Random installation and driving notes with these headers...
Well, installation of headers on an SC400 is a PITA. Likely one of the most difficult mods to do on the car. I had the front subframe pretty much dropped, the only things I didn't mess with were the brake lines, abs wires and the sway bar. With all that still connected, I had the frame lowered from the body about 6 inches or so. Removal of the driver's side heat sheild was one of my biggest battles. I also removed the oil and transmission dipsticks, easy to remove but difficult to put back. I also removed the motor mounts on both sides. Most of the manifold bolts aren't too bad to get to from underneath with the right combination of swivel sockets and extensions. The passenger side manifold is easily to remove compared to the driver's side.
Installing the headers is pretty much the reverse of removing the OEM manifolds. The pipe routing of the driver's side header made it impossible to tighten two of the bolts from underneath, I had to shove my arm inbetween the valve cover and the strut tower from under the hood to get at them. They fit right in, clearing the motor mounts, steering shaft, frame, trans, ect. No problems fitting to the engine and the body and everything else.
But...the header flanges did not line up with the y pipe flanges, not even close. The passenger side wasn't too bad to force over but the flange angles were all wrong causing a bad leak. The driver's side was way off. I managed to pry the header back exhaust over enough to get the bolts in but it wasn't pretty. Again, the flange angles were way off and pushing the header back exhaust over was causing it to hit the body in a couple of places.
I left the car on the lift overnight and drove to an exhaust shop the next day to have the problem fixed. Cost a pretty penny. The flange alignment is the only major problem I had, everything else fits great. Funny that the seemingly easiest part of the design (making sure the flanges line up) was way off and all the hard parts (clearing everything else in a very tight engine bay) were perfect. Go figure. I suppose it could have been much worse. I have also modified the manifold support bracket so that it could be used. I think this bracket is very important for the life of the headers. Keeps the flanges from flexing on the heads, they move with the engine rather than with the rest of the exhaust.
So I had the battery disconnected during the install. Drove to the exhaust shop and dropped the car off. I didn't get a chance to really drive it, do any testing that night. My ride home was full of traffic. Over the next couple of days I started to drive it a little bit harder. At first, I did seem to lose a bit of low end response, but this seems to have cleared up. Possibly the ECU is learning.
Now, after driving for a few days, I can say that I LOVE the headers. My car feels like a completely different car. Sounds completely different as well. I still have plently of low end and awesome mid and top end. It's fantastic really. If I stomp the throttle while rolling at 20mph, I loose traction, even with the pair of 275's in the back being turned by the Torsen diff. All I can say is wow.
Despite the 9 hours I spent at work on my day off to install them and the unexpected expense of making the headers line up with the rest of my exhaust system, I am very happy with them and very glad to have finally gotten and installed them.
Whoo Hoo!
Now I just need to figure out what to do with the rest of my exhaust, and figure out how to pay for it. LOL. Since it seems I still have plently of power down low, I'm really leaning towards a 2.5 inch setup installed with either an OEM like y to y setup or an x pipe. I'd like to get some better flowing mufflers but I'm not sure what to get yet and I am concerned about getting TOO loud. I wouldn't mind a bit more noise but I don't want it to be obnoxious.
I would be happy to hear suggestions....
KC
