Nick's 1991 200q Project - QUAT44RO

[EDIGREG]

Lookin good. You want the lightest spring possible in the BOV that will still keep it closed at idle. It should easily open by blipping the throttle in neutral

[amd is the best]

Lookin good. You want the lightest spring possible in the BOV that will still keep it closed at idle. It should easily open by blipping the throttle in neutral

http://www.tialmedia.com/documents/BOVspc.png

Ed, how do I convert 38kpa to In/hg? I don't have a normal boost/vac gauge.

[amd is the best]

Never-mind, I think I found it.

40kpa = 18.12 in/hg. -> http://www.engineeringtoolbox.com/vacuu ... d_460.html

Which would mean I have the correct spring, assuming my valve came with the default "plain" spring. I'll open it up to be sure it didn't somehow get a pink one.

Thank you by the way


EDIT! I think I found the problem...My vacuum line is certainly smaller than the recommended 1/4" line. My line is like 3mm ID which is almost half of what is advised.

[EDIGREG]

I don't think that's the problem - I have always used a standard 3mm vac line with the tial BOVs.

I idle at 45-48 kPa which is ~13-15 in hg.

[amd is the best]

I don't think that's the problem - I have always used a standard 3mm vac line with the tial BOVs.

I idle at 45-48 kPa which is ~13-15 in hg.

What color spring do you have?

Mine is right around 38 at idle, so I've got a bit more vacuum it seems. The same vac line also goes to my N75... I'll make sure there are no leaks too.

[chaloux]

NO LEAKS

[EDIGREG]

Well, that could be part of the problem - I've always ran a dedicated line direct from the manifold to the bov (stock 3mm nipple on the AAN manifold). I have a white and a black spring, I forget which one is in there now.

Does the BOV open when the throttle closes after a blip in neutral?

[amd is the best]

Well, that could be part of the problem - I've always ran a dedicated line direct from the manifold to the bov (stock 3mm nipple on the AAN manifold). I have a white and a black spring, I forget which one is in there now.

Does the BOV open when the throttle closes after a blip in neutral?

It does not.

[EDIGREG]

I would give it a dedicated vac line, if it still isn't opening try a diff spring. I can look for the spare I have in the garage tomorrow

[amd is the best]

It's the same line I've been running to the DV valve I've had on there since the turbo was put on, split with the N75 as well. I'll play around with it and see what I come up with.

Thanks Dude.

[WOMBAT]

It takes boost over 7ish psi for my tial to go. Otherwise I get a fun rattlesnakeish sound (mild turbo stall. Haven't worried about it

[loxxrider]

Yep, that kind of flutter is nothing to worry about. That is very likely not affecting compressor speed much at all... just pressure which doesn't matter in the grans scheme of things.

[amd is the best]

Got everything 99% installed today and finally got a chance to test the system out. This isn't a perfect comparison as getting identical weather, boost and other uncontrollable variables even but I still think the results are pretty clear and in favor of the new system. That being said, I took logs the other day on the previous setup and compared them to todays logs.

Stock log info: 31°C ambient temp and 265kpa boost
AWIC log info: 28°C ambient temp and 250kpa boost

The following runs were 2nd gear to the top of 4th gear over 13 seconds time.



The dips are between shifts.

15°C/59°F difference at the end of the run! Not bad!

I still have a few things I plan on doing involving heat shielding, turbo blanket and adding Motul Mocool coolant additive to the system (right now 75% water 25% coolant).

Good read: http://www.autospeed.com/cms/article.html?&A=107760

[Mcstiff]

Nice!

I'm interested to see how stable to temps are over a longer period (road course, road trip).

[amd is the best]

Nice!

I'm interested to see how stable to temps are over a longer period (road course, road trip).

Further testing will happen for sure. I'll be sure let everyone know my findings.

[WOMBAT]

That's enough to deter me from going bigger on my current IC

[loxxrider]

Nice, water is pretty much the best cooling agent around (high specific heat capacity) so these types of systems work well

[Clem86]

Very interesting

[chaloux]

Nice Nick. Definitely an improvement there.

[WOMBAT]

blows my mind how big of a difference was made with such a small system. I wonder how my FMIC compares, time for a log!

[Mcstiff]

I'd love to see someone disprove the theory that AWICs are only good until the coolant heat soaks at which point they take longer to recover efficacy.

I had a cool idea for AWICing in my CQ for a stealthy turbo setup but now I'm past that.

[loxxrider]

I'd love to see the theory that AWICs are only good until the coolant heat soaks at which point they take longer to recover efficacy.

That should never happen if the heat exchanger (not the intercooler part) is sized properly for the application.

One thing I was thinking about today was having an air to air AND and air to water IC. I haven't thought about it much, but I'm pretty sure you'd want to put the air to air first, then have the air to water after that since the air to water should have a much greater ability to extract heat from the air than the air-to-air (therefore it would be most effective as the second intercooler in the loop). It'd be kinda cool because then you could choose to use it or not... if you just want your air to air, just go! If you want to super cool it for a few quick runs on a really hot day, put some ice in your tank and ride out (no radiator-type heat exchanger needed).

Anyway, good work Nick.

[EDIGREG]

Regarding the BOV discussion above: Yes, it will "work" with a stiffer spring, but for the fastest response, the valve should just barely stay closed under idle conditions. Ideally it's also as close to the throttle plate as possible.

The flutter is not going to hurt the turbo...hell, you can run a closed system and not damage it (although likely shorten it's lifespan), which is actually quite awesome if you've never experienced it

AudiSport never ran BOV/bypass valves on their race cars, which is part of the reason for the turbo sounds we all love so much...but of course they had no problem replacing KKK turbos every race if necessary. Even with the compressor stalling, boost response was still far better than if the system is vented.

[amd is the best]

So, just to update here; prior to the intercooler install the 200 had obtained a misfire. Normal steps were taken to try and resolve the issue including new plugs (NGK 4554) and proper gaping. Didn't resolve much. That's what led me to purchase a set of new plug wires as mine were stock and tired. New wires didn't help anything. The misfire was only noticeable at maybe 16-17psi or more. Anything less is completely fine.

With tips from Marc, I picked up a spark tester from the parts store and started testing. He said that good working LS2 coils should fire across the tester set at 40 (40k volts maybe?). Mine wouldn't even spark once set at 40. Close it down to 25 and it would hit maybe 3 out of 5. At 20 it was almost perfect. There was slight variation between the 5 coils however it seems like all of them are weak, or something else is wrong. I verified a solid ground and a good source of 12v to the coil harness. I even moved the 12v right to the alternator post. Same results.

I went through Marc's harness connections and found a slight amount of corrosion. Cleaned that, no difference.

Marc is pretty convinced that the coils are at fault. A new set is on their way to me and I hoping this takes care of it. Kind of odd that they'd all go bad at once however, sometimes when the car misfires I start to slowly increase dwell a bit. Maybe I went too high and damaged them...not sure. I've never gone over 4ms dwell and LS2 coils can run up to 8ms from what I read, but who knows.

That being said, the Nology plug wires I bought are NO gimmick. I will provide a video of the difference. It's RIDICULOUS how much stronger the spark is in comparison to the old wires I was using.

Side note, recently a 200 20v Avant went up for sale and I am possibly interested in it just to make sure it ends up in a good owners hands. What do you guys think? Should I buy it? The price is hard to pass up but I really don't need a 4th car.

[mushasho]

Yes, Buy It!