StormRune

gasongasoff: I'm having a really hard time reconciling the differences between your tests and my tests back in my post 25, which also provided some hard facts and figures. In my tests with all of the OBD-II screen shots the temperature deltas were dramatically less. The outdoor temp in my case was 70 degrees and I imagine it was similar for your tests... so I doubt there is much explanation to be found there since big ambient differences could affect the deltas as well.

You never did say whether you were doing the Fabspeed tests with their heat shield in place, the mostly flat carbon fiber one that installs on the engine mount bolts and largely separates the engine from the intake cones. Is that installed?

gasongasoff

Yes of course the heat shield was installed.
BTW, how long was your drive before you took you temp snapshots? I notice that just idling and driving slowly, the Delta Temps with the Fabspeed was only around 10 or less. And hopping on the freeway initially, the deltas were only 7 to 8. That's pretty close to what you were getting. However once the engine was hot, thats when the delta T's started going up at non-freeway speeds. You also recorded a delta temp of 18 at one point. Do you remember the conditions?

One benefit of the data I collected is that they are not single snapshots. I can graph the delta Temps vs speed and time every 6 secs or so over the course of a 1hr drive.

I'll see if I have time to run more tests today. It probably takes me about 20 mins to swap everything in and out. I think I might have seen a pattern where MAF flows reach higher values at lower rpm's but I'll have to do more runsense.

Btw I have the same obdlink as you, you're welcome to try to replicate my temp tracings to compare notes. Just required a little work in excel.

RaidersR1

The outside ambient temp can me whatever it is doing this test. The point and info to be determined is the Delta from running both products in the car on the same day same driving conditions. The engine temp will always be fairly constant. Cold day or not the engine will always be +200 f while running in any conditions. On hotter days the fans kick in to help cool. Doesn't help cool the air coming into the engine compartment.

This thought the heat shield keeps hot air from the intake is just wrong. Think about the car moving along the road. Air comes up from under the engine and does what to the engine heat?? Blows straight back into the bay towards the air intake. The vents allow the air to leave with the help of the fan. However not as quick as its coming in.

I can care less about the ambient temp. It's the delta that matters for the test. It shows how much different the temps are from using the Fabspeed and stock box on the same day same conditions.

It would be interesting to see the test on a very hot day and a very cold day. Just out of wonder!

StormRune

Although it isn't intuitive, the air flow through the engine bay actually runs from the top down, entering from the slats at the top then allowing the heat to travel out of the bottom of the car. When moving there is more vacuum under the back bottom of the car than there is at the top, The spoiler deploys at higher speeds to help maintain a higher pressure along the top, otherwise a vacuum would develop. The fan pulls air in from the top and pushes it down. If you stand by the car when it is parked with the rear fan running, you can feel the heat being pushed down and out the bottom of the car around your feet.

But this thought does lead to a possible difference in our cars that could be explaining the observed temperature differences. I have a Turbo wing, which generates about 200 pounds more downforce, plus the deck lid is different and the plastic ducts sit exactly on top of the cones. I don't know if the extra downforce for the wing would also increase the pressure along the slat intakes... but maybe. Right now that and the ducts dumping right on top of the cones is all I can think of to explain it.

gasongasoff

More STOCK airbox numbers, this time at 67F ambient. After a long warm-up run:

Delta T's:
Driving around town = 14F
Freeway steady-state = 8-12F
Driving around town, after exiting freeway = 13-16F
Driving very slowly around neighborhood = 18F

user 72902

I have the before and after numbers and I don't have a fixed wing. On the highway FabSpeed intake temps were 3 to 4 degrees higher and at lower speeds the delta was around 10 to 12. I'm having hard time trying to understand why your deltas are so high. Have you contacted FabSpeed for technical assistance?

Just to clarify. FabSpeed intake temps were 3 to 4 degrees higher than the stock intake temps. My stock intake temps are typically 7F above ambient so the FabSpeed intake temps were 10 to 11 degrees higher on the highway.

user 72902

I check my intake temps regularly before and after the FabSpeed Y-Pipe install. Checked them for four months while I had the FabSpeed unit installed and regardless of ambient temps the deltas remain/remained consistent.

gasongasoff

Great to be able to compare!
How did you obtain these values and under what conditions?

user 72902

I have a GoPoint OBDII reader that provides real time data. I find this easier than using my Durametric Pro while driving. It was spring time so outside temps varied from 30 to 80 degrees and I didn't record intake temps until oil and water were up to normal operating temperatures.

gasongasoff

Interesting post I found for the 996 version:
"Those are hot air intakes, unless the deck lid is greatly modified, and the air box insanely insulated.

I have seen IAT increase 32 degrees when adding a CAI in the past. That was a back to back test, the same day, ambient temp only varied 3 degrees, engine bay temp only varied 5 degrees.

Jake Raby
Flat 6 Innovations"

https://rennlist.com/forums/996-foru...l#post12417582

Also, after parking and shutting off my car for 5 mins, I opened the engine lid. The air was really hot. I measured the air temp with a Thermopen and also took IR temp readings of various plastic parts (intake, plenum, etc.). Everything came out to about 120F. I'm not sure how mixing 120F air with 70F ambient air isn't going to increase your temps significantly. Even if you could get 4 parts ambient air for each 1 part engine air, that's still a 10F delta.

phaphaphooey

Respectfully, that link has little bearing on the current discussion because the 996 and 997.1 intake design are incomparable to the .2 design. For starters, unless the OEM lid is modified, on the 996 design there is only one cutout for incoming air as opposed to the two cutouts on the .2 design.

gasongasoff

Notwithstanding the increase in Delta temps I recorded, I also made some MAF measurements (posted as a new thread).

Flat6 Innovations

The increased temps lead to altered fuel maps being looked at by the ECU... Hot air also loses density, and doesn't make power.

gasongasoff

Good news, I was able to create conditions where the Fabspeed intake delta temps were around 4F higher than ambient. This was on the freeway travelling around 65mph. However, it takes 3-6 mins of freeway driving to get this point. (My previous runs had shorter freeway durations.) Interestingly, after exiting the freeway, the Delta T's increased rapidly to 25-30F.

gasongasoff

Jake, would you be able to elaborate more on this? There's a different engine map for different temperatures? What do these affected maps determine (i.e. timing for a given mass air flow, fuel injected for a given MAF, etc.)?