I downloaded some new software for my OBDII scanner so that I can log up to 6 parameters. I did three tests with various stock intake setups to lookk for any potential gains. I measured timing advance, intake temp, rpm, and air flow at the MAF (grams/sec).

My cars mods: Z-pipe and 5/16" spacer

The intake setups:

1) Stock airbox with Z-pipe
2) Modified Powerduct (cut lower lip of Powerduct cover to let more air in)
3) Power Duct cover and over radiator snorkel removed (this setup was to emmulate a POP charger setup). I'll call this the open airbox

Conditions: late night, lower 70s, 50% humidity, 30.0 baro pressure, 1100' elevation.

Test run: Highway, 3rd gear from 3500rpms to 6500rpms. 3rd gear was used to capture as much data as possible because the gear winds out longer.

Runs: two back to back runs with 5 minutes cooling (highway speed) between runs.

Interesting notes:

1) The stock airbox and modded Power Duct cover attain very similiar temps at cruise and at a stop. Both will spike 10-15 degrees over ambient when at a stop for longer than 30 seconds. It takes about 5-10 seconds for the intake air to get near ambient (+5 degrees) after a cruise from stop.

2) The open airbox will spike to 30-45 degrees above ambient when at a stop for longer than 30 seconds. It takes about 20 seconds to cool the air down to near ambient after a cruise from stop.

3) The open airbox is very aggressive sounding. Sub 4000rpm tip-in acceleration and tip-in highway acceleration in MM 5 is negatively impacted. Normal acceleration feels softer. Torque converter lock-up and unlock is much more pronounced and somewhat aburpt. It takes a bit more throttle to achieve the same acceleration compared other two setups. Tip in WOT at 4000-4500rpms feels great and more responsive, snappy. It sounds great too. Brake stall launches feel a bit weaker. The typical 5AT bog on launch is a bit more pronounced. 0-40mph acceleration feels a bit weaker, but sounds much faster.

4) The modded Powerduct setup is fractionally louder (15%) than the stock setup. Part-throttle acceleration is much improved as is off the line, part-throttle and WOT. 4000rpms+ tip-in WOT doesn't feel as snappy, but after 500rpms, there's no discernable difference between this setup and the open airbox, other than noise. TC lock/unlock is far better. The engine at a low rpms cruise feel smoother. The engine is far more responsive to throttle input around town. There is a constant wave of acceleration at medium throttle on the shifts. Under the same situation, the open airbox feels boggy initially after the shift.

5) The stock airbox is obviously quieter. It delivers the best around town driveablity. It delivers the best downshift WOT performance. There is a surge of power on every shift. This setup has the least initial snap on a 4000rpm WOT run.


The WOT test results showed that the timing on all the setups was basicially the same (+/-2 degrees, random). Intake temps were basically the same (+/- degrees). The kicker was the airflow. The stock intake showed the most airflow at the MAF followed by the modded Power Duct and then the open airbox. Max airflow with the stock airbox was 169 gm/sec (ave 142 gm/sec) where as the modded Powerduct saw 162 gm/sec (ave 138 gm/sec) and the open airbox saw 159 gm/sec (ave 136 gm/sec) .

 

Amazing! Truely amazing!! When others did this type testing over a much longer time frame the clueless one bad mouthed their methods and results. Saying anything else about this would exceed 30 seconds.

 

It's probably the best for performance of all intakes, considering most big name tuners like Nismo and others use the stock box.

I really want to go back to my stock box setup, but I just can't bear to lose that JWT PopCharger scream. It's quite a sacrifice if you ask me. That sound is just too addicting.

 

When an episode of Walker Texas Ranger was aired in France, the French surrendered to Chuck Norris just to be on the safe side.

 

In the battle of wits some people are half armed. I seldom spend much time with them. 23 seconds.

 

Nice data logging! Confirms my thoughts on the stock airbox and aftermarket intakes.

The spikes in temps is because the engine coolant is heating up and after about 30 seconds, the radiator fan kicks on and starts to blow hot air into the engine bay, flooding the open airbox with hot air.

 

^^^ I don't think so. When the radiator fan kicks in, my intake temps drop precipitously.

 

What, no plots? Nice work though.

 

Any comparison Between G-tube And Ztube ?

 

DaveB - very nice writeup! I'd be interested in seeing how the setup I have compares to these. My G coupe has a stock airbox and Z-tube with the Power Duct and radiator snorkel. The difference is that I removed the lower resonator that sits below the airbox. When I put the stock airbox back in after having a CAI for a while, I thought the resonator would rob me of some flow just like the resonator in the G-tube. I knew it might mean slightly higher temperatures but assumed that effect would be minimal given the location of the resonator opening relative to the filter.

 

Nice word Dave. Nothing like actually providing data. A lost art here is seems. Would be nice if someone let you borrow their stillen/jwt for testing though.

 

thanx for the read DaveB, you got me thinking since i have a POP charger, i went to my car and removed the heat shield and installed the plastic part that connects with the "ram" in the middle and connects at the bottom "resonator"(btw i covered the "resonator" hole), if you guys dont know what im talking about is the plastic part where the power duct is, i tested it with the power duct on and off, with the power duct on it was too quiet, almost stock like quiet, it felt i had more power down low, then i removed the power duct and it got a bit louder, still i felt i had more power down low and i got the "constant wave of acceleration" DaveB was talking about as well as more responsive, well thats compared to the way i had it set up were i felt no power down low untill 4000rpms, it did felt i had more of a steady acceleration even though after 5000 rpms it felt the same as before, i dont get that "pull" i used to feel around 4000rpms though. Before it was very hard for me to make my tires burn from a dig, now i finally got them to burn from a dig!!! im leaving it like that since i feel more acceleration/response, even though its a lot quieter, maybe in a week from now i will remove it and put the heat shield back on to see if its not my mind playing games with me

 

Good work on the data!

I was wondering though, why would this affect the TC lock-up like this? Is it because of the rate that the engine spools up?

 

I don't have a clue as to why the TC lock/unlock is so much more abrupt. Yank the intake snorkel and Powerduct cover and see if your car does the same thing. I'd be interested to see.

 

I guess I could dump everything into Excel and graph it, but I'm pretty sure most people wouldn't a clue at what they're looking at