Please note this post is not about how good or bad aftermarket intakes are on G, it is about that scary heat soak, which turns our supercars into chronic underperformers...we loose so much power, diesel Jettas beat us off the line.

I got Android app with bunch of different readouts out of ECU, one of them was intake air temp. I always thought that "heat soak" is a BS to sell us more COLD air intakes. So I did some of my own testing. If you cannot understand temperature in C, sell your G and get El Camino, I have Apex'i intake-basically just an air filter bolted to MAF, no heatshield.

Outside temp was +25, I hooked everything up and went for a drive. Nice and slow drive obeying speed limits and traffic lights. Stopping in front of my parents house and idling for good 10-15 minutes...then going for a drive again...then idling again for another 10 minutes...
So here are the results.
After extensive idling intake air temp would slowly creep(not shoot) to 70-72 degrees. After 20 second modest acceleration to 40 km/h it would drop to 40 degrees. That's it. End of story.
I go 80 km/h-it i was still 40 degrees. I would idle more-it would not go past 70 degrees.
Now, how much power am I loosing from 15 degree change in intake air temp? Is "true" cold air intake providing me with same 25 C as outside temp? Doubt that.
Are 15 degrees that dreaded "heat soak" which makes me loose power and I can actually feel that loss? On a 280 hp car? Doubt that too.

Coolant temp was 92 degrees, after fan kicked in it would drop to 85-88.

 

This has already been covered by Rob in a very thorough dyno test thread which shows many after market intakes do affect power

https://g35driver.com/forums/intake-...s-results.html

btw, our cars are not really 280, more like 220 at the wheels stock

 

I did this test with the Injen CAI when I had the Cobb accesspot, it too reads intake temp. There was a minimum of a 20 degree difference between stationary and moving. You need to consider the temperature of the tubing behind the MAF as well. My CAI was hot to the touch after regular driving. Heatsoke does effect the performance, I was able to notice the difference between a cold and hot engine bay.

 

You're car is ingesting FAR higher temps than the OEM intake and you just posted data supporting this. If ambient temps outside were 25 degrees C, the OEM intake will see those temps at MAF. At a prolonged stop, the temps go up about 10 degrees C over ambient and drop quickly once moving. You're intake is making the temps skyrocket 50 C over ambient. Good job, your car will be a dog from 0 to 50 mph if you ever take the car to the strip.

 

lamo Dave, good stuff. OP I bought a pop charger shortly after I got the car not knowing the ramifications. Put it on in June when the temps were already scorching here in Texas, and to make a long story short yanked it off after 3 weeks and sold it. The power loss was significant in this brutal heat. Do I have mathematical proof of this loss, no and I don't need it. I've been driving for 35 years and I know my vehicles.

 

Wait so what all you guys are getting to is to stick with a stock rev-up box and slap some sort of hi flow or new air filter and mate that up to a stock Z-tube. Hmmmmm...i thought if I spent $200 on an intake I would gain 200whp

 

Gentlemen,

We are talking about 15 degrees here... Is it THAT bad? That is what I am trying to find. I mocked up elaborate heat shield/box and even bought Lava Mat(look it up-really cool stuff!), but now I do not want to spend half of the weekend building it for mere 2 hp. I suspect that reported sluggishnes could be caused by something else-another variable we are missing. I do not notice any power loss at low rpm-but I have 03 which seems to be less finicky than later models. What if problem lies in clutch slipping due to the heat? Heated up fuel lines?

I do not do drag racing-I do track with rpm range 4-6.5k. My main straight away max speed has dropped after I took Stillen intake out and put factory box in. I gotta try new things!

I read Rob's report, thank you very much for pointing out. I also know exactly hom much my car makes- 239.1 whp. Do the math to get to crank hp.

 

I'm certainly not trying to tell you what your experience has been. I'm saying that when I ran the pop in 100-103 degree outside temps, my power loss was significant with an open filter feeding the motor the air under the hood. nomsayin??

 

Is ATX Austin Texas? You are cooking there! I am in cool Toronto.
Just got another thought-what if relationship is not linear?

 

Yep Austin, Tx. Not sure what you mean by linear relationship.............

 

When it gets hotter, some other factors start to play? Not just temp?

 

AHW, are you asking him out on a date???

 

Ninja edit I see, e-mail notifications FTW. You might be onto something.

 

^lol

 

You said ambient temps were 25 degrees (77 F). With your Pop Charger and at speed, you were seeing 40 C (104 F). That's very significant when the OEM system will see right near ambient at speed. At a stop, your temps skyrocketed to 72 C (162 F). That is HUGE. That's easily 30 to 40whp bleeding out if you were to mash the throttle at that moment. At the drag strip, that means your car would launch like an absolute dog and temps wouldn't drop until you were deep into 2nd gear. Even then, the air coming isn't the cool air available.

Facts are facts, there is no real power to be gained with an intake on an NA VQ motor. The OEM setup already flows way more than enough air than a VQ could hope to ingest. There might 1 to 2hp gained here and there on a dyno, with the hood up, on a cold day, but overall, an intake will result in a slower car or a no faster car (cold air). It's simply a noise maker. Drive around with your stock intake for about 4 weeks then swap the stock intake back on. You'll eat those words. I promise. An intake is simply a noise maker. If you want the noise, you could have simply added a Z tube or chopped the G tube resonators out and added a Revup airbox and had the ideal induction temps.