Ok, I got my coolant temp sensor working. Just played with the wires a bit and it started working. Took the car to an exhaust shop and had them extend the downpipe to meet up with the gutted cat. It's a little loose so it's still ticking a bit under throttle since I didn't have a gasket and they didn't have one to sell me.. gonna fix that this weekend.

I also tackled the wastegate line situation. Got all the melted crappy vac line off, used some 1/4" fuel injection hose rated to 400 degrees to replace it so this shit won't melt.

I'm holding boost fine and it's very powerful all the way to redline.. vast improvement from stock form. However, I can NOT get past 4psi. I am using a Hallman Pro HBC and an XS Power 38mm wastegate. I think the spring is 6psi, but it may be 4..

Any ideas? I want to feel 8psi! I accidentally felt 15psi the other night when the WG line melted and it was amazing.

You probably have a large boost leak.

Yeah, I think that's it. On the way to work this morning I realized I'm only pulling 5 in/Hg of vacuum at idle and hitting 4psi at WOT. When I get off tonight I'll trace all my lines and see where a leak could be coming from. I got a vacuum manifold kit from 42 Draft Designs, who sell lots of parts for Volkswagen & Audi applications, and it came with some cheap plastic-type vac hose which I used wherever I could. The one I put on the wastegate melted, I may have one melted elsewhere.

Another thing I wanted to ask about is the boost gauge & BOV. I have the boost gauge tee'ed into the BOV line since the vac manifold didn't have enough ports for everything. Is this a bad idea, could it be affecting the BOV's ability to respond promptly or the gauge's accuracy? The HKS SSQV isn't making it's common whistling sound, just more of a fluttering sound.

You should be seeing around 14-16in/Hg of vacuum at idle, IIRC. I think you've identified the problem. :)

Ok, got home yesterday and took a look. I used that crappy cheap plastic-like vac line on the BOV too, and failed to realize it was going right over the EGR tube. So it was melted. I did the trick where you put the cardboard over the compressor inlet, and the car didn't die, it just kept idling like normal.

So last night I replaced that vac line, still has the boost gauge tee'ed into it but the gauge seems to be reading just fine. The car is blowing off more promptly now, but the vac line didn't fit just right on the BOV, it's loosely on there and if it wasn't wedged against the frame I think it would probably fall off. I didn't have any small clamps so I'm gonna get some tonight and tighten up all these connections.

I'm reading 11 in/Hg of vac at idle, and when I get on the throttle and let off I'm reading 18 in/Hg. As soon as I take it out of gear and come to a stop it's back at 11. I'm hitting 3psi of boost now. Ugh FML. I want boost.

There's one other thing I think may be an issue. We had to clock the turbo compressor and center section to work for my setup; when we got the oil drain back on we had to rotate the center section where the drain was a bit more "forward" (but still pointing down) so the oil return line wouldn't kink and would be a straight shot to the pan. We had taken one of the bolts from the compressor all the way out so we could rotate it freely and not hit the return flange. Went to tighten it back up, and we couldn't get this bolt on cause the hole was right there facing the flange. So we left it off. I assumed it would be ok since there are like 5 or 7 more bolts but could this be the problem? Is boost escaping from the compressor this way?

Oh, another unrelated thing-- I had to remove the passenger-side radiator fan to fit the downpipe, which is common. But when I run it at WOT the temp will jump to 3/4 of the way to max, and slowly back down back to just under 1/2 on the temp gauge after I let it idle for a minute or just drive it easy. I'm a little concerned that this heat cycling may warp the head or have some other negative effect. Is this normal or is it ok?

Originally posted by Mike431635
Oh, another unrelated thing-- I had to remove the passenger-side radiator fan to fit the downpipe, which is common. But when I run it at WOT the temp will jump to 3/4 of the way to max, and slowly back down back to just under 1/2 on the temp gauge after I let it idle for a minute or just drive it easy. I'm a little concerned that this heat cycling may warp the head or have some other negative effect. Is this normal or is it ok?

No, it shouldn't do that. I would either modify the downpipe to keep the fan, or install a slimline replacement that will fit.

Not sure what model you got, but here is a nice fan...

http://www.machv.com/flexslimfanc.html

I still have a DEI turbo heat shield I haven't put on, and I have some extra wrap I can use to insulate the water line that runs directly over the manifold. I'm going to tackle that first and see if it helps. The downpipe is already wrapped, and so is the wastegate dump tube.

I've seen some very well respected people putting out a LOT more power than I am run push-type fans on the front of their radiators, between the IC and rad, as well. I might get a 10" slim fan and try that out on the passenger's side too, along with some Redline water wetter.

But I'm still curious about the boost issue.. why can't I hit higher pressures? I seriously doubt a single BOV line is limiting me. Is the missing bolt on the compressor housing the culprit?

Originally posted by Mike431635
I'm reading 11 in/Hg of vac at idle, and when I get on the throttle and let off I'm reading 18 in/Hg. As soon as I take it out of gear and come to a stop it's back at 11.

I strongly dislike these numbers. You don't have a crazy cam or anything in there correct? Just a stocker?

Too low. Should be arouind 18 at idle. Boost leak test? Vac leak test? Comp test? I ask about all these because they are all "leak" points.

MB

Had a compression test a while back, everything was good. Over 215 on all cylinders. I got some clamps today and clamped down all the connections on the line from my vac manifold to the BOV, including all three connections to the tee which feeds the boost gauge.

I'm now reading 18ish in/Hg at idle, 22 when I let off the throttle, and I was able to crank the boost up to 6psi. I didn't go any higher than that, yet. When I put a piece of cardboard over the compressor, the idle gets very low but the engine doesn't die. So I'm guessing I still have a leak somewhere. Got the pieces to build a boost leak tester, gonna assemble it tomorrow, get the downpipe and exhaust finally bolted up together with the gasket on Saturday, and then do the leak test.

It's scary fast, though. Loving it.

Your on the right path, keep us posted

Regarding the temp issue... I started having that problem the beginning of last summer. Changed out the thermostat, no change, but my fluid was a little brownish. Flushed the system, and within a week it was browish again, still climbed at WOT. Wound up flowin the radiator and it was plugged to high hell. Changed it out with an automatic's and it runs great now. Tore the tanks off the old one and it was 1/4-1/3 restricted - don't know how it made it that long on 15 psi at the time. Now I have a similar issue, but it's because my exhaust gasket leaks right onto my tstat housing under boost.... if it ain't one thing it's another!

Wow, I think you may have the issue pegged then. When I got my t-belt and water pump done, we ended up with really murky coolant. All the dark crap settled to the bottom after sitting for a while. I thought it was soot and I was having hesitation issues (which ended up being a clogged cat/exhaust) so I thought it was the head gasket. Did the compression test multiple times and everything was good. Now that you mention it, I think I may be having the same problem. But in a 99 with 60k original miles on it? Seems strange.. but it's not hard to find a radiator, they're not super expensive.

Originally posted by Mike431635
Had a compression test a while back, everything was good. Over 215 on all cylinders.......I'm now reading 18ish in/Hg at idle, 22 when I let off the throttle, and

Yup, liking those numbers.

The damn thing hit over 4/5 of the way to max today on the way home from work. Had to keep turning the heat on full blast to keep it from overheating. I'm convinced it's the radiator now..

What are my options? I'm gonna start looking at stock type radiators but not opposed to a fluidyne or koyo or something like that for the right price

Originally posted by Mike431635
The damn thing hit over 4/5 of the way to max today on the way home from work. Had to keep turning the heat on full blast to keep it from overheating. I'm convinced it's the radiator now.. What are my options? I'm gonna start looking at stock type radiators but not opposed to a fluidyne or koyo or something like that for the right price

You need to add another fan to your setup as well man. Get a pusher.

That's what I was thinking. Temps stayed at about 1/2 almost all the way to work this morning, but I did a WOT pull to keep some retarded soccer mom and an infinity FX891624781578 or whatever the humongous gas-guzzling one is called and hit almost 3/4 again.

I'm thinking about getting a CX Racing DSM radiator from Ebay, I've read great reviews on them and they're all aluminum. I guess I'd have to run custom water lines to it, though. The inlet & outlet are in different places. Hopefully that would work for me.

Also want to put a 12-14" pusher on the passenger side.

stock radiator works fine - no fitment issues and the core's thicker, whole thing is probably cheaper. Only downside is it's plastic end tanks, if that matters. Adding another fan will help, but you shouldn't need it, kinda covering up the problem. If you were boosting like 20/25 psi maybe you'd be putting out enough heat you'd need the extra flow, but otherwise I think a normal 2nd fan only kicks on when the a/c is on. For a while I unplugged my compressor and just kept the fan on low and it would run the 2nd fan until I got the new radiator in.