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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 7:34 am 
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Joined: Fri Dec 14, 2007 1:46 pm
Posts: 1606
Location: East L.A.
I have a set of LH2.4 ECU/EZK with TLAO chips sitting on the shelf if you want to try something quick and dirty. Bought and sitting on the shelf so no idea on what you're getting, might be introducing new issues but like you said it's quick to try. LMK and I'll start looking for them... :lol:

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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 7:46 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3394
Location: Calgary, Ab
What else would give you an intermittant 80 ft-lb jump in torque besides a sticky wastegate?


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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 9:59 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
Ugly Duck wrote:
What else would give you an intermittant 80 ft-lb jump in torque besides a sticky wastegate?


I know...I'm just trying to make this wastegate thing make sense. I'm in sponge-mode right now, so fire away.

Here's what I've come up with...the only difference between the pulls is ΔRPM/ΔT related. If the wastegate in the second gear pull went from closed to open quickly and was controlling the boost pressure properly while we get the same TDO4 look to the plot (it's building very quickly (looking at the torque curve) - all in by 3.5K rpm. It looks to me like we're rapidly building boost from 3 to 3.5K (pink line) then the engine is seeing a pretty steady boost past that point.

On the graph that has the blue and the pink lines, we see a similar shape to the blue curve, it's just happening more rapidly and starts sooner. It's almost the same shape, but happening 300 rpm sooner and it's going up faster (Δtorque/ΔRPM). The first sign of something wrong is around 3300 rpm (blue line). Then over the next 200 rpm, then the power goes (spark pull) and AFR's go to 9.

When we have the mechanical advantage of second gear and can spin the wheel faster (ΔRPM/ΔT) the wastegate may be opening more quickly (as we spin up the dyno) vs. when we're in a higher gear and can't move the drum that fast and perhaps if the wastegate was sticking and then building too much boost, then the MAF/LH sense knock, it then pulls timing and goes pig rich?

What I really don't understand is why the wastegate would be sticky. When I was adjusting it last week, it moved freely (even loose) and when I put pressure to the wastegate it opened every time as it should. But all the evidence points to something MECHANICAL not computer related (though, Jim...start looking please. I've got Philski looking as well).

Maybe I should ditch this 15G for a Cossy T3 over the winter? They at least have a reasonable wastegate.

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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 12:10 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
Some have suggested boost leaks - so I'll cobble together something tomorrow to test for that.

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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 2:07 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3394
Location: Calgary, Ab
It might move nicely when cold but not when red hot. I wonder how much the ceramic coat fills the gap in between the WG shaft and turbine housing? That would explain why sometimes it doesn't seem to open and why sometimes it seems to come on more slowly than it should.

I have a couple turbos that might *ahem* ruin your driveability somewhat, but would definitely bump you into the area of NEEDING those injectors of yours.


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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Sep 25, 2015 5:46 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
Just got a PM from one of the older guys on TBrix and he's had exactly the same problem. He's got the same set-up (minus the ceramic coat) and says is a knock sense issue and I'm to test pin 4 on the ICU while driving. Others have said they have the same sort of issues with these larger injectors and to go back to smaller ones. None have produced dyno sheets or real data, so I'm going to just test what's easy/possible and make sure it's not something simple. I'm not sure anyone over there has answered my "how is it possible to make 80 ft/lbs more torque (to quote Matt) and have it not be a boost problem, with satisfaction. Most just skirt the issue.

I'm still puzzled - point taken about the possibility of having the wastegate sticking because of the ceramic coat. I'm thinking right now - could be a possibility, but R&Ring the turbo is now a longish way down my list of things to try.

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 Post subject: Re: Turbo Weirdness
PostPosted: Sun Sep 27, 2015 11:02 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 7:14 pm
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Location: Missing my garage in Sunnyside
FYI I was on chipped 2.2, though it ran just as well on stock ecu, and stock 29 lb injectors. Couldn't even step up to lh2.4 32lb injectors, 2.2 wouldn't adjust enough. 205whp at the roller, 12psi on a big t4 compressor.

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 Post subject: Re: Turbo Weirdness
PostPosted: Sun Sep 27, 2015 12:30 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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Location: Calgary, Ab
Thanks for clearing that up, Athal.


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 Post subject: Re: Turbo Weirdness
PostPosted: Sun Sep 27, 2015 6:31 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
Redux time. Here's what I've done. I changed out the injectors for a set from an 850T (orange tops - 30 lbs/hr - so basically the same as the stock injector). Then I pressure tested the system from the turbo compressor outlet to the throttle body.

Image

Put around 20 psi in and I had a hiss under my cover by the end tank on the outlet side of the IC. I found a pinhole leak at the top tube. So I JB welded it inside and out. It should hold for a while.

Image

I then added a bung so I could put the old wideband O2 meter to good use.

Image

At idle/cruise it waves around a lot (it's a JAW controller and they do this from what I understand). I did manage to capture it when it was just right.

Image

Then at full boost in 3rd gear, I saw this (solid - no bouncing around).

Image

It was solid around 12.3 - 12.5 with the richest I saw being 11.8 for a moment.

We're going to continue driving and I'll check the AFR's every once in a while and see how LH is doing.

I ran the car very hard yesterday and today on the paved (and mostly deserted) section roads. Many, many pulls in 3rd and 4th gear and no more issues. It's only a few days of testing - so we're not done yet. At least I haven't had to pull the turbo for now. Oh and this cost me nothing other than time as I had all the parts.

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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Dec 04, 2015 11:19 am 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 238
Location: Regina, SK
Hi Craig,

With your last results - what boost are you running now after all the changes?

I read this last night and thought a possible cause could be spark blow out at higher boost / higher loads.

This would explain the good 2nd gear pulls, but it breaking up in taller gears higher loads.

Closing plug gaps, making sure coil os 100% coil, and good plugs (I love WR7DS (Siber)) would be my suggestion if it does it again.

Sounds like you got it cased now - but I still don't know which part would have fixed it out of that list of work you did.

Rabin


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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Dec 04, 2015 1:20 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
Well Rabin, I can say that I spent a lot of time scratching my head and even considered selling the car at one point. It's been a real trial. I'm running 15 psi at the moment and have zero run issues after first changing the injectors to a set of smaller white injectors (0280155868 - 370 cc/min not the ones that are 380 cc/min). These solved most of the boost run issues...but then all hell broke loose again and it wouldn't idle and was tossing codes and the like. Anyway, long story short, I changed the ECU for one without a chip tune (left the chip in the ICU) and it's happy as a clam. Starts first time at -20°C and has been running like a champ. I'm going to quit farting around with LH. If I wanted to go further or up the turbo size (like if no one ever buys my 20G and all my other projects are done and I'm looking for trouble) then I'll go stand-alone with MS3Pro and ditch LH all together. But then again, this is my WINTER car and it's filling that need perfectly right now.

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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Dec 04, 2015 2:24 pm 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 238
Location: Regina, SK
Flakey ECU does explain alot - but what is still baffling was how you could pull strong in 2nd gear no problem, but fall on it's face in 3/4? Makes no sense that the ECU would know, or even care what gear you were in.

I'm happy the car is running real nice now though, and it does sound like the modded ECU was partly at fault - but just the issues it showed on the dyno still make me wonder how...

Totally agree with the stand alone direction - I went with VEMS personally. Much like MS3 actually.
Rabin


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 Post subject: Re: Turbo Weirdness
PostPosted: Fri Dec 04, 2015 7:48 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
It was a compounded problem...they're the worst to diagnose. So the injectors were too large for LH to trim at higher loads (the green giants - 440 cc/min can't recall the PN) in general. Sometimes this extra fuel would overload the system (first noticed by Dale when we were racing an autocross event - he noted that I was rolling coal accelerating out of a corner). The ECU sometimes picked this rich condition up as knock and pulled a bunch of timing and that was quite random and hard to figure out. Then I had the wastegate not set up properly, so this was causing turbo weirdness that was presenting as boost creep and had me minutes away from taking that 15G off and porting the heck out of the wastegate and using a larger puck. So all this coupled with a random ECU issue (that stopped being random - thank goodness or I'd have never worked it out).

When the ECU told me that the TPS, CTS and MAF were done and that the idle was rich (in essence, four new sensors- all known good) then it was time to pin out the harness and verify the function of these sensors. The day I was set up to do that (it's been very busy at work and I've got very limited time, and I needed this car to get to work) it was cold and crappy out but my "new" ECU had arrived. So instead of going through the 30 step procedure to test sensors that I had either recently changed (like the coolant temp sensor and throttle position sensor and MAF) then I just plugged the "new" ECU in and took it for a drive. Damn if it didn't work perfectly. I checked for codes, nothing. Took it out and beat on it - worked fine.

So that's how having 3 things wrong at the same time can make you almost wish you had K-Jet.

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 Post subject: Re: Turbo Weirdness
PostPosted: Sat Dec 05, 2015 8:59 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3394
Location: Calgary, Ab
You could try putting bigger injectors in there again, I'm betting the ECU was the problem with trim and not LH itself.


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 Post subject: Re: Turbo Weirdness
PostPosted: Sat Dec 05, 2015 9:48 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3017
Location: Lethbridge, AB
Ugly Duck wrote:
You could try putting bigger injectors in there again, I'm betting the ECU was the problem with trim and not LH itself.


What I've learned is that you would also have to put in the 3" MAF from the 960 to get it to scale correctly. I would also call into question most generic chip tunes. I'm not really sold on the idea based on what I can gather. There is still a lot going on in that black box (not by modern standards...but) that we don't understand. It's no where near as flexible as a modern standalone. Also, no evidence of need with this current set up. So unless I give it more air, there really is no need.

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