Let the tinkering begin...

[Jaymz]

What is the scientific method (ie. your methods) for getting an intake airbox temperature? I have in the past used a cheap probe type (read $5 ACME brand) but it is not what I refer to as degree perfect in accuracy...

Mik I used one of these. It is acurate to + or - 1 deg. Its only $40 from Jaycar.

Greg what i did with mine is put it on top of the filter, just after the inlet, so i new what temp it was ingesting.

Cheers,
Jamie

[Greg Roles]

OK mate, my temp probe is in the airbox.

I'm going to spend a few days pre filter, with the probe sticking up from the bottom of the filter box, then move to your spot, and so on.

My gauge is an aquarium one, also from Jaycar, so it'll be similar in it's amazing accuracy

What I am being careful to do is to tape down the wire and have my probe tip actually raised, off the plastic, so i am getting real air temps. I'm sure taping it directly to the side of the box will yield higher temps. I'll take a pic of each probe spot and report on my findings.

I also have a digital dual measurement manometer coming... and one that I can get real time pressure differences. Will make it easy to get pressure drops across various inlet parts. I'm convinced Mikoz is on the right track, and have plans for a fairly modified inlet tract mid term, so drilling holes in my OEM inlet here and there doesn't worry me. Should be interesting....

[Transporter]

I would place one probe to measure temperature of air coming onto air filter box and second probe as close to cylinders as possible.

[Greg Roles]

Well at this early stage, the temps in the bottom of the air filter are only 2-3 degrees above ambient according to both the aftermarket thermometer and the golf display in traffic. When driving it quickly drops to within a degree. My airbox is quite insultated though.

May be moving to your temp spot shortly Jamyz. Can you explain exactly where your probe is / post a pic??

[Jaymz]

Well at this early stage, the temps in the bottom of the air filter are only 2-3 degrees above ambient according to both the aftermarket thermometer and the golf display in traffic. When driving it quickly drops to within a degree. My airbox is quite insultated though.

May be moving to your temp spot shortly Jamyz. Can you explain exactly where your probe is / post a pic??

Oops must have been on somethng that night i posted that up. I've actually got it underneath here:


And run it through here:


To here:


And up to the dash here:

[Greg Roles]

Ok cool. Yours is resting on the plastic, so it will be getting heatsoak from below. I have put mine closer to the element, and raised it off the plastic so it is a bit more indicative of the actual air temp.



On starting and running the car from cold, the air temps generally sat only a few degrees above ambient ( room ). It raised slowly on idling in traffic, but overall I'd have to rate the insulation as a success.

On returning to the hot car after an hour at work, I was amazed to see the temp in the 50's. Seems heat soak happens eventually, and on resting the whole inlet and the air within gets quite hot. Driving around yesterday, in heavy traffic on a 30 degree day, the inlet temps hovered about 8-12 degrees above this. Seems once the inlet is hot, it takes a good run to actually lower it back down, and perhaps the insulation is actually a hinderance here?

The AC added to the inlet temps noticably, as I messed around turning it on and off, especially idling at the lights.

Late yesterday arvo, on a highway run, I was pleased to see the inlet temps consistantly a degree or two lower than ambient, with the windows down.

Cooler day today, but will keep watching it.

[Greg Roles]

Look at that nasty hose in red touching your airbox...

And the big radiator hose in yellow passing directly under the probe area....



nasty!

[gregozedobe]

Late yesterday arvo, on a highway run, I was pleased to see the inlet temps consistantly a degree or two lower than ambient, with the windows down.

I'm curious, how is that possible ? (unless you have a discepancy between the two gauges due to calibration or location of sensor).

I thought you would have to add "coolth" somehow (with ice, water evaporation or a/c cooling), otherwise I don't understand how that could happen.

I would have thought that after a while everything has to be at the same or higher temperature as ambient, as heat moves from hotter things to cooler things to make everything the same temp (in this case ambient air temp or higher, depending on exposure to engine heat).

[Greg Roles]

Dude I put it down to either airflow being much greater through the airbox than on my dash in the cabin where the second sensor is ( it's located inside the display housing itself ).....

or more likely to the fact I am using a high quality Jaycar chinese thermometer. I'm working on "approx" temps, so I'd say they were the same.

Again this morning, the whole drive into work from cold, the inlet never got over 25 degrees, and ambient was about 23. Mild traffic.

[gregozedobe]

Dude I put it down to either airflow being much greater through the airbox than on my dash in the cabin where the second sensor is ( it's located inside the display housing itself )

OK, now I know your meaning for "ambient" is different to my undersatnding of "ambient" what you said previously makes perfect sense.

There are some significant heat sources in/near the dashboard (heaters, engines, exhausts, heat from the sun etc), so your dash is probably always at least 2-3 degrees warmer than the outside air temperature (which is what I assumed you were referring to as ambient temp). I should have checked my assumption

[Jaymz]

Look at that nasty hose in red touching your airbox...

And the big radiator hose in yellow passing directly under the probe area....



nasty!

Yep, i think its all gotta go

[Greg Roles]

OK, now I know your meaning for "ambient" is different to my undersatnding of "ambient" what you said previously makes perfect sense.

There are some significant heat sources in/near the dashboard (heaters, engines, exhausts, heat from the sun etc), so your dash is probably always at least 2-3 degrees warmer than the outside air temperature (which is what I assumed you were referring to as ambient temp). I should have checked my assumption

No you are right, my comparison isn't strictly "ambient" but this is a "rough" guide, and I'm personally much more interested in finding the hot spots than the exact temps. What I consider ambient is somewhere between the golf display temp, and the "in room" temp on the face of the dash.

Where is the temp probe for the golf display? Under a rear view mirror?

Jay, I was pleased to find today that when returning to a heat soaked car, on a cooler day like today, my inlet temps quickly returned to 1-3 degrees over "ambient". Seems the insulation doesn't trap the heat, and only on 30 plus days does the whole system suffer.

On the weekend I'm going to put it in front of the intercooler at the bottom hose / intercooler junction.

[Jaymz]

Greg, going to put the GT on the rollers next weekend at Mercury for s**ts and giggles . Will lift the lid on the airbox under full noise, will know then if there's any restriction.

You should come, would be good to see the difference in the curves

[Greg Roles]

Ok, I'm in too. Look forward to scaring everyone with our oilers!
I see a fair bit of restriction in the stock MAF, but airboxes first.....

Edit: Modshack website states 18% restriction in the grid prior to the MAF sensor. This is there to smooth the airflow from the top cover of the airbox, where I figured the "bad" spot was. In my uneducated opinion deleting the 90 degree bend in the airbox lid, and removing the restrictive MAF grid would be good ideas. Certainly my next step. stock MAF's go for $65us on e-bay, so I'll probably get a test mule.

I'd also suggest people out there go for an aftermarket boxed pod like the Mod shack one, rather than frigging with the stock box like I have been. Biggest issue is that 90 degree bend.

[Greg Roles]

Been a quiet week on the dirty hands front, but been spending all my money. This month should be fun
Here's just some of what the nice mailman delivered just today!




On a side note I had my 1500km checkup service yesterday ( not that there was any thing wrong in my opinion ) and I noticed the car was a fair bit more punchy on the drive home. It is breaking traction on boost in the first few gears. Not laying rubber levels, but the traction control is kicking in, and the tyres are chirping a fair bit whereas before it was somewhat smoother and it took uneven road or hills to get the rubber upset.

I'm very happy, but the question is has anyone else noticed this? Perhaps they reflashed it? Mabey a battery disconnect sets the computer back to overfuelling or something? I've e-mailed my contacts at the dealer to ask, but wondered if anyone else has had this experience.