Intake Temperature IAT question

markward

Veteran Member
Joined
Jul 5, 2007
Location
Loxahatchee, Florida
TDI
82 Vanagon and 2011 JSW
I realize that Intake temperature is affected by ambient temperature altitude and load. Could someone tell me an average of what the IAT should be when the ambient temperature is around 85 degrees under acceleration load? I did use the search. The reason for my question is my TDI is in a conversion and I was wondering if my intercooler setup was removing enough heat. The other day on my scan gauge I saw 130F under acceleration. That seemed high, but I have no idea what is normal. I did do a search, but what I found turned into a 5 page discussion of coolant temp. Not quite what I was looking for. thank you.
 

nicklockard

Torque Dorque
Joined
Aug 15, 2004
Location
Arizona
TDI
2010 Touareg Tdi w/factory Tow PCKG
What were ambient temps? On a WOT acceleration run up my favorite test hill, mine hits 65C on a hot summer day. I have stock intercooler, turbo, and pipes, but am running Sprint 764 nozzles with a VWMikel tune.

In this weather (50's farenhiet and quite damp) it never gets above 45C.

130F is 54.45C for comparisons.

In addition to ambient temperatures, ambient humidity seems to have a large effect as well. It cools charge air better as if flows across the IC and also the humid air lowers PCT's a wee bit. Turbo performance seems just a tad more efficient also.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Yes, it's all relative to ambient temp, amount of load, and duration of said load-among other things. All I can really tell you is that after warm up at a "steady" load (maintain speed, flat terrain) at 60 mph I usually see IAT aprox 15F higher than ambient during moderate temps. Below 0F, for example, not as much difference-don't know why. IAT during acceleration/load would, and do vary greatly. Climbing a long grade in hot temps will really get it up there, but I don't know how high is too high. I don't have that terrain to deal with here. The ECU will back off fueling or boost to prevent fiascos, I have been led to believe. Certainly seems like it when high ambient/fuel temps occur, the engine gets a bit sluggish. I don't think 135F under sustained load in 85F ambient is too bad.
I think EGTs may be your bigger concern, not IATs.
 
Last edited:

markward

Veteran Member
Joined
Jul 5, 2007
Location
Loxahatchee, Florida
TDI
82 Vanagon and 2011 JSW
That information is helpful. EGT is on the long list of things to do to finish my conversion. I have and air to air intercooler mounted under the LS rear side vent. Any air entering the vent has to pass through the intercooler. Some Vanagon conversions are using watercooled intercoolers. I was thinking of adding a small electric fan, but wanted an idea of what is "normal". I need to install AC before I do anything else. The Vanagon is more of a highway machine getting us from campsite to campsite. Thank you.
 
Top