SP Air Temp Sensor Help

chrisearl88 · Postby **chrisearl88** » Mon Jan 06, 2014 12:37 pm

Hey guys,
I'm doing an SP replica setup on my nb8b and the last piece of the puzzle is the location of the air intake sensor. Ive currently got the sensor in the pod filter so i can get around on the base map (only running 5psi atm).

Spoke with Chiptorque who are doing the tuning and Lachlan confirmed that the sensor should be placed just before the throttle body. He suggested to have a look at how the SP does it, so I'm hoping somebody on here with an SP was able to take a photo of the intake sensor location so i can get creative on how to replicate this.

Cheers!

Regie · Postby **Regie** » Mon Jan 06, 2014 6:38 pm

id have a guess the temp sensor will be mounted in the airbox

NMX516 · Postby **NMX516** » Mon Jan 06, 2014 7:01 pm

It's mounted on the intake piping elbow that attaches to the throttle body. Std SP has a fitting on that elbow which tees off to a hose with the sensor fitted to the other end of that hose. This puts the sensor outside the intake piping and so could be slightly less accurate for an instant measurement. Mine has been modified to have the sensor fit into the centre of that elbow, which it could be argued makes it more accurate or faster to change readings.

Postby **NitroDann** » Mon Jan 06, 2014 7:03 pm

This location (na6 so the idle tube seen isnt needed on yours.).

Dann

NMX516 · Postby **NMX516** » Mon Jan 06, 2014 7:06 pm

But hidden behind on the inside of the bend of that pipe, not like the photo above.

Postby **NitroDann** » Mon Jan 06, 2014 7:39 pm

That makes wiring more difficult and uglier on a 1.6L.

On a 1.8L its ok.

Dann

chrisearl88 · Postby **chrisearl88** » Mon Jan 06, 2014 7:53 pm

NMX516 wrote:Std SP has a fitting on that elbow which tees off to a hose with the sensor fitted to the other end of that hose. This puts the sensor outside the intake piping and so could be slightly less accurate for an instant measurement..

Cheers, yeah that what i had heard and I tend to agree that it would be best to be in the flow path. Lachlan suggested doing something similar with a pipe and a short section of hose.

The shame is that the nb8b sensor is a snap in style, so cant just weld in a threaded fitting. The other thing I thought of was maybe using an SE air intake sensor as i saw the intake pipe that mania sell had a threaded bung for the intake. But i wonder if the sensors are the same resistance and would give the same reading ect?

Postby **NitroDann** » Mon Jan 06, 2014 8:20 pm

Why not use the same sensor as the sp?

Dann

chrisearl88 · Postby **chrisearl88** » Mon Jan 06, 2014 8:31 pm

Apparently the SP sensor is the same as the nb8b once just doesnt have the barb on it, but a file can take care of that.

I was just thinking the SP solution was a bit crude thats all and a screw in sensor might be more solid.

Postby **NitroDann** » Mon Jan 06, 2014 8:36 pm

What sensor is it?

If its a standard GM ait like 99.8% of everything uses just go buy the one with a thread every aftermarket ecu'd car has.

Dann

chrisearl88 · Postby **chrisearl88** » Mon Jan 06, 2014 9:19 pm

http://www.ebay.com.au/itm/like/1308946 ... e&lpid=103

Looks like that. I thought the SE one might be the go as i would bet that it likely has the same voltage scale. If i went to an unknown sensor it may not be 'calibrated' to what the ecu would expect to see.

chrisearl88 · Postby **chrisearl88** » Mon Jan 06, 2014 11:36 pm

Thanks for the replies guys,

Had a look into the GM sensors but have discovered that their resistance values don't match up with the stock sensor. This isnt a problem with the megasquirts ect as you can select the resistance curve or calibrate from a few data point. But as I'm using the stock ecu that's been chipped I need to keep things simple to keep my ecu happy.

So my options are using the stock sensor and doing the SP style mod to the TB inlet pipe or going with a SE sensor that way i can use a screw in adapter and get the sensor right into the flow path.

Ive read up that for the NB IAT sensor the acceptable range is 2200-2690 omhs at 20 degrees. Is there someone with an SE and a multimeter that could confirm the SE is the same or someone in Brissy that wouldn't mind me testing theirs sometime?

timk · Postby **timk** » Tue Jan 07, 2014 12:13 am

Unfortunately the SE sensor impedance is VERY different, here are some quick measurements I have taken:

IAT (plastic airbox sensor):

20c - 2460 ohms
40c - 1180 ohms
60c - 560 ohms

IAT2 (OE on MX-5 SE just before throttle body):

20c - 42670 ohms
40c - 17330 ohms
60c - 8000 ohms

Postby **Okibi** » Tue Jan 07, 2014 1:59 am

Tim you've spent hours researching and testing, thanks for sharing. :beer:

chrisearl88 · Postby **chrisearl88** » Tue Jan 07, 2014 10:29 am

Thanks Tim, much appreciated! Looks like I will be using the stock sensor in that case, i will just try to weld on a stub a little longer than the length a hose clamp is wide to try and get the sensor as close as possible to the flow.

Thanks for all the assistance guys! Once this is sorted will be getting the car on the dyno, aiming for around 150-160rwkw so should be a whole lot of fun! Will post up some pics of the install once im back in Brisbane.