IAT monitoring and water injection

[20Vcqdriver]

In the hot few days we have had the ol' Cq has slowed noticeably and was wondering if there is an easy way to monitor the IAT. Came back after a blast yesterday and although the chargecooler was only warm, the pipe over the cam cover to the throttle body was too hot to touch and am starting to wonder if an aquamist water injection kit would help. Performance drop at high revs in hot weather is very noticeable and am pretty sure I can hear the 'tinkle' of knock too...

[andy10v]

You can buy an air temperature gauge and sender, or are you looking to log air temperatures? If so I would imagine a more expensive bit of kit may be required.

[EspenW]

Get a plastic pressure pipe (if available). Won't heatsoak like the steel ones. Painting it silver and putting some aluminum tape on the bottom of it helps further.

[mcandmar]

Easy way is to use Vagcom to monitor the IAT sensor. My crappy old laptop dosent have any battery life so i wanted something a little more simple.

So, i bought one of these to play with, http://cgi.ebay.co.uk/LCD-Digital-Th...item1c131c213a

Silly cheap and work very well. Updates once a second so it responds quickly to changes. The plan is to place the sensor just before the throttle body to monitor the air going into the manifold. I havent figured out exactly how to mount it yet.....cutting a hole in a spare throttle body boot is most likely.

The other thought i had was to compare the temp sensor range with the IAT sensor. Would be sweet if they were similar so you could just wire the display up to it...

I have a plastic intake pipe and RS2 inter cooler to fit, so the overall plan was to try and get some baseline temp figures daily driving, and peak temps under WOT acceleration. Then change a part at a time and compare the results. Mainly just for the fun of it

[A80Avant]

water injection will help under boosting conditions. It cools the air down and allows for better EGTs.

[Rusty]

Could try and log the IAT sensort voltage or resistance using a multimeter or something more exotic if you've not got VAGcom.

What sort of feed to the inlet have you got, cheap boost if it's not too good at the mo.

WI is an interesting idea, I've looked at it a few times, Snow Performance are a good bet from the states, Joe @ Axis was doing the MAF voltage contraolled kits for about $400, cheaper and more complex than Aquamist (you pay a lot for their pump).

[urS6Tom]

I've just bought an aftermarket IAT sensor and would be interested to hear the best place to mount the sensor. Do I have to drill a hole and tap, and if so, what about the risk of the drilling debris entering the engine?

Cheers,
Tom

[Greg_S]

I can definetly recommend the water injection. I have an aquamist plumbed up on mine and makes a big difference when its on boost, using a 50/50 mix of washer fluid to water and works a treat. It is just set to switch on at a set boost and delivers the same amount from there onwards. Can get a more fancy mappable version, but didnt see the need yet,

[20Vcqdriver]

Could try and log the IAT sensort voltage or resistance using a multimeter or something more exotic if you've not got VAGcom.

What sort of feed to the inlet have you got, cheap boost if it's not too good at the mo.

WI is an interesting idea, I've looked at it a few times, Snow Performance are a good bet from the states, Joe @ Axis was doing the MAF voltage contraolled kits for about $400, cheaper and more complex than Aquamist (you pay a lot for their pump).

Think I'll try and wire in my fluke multimeter and measure resistance first in stock mode and then homefry mode. Then measure the IAT sensor off the car in an oven with a temp meter.
Where can you get the plastic inlet pipe?
Performance was great in early April in outside temps of 3 degrees
Charge cooler water circuit is also cool so looks as tough water injection prior to cam cover pipe would work well.... Could do with finding someone who has fitted this already and has before and after figures...
Yesterday performance dropped off markedly in 3rd after 5800rpm whilst making an old 328I Beemer look slow..

[DJones]

Think I'll try and wire in my fluke multimeter and measure resistance first in stock mode and then homefry mode. Then measure the IAT sensor off the car in an oven with a temp meter.
Where can you get the plastic inlet pipe?
Performance was great in early April in outside temps of 3 degrees
Charge cooler water circuit is also cool so looks as tough water injection prior to cam cover pipe would work well.... Could do with finding someone who has fitted this already and has before and after figures...
Yesterday performance dropped off markedly in 3rd after 5800rpm whilst making an old 328I Beemer look slow..

I have it fitted to mine on the exit of the second intercooler, not sure about before and after tests but it certainly works. Temps only rise by 10 - 15 degrees from cruise to full boost.

I have the biggest jet the engine can handle, I very occasionally get a back fire when the water comes in so know i cant go bigger... all adds to the experience..

[S2central.net]

If your air temps are creeping up much more than approx 40 celsius then the ECU is going to try and reduce ignition if it detects knock... then it will reduce boost if it still hears knock. What fuel are you running by the way.

This charge cooler is a bit of an unknown... where is its source of cold water to aid the reduction in air temps when cruising around on hot days ?

Might the charge cooler be suffering from heat soak during this weather ?

You definitely need an IAT monitor - you could just track the resistance value of the 3B thermistor as we can correlate that to air temp.

[20Vcqdriver]

If your air temps are creeping up much more than approx 40 celsius then the ECU is going to try and reduce ignition if it detects knock... then it will reduce boost if it still hears knock. What fuel are you running by the way.

This charge cooler is a bit of an unknown... where is its source of cold water to aid the reduction in air temps when cruising around on hot days ?

Might the charge cooler be suffering from heat soak during this weather ?

You definitely need an IAT monitor - you could just track the resistance value of the 3B thermistor as we can correlate that to air temp.

Sounds good to me, If I wire up my meter and log the IAT resistance values from cold upto full throttle in 6th upto 5000rpm, can you then work out the actual Temp.
Always use V-power fuel which is now 99 octane.
The water rad for the charge cooler sits in front of the main rad with its own fan and thermo switch.
Looks like I need to put water injection on my birthday list if the IAT's are shown to be high....

[S2central.net]

What is pumping the water for the charge cooler - is it engine coolant ?

[S2central.net]

Yes - if you log IAT resistance, I can convert that to air temp - well anyone can with the graph... let me dig it out

[sam80quattro]

i remeber my dads mate years ago built diy water injection on a turbo'd pinto, using a hobbs switch, 5th injector and washer bottle and pump lol worked to. but the injector went rusty after a while lol