Some observations on removal of intake flap
 

I wrote this in reply to a thread that Smashtheqube posted about deflapped dyno number, and a comment he made about flap out horn in....I felt it deserved its own thread, so here it is.

In my flap adventures so far I have seen the following....

With no flap, but horn still in....

1. Greatly increased temps: In general my car ran around 196 to 198 degrees on a normal drive before removing "the flap."

With the flap removed and horn still in place I was seeing on average 207 to 210 degrees. Up to 240 degrees sitting in traffic heat soaking, getting to the point where I was a little worried and considering shutting her down on the side of the road for cooling time. After getting out of traffic I was doing 80+ for over an hour and it never went below 215 degrees.

2. Loss of perceived power: After running the car hard, and temps getting up, the power that removing the flap seemed to add, was lost. I know its all butt dyno, but I did quite a few runs that confirmed the feeling over and over again. (This came after the highway incident) These are in upper 40's to low 60 degree temps, I would imagine middle summer would be worse.

Four days ago I removed the horn too...that day I saw temps drop to around normal or below in some cases, coincidence potentially but I don't believe so. Add to that I believe the car even might have gained a few more ponies.

My take after 3 weeks of no flap is this....with no flap and horn you have a low restriction HOT air intake, the proximity to things is just to close to have any long term benefit. However, without the horn it seems you have a low restriction cooler (yet most likely still hot) air intake. Both give you much more sound, but if you are going to deflap I would only do it with horn removed. Just my opinion on what I've seen over the last couple weeks.

Lastly, I was doing some in depth looking around when I removed the horn, and I don't see an easy way of developing a true cold air intake for this car. If we could find a way to route it into the wheel well it would be great, but it looks like there would be so many turns in the intake line I don't know if you would even get the air to travel all that way with any benefit?


Jason
07 Ibis

Re: Some observations on removal of intake flap
 

I think GMG is about to release a cold air box that is flapless but I need to double check that

I am interested in where they are going to pull the air from

it's physically impossible for the intake horn and flap to have that impact on your oil temperature
 

I'm modified with the switch to open and close the flap, without horn removal, and there is zero difference in oil temperature. There is, however, a 10F increase in intake air temperature, with still a slight increase in mass air flow. My mass air flow readings still look very similar to others I have taken in the past.

IMO, unless you do multiple back-to-back runs on the same day, within the same hour, at the same atmospheric conditions, you may be kidding yourself. My guess is that the difference you are see is the ECU pulling timing. The only way you're going to get a valid comparison is do the test runs on the same day, let the engine get up to full temperatures and then log the results of multiple back-to-back WOT runs with VAGCOM.

Re: it's physically impossible for the intake horn and flap to have that impact on your oil tempera
 

I didn't believe that the intake temp would cause such a drastic change on oil temps either, and completely agree that it is a change caused by some other factor.

With that said, the car has never ran 240 degrees sitting in traffic with the flap installed, and I would have to imagine that under driving, (not sitting/heat soak) conditions there are other factors in play.

I still believe however that pulling in the heated air while sitting played a role in the increased oil temp, even if it was the ECU pulling timing due to the decrease in overall mass air flow. That still says to me that pulling the flap when you are driving a car that is going to be running hard or sitting in traffic can potentially cause some unforeseen effects.

I know that this is still up for debate on overall effects of the flap, but I know I wasn't the only person to see increased temps from pulling it.

I also figured I must add I was sitting in traffic for over an hour, so there was time there for the car to do whatever it was going to do.

Lastly, do you have a graph showing intake temp and mass air flow with stock flap, without flap installed (your case open), and without flap and horn. I would be interested to see what the overall numbers are saying. Lastly do you think that days where it is 90+ degrees those results could change?

Jason
07 Ibis RS4

I posted these before, but here goes
 

The only way you're going to know if you're actually seeing increased oil temps is by a valid A:B comparison under the same conditions. Sitting in traffic for an hour, essentially idling, you are going to be dumping a load of fuel into the oil. This alone will cause the temperature to raise.

Anyway, 240F is not an issue. The engine is designed to run hot. I typically see 269F on the track with no issues, and up to 240F on the street.

<img src="http://www.teraspeed.com/RS4/temperatures.jpg">

<img src="http://www.teraspeed.com/RS4/mass%20air%20flow.jpg">

my MAF logs look a little better without the horn as well.
 

not significantly better, but a little bit.

You're really have to do the logs back-to-back to be sure, though.

I had honestly never seen over 210-215, ever....that is what caused my concern
 

I am willing to admit I am surely no expert in this, however it was just a startling change from before removal, in all aspects of oil temp. It honestly could just be I need an oil change and I am seeing more dramatic temperature fluctuations due to fuel dilution over the life of the oil. You would know much more than I.

Jason
07 Ibis RS4

well, ambient was 14 degrees hotter on the 'no horn' run, yet MAF was higher.
 

on back-to-back runs at the same temp, I think the difference would be even greater.