OK more updates. I keep driving, finding issues, fixing them and then driving it harder and repeat. Scrambling to get the car in a good place for the UMI Autocross coming up next weekend!
One I solved the overheating issue I was able to get out and take the car on some longer drives, but keeping close to my house in case something were to let go. The next issue that popped up was a loud ticking noise from my passenger side valve cover. Since I had been having some driveability issues I mentioned in an earlier post, I thought maybe I was getting a sticking valve or a lifter was not fully pumping up. If either of those was the case, I wanted to get it fixed pretty quickly because they can cause some major engine damage. So I pulled the valve cover and took a close look at all of my rockers and pushrods on that side. All the pushrods were straight, none of the rockers were loose and nothing else seemed out of place. I also pulled the plugs to see if one cylinder was behaving differently than the others but they all looked the same.
The next possible thing that could cause a ticking noise is an exhaust leak. So next, I pulled the headers and found my problem:
As you can see, there was an obvious mark on the center exhaust port where the exhaust was leaking. Digging a bit deeper into this, my heads have D-port exhaust ports and my headers are oval port. Another thing I didn't quite check when I put the car back together and just assumed the previous owner picked the right parts. This makes it tough to find the right size header gasket. If you look closely in the pic, you can see the sealing area is a bit off center which doesn't help but even if it was centered there would no be much sealing area. Being in a time crunch, I didn't have time to swap headers and re-do my y-pipe, so i replaced the gasket with the same part number and did my best to center it better. So far it seems to be holding up.
While i was working on the passenger header, I checked the wires nearby and noticed that some were starting to melt from being too close to the headers. Glad I caught it in time as re-soldering the harness way down there would be a tough job. I did my best to hide as many wires as I could during the build, but sometimes functionality takes precedence over appearance. Here are the wires that were getting melted... this is looking down at the passenger header with the AC box on the left:
I would have liked to have routed the harness higher, but was only able to raise it up a bit and wrapped it in DEI heat shielding, Should be OK for now but I will keep an eye on it:
Next issue to address was a rough idle I was getting while out driving around. Sometimes the car would idle OK around ~700rpm, but other times it would be up around 1200 or 1500rpm. When it was idling high, I would try adjusting the idle speed screw but nothing was happening. Weird. Digging into it a bit deeper, I found that one of my throtlte blades was hanging up on the inner bore of the throttle body. This was preventing the blade from fully closing, essentially keeping the engine at part throttle. I loosened up the screws and let the blade self-center which helped a lot. I then reset my idle speed a bit and made sure the TPS was in spec.
So, after getting all these issues figure out I was back out to driving. Driveability seems to be improved but still needs some work. There seems to be a big hole in acceleration between 3000 and 3500 rpm and not much response down low. I think I may have maxed out my abilities with tuning using just base timing and fuel pressure and need a custom chip to get me the rest of the way. I am currently running a stock chip which I'm sure is struggling to keep up with the increased air and fuel required by my AFR heads, cam and big intake. That'll be on my list soon.
SO everything seemed to be going OK and I started making some harder pulls on some on-ramps and taking some harder corners which revealed a couple more issues. First, I had some rubbing on the driver side rear which just needed a bit more persuasion with the big hammer. My strategy to find rubbing issues has been to fix the area with either a hammer or removing some material but then the key part is making sure I paint it before going for another drive. If the tire rubs again, it will take off the paint and makes it very obvious where the issue is (and if I fixed it or not).
In the front, I did a nut and bolt check and found my wheel bearings were a tad loose so that was another thing I was glad to find. Tightened those up a bit and snug up some other bolts in the suspension as well:
Alright, so back out for another test drive. Everything in the suspension feels great, but halfway through the drive my exhaust gets SUPER loud so I pulled back home to check it out. I found that the bolts on my header collectors had backed out and some were even missing. When a bolt loosens up on a header collector, the gasket really doesn't stand a chance as the hot exhaust gases blowing by it just destroy it:
So, I didn't think much of it and popped in these aluminum ones which supposedly can stand up a bit better to heat and seal really well.
Installed, went for a drive and same thing... the gaskets blew out within 20 minutes of driving. Look at the melted aluminum!
So obviously I had a bigger problem here, I pulled off my y-pipe to take a closer look. It looks like my flanges are pretty warped... which explains why the exhaust was able to leak out despite my tightening the bolts as tight as I could:
So we are totally up to date now.. I just dropped my y-pipe off at the exhaust shop to straighten the flanges last night. Should be done today and I can hopefully get the exhaust installed and tested by tomorrow. After that, I think this is as good as the car is going to get for now. I'll see how it goes at the autocross, I might go a little easy at first and ramp up from there. If I come in last that's ok, I'm just happy to be out there!
Back out to the garage...