[ UPDATE 2003/04/08 - Since doing this install for my 1g MAF and 16g, I've installed one for a 1gMAS/20g style (for my L1R), and one for a 2g MAS/20g style. Each pipe has been well made, well powdercoated, and generally quite nice. Nothing useful to add as far as numbers, but Dejon consistently builds these pipes so that they fit well, and look great. Aside from the bible-thumping pamphlets (I mean, WTF??) he puts in the boxes, there's not much to argue with about these intakes. ]
Introduction
The stock intake, from air can to the turbo inlet, is designed to be as quiet as possible. Most folks don't like hearing what the turbo (what's a turbo?) is doing under their hood, they just want the car to go when they hit the gas. As such, it the compromise is a bit bit less power. Replacing this black accordion-rubber-hose with a hard intake pipe is an easy way to gain back a few hp.
Replacing this pipe is a pretty simple proposition. Several vendors have a version of this, and Dejon Tool (run by Dave Johnson) is one of them. I went with Dejon since I was ordering a few other items, and I wanted a red powdercoated pipe. Dejon has several models available to fit whatever size turbo or air metering system (1g MAF/2g MAF/VPC/etc) you're using. Mine was the "F" model for a 1g MAS and 14b/16g sized turbo. 122 Performance makes them for a bit less, and you can even just buy a few bends and have a friend weld them up if you're so inclined. One practice I recommend against is the use of PVC piping. the "C" in PVC is for chlorine, which gives off nasty vapors when the pipe gets hot, I'm told.
Installation Notes
This is another cakewalk mod. Pull your existing MAF and tube out of the car. You'll have to unscrew a few clamps, pull off the BOV return hose, and unplug the MAF. Don't forget any hoses like the BCS, valve cover breather, or the fuel tank vapor line, if you still have those connected.
Remove the aircan from the stock rubber pipe, and slide the new pipe over the aircan. The coupler on my intake was a bit tight, so I coated the outside of my air can lip lightly with oil, and the new coupler popped on a few tries after. Test-fit the assembly to your car/turbo, making sure the MAF plug is still basically on top, and that you can still connect your BOV dump tube (if you're using MAS, that is). The tube for the BOV was in the exact same spot on the Dejon Pipe as my stock intake, so I didn't have to do any trimming. That's it. Plug in the MAF, and the rest of the hoses, and you're ready to rock.
Testing and Results
As before, with the underdrive pulley, I did baseline runs with the stock intake. Then, changing nothing else but the Dejon pipe, I did some "after" runs. These were all with a first-gen g-tech "pro". Should have data from the new "competition" before too long for future mods.
Constants:
- same section of road, direction
- small cool-down lap after each run, same each time
- car weight entered into g-tech was 3100 (probably a bit low)
- did not move gtech between experiments
- short shifted 1st and took second to redline each time.
- 16psi (to reduce effects of knock, leaks, etc etc)
- same amount of gas
- "rich" autocross tune settings
- reset ECU before each group of runs
- ambient temp 58*F
Results:
Before:
- Run 1: 222 (sat idling for a long time)
- Run 2: 238
- Run 3: 241
- Run 4: 241
- Run 5: 241
- AVG 2,3,4 = 240hp
After:
- Run 1: 244 (idled for a long time)
- Run 2: 252
- Run 3: 252
- Run 4: 258
- Run 5: 257
- AVG 2,3,5: 253.3hp
Analysis
Throwing out the highs and lows, (above) those numbers give an average gain of about 13hp at the wheels, even at this low boost pressure.
Impressions
Subjectively, I could hear more turbo & BOV noise, especially when the turbo was spooling up. Throttle response in this car is already very good, so I had a tough time deciding if it was any better. The pipe looks nice in the engine bay, and it has the visual effect of making it seem like there is more room in there. In actual fact, missing the various ribs and nipples of the stock intake, it does provide a bit more room to get your hands down near the transmission. Verdict? 13ish hp, better looks, and a bit easier motor access -- I'm keeping it.
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ugh.
what the air sees.
installed.
notice air can in stock loc.
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