|06-23-2003, 12:26 PM||#1|
Member Sales Rating: (0)
Join Date: Feb 2001
Location: Rochester, NYVehicle:
WRX, Ninja, RX-7
Legacy, Fiat 850
GT Spec II Headers + Uppipe
I installed GT Spec II headers on my cara week or so ago. These came from turbometrics, [email protected] is the guy to talk to. I reset my ECU, and itís had time to learn the new map by now, so hereís a review of the headers.
First, a background. At the moment, my car is running stock boost control and stock engine management. The only aftermarket parts that would affect the performance are a catless downpipe, an underdrive pulley, Samco IC hoses, and STi motor mounts and tranny mount. I had a catless uppipe as well, but that was replaced with the new one that came with the headers.
The headers are all stainless and well built, with very nice welds. They are not equal length, but it looks like there is some design to them, based on a few extra bends that are in there. Itís possible theyíre tuned for a specific RPM band. There is a stock shaped uppipe, with no cat, but it has a 3-bolt flange on the bottom for better sealing. It looks like the inner diameter of the uppipe was almost half an inch wider than the Vishnu uppipe I replaced. The fit was perfect. They went into place with no trouble at all, and everything bolted down tight.
Since I reset the ECU as soon as they were installed, the car was in safe mode for any immediate driving, but right away I noticed the turbo spooled smoother. I donít know if I would say at a lower RPM, but power came a lot more evenly. Now that the ECU has adapted, itís even more obvious. Now I can really feel a difference with them. The car definitely pulls harder then it did. At full throttle, there is a noticeable difference in acceleration, but the biggest thing Iím enjoying about them is the fact that power seems more readily available all the time. For example, normally in 5th gear, on the highway, around 65, 70mph, it took a little feathering of the throttle to get the turbo spooled quickly. If I just hit the gas, I got to listen to that sucking noise for a couple hundred RPM before it finally went. Now, no feathering is needed. The same holds true in every gear, it seems like there is a bit more off-boost power, more on-boost power, and smoother spooling to transition between the two.
Itís hard to quantify it, since itís all butt dyno, but to put it simply, the car pulls smoother and harder, and this is on a car that is pretty mild at the moment. Itís nowhere near as fast as it was before I pulled some of the parts out, and Iím curious what I would gain with aftermarket engine management, higher boost levels, or even just a dyno tune.
The new header also changed the tone a bit. I didnít lose Subaru sound, like you would with a true equal length header, but since the cast iron is replaced with stainless steel, you hear more exhaust noise. I like my exhausts quiet, though, and this was fine, because you really only get louder at full throttle. At idle, it sounds close to the same as before, definitely not any louder.
For this install, you will need to buy an uppipe to turbo gasket, turbo to downpipe gasket (might as well replace it while you have the downpipe disconnected), 3 bolts to hold the header to the uppipe, and the uppipe studs. As for the 3 bolts, I carried the uppipe into Home Depot and found what I needed for under a dollar. The studs will have to come from a dealer, or someplace like subaruparts.com. Same for the gaskets. Do NOT try to reuse old uppipe studs. With the proper prep work (you have all the parts, studs are in the uppipe, no bolts break), the length of the install is about the same as a new uppipe.
If anyone wants one of these, send Sam an email at [email protected]. Pricing and pics are in this thread here:
$500 for the GD, $450 for the GC.
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