We all know the 4.2L motor runs Super hot and this can cause some issues. I thought I would take some temp readings on not just our car but 2 others after a 20min drive threw down town Chicago.
The 2 other cars were a 2007 A4 TFSI and a 2007 F150. The idea was to test the intake area the valve covers and the inlet temps before the throttle body.
There were some obvious issues in the comparison due to motor design but this was for reference only. On all the tests the S4 Had the higher readings for all the temps. The important ones to me were the temps before the intake manifold. The A4 has a plastic type of intake so the temps were going to be lower due to the design and location of the intake tube and throttle body location. Our S4 has the intake going over the 170+F Valve covers where there was No place on the A4 or the F150 that had the same temps.
First pic here is of the throttle body right after the intake elbow. You can’t see all that well in the pic but I put small pieces of heat tape to try and stop from getting surrounding heat readings. So the reading on the Actual throttle body is 133F
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The next pic is of the oil filter and the back of the intake manifold. you will see its 158F.
http://farm4.static.flickr.com/3661/3419784057_44f033a0ed.jpg
The last one was important to me. This is part of why so many believe there is an issue with the open element. This is a temp reading from the general Area where you would have the intake Even with a good barrier there is the most heat in this area if you moved more from the Valve covers towards the cylinder head/air box Gap obviously the Temps increased quite a bit. Average was about 175F
http://farm4.static.flickr.com/3367/3419784007_41e5399bb8.jpg
The last place was closer to the Air meter and intake rubber elbow. Much unlike the ford and the A4 in witch didn’t have the intake track going over the almost 175F degree part of the motor this seemed to be something that may be a place of interest. The intake temps were hard to pin down the exact temp cause the intake spans over a area where you have temps that range from 190-175.
If you do the coolant bypass and the intake spacers you are definitely going to dump a ton of heat out of the intake track. They definitely seem like a good idea considering the surrounding temps.
So I thought I would do the intake testing on the spacers I got from JHM. I was going to wait but I just decided to put them in and see the temp difference. This temp reading is after a hard run, with no cool down and a quick road side temp reading BEFORE THE SPACERS
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This next one is WITH the JHM spacers in. I noticed that the new intake manifolds seem to have a heat resistant coating on the bottom. So I put some heat barrier tape on, to try and help keep even more heat out. This temp reading, is AFTER the JHM intake spacers and a Pretty hard run with the car, with the same test area and reading AS quick as possible after opening up the hood.
http://farm4.static.flickr.com/3390/3420051827_315bc42c1c.jpg
Depending on how you drive the car and what conditions you are in, the intake spacers Really do knock out some heat from the intake. The test I did, I tried to keep the car under acceleration with almost no long straights that might bring cool air in from the speed the car is traveling. The intake spacers, Obviously make more of a difference between hard driving and Easy driving with the temp difference between with and with out. Even with easy driving I noticed a 40+ drop in the temps Over not having the spacers in.
The difference was even larger 60+ difference in Temps where the car would be in a heat soak situation like in slow or city traffic where there isn’t cool air flowing into the intake and the heat is able to soak into the manifold.
The Temps didn’t just drop and that’s it. Logging the car I was able to see lower knock voltage values. This allows the car to accelerate faster as the motor is seeing a better quality of air charge. The logs and acceleration show that.
The spacers How ever don’t help once you turn off the car. The intake will still get the slow heat absorption from the motor. So if you are at the track you will need to keep the Ice on the intake while you are in the pits with the motor off. How ever if you keep the motor running and constant air flow going threw the intake you are good.
also the spacers are there to create a heat barrier and reduce intake manifold temps. The hotter the area the bigger the gain with use of the spacers. Hotter days and hotter motor conditions when you need some help reducing temps are when the spacers are going to shine more and more
Over all I think its a great Idea and mod for the money. Any time you can get heat out of the intake that is a good thing. It’s a great heat barrier and it does that job incredibly well.