Turbo/Boost Problem

[peruccy]

Hello!

First, let me introduce myself. My name is Dejan and I come from the EU, Slovenia to be precise. I have been visiting this great forum for some time, but haven't had a chance to register and post something useful, until now.

The thing is, I have a problem with my car, err more specific, with my turbo. Since I don't own a DSM, I know this might not be the best place to ask, but I do have a similar turbo to the stock DSM one - TD05H-12B.

I did an engine swap about 6 months ago on my alfa romeo 145. I took out the stock 1.8 and put in a v6 turbo unit, from an alfa 164. The engine in the 164 was completely rebuilt, prior to the swap. But since the swap, I've had low boost issues. I have really tried everything I could think of, to no avail. I'm running out of ideas guys.

What I've done so far:
Firstly I bought a new boost gauge (I've already tried two gauges with no luck). Then I swapped the stock bosch dump valve, with an adjustable one (bosch unit had a broken membrane). After that, I found that my wastegate actuator rod acted strangely (it was moving way too much). So I purchased a forge unit for a sierra cosworth (mainly because parts for an old alfa, are impossible to get in my country). Recently I bought a big 16G wheel and compressor housing and a full rebuild kit. So basically the turbo should be spot on. I also replaced all the vac/boost lines with brand new ones. I have fitted an MBC (left the stock electronic valve plugged in, but blocked off the lines). I did an intercooler leak test with a compressor and it held 2.5bar (37psi) of boost for 15min without any leakage. I also replaced the throttle body, triple checked all the sensors with the workshop manual and everything is in the tolerances...

My problem is like this... At idle, I get normal vacuum readings, but as I accelerate, the gauge jumps from cca -0,7 to -0,2 and then slowly goes above 0, to about 0,5bar (~7psi). And I mean slowly - boost is rising so slow, you might think, something was blocking the flow. I could record the gauge, if that would be of any help. I do hear the turbo whistling/spooling. There is also no noises coming from the engine, that would suggest exhaust leak/boost leak (checked both about 5 times now). When I rebuilt the turbo, I did however notice a crack in the wastegate (but after some research, almost every TD05 has a crack there).

So my question is... what else could I check? Could the WG crack be at fault? Is there a small leak, that I've missed? Turbo now, with new bearings has virtually no shaft play whatsoever. Almost everything is brand new, what else could it be?

BTW, here's my car, so you wouldn't think I'm making stuff up:

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Thank you in advance for any info. It is much appreciated!

Edit: I almost forgot... Stock boost for this engine should be 0,9bar (~13psi). Also, if I rev the engine at idle, I don't hear the turbo whistling/spooling and the boost gauge goes up to 0 (no DV noise either). I only hear the turbo when I'm driving, if that helps...

'talla

 

[TSi Kid]

@TSi Kid: Any suggestion, how to check if all my exhaust gases spin the turbine wheel? I've fixed all my exhaust leaks, is there another test I could perform?

The turbo is all mechanical. Takes exhaust, spools the turbine blah blah blah. So if you're having lag then either you're not getting enough exhaust or your leaking too much of it out. An easy way to tell if you have an exhaust leak is (when the motor is cold) take soapy waterr and spray around the exhaust manifold and then start the car. See if there's any bubbling (air escaping) and then put your hand back there and see if you feel any air as well.

Also, this being a shot in the dark, but I've had a cat go back and was causing so much back pressure that I couldn't build boost. I've also had actuators go back so I would check both as well.

Disconnect your downpipe from your o2 housing and see if that makes an difference.

 

[JusMX141]

@jusmx141: I found one on ebay. This one is ok, right?
Adapter Fitting M12x1.5mm to 4AN w/ 1.5mm Restrictor on eBay (end time 24-Jan-11 18:19:43 GMT)

That is for a ball-bearing Garrett and will not fit your turbo.

Try item # 250518630566.

 

[peruccy]

The turbo is all mechanical. Takes exhaust, spools the turbine blah blah blah. So if you're having lag then either you're not getting enough exhaust or your leaking too much of it out. An easy way to tell if you have an exhaust leak is (when the motor is cold) take soapy waterr and spray around the exhaust manifold and then start the car. See if there's any bubbling (air escaping) and then put your hand back there and see if you feel any air as well.

I've done that already. I had a leak between the turbine housing and downpipe. Took it to a guy who machine straightened it for me. Put a new gasket on and and I couldn't find any leaks afterward. Before the machine work on both my turbine housing and downpipe elbow, I could clearly see exhaust gases escaping, but now there is nothing visible or audible...

Also, this being a shot in the dark, but I've had a cat go back and was causing so much back pressure that I couldn't build boost. I've also had actuators go back so I would check both as well.

Disconnect your downpipe from your o2 housing and see if that makes an difference.

I'm running a straight through free flowing exhaust system - no cat, only a mid silenced box (because I didn't want a very loud car) - don't mind the gauges, I was doing some testing back then

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Wastegate actuator is almost new as well (pretty much, most of the engine parts are). My old WGA was nearly gone (rod movement in all directions), so I replaced it with a bigger/better one. It's membrane is so strong, it's nearly impossible to move the rod in/out by hand (I could only move it out, when I had it on a bench)...

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And I had to move my O2 sensor (it's also nearly brand new), because of tight space. It sits now between my mid box and flex pipe...

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I really tried everything I could think of. Just can't seem to find my problem. And since my gauge goes up very slowly (when I let go of my throttle it jumps to vacuum immediately, only positive pressure is slowly risen), I cannot tell what boost I'm actually running, nor how much lag I've got. Because I'm using stock dashboard dials and my rev counter is for a 4 cylinder - so I disconnected my rev counter, because it doesn't read correctly and it's pointless...

That is for a ball-bearing Garrett and will not fit your turbo.

Try item # 250518630566.

Thank you!

 

[peruccy]

So as the new title says, I've only got my gauge problem to fix. I literally went through hundreds of threads, but I could not find a single video with a similar problem. That is why, I uploaded my own video of my boost gauge, if that will help on solving my problem.

As mentioned before, I've done a boost leak test, vacuum leak test, replaced my boost gauge (but it turns out, that wasn't my problem) and for this video, I ran my gauge from under the hood through an opened window (so to mark off my original gauge line as being the culprit), but I still get a slowly risen boost gauge needle. Please check the video and tell me what you guys think. Thank you!
<a href="http://videos.streetfire.net/video/slow-rising-boost-gauge-needle_2188329.htm"><img src="http://px5.sfstatic.com/thumbs/0002/38/92/2188329.jpg"/><br>Slow rising boost gauge needle</a>

'talla

 

[christian6932]

wow good info...

 

[ramsack]

Have you tried testing your boost gauge with a source of positive pressure that has nothing to do with a car? An air compressor will show you if the gauge just responds slow. How does the needle generally respond slowly going towards positive pressure rather than moving towards negative pressure (does it bounce up to 0 instantly while revving or is it slow then?)

 

[peruccy]

No, I haven't tested the gauge off the car. I could try that tomorrow. But could it be possible, both gauges (old & new) were bad? What are the chances of that? I used this gauge in the video, on my previous turbo car and the needle was instant on positive pressure (like it should be). I'll test both tomorrow and report...

At idle, if I rev it, it jumps yes. To about -0,2 vacuum (but never 0). It's slow only when I'm driving. I've never seen anything like it, I must admit...

OK, so I've tested my old gauge off the car. I used an air gun, but I wasn't sure how much air to blow in the gauge line, that's why it's not jumping to max. Anyways, compare this video
<object width='428' height='352' classid='clsid27CDB6E-AE6D-11cf-96B8-444553540000' id='SFID016554228495806456'><param name='movie' value='http://www.streetfire.net/flash/SPlayer.swf' type='application/x-shockwave-flash' /><param name='allowScriptAccess' value='always' /><param name='wmode' value='transparent' /><param name='allowfullscreen' value='true' /><param name='FlashVars' value='&video=bef60ef8-6271-45a1-84ec-9e6a007f6e66&servicecfg=386'/><embed src='http://www.streetfire.net/flash/SPlayer.swf' flashvars='video=bef60ef8-6271-45a1-84ec-9e6a007f6e66&servicecfg=386' allowfullscreen='true' wmode='transparent' width='428' height='352' allowscriptaccess='always' type='application/x-shockwave-flash' pluginspage='http://www.macromedia.com/go/getflashplayer' /></object><br/><a href='http://www.streetfire.net/video/boost-gauge-test_2188783.htm?ref=b3e6a7ae-18c4-4472-b5b2-9e69006968d0'>Boost Gauge Test</a>

With the in car video
<object width='428' height='352' classid='clsid27CDB6E-AE6D-11cf-96B8-444553540000' id='SFID016554228495806456'><param name='movie' value='http://www.streetfire.net/flash/SPlayer.swf' type='application/x-shockwave-flash' /><param name='allowScriptAccess' value='always' /><param name='wmode' value='transparent' /><param name='allowfullscreen' value='true' /><param name='FlashVars' value='&video=81561f09-73ad-41cd-a903-9e69006d2c57&servicecfg=386'/><embed src='http://www.streetfire.net/flash/SPlayer.swf' flashvars='video=81561f09-73ad-41cd-a903-9e69006d2c57&servicecfg=386' allowfullscreen='true' wmode='transparent' width='428' height='352' allowscriptaccess='always' type='application/x-shockwave-flash' pluginspage='http://www.macromedia.com/go/getflashplayer' /></object><br/><a href='http://www.streetfire.net/video/slow-rising-boost-gauge-needle_2188329.htm?ref=b3e6a7ae-18c4-4472-b5b2-9e69006968d0'>Slow rising boost gauge needle</a>

I mean... what gives? Clearly there's a problem, but I can't seem to find it. Any ideas fellas? Because it's driving me crazy...

 

[ramsack]

The gauge is fine. The turbo is just spooling really slow. How much force is there from the wastegate actuator to keep the wastegate from blowing open? I have mine adjusted so that to install the actuator on the turbo it has to first go on the flapper arm, and then I have to put a lot of might into pulling against the tension to get the actuator on the compressor housing. I hope that makes sense.

 

[peruccy]

The gauge is fine. The turbo is just spooling really slow. How much force is there from the wastegate actuator to keep the wastegate from blowing open? I have mine adjusted so that to install the actuator on the turbo it has to first go on the flapper arm, and then I have to put a lot of might into pulling against the tension to get the actuator on the compressor housing. I hope that makes sense.

Is that even possible? This turbo spooling slowly? This is a 6cyl after all and it's not like I've got a T67 turbo on it, to have so much "lag"...

Yes it does. I have a similar setup. I have it set approximately one and a half WGA rod hole away from the flapper. Erm... how to explain it best... My flapper "bunk" (or whatever the correct term for it is), is about one and a half rod holes away, when not joined together. So I had to pull quite hard as well, to get the WGA rod on the flapper. But judging by the strength of this WGA membrane, I think it should do it's job pretty well, especially with my low-ish boost.

The only other thing I could think of, for causing this problem, is my electronic boost control solenoid. Even though I use an MBC with EBCS lines blocked off, I still have it electronically connected. Otherwise my ECU's (yes, this thing has two ecu's) don't allow more than 6psi of boost. I've measured it a few months ago and it had 30Ohm (like it says in the manual). But recently I've measured it and it only has ~27Ohm impedance. Could it be, that my EBCS is faulty (because of low impedance) and so my ecu's get a wrong signal? Even though my boost is not controlled by the ecu's anymore, can this affect performance in any way?

Apart from that, I'm lost on what to do next...

 

[ramsack]

How many cylinders spool this turbo, 3 or all 6?

 

[peruccy]

How many cylinders spool this turbo, 3 or all 6?

All 6. Here is the stock exhaust system for this engine, found in the workshop manual

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Mind you, I've got a free flowing exhaust on mine. Starting from the turbo

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... why do you ask?

 

[ramsack]

I could've understood slow spool if only 3 cylinders spooled the turbo. I really don't know what else to tell you to look for at this point. You eliminated all boost leaks, you have no exhaust leaks from what I've read. It certainly isn't too small of a turbo to feed that engine.

 

[peruccy]

I am grateful for all the help, don't think I'm not. I know this problem is quite peculiar, so I understand. It's driving me crazy, because it should be a straightforward fix, but it just isn't...

Like today, I took my IC off, to see if it was clogged or anything similar. It was of course fine. As were the intake pipes.

And since I still can't figure it out, I'll repeat some tests this weekend. I've made a short list:
- Redo the boost leak test
- Redo the vacuum leak test
- Check the intake manifold for leaks
- Check if the throttle body is sealing
- Check all the clamps
- Look for an exhaust leak
- Check if exhaust manifolds are sealing
- Replace all the silicone vac/boost lines with clear rubber ones
- Connect the stock electronic boost control solenoid, instead of an MBC

... and if that won't fix it, I'll take the turbo apart and replace my turbine shaft/wheel. Turbine wheel and turbine housing, are the only old parts left in the turbo. Then I'll basically have a brand new turbo, which SHOULD produce instant boost on the gauge. But if for some reason, that still won't fix my problem, then I'll take out the engine and do a complete and thorough check all around.

There must be some kind of a fault somewhere... I just need to find it!

 

[peruccy]

Hello!

I can finally say, that my problem is fixed. I've been tinkering with the car again, doing tests and whatnot. When I almost gave up hope, I've found and fixed my problem, which I would have never though would be the culprit. It seem my boost gauge problem was my mid silenced box from the golf gti. I replaced it with a straight pipe and boy what a difference! Yes, my car is a bit louder now and yes, I still get a little boost gauge needle "lag" until 3psi, but man does she pull after that! I'm seeing 1,5bar on the gauge (22psi) and butt clenching performance. Although, I have to admit, I might be pushing a bit too much with 1,5bar of pressure. I have decided to decrease boost to 1,2bar (~18psi) tomorrow, which I think will still be sufficient in performance.

Thank you all for your help and I hope, my thread will help someone with a similar problem in the future.

'talla

 

[ramsack]

Interesting. What is this mid silenced box?

 

[peruccy]

Interesting. What is this mid silenced box?

It's this standard middle muffler from a golf gti.

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The reason I used it, was because it is very small and silenced. I didn't want my car to be very loud. But as it turns out, it isn't that much louder now, with a straight pipe, so...

I guess it was restricting exhaust flow in such a way, that my boost gauge went mental. Or who knows what the reason was. It's finally ok now

 

[ramsack]

Yea, turbos love to spool with no mufflers or any restriction after them.