TMIC Install, Boost Leak

[Kevin M]

Originally Posted by sp00ln

Check your intake! I think that could be it.


Also, no point in resetting the ECU or needing a "re-tune". Unless I'm mistaken, evey ECU is in constant adjustment. More over, the TMIC isn't a drastic change.

Dude, seriously... you do not understand Subaru engine tuning whatsoever, and you have proven this over and over again on this forum. Please refrain from discussing EJ series engines and tuning until you do the research and learn how they work. I'm not trying to suggest that you're not smart enough to understand them, or that what you know about the 4G63 isn't highly useful, but what works for DSMs and Evos DOES NOT work for turbo Subarus, period. We've gone down this road before and I don't want to start arguing again, but when you post up in a novice engine tuner's thread with blatantly incorrect advice, I can't not say something. Please note that Ed gets paid to tune Subarus... and everything he says directly and absolutely contradicts you. Please consider that if you can't even be in the same ballpark with a professional tuner on your advice and comments, you should keep them to yourself.

[WRXRallyBlue]

Pulled a log this morning. Can I post it on this thread somehow?

[Kevin M]

If it won't let you post it directly using the attachment feature, just zip it first.

[WRXRallyBlue]

3rd Gear Pull

[EQ Tuning]

I took a look at your log. After the initial spike, your boost levels are on the low side. I also see signs of knock around 5k RPM, but this is a fairly common problem area on 91 octane. I'm assuming this is a Cobb map? I deffinately don't see anything that would exhibit itself as power surging. Could you try to describe in more detail under what conditions and exactly what you're feeling? Maybe you can log those conditions as well.

Thanks
-- Ed

[WRXRallyBlue]

Originally Posted by EQ Tuning

After the initial spike, your boost levels are on the low side.

Could this be attributed to our altitude or something else?

Originally Posted by EQ Tuning

I'm assuming this is a Cobb map?

Yes, it is.

Originally Posted by EQ Tuning

Could you try to describe in more detail under what conditions and exactly what you're feeling?

Not sure how to get more detailed. The car is slower than it was before the install in every condition. There was a bigger kick from the onset of boost before the install. There are also harsh hesitations at wot that pull power even more. This particular logged pull didn't feel too bad, though. I'll see if I can get it to misbehave and log it again.

[WRXRallyBlue]

I drove it around for a bit and it decided to run fairly smooth. Go figure. I'm still skeptical of a boost leak.

Anyway, I forgot to mention pertinent mods:
cobb ots stg 2
tbe
up
intake
turbo inlet
tmic with hoses
crank pulley

[EQ Tuning]

It sounds like doing a couple pulls gave the ECU a chance to learn in some knock correction and smooth out the power band. This generally means you should really consider a custom tune. Based on your logs, I would also deffinately recommend checking for boost leaks. Maybe try re-installing the stock TMIC and see if everything goes back to normal.

Thanks
-- Ed

[WRXRallyBlue]

Thank you, Ed. I asked a member from another forum to look at it and here was his response:

not a bad pull

i see you're at altitude by virtue of your 12psi atmos. pressure.

your mafv is decent for the lowish boost you're running.

thing is as you probably know you can't net the same gauge boost pressure
(mrp) as we can down here at sea level... when you see 12psi mrp that's like
seeing ~15psi at sea level in terms of how hard you're pushing the turbo.
so in the midrange 35-4000 you're running an equivalent to 19-20psi. you're
not going to get much more out of that turbo in the midrange, not without
adding a helper spring (and thereby fubar-ing your boost control map).

up to redline you're holding an equivalent 12.5psi, which isn't bad. it
looks like the ots map starts tapering boost (the wgcd drops) as yo
uapproach, which is good for turbo longevity, and is fairly standard
practise.

as far as timing, your KC seems high. of course, not having access to the
background tables I can't tell you how close to max they are, but they all
seem good, which means no knock. otoh, they aren't very aggressive
either... that's ONE thing you guys at altitude can get away with--more
advance. that's because the rarer air corresponds to a less-dense charge in
the chamber, and that means a slower flame front. the ecu to my knowledge
does not skew advance wrt ambient pressure, so you get the same ots map
everyone else gets. advance ramps up quickly towards redline but that is
also where wgdc cuts back an dyour boost is dropping quickly, so that's
expected and safe (total VE is dropping and again, charge density in chamber
is low, flame propigation is slow, you need to light it off sooner). I
would say as a first estimate you could bump timing 4 degrees in the
midrange which would give you an assload of torque.. maybe 30 ftlbs. know
anyone with street tuner?

as another benefit to being up high, you've got plenty of injector left
over... no need to worry about running out of fuel.

[WRXRallyBlue]

He mentions the high kc which corresponds to what you're saying, Ed.

So I guess back to my original question? Would anyone care to look at my install for any boost leaks/abnormalities?

[cody]

What about the old spray-starter-fluid-on-the-vacuum-lines trick? I know it's a common way to search for vacuum leaks on N/A cars. You just spray it all over the vacuum lines and if the idle gets higher, you've sucked some of the starter fluid into a vacuum leak.

[EQ Tuning]

That response is on the ball for the most part. The only parts I don't agree with are his comments on boost. Running the same relative boost at elevation as you do at sea level will not necessarily work the turbo harder. You have to remember that this pressure is relative to atmospheric pressure. So at the same relative pressure, you're still running less absolute pressure than you would be at sea level, so you're not actually working the turbo any harder. You would be pushing less air at that relative pressure, but again that's just because you're running less absolute pressure, not because the turbo is less efficient.

We've shown this to be true empirically on Cody's car as it kept flowing more air and making significantly more torque right up to 17.5psi of relative pressure even at elevation without creating excess heat. You also don't need a helper spring to run these boost levels. The limiting factor here is not the wastegate actuator spring, but rather the stock boost control solenoid and restrictor pill. Using a 3-port solenoid, MBC, or even a smaller restrictor pill will easily allow you to run whatever boost you like without adding any helper springs.

My main question here is what boost were you hitting with the stock TMIC? If your boost levels are now significantly lower, I would deffinately look for a leak or start questioning the efficiency of the bigger TMIC.

I'm also concerned that the car seems to be making less power and had a rough power band upon ECU reset. To me this says that the ECU encountered some problem spots and had to pull timing in places where it didn't have to with the stock TMIC. Again, this could point to a leak or just a poorly designed IC.

Thanks
-- Ed

[WRXRallyBlue]

Originally Posted by cody

What about the old spray-starter-fluid-on-the-vacuum-lines trick? I know it's a common way to search for vacuum leaks on N/A cars. You just spray it all over the vacuum lines and if the idle gets higher, you've sucked some of the starter fluid into a vacuum leak.

Interesting. I'll try that.

My main question here is what boost were you hitting with the stock TMIC?

According to my ap it's hitting the same peak pressure and holding the same boost as with the stock tmic. I never had a chance to datalog before the install so I wouldn't know with regard to ecu explorer.

this could point to a poorly designed IC.

It is a TurboXS knockoff and many others have had success with it, especially after tuning, though maybe I got a bad apple..

What it seems is going on is that yes, the ecu is having to adjust quite a bit to cope with it but there is probably a boost leak going on. I can't get past the fact that my turbo got so much louder under boost when no one else's did.

The other people I refer to are here:
http://forums.nasioc.com/forums/show...9&page=1&pp=25
If you're interested in reading it skip to within 7 or so pages of the end.

[EQ Tuning]

The turbo deffinately shouldn't get much louder when swapping IC's. I would deffinately suspect a leak somewhere. Maybe the actual core is damaged?

[WRXRallyBlue]

I hope not

[cody]

Update?

[WRXRallyBlue]

I haven't had the time to mess with it much. I planned on loading the cali 91 map to decrease my chances of any knock but I couldn't find my ap power cable to load the map on my ap.

[cody]

If you need to borrow my cable let me know.

[Kevin M]

You should have been on the cali map already, since you're burning cali gas.

[WRXRallyBlue]

Thanks, Cody.

[A1337STI]

I would think it would be a pain in the ass, but have you considered putting your stock IC back on with your new IC hoses (if the new IC hoses fit the stock IC) to see if you still have boot leak ? (if you did , then you could probably rule out the IC itself, and if you didn't , then maybe its the IC itself)
?

[WRXRallyBlue]

I may need to do that. How disappointing

[A1337STI]

Any luck discovering the cause?

[WRXRallyBlue]

Thanks for checking in. I have been remarkably busy lately obtaining a job and just got one this week, fortunately, so I've been putting around until I can get things sorted out.

What I need to do:

1. Load cali base map
2. Get silicone gasket sealer to resolve possible leaks
or
Reinstall stock tmic until everything is sorted out and I have an opportunity to tune

[WRXRallyBlue]

UPDATE


I decided to do an experiment. Yesterday I picked up some Lucas octane booster (remarkably, I've had great success in the past with this product) from pep boys and poured it in the tank and filled up. Reset the ecu and drove around normally for 25 miles or so.

That night when the air was cool I found an open stretch of road and floored it 1st through 3rd and was immediately impressed. It pulled just like it was supposed to. A couple minor hesitations that are hard to feel unless you're really paying attention, which will hopefully clean up after loading the cali 91 base map.

This leads me to believe that with the stock tmic I was getting by on the standard stg 2 91 map but the aftermarket tmic just pushed the tune over the edge. So if I'm correct then the less aggressive cali 91 map should hold me over until I get tuned.

Right now I'm just trying to borrow Cody's AP power cable and we're looking into getting Ed down here sometime soon to protune.



-Rob