WClark

There has been a lot of discussion and speculation about the dark side of chipping a 1.8T with the stock turbo setup generated mainly by the December ec A4 project car article.

The data and unfavorable conclusions presented by the author is based primarily on dyno testing which by nature is very high boost duty cycle. This may relate directly to racing but my position is that it cannot be applied directly to more normal driving which is much lower duty cycle high boost. The questions remain, what is "normal" and what kind of heat cycle does the charge air exhibit under various definitions of "normal".

So today I began to collect some data using my VAG-COM tool on a laptop and my '01 equipped with the APR EMCS performance and stock options. My boost gauge is the digital unit Ed produced. I also have the Europeanspeed airbox mod with a clean stock air filter, but that is about it.

The VAG-COM does not yet have a data logging function so I am stuck trying to observe the data block and drive.

This morning I chose to monitor conditions on my commute to work in performance mode. I deliberately performed 2 unnecessary WOT 2 and 3 gear romps to get some peak temps and observer recovery. The drive is predominately stop and go over about 25 miles with stop lights averaging about 2 miles apart and the traffic speeds ranging from 25 to 70 max on a 4-6 lane divided road with a few limited access stretches. The outside air temps averaged 43F. The altitude is generally 100-300 feet above sea level and the roads are mainly flat with a few minor grades.

Observations:

1) average charg air temp when moving was 16-20C.
2) average charge air temp when stopped and idling for over a minute was 24-27C.
3) the 1) temp above did not increase anytime while driving with the manifold pressure at or below 0psi.
4) peak charge air temp reached 28C at the end of a 1-2 gear WOT sprint. This was done immediately after stopping and the charge air temp was 18C.
5) peak charge air temp reached 37C at the end of a 1-2-3 gear WOT sprint (did not reach redline in 3rd before having to back off). This was done after sitting at a light and observing the air temp increase to 24C.
6) recovery of temps after WOT runs (to 20C) was within 2 minutes driving at normal traffic speeds.
7) my average gas mileage as computed by the car was within .5 MPG of what I have historically observed while commuting.
8) very short periods (2-4 seconds) of WOT while in 2nd, 3rd and 4th resulted in momentary temp increases of only a couple degrees which recovered in a few seconds.

It is WAY too early to draw conclusions but I was encouraged by a couple observations. Charge air temps recovered rapidly when moving at a normal relatively constant speed in admittedlty cool air - and the speed itself didnt seem to matter. Sitting at idle does a lot to heat soak the IC.

Further thoughts...

When initially checking out the latest data block retreive capability of the VAG-COM the other night I noticed the air temp reading with the car idling for some 20 minutes continued to climb. I set a fairly large floor fan directly in froont of the IC inlet and watched the temp drop quickly back to almost ambient. This and the idle temp observations above suggest to me that a small 12V fan mounted behind the IC and powered by a thermostat, or perhaps some smart circuit that detects 0mph will probably improve that heat soak a lot. I would guess that a fair amount of WOT action among enthusiasts comes immediately after a period at 0mph, so this is probably the worst practical case of heating most of us will see.

It is not particularly safe to drive around while focusing a fair amount of attention on a laptop screen in the passenger seat...hurry with that data logging feature Uwe!

Colonel Bogey

I'm presently shopping thermocouples & gauge for TT. I've decided its a must have b/4 proceeding with further mods.

Mpancheri

This data would also lend credence to the use of an IC misting system, to cool the IC before any WOT action, and to speed cooling afterwards....

Adam S

Who don't want to spend big $$$ on a new IC for our chipped K03 cars. ;-)

CharlieGSanD

i know some has been posted B4 but it could bring up the efficiency of your IC

CharlieGSanD

<ul><li><a href="http://www.psm1.com/">http://www.psm1.com/</a</li></ul>

CharlieGSanD

<ul><li><a href="http://www.autospeed.com/C_articles/A_0527/P_1/article.html">http://www.autospeed.com/C_articles/A_0527/P_1/article.html</a</li></ul>

CharlieGSanD

check out the oil coolers too! (bottom of page!)<ul><li><a href="http://www.racerpartswholesale.com/fan.htm">http://www.racerpartswholesale.com/fan.htm</a</li></ul>

WClark

Cool...pun not intended. Small one might work nice. Thanks!

ReyHey

Great write-up Wclark!!!