A recent discussion made me think of these as the next best thing. I found this link to a prototype motor racing version. Wireless and battery-less no less. It looks like a large electronics manufacturer has licensed the technology. No idea where to buy such a system. Here is a link to a brief review on the common models now for sale:

http://www.consumerreports.org...33153

The Alps version of the IQmobil technology


and a press release on it
http://www.alps.co.jp/e/press/new2003/f1030_e.htm#

The motor racing prototype display



http://www.iqmobil.com/index.p...ge=en

and a technical description of their system
http://www.iqmobil.com/index.p...ge=en

along with a PDF file that is a little more in depth (click on PDF File button)

http://www.iqmobil.com/index.p...ge=en

Seems to me it would be very nice for tuning if I knew how hot the tires are and how much pressure is in them in real time as I drive around the track. So does anyone have any knowledge about this stuff?

 

That valve looks A LOT like the system in todays Hondas. You might be able to get a set up from the dealer even.

Here in Canada, the Pilot and the Odyssey Touring model come with the system. The new Ridgeline might as well.

 

I guess the problem with an OEM type of unit is that the sensors might be easy to get, but the electronics might be integrated with the ECM. I would think that to use one of these systems for tuning a racing suspension, you would need it to be fairly accurate, say plus or minus 0.5 psi, more so than what is required to tell you if the tires are being run in a safe condition for a road car. And temperature is what you really care about for the rubber on the road, so you would need electronics that show you that. They need to measure temperature in any case to calculate a precise value for pressure, but might not display it in a conventional system. And then you would need to record it as you drive around the track so you can make suspension adjustments and see the effects next session to get all tires working to maximum. That is why the concept of a system designed specifically for motorsports looks interesting. Someone told me he thought they were using such a system n CART cars, but I have never seen an article.

I think I also saw an article about a court judgment where they would not allow the simpler ABS system info to compute tire pressure via tire rotation speed in the upcoming 2008 mandated systems due to it being potentially inaccurate 50% of the time. Like when pissing the dog, the ABS system would be very confused to tell you what the situation was, with one rear wheel stopped and brakes not even on.

 

Have you looked at the smarttire system? and if so, why have you discounted it as a non-option?

a friend of mine had a smarttire setup on his Z3 (granted he only ran HPDE, not "real" racing) and it tells tire rpessures and internal temperatures in real time very well.. the only thing it lacks that might be nice is logging capabilities, but that can be "faked" by putting the display within the view of an on-board camera...

one thing to note about valve-stem mounted sensors like that vs. the smarttire sensor though: the smarttire sensor mounts to the inside of the rim with what is essentially a huge hose clamp - this system has a weight that sits directly opposite the sensor to keep the wheel in-balance, where with a valve stem mounted system it might un-balance the wheel, leading you to need more weight to re-blanace it once the tire is on. the more weight it takes to balance a wheel, the more likely you are to "throw" a weight.

 

http://www.tirerack.com/tires/...id=44
http://www.tirerack.com/access...2.jsp
http://www-nrd.nhtsa.dot.gov/vrtc/ca/tpms.htm
http://www.hunter.com/pub/undercar/TECHLINK/

 

The TPMS system that are going in today's cars are VERY accurate. I work for a dealer, last year some of our cars came out with TPMS (why can't people learn that your suppose to check your tire pressures cold and often). The sensors in our cars is mounted to the valve stem (the sensor itself weights less than 5 grams), and I have not seen it really cause any balancing issues. The on-board computer can read air temp inside the tire, live tire pressure, pressure drop rate, and battery life of each sensor. The display in the car only shows if you are getting a flat, but with the scan tool you can read all the info. I was looking into installing a system on my RR car, but was not sure if my class would allow it. mm..

 

So assuming the regular car systems are very accurate as you say,(as in they match a good digital/calibrated pressure sensor ot 0.5 psi or so and all four sensors are matched), can you actually install a complete OEM system as an option, without using the manufacturer's ECM? And have you checked the accuracy with gauges?

My inclination is to think (I might be wrong here) that aftermarket systems might not be so accurate, as in they could be plus/minus 2 psi, which means two sensors could read 36 and 40 psi for a tire that is in fact 38 psi. I think that would be too much error for the track. At the track, you use the same pressure gauge for all tires, so at least you get very consistent tire to tire results. Same goes for temperature, where you use one pyrometer to check all the tires. If these systems can be shown to be accurate and easy to install, then I am definitely interested in trying one out, but I would really like the option of logging the data, as this is where you could learn a ton and really use it to tune the car.

 

The ones used on the factory's cars (well the MFG I work for) seem to be very accurate. I use the same tire pressure gauge at work at I use at the track. The systems on the cars seem to always read 2 psi above what my gauge reads (i have also notice seance I started using this gaugde that my tire seem to perform better 2 PSI lower than before). As for using them with an aftermarket display, I have no clue if that will work. I do know that Tire rack sells sensors that work with our system.

BTW the systems on these cars have to be accurate. They will indicate a low or flat tire within 2 PSI of variance (with tire temp variance). The mfg want you to know if your getting the best MPG and make sure your tires are inflated to a safe amount!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Safir &raquo;</TD></TR><TR><TD CLASS="quote">Have you looked at the smarttire system? and if so, why have you discounted it as a non-option?
</TD></TR></TABLE>

I know of the SmarTire system. Here are the specs:

http://www.smartire.com/produc....html

Pressure accuracy is +/- 1.5 psi and temperature accuracy is +/- 5.4 degrees F. I would like something more accurate, or least one that can be calibrated by me with an external gauge. I think +/1 1.5 psi is not really good enough, or at least not as good as I would like on the track. The other issue with it is that to get actual readings, you need the optional display. Here is what they say about the unit:

"The Full Function Displays automatically identify the nature and location of pressure or temperature irregularities and allows the driver to read the tire temperature and pressure status by scrolling through each tire position."

I don't want to scroll through the display for each tire reading. I want all four pressures and temperatures simultaneously, and at worst I would videotape display, or better still log the results all the way around the track. I am hoping to find a system made for track use, but until I use one, it is hard to tell how useful it could be, but I am sure it would show how hard the tires are working at all four corners all the way around the track. For example, I know one championship winning team in Formula cars (FR2000 etc) uses tire pressure as a major tuning tool and they like to know it within 1/4 psi. But that is in the pit lane.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BrianZ &raquo;</TD></TR><TR><TD CLASS="quote">I work for a dealer. The sensors in our cars is mounted to the valve stem (the sensor itself weights less than 5 grams), and I have not seen it really cause any balancing issues.</TD></TR></TABLE>

Well, you should know from your self studies that the TPMS wheels are diff. from non-TPMS wheels. they have a diff. casting or less machining opposite the sensor depending on the wheel.

 

The other major strike against a the OEM and aftermarket systems I know of is this, quoted from the SmarTire FAQ:

"How often is tire pressure transmitted?
Tire pressure is transmitted as soon as the vehicle starts moving. Pressure data is then transmitted every 4-6 minutes randomly. The transmitters read tire pressure every 7 seconds and if the read pressure differs from the last transmitted pressure by more than 3 PSI/.21 BAR, then the data is transmitted immediately to alert you of a problem.

How often is tire temperature transmitted?
Tire temperature is transmitted as soon as the vehicle starts moving. Temperature data is then transmitted every 4-6 minutes randomly. The transmitters read temperature every 7 seconds, however the system will only alert you if the temperature exceeds 80°C/176°F."

And those would be of limited use for track tuning, as you could not see corner by corner data, just long term average temperature, one value every few laps or so. We need real-time data, not pressure "transmitted every 4-6 minutes randomly". The passenger car systems are warning devices, not track tuning devices. The Iqmobil one is the only one I know of that seems specifically intended for motor racing, but I am not sure it is yet available, and specs are not complete at this point.

 

[QUOTE=BrianZ]The ones used on the factory's cars (well the MFG I work for) seem to be very accurate.


i work as a vw tech and were having a terrible problem with tpms on touareg's
and i have heard some complaints from bmw guys but who knows how accurated that is. hopefully it's just the germans with problems concerning this.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tom_l &raquo;</TD></TR><TR><TD CLASS="quote">

Well, you should know from your self studies that the TPMS wheels are diff. from non-TPMS wheels. they have a diff. casting or less machining opposite the sensor depending on the wheel.</TD></TR></TABLE>

I cannot say I have notice this. I have has several customers put aftermarket wheels on the car and had us transfer the wheel sensor. I even have one customer running around on steel wheels with the TPMS sensors in them. I do not believe that the type of rim is a factor here. as I said these sensors weigh almost nothing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool &raquo;</TD></TR><TR><TD CLASS="quote">The other major strike against a the OEM and aftermarket systems I know of is this, quoted from the SmarTire FAQ:

"How often is tire pressure transmitted?
Tire pressure is transmitted as soon as the vehicle starts moving. Pressure data is then transmitted every 4-6 minutes randomly. The transmitters read tire pressure every 7 seconds and if the read pressure differs from the last transmitted pressure by more than 3 PSI/.21 BAR, then the data is transmitted immediately to alert you of a problem.

How often is tire temperature transmitted?
Tire temperature is transmitted as soon as the vehicle starts moving. Temperature data is then transmitted every 4-6 minutes randomly. The transmitters read temperature every 7 seconds, however the system will only alert you if the temperature exceeds 80°C/176°F."

And those would be of limited use for track tuning, as you could not see corner by corner data, just long term average temperature, one value every few laps or so. We need real-time data, not pressure "transmitted every 4-6 minutes randomly". The passenger car systems are warning devices, not track tuning devices. The Iqmobil one is the only one I know of that seems specifically intended for motor racing, but I am not sure it is yet available, and specs are not complete at this point.

</TD></TR></TABLE>

I cannot talk vouch for any of the other systems, but in our cars the display shows you almost nothing other than a tire is low/flat. With our shop scan tools I can watch the "live" data.. I cant say it does update more often than 4-6 min, but not as quick as 5 sec (unless it detects PIS loss, then it will transmit at about 5 sec.

For a OEM car this was done to save battery life.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wesisrael &raquo;</TD></TR><TR><TD CLASS="quote">
i work as a vw tech and were having a terrible problem with tpms on touareg's
and i have heard some complaints from bmw guys but who knows how accurated that is. hopefully it's just the germans with problems concerning this.</TD></TR></TABLE>

So do I. What problem are you having? Our shop saw a rash of them before they came out with the updated units. and even then 90% of them were due to tire pressures being low. From what we have found is the sensor is very accurate(how many sensors have you replaced), the software is a little to tight on its tolerances. You will see cars that you serviced during the summer come back around in the winter with TPMS lights, and the tires will be low. This is not a problem with the system, but the fact that the customer does not check their tire pressure as recommend. How many Phaetons have you seen with a TPMS problem? (not just a tire that was low). Its the same system.

Just trying st set the record strait. The sensors are accurate. they do report whats going on, even if the computer that reads them can be a little screwy.

I even had a cust come in today complaining about the TPMS light being on. I went out to look at the car and notice the TPMS showed the right rear to be low. upon inspection i found the tire FLAT (under 10 psi) and a large nail in the tire.

 

the bmw's have had trouble with them but I think it was more of a software issue and pressures being too low.