RIAT Temp sensor for ST205 - O for Awsome !

[fivebob]

My only question: how fast ECU samples that sensor?
It will not be good of fast sensor if ECU samples slow and filters heavily the input.

Not sure how fast the stock sensor would sample and how much filtering there would be, but given the nature of the stock sensor I'd guess that the sample rate would be low(<10hz), but not much filtering would be applied.

By contrast my Motec M-800 samples at 150hz and the suggested filter level is for intake air temp is 8 samples, i.e. the value used is the average of ~ 0.05secs or around 2-3 combustion cycles @ 6000rpm, which is probably more than accurate enough bearing in mind that the response rate of the sensor is probably <20°C/sec i.e. about 1°C in the same period.

FWIW (ignoring humidty) 10°C change in temp give approx 3% change in density. The following table give the fuel compensation values for Apexi and Motec ECUs and it can be seen that they don't exactly follow density changes, with resulting mixtures being richer at higher temps and leaner at lower temps, with the Apexi being notably richer. Probably in an attempt to control detonation, though to be fair it uses less ignition retard that the standard Motec Settings (5°@80°C and 3° at 70°C vs 6° & 5° repectively).

Code: Select all

                   80°C      50°C      30°C      10°C     -10°C    -30°C
__________________________________________________________________________
Density Change   -20.5%    -10.2%     -3.4%     +3.4%    +10.2%   +17.1%

Apexi Correction  -8.2%     -5.1%     -1.2%     +2.7%     +7.8%   +12.9%

Motec Correction -12.0%     -6.0%     -2.0%     +2.0%     +6.0%   +10.0%


[Jon Fennell]

Hi, thats usefull infomation.

For your info, the sensor, when fitted to Dragons car was changing temperature at 1°C every 90ms, so pretty quick. How do I post pictures of this? Is it by linking to a hosting website?

For the RX7 the temperature correction curve is known to be incorrect. If you sit and warm the car up from cold the AFR's change greatly. Mind you, thats more to do with the water tempertaure correction curve.

I'm not surprised that the retard figures are different as they vary from engine to engine, dependant on propensity to knock. As you probably know.

Mr 30%, three questions:
1. What is your name bud?
2. Is your car running so that you can actually test the sensor?
3. Can you remove that sensor and post a picture of it please? It doesn't look to be in the airflow.

[Akane]

I took my MR2 out for a spirited run onto the onramp, my conclusion is either:

1) My Greddy side mount is magical and works wonders, or

2) The Gen 3 MAT sensor is slow.

For that 20 sec or so run, My Air-T is pinned at 31c

[sergei]

3. Can you remove that sensor and post a picture of it please? It doesn't look to be in the airflow.

I can answer this one.
The sensor is in airflow, it is fairly long and with plastic body.
Here it is:


The length of black plastic housing is ~33mm.

[mr30%jr]

Hi, thats usefull infomation.

For your info, the sensor, when fitted to Dragons car was changing temperature at 1°C every 90ms, so pretty quick. How do I post pictures of this? Is it by linking to a hosting website?

For the RX7 the temperature correction curve is known to be incorrect. If you sit and warm the car up from cold the AFR's change greatly. Mind you, thats more to do with the water tempertaure correction curve.

I'm not surprised that the retard figures are different as they vary from engine to engine, dependant on propensity to knock. As you probably know.

Mr 30%, three questions:
1. What is your name bud?
2. Is your car running so that you can actually test the sensor?
3. Can you remove that sensor and post a picture of it please? It doesn't look to be in the airflow.

Hi Jon

My name is Ben Hall.

Yes the car is running and i can drive and test the sensor the motor is in ok condition all but a small turbo oil return leak (this might prompt me to fix it and road register the car again)

sergi answered no 3

on most toyotas you can monitor the "VF" signal it will give you a fair idea of what the ECU is up to.

Ill post some more info after i have a brush up on it.

this artical is a VERY good read
http://www.autoshop101.com/forms/h27.pdf

[Jon Fennell]

Hi Ben and Sergei,

Thats great, and thanks for the pictures. The sensor is similar the type I have seen replaced here in the UK giving an instant inprovement. If you guys would like to try one of the sensors, please buy one off ebay. If your not happy I will give you a full refund and you can keep the sensor and sell it on. I'm looking to prove this sensor off in any car other than the Rx7 and ST205's already tested. Send me your address in an email and I will post them out.

Akane,

You have experienced exactly what I found with my RX7 when I first got it, impossibly good intercooler! Do you know what thread your sensor has? I can have an adapter made up and list it on the 'bay for you in a couple of days.

[Akane]

Hi Jon

It's just a standard Gen 3 MAT sensor, I don't know what the thread size is, and I rather not undo the sensor although it's easy access, since I don't have the pigtail for the sensor, it's a bit of a crappy blu-tak job with the wires at the moment, undo-ing the sensor will cause havok.

[no_8wire]

Sensor is 14 or 16mm with 1.25mm pitch...have one lying around the garage somewhere...(lazy little sensor, lounging around while Im at work...grumble grumble grumble)

[no_8wire]

That sensor is 16mm with 1.25mm pitch.

[Jon Fennell]

Hi Akane,

M16 X 1.5 is the same thread as the Celica St205. Fivebob has posted previously that the MR2 uses the same calibration for the sensor. I have two thread adapters at present that allow the fitment of my sensor without any special tools other than a spanner and a soldering iron. The sensor comes with a wiring harness that would replace your tempory adaption. Let me know if you want to try my sensor. I promise you will see an improvement in the response time, or your money back (as they say).

Regards, Jonathan

[Jon Fennell]

Hang on, I read that wrong. I'll have to get some thread adapters made with a M16 x 1.25 thread. Are we sure its different between the celica and the MR2 before I spend on some adapters?

[fivebob]

That sensor is 16mm with 1.25mm pitch.

Did you use a pitch gauge, or just guess???

If you used a pitch gauge then you read it wrong, because it's 16x1.5mm.

[fivebob]

Hang on, I read that wrong. I'll have to get some thread adapters made with a M16 x 1.25 thread. Are we sure its different between the celica and the MR2 before I spend on some adapters?

There is no difference, they are all the same part #. I just checked with my pitch gauge and they are 16x1.5mm.

[no_8wire]

Really? mmm ok, used it to size an adaptor I made for another temp fitting and that seemed to work...

But I just measured the diameter today and the pitch was from (obviously a bad) memory

[Jon Fennell]

I have sold a fair number of the Celica sensors since I last posted. Has anyone on this forum bought one?

I'm also looking for someone with a running MR2 Turbo to trial one now. The car needs to have an Apexi and commander. Can anyone put someone in contact with me?

Jonathan@fennelldevelopements.co.uk

Thanks.

[Akane]

email doesn't work
what do you need done?

[Jon Fennell]

email doesn't work
what do you need done?

Try that again!

jonathan@fennelldevelopments.co.uk

I need someone to check the resistance of the standard sensor against mine to verify the calibration (at room temperature and at closer to boiling point) and also to drive their car before and after to verify that heat soak of the sensor is reduced. Hence the need to to have a Commander so that the intake temperature is visible.

Regards, Jon

[Jon Fennell]

Guys, a chap has just asked if my RIAT sensor will suit his 1jzgte Soarer.

Can anyone advise?

Thanks, Jon

[Mr Ree]

Hi Jon,
I first read about your sensors when I was trawling through ebay one day and have to say I was interested in knowing more, especially regarding making sure the RIAT was going to be properly calibrated to suit my ECU.

I have converted my JDM (Map based) 2JZ-GE to an NA-T set up and am looking to buy a new IAT sensor in the near future as my current one sits in its factory location in the intake pipe between the air filter and the turbo, and only reads ambient air temps, rather that post intercooler temps.

Im only running 8psi on a relatively small T4 turbo and given our cooler climate, I dont forsee any real potential for engine damage at this boost level as it wont be pumping out air that is far hotter than ambient, but once my new gearbox is fitted and boost is increased, IAT's will increase too so I would like to monitor this with an IAT sensor installed somewhere between the intercooler and the throttle body so thr ECU is reading correct temps of the combined ambient and compressed air.

Have any of your customers used your RIAT on a non turbo JZA80 Supra? And if so, what were the results please?

Cheers

[Jon Fennell]

Hi Mr Ree,

I have given this some thought my self recently. There are a number of models out there with IAT sensors built into the airflow meters, or such as yours, NA cars that have been converted. Both these applications would benefit from a modern open element sensor. I have had a number of enquiries for the RIAT from people converting to forced induction. A number of MX5's and a non turbo RX7. Although of course, not all customers tell me what they are purchasing a sensor for. No customers I am aware of have bought a sensor for the JZA80.
Its worth mentioning that most ECU's have the capability to retard timing at higher intake temperatures so be aware of that when programming your ECU for the higher boost your planning for.
Have you checked the calibration of your sensor against the published RIAT values in the ebay advert? Let me know your email address and I will send you the install instructions, they may be useful. I'm out of time tonight, post up any more questions you have and I'll try and help.

regards, Jon.