do anyway for street and track purposes so that is where I will likely end up anyway.

Thanks for the feedback guys,

Brian Goodwin
Good-Win Racing

Very logical, I will ask friends at Mazda and see if I can find out about simply turning the TPMS off....hope there is a way. I also like the idea of making a display that would show the actual pressures (assuming the data from the sensors allows for such). Then at least the system would be useful. Could you imagine if it could be changed so that on a track day you could watch the temp rise in the tires individually? That would be a powerful diagnostic tool if it could be done.

Brian Goodwin
Good-Win Racing

Brian,

Hi. If you have not already seen this,
check out http://www.finishlineperformance.com...02-002-03.html
for info on how the TPMS (Tire Pressure
Monitoring System) works in your qwest
to disable it (from thread
https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/what-happens-if-tpms-wheel-units-not-installed-13045/).

Here's an idea - take the pressure sensors (TPMS wheel units) off your stock wheels, mount all four into some sort of container that can be pressurized (a small wheel/tire assembly comes to mind, but I'm sure some else will have a better solution), set the container's pressure to 32psi (or 26psi < pressure < 49psi) , then put the pressurized assembly into your trunk.

Now with your aftermarket wheels/tires installed on your car, follow the "Replacing a TPMS Wheel Unit"
instructions in the service bulletin.

Hopefully, the TPMS control module picks
up the signals from the four battery operated TPMS wheel units and there is
no TPMS warning light. If this works, the
best part is no warranty voiding mods had to be done.

Okay, you people with the motivation and resources to easily try above, please
post your results :).

Thanks,
rx8cited

Problem with that, rx8cited, is the transmitters are turned on by centrifugal switches in them (the manual talks about 12 mph or something like that). So just mounting them to a pressurized unit will not work. Best bet i can think of is to just remove the light bulb from the TPMS light on the dash. This should be fairly easy, as I'm sure the bulbs have to be replacable.

CraziFuzzy,

Hi. Thanks for pointing out this major detail I overlooked: . Back to the drawing board :( .

Has anyone tried installing the pressure sensor wheel units to aftermarket wheels?

Thanks,
rx8cited

Yes, they can be mounted to some if not most aftermarket wheels. But Brian is trying to get rid of them when he purchases his competition wheels, because it doesn't make sense to bolt a heavy sensor to one side of a lightweight wheel and then add another bunch of weight to the opposite side to balance it out again.

YEP!

Thanks all for the ideas folks,

Brian Goodwin
Good-Win Racing

Hi. Can anyone tell me which aftermarket wheels the wheel units have successfully worked with please?

I understand now that Brian wants to get rid of the wheel units. I'd like to know which wheels they work with if I want to keep them .

Thanks,
rx8cited

tirerack said that the SSR GT3s will accept the OEM sensors. too bad the 18 and 19 inch sizes are 24 and 27 lbs each, respectively. too much weight, and that is before the sensors and balances.

santino

the Tire sensors are remote devices. they send a radio frequency signal to the CAN (Control Area Network) which contains computer controlled systems such as the TCS, Tire pressure monitor computer, etc. I believe they are wiring in series so disconnecting one system will alert the CAN. I suggest either taking the gauge cluster off and disabling the LED for the tire pressure sensor or simply trying to find a rim that will fit the tire pressure sensors.

just an FYI, my dealership here in Boise, Idaho will not do anything to get rid of the STUPID ASS TPS system. In fact he said there is nothing he can do as far as reprograming cpu or any of that. what a crock of SHIT. this system is obviously just for the average idot that doesnt check tire pressure regularly, In my Opinion you should not own a sports car without being able to conform to the basic responsabilities of owning any car.

yes the TPS sucks, it goes off at random intervals and worries me. its annoying and not really all that great to begin with. It only warns you if its way too high pressure or way to low, and also it has a delay in doing so, so most likely when I get rims, its going out!

Yeah, I'm not too happy with it either. When the weather changed here, when it was cold in the mornings, the TPMS would start beeping and the light would illuminate. I wish there were a way to make the Rev Buzzer use the same buzzer the TPMS uses - it sounds much louder. And that would suck if you disabled the light on the TPMS, it would still beep when activated.

this is good

photo 2

Re: Tire Pressure Sensors Gotta GO!
 

Why do you consider it "inartful" to cut a wire to a warning light you never want lighted? to me that seems like the most elegant solution possible.

You are certainly right about me not wanting that light. But let's imagine that two years down the line a new hotter MazdaSpeed RX8 hits these shores and we buy one of those and sell the current RX8....at that point I will obviously not want to be explaining to a potential buyer that we cut wires in the dash. Moreover, generally speaking I don't like to cut OEM wiring, much prefer to turn things off or unplug...just in case we want that connection later.

Brian Goodwin
Good-Win Racing

Work around?
 

Just finished reading this thread. Quite interesting. Yes the TPMS is more of a pain then help.
Looking into purchasing dedicated snows for the 8 (not yet purchased, but soon). Wanting to slap the snows on the OE wheels (18") along with the sensors. However, come spring planning on using the OE tires with after market wheels along with an additional set of Mazda TPMS sensors. This should solve the problem of the warning light/audio as well as utilizing the TPMS system as designed.
Bad thing is that I would have to dish out the $ for the second set of sensors (as well as the added unsprung wheel/tire weight). Anyone happen to know how much for the sensors? Just my $.02.
Al

I'm getting conflicting information here. This thread indicates that there is an audible "beep" in addition to the light on the dash. Another thread, VividRacing.com said that the light on the dash flashes - there was no mention of a "beep".

I wonder if there is a difference if the sensor receives a signal of an under or over inflated tire, as opposed to no signal at all (no sensor in the tire).

I was planning on NOT using sensors in my winter tires/wheels. But, if there is a constant "beeping", that could get annoying. I could handle a random light flashing off an on.

Any thoughts?

My light does not flash, and if the pressure is low when the car starts up, there is no beep. It only beeps if you are already driving, and then the pressure goes low, and it is not a constant beep. My guess is that if you don't have the sensors at all, than the light will be on, but no beep (other than the normal start-up test of the beeper)