My car doesn't like warm weather

Once your intercooler gets above 120F it starts to retard the timing, which kills the top end power. It won't boost nearly as high, which is why you are seeing the power loss in your turbo spool range. Nothing to worry about. This can be remedied by adding a thermostated I/C sprayer, but they can be costly. When I am at an autox, I just use a spray bottle with water to keep the temps down.

You can also try different I/C splitters, but your hood scoop should be large enough. At least you don't have an earlier model hoodscoop. They are tiny.

 

I think you might be a little confused here; as far as I know the intake temp is what matters (not post-intercooler or turbo; the temp sensor is part of the MAF). If you're seeing 122 or higher intake temps unless it's 100+ outside, you have a pretty serious problem.

Also, while it DOES retard the timing at that point I don't know that it affects boost in any way...

 

Temperature of the I/C directly affects the density of compressed air that can go into your engine. If its hot, you won't reach target density. Its also very easy for the air inside of your intake to get pretty hot since its sitting right over you engine. All of the piping will be completely heat soaked. Not to mention the recirc valve can recirc. hot air. If your I/C is at 120F it also means that the intake air is about that hot as well. I was just confused where the sensor is, but not about the timing being retarded at those temps or the power loss from higher temps.

I think about it in terms of your tires. The density of air changes when it gets colder out, thats why your tires look underinflated. You can put more air into your tires at colder temps than at hotter (higher density). The more dense the air going into your engine, the more power you can achieve, because there are more gas molecules at that pressure and lower temperature. Its Charles Law of thermodynamics.

 

The heat of the air itself certainly does affect the boost levels attainable, but the ECU has little to do with that portion.

Your IC being at 120 degrees or more has zip, nil, nothing to do with your measured intake air temp. You might be pumping 200 degree air through the IC into the motor, and as long as the intake temp sensor sees below 122 (I think it is, stock) it won't retard timing.

My point is that if his car has troubles at moderate temps like he claims, the ECU pulling timing due to intake air temps is NOT the reason. The air temp after the intercooler is not being measured anywhere so is entirely irrelevant in that aspect.

 

scott can you chime in on this?

 

I agree with the temperature of 55F being too low for the timing to be retarded. That in his case, its probably not pulling timing for being too hot. Now on a 90F Atlanta day, it will pull timing after a certain amount of usage, because everything is so hot.

If the car is pumping insanely hot air around like "200F", it means that the density of the air going into the engine will be lower. If the air density is lower, this should mean the car will run rich. The ECU has a way of detecting a rich engine. So a car does have an indirect way of measuring the temperature of the air after ther turbo and compensating.

 

Actually, the MAF takes care of it: it measures the mass of the air, so denser air = more mass = more fuel, and vice versa. A rich running engine would just cause tweaks to the short and long term fuel trims via closed loop feedback.

FWIW, with the stock intake tract I never see more than ~10-15 degrees above ambient, so unless it hits well over 100 I won't see any retardation of timing due to intake air temps.

 

Doesn't fuel trim affect power? Why do people care about heat soaking your intercooler? I am just saying the temp. difference from the intake to intercooler does matter.

 

Fuel trim is the ECU's way of hitting its targets. If the table says 14.7:1 is the a/f target and it's reading 13:1, it'll lean the mixture out to meet the target. The a/f ratio itself definitely does affect the power, but the fuel trims are actually there to ensure that the ECU gets to where you say it should be.

And to address the original post: If you're running a stock ECU, I suspect you're just seeing the effects of the delayed switch to open loop fueling. Considering the ECU tries to go from 14.7:1 to something like 10:1 in an instant, you will experience some rather bumpy power at that point. It might just be more noticeable when it's warmer out for some reason.

 

if this helps, scott when he was tunign ym car said " timing looks really good for a topmount"
so yeah

 

Better IC = cooler air into engine = capable of taking more timing. Nothing new there.

But the discussion was about the ECU pulling timing based on measured intake temps, which is a different issue.

 

My comment wasn't about intake temps, but hot intercoolers sucking power. ECU reading I/C performance from the EGT sensor.

 

The EGT sensor isn't really indicative of intercooler performance.

 

If the EGT is reading rich or lean, and its because the I/C is too hot then I would think it is.

 

I re-iterate, the IC performance won't cause the engine to run rich or lean. The MAF sensor measures the mass of the air going into the engine and that's all that is required for a successful fueling calculation.

 

Mkay, would you at least agree that a hot I/C would make a cars performance suck?:sx:

 

Yep, and would probably cause timing to get pulled because of detonation if it was bad enough.

 

Well that is what I was trying to get at, but I mixed up the 120F MAF number with just a hot I/C. My fault :hsugh: .

 

Well, to relate this whole discussion back to the OP: unless he's running a tune with very very aggressive timing it shouldn't get pulled because of IC heat in the first place.

 

Well, let's start with listing the mods you have done so far.

 

Then my bet would still be the open loop delay. It's easily fixed if you can find somebody with a tactrix cable (just a couple parameters in a table). If you think there's more to it, it should be under warranty still.

 

A cable that lets you program the ECU using free software. Nice alternative unless you want to fork out $500+ for engine management.

 

Yep.

 

Well, take this into account...

You're not running your engine on open source code. The OpenECU tools just manipulate the maps (data tables) and don't much with the actual code itself. Lots and lots of people use them, and any bugs would've been ironed out fairly well by now.

Like with Ecutek, you do flash when you change things. Though, you only flash the block of the ECU that has been modified. The Enginuity team is doing beta testing on 'real time' maps much like the Cobb ones however, so a free solution to that may not be far off; do note however that at this point you ARE changing the ECU code a bit (adding hooks to look at RT maps when available).

Killing your car? One of two ways: really screw up a map, or have a laptop/cable issue when flashing. You can easily kill your ECU with the AccessPort if you have a battery or connection problem while doing the flash. For what it's worth, I've flashed my car over a dozen times with zero issues using EcuFlash.

And finally: OpenECU tools aren't a software replacement for a skilled tuner. When you're paying $850 or whatnot to get Scott to Ecutek tune your car, you're paying for the license as well as for his knowledge. In order to take full advantage of the tools, you need to ensure you have a solid foundation/education so that you know what you're doing tuning wise. That said, you can use one of the 'stage' maps out of the box, like you would with an AccessPort; and like with an AP OTS map you will have a moderately safe less-than-optimal tune.

 

I think Subaru did release a flash to address some issues, but have no idea on when it was nor how effective it was...

If it was me, I'd borrow a cable and load an OpenECU stage 1 map, but that's just because it's in my comfort zone. I don't have a problem with people paying Cobb or Ecutek to use a more established tuning setup; it's just not my thing and I'm too cheap/poor.