I have been meaning to do some temperature logging on the Crossfire intake for some time to see if how good or otherwise the stock setup is. It was a nice spring evening so I though I would get on and do it. Unfortunately the British weather and some technical gremlins more or less scuppered the whole exercise, but it has convinced me that is something worth pursuing. Here's what happened...

I first removed the air filters to fit the loggers and was instantly reminded of the need for good filtration!



At least all the grit and debris was reassuringly on the upstream side of the filter!
I ended up fitting loggers upstream and downstream of each filter, one in the throttle body intake and one on each intake near the grille. I also fitted one near the dipstick (where some aftermarket filters sit), one at the back of the engine bay and one in the fog light hole where my brake ducts will be, just to see if there is any mileage in running an intake from there.

I also hooked up my OBD logger to log speed, IAT, MAF and RPM just to see how the graphs would compare.



The loggers were all set to log at minute intervals (the minimum they will do) whilst the OBD logger was set to log at 2 sec intervals.

My test route was a circular route with mixture of high speed (100+) carriage way and twisting county roads which I did twice. The first 10 mins was fine then there was a violent rain and hail storm which was so bad I had to pull over and stop!



I wasn't sure how all the water would affect the results but I downloaded the data anyway to see if there was anything useful to be seen. At this point I found that three of the loggers had not launched properly. Annoyingly they were the engine bay and external duct locations so I had no ambient trace to compare with the intake trace. Luckily I had kept an eye on the external temp gauge on the dash which had remained at 8 to 8.5 degs C (47F) so I at least had rough (very!) reference point. I know most of you guys work in Fahrenheit so that's what I plotted the graph in.

Here's the graph:



The temps all start off high since the engine bay was hot from a previous run. The first thing that surprised me was the difference in temps for each inlet tract. The 15 minute mark was the point I had to stop and wait for the storm to pass - notice the heat soak. At this point I think the RH inlet logger got soaked and was being damped. I don't think I was getting proper airflow over the intake sensors either!
The whole test was really void so there was little point overlaying the OBD data on the graph or try to reading too much in to these dodgy results. However it is still noticeable how much hotter the air at the throttle body is compared with the intake - the filter boxes are roasting when you pull the cover after a run.

I am going to repeat the test after checking the logger positioning/functioning and hopefully in more consistent conditions!

More later...

Simon.

 

Excellent work! I hope you continue to gather data, hopefully on a day that is a little less wet. And thanks for posting the graph in Fahrenheit.

 

Was the sensor isolated from the duct work? (to rule out conduction of the hot pipes to the sensor?)

I'm surprised the air at the LH/RH intakes was any different than ambient, esp, if the probes were outside of the engine bay...must have some conduction ie you measured the pipe temp not the air inside (or some of each).

I'd guess that the IAT sensor (air temp in the inlet manifold) should be within 20 degrees F of ambient. This sensor should be insulated from the manifold by design.

 

Hi Scott,

The sensors were supposed to be isolated but the whole test was a disaster really with everything getting soaked and sensors moving etc. I think you are probably right about the conduction issues - its darn annoying since I measure temperature for a living. It was all in a bit of a rush while I had all the kit to hand.

I checked the OBD IAT trace and that was cooler but still followed the trend of the loggers. I am going to wire everything in semi-permanently and have another go when I get time.

Simon.