RomRaider

One of the main problems i hear with ECUTEK is that if you vary from a set package that has taken a while in R&D to perfect, it is a nightmare to control the boost. The costs involved in dyno time make the whole exercise not worth it, compared to buying a standalone ECU.

Is this a problem with the Subaru ECU or is it software related? Could the solenoid be the problem?

Thanks

It's not so much a Subaru problem as much as tuning boost is just a very time consuming process. It's not terribly difficult, though. Basically, you'll set your boost targets how you want them. You'll then need to adjust the wastegate duty to hit those targets. You may find it's taking too long to hit peak boost (WG duty is too low), or that you're seeing spiking (too high).

Now, some people have differing opinions, but to me, you really only need to comprehensively tune at 100% throttle, and then make sure you're not seeing any spiking at lower throttle positions and just smooth things out. You could spend forever tuning to get peak power at different throttle positions, but when I'm driving and want more power, I just give it more throttle.

Boost is certainly the hardest part of the car to tune correctly. I don't think there's anything wrong with it per se, but it's not like timing, where you set a value and the car 'just does it.' It requires modifying several maps, which all together, for a closed loop system.

I think many people have the perception they can just set boost targets and the car will just hit them. That's not the case, nor is it with standalones I've seen. Each system has it's advantages/disadvantages, however, once you get used to the ECU, it's not that bad.

Mike

How do you get the ECU to ramp up the WDC faster? It seems to take the ECU forever to do that.

Is there a way to keep the wastegate shut for anything under 8 to 10psi?

slightly different question here but still boost related. I think i have got the theory of tuning the target and then the wastegate duty (duties in my case) to reach that target and not overshoot.


I was wondering what is a good way of telling where it would be safe to add boost. Would i be correct in assuming that if the knock correction is high at a point (7-10 degrees) it would be safe to add some boost in that region.

The best thing to do is make a lot of logs and be patient. Log RPM, throttle position, MAF and boost. Increase your boost wherever you want, and compare logs before and after. If you see a corresponding increase in the MAF voltage, add more and try it again.

qoncept, could you elaborate on the underlying logic on your instructions?

Adding boost doesn't necessarily give you anymore power, even if you aren't experiencing any knock at that load site. Like Jared said, you can monitor your MAF voltage or g/s and this will tell you if you are seeing more airflow. Of course, this can change with colder temps and other atmospheric conditions, so you want to log with consistent conditions.

First thing I would do is to make sure you hitting your target boost, or close to it. Make sure you are not spiking as well. Once you have that ironed out, then I would start in the WOT column and log what Jared said plus ignition timing, knock correction and engine load. Also, check on your ignition advance multiplier before and after each run. When you start upping your boost, you may also have to raise your wastegate duty cycles to hit the new target boost. Check your ignition maps verses your logs and see if you are hitting approximately the correct timing at your new boost levels (ignition base + ignition correction = ignition timing). There are other factors, so it is not exact. If your IAM starts dropping, then it means the ECU is experiencing enough detonation to drop your ignition correction max across the board.

here is my log with a pretty graph from a 1st - 2nd - 3rd gear pull.

Car was accelerating brilliantly and IAM sat on 16 which is a first for me since ive dropped a few degrees timing in a couple of places.

But its just not quite hitting the boost targets im looking for, it hits them and then trails down. But i dont really know what to do with the wastegate duty cycles as the logs dont seem to make sense. During this pull the secondary wastegate was set at 0% duty and im pretty sure thats not correct, has anyone else had this sort of thing happen?

also i have heard that there may be a need to strengthen the wastegate to make it hold boost, is this an adjustment or does it need to be replaced with a different type?

Hmm, not sure what secondary wastegate duty is, other than if we are talking about a twin-turbo setup. What is your car and mods?

sorry .. shoulda said that.

Its a 2001 Liberty B4 2.0 Litre Twin Turbo.

Its run as a 2 stage setup primary wastegate is a normal turbo with a internal wastegate (its a very small turbo but). secondary wastegate is actually a valve in the exhaust that blocks of or opens flow to the second turbo which has no real wastegate, boost is controlled with a combination of these two "wastegates" but whenever the secondary reduces the primary must increase otherwise the primary turbo will overspool, which makes for some weird looking graphs when this happens as it seems to try and make the majority of its boost with the secondary once in high rpms.

Twin-turbo makes it a lot more complicated. Us yanks don't get the pleasure of twin-turbo Subaru anything, so we don't have a lot of experience in tuning that kind of setup. 0% WDC on our single turbo cars means that there is the least amount of force being applied to the wastegate, so it is basically open. Perhaps, on your setup, 0% on the secondary "wastegate" means the same thing - that no to little force is being put on the secondary valve in the exhaust, meaning that, maybe the maximum amount exhaust flow in going to the second turbo. This would make sense as to make maximum boost once the smaller turbo reaches its peak efficiency, you would want to divert the exhaust to the second turbo which can then help you attain maximum boost. So, seeing the 0% secondary numbers would make sense. Not sure how it controls peak boost, though, as if the assumption is correct then you should see higher than 0% near peak boost to avoid spiking.

in these logs that would make sense, in other logs i have had both WG duties rising to ~60% and then dropping when i came of the throttle so im confused. But anyway .. ill keep playing, the 5 degree temps im getting in the morning is making it hard to do anything wrong with the tune it just runs amazingly well.