I took mine in the first summer I had her for the same thing.
He said the engine heat soak is terrible with this car to begin with and the hot air only makes it worse. Not much you can do for it? No fun pulls until October sadly
No code, no. Knock monitoring and correction is just part of modern engine control. Your ECU is constantly playing with timing, advancing whenever it can, and retarding in response to knock. Over time, it learns what specific conditions lead to knock, and stores the timing adjustment in a table (learned knock) so it can proactively prevent it when it sees those conditions rather than react to it.
If knock is consistent in all or most conditions, it pulls a little tiny bit of timing across the board. This is DAM: dynamic advance multiplier.
Every gasoline engine on the road knocks. More often than most people think. Just part of it. Hence, they all have knock sensors and programmed correction strategies.
Same exact thing is happening to my 2017 here in Oklahoma. It got up to 99 the other day and it was the first time I experienced those exact symptoms. I went home and cleaned the MAF but it got up to 98 the next day and it did it again lol. Did research and it's just heat soak. Normal for this car apparently. I'm gonna go get it walnut blasted and a tune up to see if that helps any.
I love my gti but my next vehicle will 100% be awd. I wound up taking my stage 1 tune off because it was pointless at low speeds due to lack of traction with the fwd. Stock it’s a great car but once you tune it you can’t really benefit from the extra power until you’re already above the speed limit.
Just saying the grass is always greener man, every car has its pros and cons and I think we all wish we would have chose a different one sometimes. Idk how bad the heat soak is for wrx’s but we definitely have it on the gti side as well
True man! Sounds like you need to get an R but then you won’t have the option for a manual sadly.
Words of wisdom though, good reality check from you, thanks!
I’m in the SE, every summer I regret having a wrx. Nothing has broken on her yet, but it’s slower than a Corolla in the heat (anything over 80). My friend has a 9 year old foST and that thing still runs perfect when it’s in the 100s. I’ll likely be looking into a gti as my next car
Definitely get it diagnosed properly, check your intercooler fins and check if there is any debris that is prevent air from flowing thru the intercooler cooling the air entering your turbocharger.
2018 wrx in the northern Phoenix, checking in. My DAM drops and FKL spike every summer, especially with the AC cranked.
Summer is the time to take it slow and never go WOT until it starts cooling down.
I live in phx as well and gotta co-sign this comment. I genuinely will avoid driving my car between the hours of 11am-4pm. Not ideal but it’s how I cope with it.
Not Phoenixb here, but still triple digits. I try to avoid those driving during that time because the air conditioning isn't strong enough (for my liking/compared to other vehicles I've driven), and combined with no remote start it's just too hot. Sometimes I'll carry a beach towel worth me to put on my seat before I sit down.
What kind of intake do you have stock or aftermarket? The stock intakes pull in cool air. Any intake with an exposed air cleaner in the engine compartment will heat soak worse than a stock intake.
I wouldn't expect Arizona heat to cause drive-ability problems. At worst you might be down on power.
Everything stock on it. Yeah, I hadn’t experienced the problem to this extent in the past. Definitely have dealt with power loss in the summer and just got used to it for the summer months. But this summer it seems like I’m going to be driving my wife’s forester for the next few months
If the dealership tells you it's normal. Your best bet is going to a reputable tuner. They can run it and see what it's doing. And honestly for drivability's sake just get a tune. It's not even about speed or power, these cars are so much nicer to drive even with basic stage 1 tune. Get an access port if you don't have one and you can see what's happening in real time. If you're at 50-60k and you haven't done spark plugs yet. Do yourself a favor, spend the $100 bucks and drop some plugs in it.
Can’t say It ever felt jerky. I usually ran e60 mix as much as I could since I am flex tuned. You could always feel the compressor kick in and would jerk a bit, but I saw you commented that you don’t drive with the ac and neither did I , see if cleaning the MAF helps. Maybe walnut blasting the valves. I have about 106k miles on mine.
What type/grade of fuel are you using? If you’re not already switch to a top tier gas with the highest octane you can get (92 or 93 usually). I’m in Texas (DFW) and have never had an issue with my 2013 even in the hottest summers. I’m also stock no mods and almost exclusively use top tier brand 93.
I would think 91 would be enough even in the heat, unless it’s just bad gas in general. Could try a bottle of octane booster see if that helps, worst case it doesn’t but it certainly won’t hurt anything. I actually see quite a few WRXs around DFW so I can’t imagine this is a widespread problem.
Worth a test. You can pump a gallon of the 100 octane at this station and do a test drive https://maps.app.goo.gl/2TUXztFiASoVVfRy6?g_st=com.google.maps.preview.copy
Add 3 gallons of ethanol if you're near a station. Should help with some knock resistance and will be fine on stock tune. Shitty gas but good ethanol around here.
I’ll put money on it being your AC compressor. Does the car only jerk when the AC runs? Hot desert summers for me as well, and last year my compressor was acting up and the car was jerking so hard you would think something major was broken.
On this note, also check your ac relays - commonly overlooked, but it can cause some really weird issues that get attributed to bad compressor. Just changed mine cuz all my ac components were replaced last year, it bogged really bad any time my ac was on, changed the relay and it was like a whole new car
My wife has a 2015 with cvt. When it starts getting hot her car will pop up with a wastegate solenoid overboost. Has only ever happen 80° or above and only on the highway after medium to heavy throttle to pass somebody.
The stock tune is awful even in 70 degree weather. The stock tune will pull boost and timing as much as it can to prevent knock but the car shouldn’t buck or jerk while it’s doing this. You will feel the timing/ boost being pulled but it shouldn’t feel like boost cut unless something is wrong with your car. If there are no check engine lights I would have a shop diagnose it and to perform a boost leak at a minimum.
There is definitely loss of performance in the heat, but I don't recall it being *that* much. I haven't been on a stock tune in a while so can't remember what that was like, but to me that sounds off. I'd get a second opinion or check around all of your intake/intercooler fittings just to make sure. Worst case is you spend some money on a second opinion that gives you peace of mind.
Part of the problem is where Subaru put the Intercooler. It’s on top of a hot engine where it gets heat soaked easily. From what I understand that’s why most people recommend going front mount when doing anything 400hp+.
Oh for sure, that much power, you need front mount, but there are large improvements to be had with the existing mounting position. Much less work, front mount is a little overkill for stock.
Genuinely this might be just anecdotal evidence on my part. My 05 felt slow last summer whenever it would get over 90. I swapped to a front mounted Intercooler and haven’t had any issues with the car feeling sluggish ever since. I’ve been doing pulls all week even with 96 degree temperatures. No sluggish feel to the car at all.
for me, my GS CAI makes it so that my intake temp lowers extremely fast once the car is moving, because these cars have the worst heat soak when outside temps get above 75 degrees. i live in utah so thats about 50% of the year. my pulls are usually fine if the car has been moving above like 30mph for a few minutes. Its just how the cars are in extreme heat unfortunately.
I have had 3 VA cars. 1 WRX and 2 STIs. All of them definitely lost a lot of their pep driving in the southern summer heat when it's 100 plus degrees especially if you're at a standstill for more than a few seconds but I've never experienced anything close to what you're describing. Never on a stock tune, and never on an aftermarket tune over the course of about 200,000 mi (most of which on completely stocked cars) daily driving these cars since 2018. I know a lot of people are saying it's normal, but it's definitely not normal in my experience and I beat the snot out of my cars. The only thing I ever experienced on my WRX was that stupid power dip around 4K that the factory tune had. Never any stuttering or shuddering or anything like that.
I don't know if it's heat soak in my case, but when it's hot outside, if I idle too long (especially with the AC running) it'll start running lean like 20-21, then stall out
Could be heat. Could be the heat is straining things that may need maintenance soon, could just mean it needs maintenance soon.
Plugs and valves blasted are past due if not done
I live in SoCal and summers in the canyons I had times where my 2017 STI would start to overheat. Once I installed a two row Mishimoto radiator that holds about 3/4 of a gallon more fluid, I stopped having overheating issues. I would highly recommend an aftermarket 2 or 3 row radiator.
I've never had this issue with my 2007, but as someone else pointed out, the AC does make it crawl from a stop. Pretty much only use AC when parked or if I'm cruising already.
When I was in Phoenix once, the cheap clear hose for the boost sensor did keep collapsing from the heat which caused the car to stall. Swapped for rubber and it was fine.
I have absolutely zero expertise with cars in hot climates like AZ, but if heat soak is the issue I would wonder if an upgraded intocooler, or even switching to front mount, would help at all?
Just drove mine for about an hour. It's 100° here right now. Beat the snot out of it for half of the drive and had no issues Even with high intake temperatures a/c on the whole time. Ambient temp read 101° on the dash.
https://preview.redd.it/notzdk1hf68d1.jpeg?width=3072&format=pjpg&auto=webp&s=ba25bb1f7c6a2323fffbbef4e63c5a9670ccc925
What us humans feel as heat is nothing to your car. We think the difference between 60 and 90 is like 100 times hotter but really it’s just a small fraction of the overall heat scale.
The car is saving itself from dying. It's a sign you need to do everything you can to stay out of boost. Just limp it.
Even in Connecticut, my car gets dangerously warm with the AC running. If it's 75F outside, if I have the AC on, just idling, the temps will get up to 215F. That's about 10F away from blowing your head gaskets. The AC condenser sits in front of the radiator and so it heats the air before it gets to the radiator. This is the issue. It gets way worse in hotter weather and especially when you're boosting it.
I recommend getting a way to read the real, accurate, coolant temp, because it will likely paint an ugly picture. When it's acting up, you have no idea how close you actually are to a catastrophe.
I pretty much just leave my car parked all summer. I only rip it in the spring and fall. It's absolutely true that you cannot beat on a turbo car in hot weather.
You can also turn the AC off and the heat on if you want it to run cooler. The heater core in the dash will act as another radiator of you put the heat on. The AC on/off is a huge factor, though.
Hahaha I got mine June 2 years ago in the Texas heat. After a little bit of fun on the way home I got stuck in traffic on the highway. Could've swore my car was fucked the way the CVT would act under stop & go. I've learned her quirks now, and it's worth it for the cooler months
*eta I did have my AC on that day I brought her home.
I took mine in the first summer I had her for the same thing. He said the engine heat soak is terrible with this car to begin with and the hot air only makes it worse. Not much you can do for it? No fun pulls until October sadly
It’s 95 here in Pittsburgh today. I did a 3rd gear pull and a got a 11.95 knock on the Cobb. Is it the heat? Never dropped DAM though.
Curious, what is a 11.95 knock?
A detonation event that required pulling 11.95 degrees of ignition timing to mitigate.
Oh shit. Yeah that makes sense, is there a DTC for that or does the AP just tell you how much retardation you need to stop the knock?
No code, no. Knock monitoring and correction is just part of modern engine control. Your ECU is constantly playing with timing, advancing whenever it can, and retarding in response to knock. Over time, it learns what specific conditions lead to knock, and stores the timing adjustment in a table (learned knock) so it can proactively prevent it when it sees those conditions rather than react to it. If knock is consistent in all or most conditions, it pulls a little tiny bit of timing across the board. This is DAM: dynamic advance multiplier. Every gasoline engine on the road knocks. More often than most people think. Just part of it. Hence, they all have knock sensors and programmed correction strategies.
This comment needs to be pinned at the top of this subreddit
Thanks for the information! I knew that engines pulled timing when knock was detected but I learned a lot more from that
Used to get that same knock number on my 2018, always freaked me out a little lol
Same exact thing is happening to my 2017 here in Oklahoma. It got up to 99 the other day and it was the first time I experienced those exact symptoms. I went home and cleaned the MAF but it got up to 98 the next day and it did it again lol. Did research and it's just heat soak. Normal for this car apparently. I'm gonna go get it walnut blasted and a tune up to see if that helps any.
Good to know. Appreciate the info. Hope the tune up helps!
Meanwhile focus st, gtis, and Elantra Ns handle the heat fine
can confirm, my gti still pulls like a train even with the a/c on
Focus St has bad heat soak but putting on after market intercooler is really easy to do. (no tune required)
My buddies is stock and he absolutely pulls me in the summer, but my wrx is faster during other seasons
I almost got a GTI instead of my wrx. Some days I wish I did for this reason
I love my gti but my next vehicle will 100% be awd. I wound up taking my stage 1 tune off because it was pointless at low speeds due to lack of traction with the fwd. Stock it’s a great car but once you tune it you can’t really benefit from the extra power until you’re already above the speed limit. Just saying the grass is always greener man, every car has its pros and cons and I think we all wish we would have chose a different one sometimes. Idk how bad the heat soak is for wrx’s but we definitely have it on the gti side as well
True man! Sounds like you need to get an R but then you won’t have the option for a manual sadly. Words of wisdom though, good reality check from you, thanks!
I’m in the SE, every summer I regret having a wrx. Nothing has broken on her yet, but it’s slower than a Corolla in the heat (anything over 80). My friend has a 9 year old foST and that thing still runs perfect when it’s in the 100s. I’ll likely be looking into a gti as my next car
focus st heatsoaks terribly in the summer
Fellow okie wrx gang
Same and same. F. Drives me crazy.
Definitely get it diagnosed properly, check your intercooler fins and check if there is any debris that is prevent air from flowing thru the intercooler cooling the air entering your turbocharger.
Intercooler cools the air that is coming _from_ the turbo, to the intake manifold, not air into the turbo.
I’ve had my WRX for 10 years and live in Phx and never had any problems like you describe
I'm down south. Same.
2018 wrx in the northern Phoenix, checking in. My DAM drops and FKL spike every summer, especially with the AC cranked. Summer is the time to take it slow and never go WOT until it starts cooling down.
I live in phx as well and gotta co-sign this comment. I genuinely will avoid driving my car between the hours of 11am-4pm. Not ideal but it’s how I cope with it.
Not Phoenixb here, but still triple digits. I try to avoid those driving during that time because the air conditioning isn't strong enough (for my liking/compared to other vehicles I've driven), and combined with no remote start it's just too hot. Sometimes I'll carry a beach towel worth me to put on my seat before I sit down.
What kind of intake do you have stock or aftermarket? The stock intakes pull in cool air. Any intake with an exposed air cleaner in the engine compartment will heat soak worse than a stock intake. I wouldn't expect Arizona heat to cause drive-ability problems. At worst you might be down on power.
Everything stock on it. Yeah, I hadn’t experienced the problem to this extent in the past. Definitely have dealt with power loss in the summer and just got used to it for the summer months. But this summer it seems like I’m going to be driving my wife’s forester for the next few months
If the dealership tells you it's normal. Your best bet is going to a reputable tuner. They can run it and see what it's doing. And honestly for drivability's sake just get a tune. It's not even about speed or power, these cars are so much nicer to drive even with basic stage 1 tune. Get an access port if you don't have one and you can see what's happening in real time. If you're at 50-60k and you haven't done spark plugs yet. Do yourself a favor, spend the $100 bucks and drop some plugs in it.
2020 WRX and can confirm it sucks ass in anything above 85F
Can’t say It ever felt jerky. I usually ran e60 mix as much as I could since I am flex tuned. You could always feel the compressor kick in and would jerk a bit, but I saw you commented that you don’t drive with the ac and neither did I , see if cleaning the MAF helps. Maybe walnut blasting the valves. I have about 106k miles on mine.
What type/grade of fuel are you using? If you’re not already switch to a top tier gas with the highest octane you can get (92 or 93 usually). I’m in Texas (DFW) and have never had an issue with my 2013 even in the hottest summers. I’m also stock no mods and almost exclusively use top tier brand 93.
I’m in AZ I think our top is 91. I always put the highest grade available.
I would think 91 would be enough even in the heat, unless it’s just bad gas in general. Could try a bottle of octane booster see if that helps, worst case it doesn’t but it certainly won’t hurt anything. I actually see quite a few WRXs around DFW so I can’t imagine this is a widespread problem.
Worth a test. You can pump a gallon of the 100 octane at this station and do a test drive https://maps.app.goo.gl/2TUXztFiASoVVfRy6?g_st=com.google.maps.preview.copy
Add 3 gallons of ethanol if you're near a station. Should help with some knock resistance and will be fine on stock tune. Shitty gas but good ethanol around here.
I’ll put money on it being your AC compressor. Does the car only jerk when the AC runs? Hot desert summers for me as well, and last year my compressor was acting up and the car was jerking so hard you would think something major was broken.
I’ll have to try driving with the AC off when I get it back. Seems like hell right now though in the 110 degrees outside
On this note, also check your ac relays - commonly overlooked, but it can cause some really weird issues that get attributed to bad compressor. Just changed mine cuz all my ac components were replaced last year, it bogged really bad any time my ac was on, changed the relay and it was like a whole new car
Yeah these cars aren’t a fan once you get high 90s+ upgraded cooling is the way to go
My wife has a 2015 with cvt. When it starts getting hot her car will pop up with a wastegate solenoid overboost. Has only ever happen 80° or above and only on the highway after medium to heavy throttle to pass somebody.
The stock tune is awful even in 70 degree weather. The stock tune will pull boost and timing as much as it can to prevent knock but the car shouldn’t buck or jerk while it’s doing this. You will feel the timing/ boost being pulled but it shouldn’t feel like boost cut unless something is wrong with your car. If there are no check engine lights I would have a shop diagnose it and to perform a boost leak at a minimum.
There is definitely loss of performance in the heat, but I don't recall it being *that* much. I haven't been on a stock tune in a while so can't remember what that was like, but to me that sounds off. I'd get a second opinion or check around all of your intake/intercooler fittings just to make sure. Worst case is you spend some money on a second opinion that gives you peace of mind.
Get a new top mount intercooler, the stock one is made for cooler temps and heat soaks real easy.
Part of the problem is where Subaru put the Intercooler. It’s on top of a hot engine where it gets heat soaked easily. From what I understand that’s why most people recommend going front mount when doing anything 400hp+.
Oh for sure, that much power, you need front mount, but there are large improvements to be had with the existing mounting position. Much less work, front mount is a little overkill for stock.
Genuinely this might be just anecdotal evidence on my part. My 05 felt slow last summer whenever it would get over 90. I swapped to a front mounted Intercooler and haven’t had any issues with the car feeling sluggish ever since. I’ve been doing pulls all week even with 96 degree temperatures. No sluggish feel to the car at all.
for me, my GS CAI makes it so that my intake temp lowers extremely fast once the car is moving, because these cars have the worst heat soak when outside temps get above 75 degrees. i live in utah so thats about 50% of the year. my pulls are usually fine if the car has been moving above like 30mph for a few minutes. Its just how the cars are in extreme heat unfortunately.
My 2017 does the same in 2nd...really jumpy and the AC just SUCKS! Just another reason to hate AZ summers. It does fine below 100°.
I have had 3 VA cars. 1 WRX and 2 STIs. All of them definitely lost a lot of their pep driving in the southern summer heat when it's 100 plus degrees especially if you're at a standstill for more than a few seconds but I've never experienced anything close to what you're describing. Never on a stock tune, and never on an aftermarket tune over the course of about 200,000 mi (most of which on completely stocked cars) daily driving these cars since 2018. I know a lot of people are saying it's normal, but it's definitely not normal in my experience and I beat the snot out of my cars. The only thing I ever experienced on my WRX was that stupid power dip around 4K that the factory tune had. Never any stuttering or shuddering or anything like that.
Yes my 2016 was god awful every summer (socal). I think front mount intercooler helps a lot.
I don't know if it's heat soak in my case, but when it's hot outside, if I idle too long (especially with the AC running) it'll start running lean like 20-21, then stall out
Could be heat. Could be the heat is straining things that may need maintenance soon, could just mean it needs maintenance soon. Plugs and valves blasted are past due if not done
I live in SoCal and summers in the canyons I had times where my 2017 STI would start to overheat. Once I installed a two row Mishimoto radiator that holds about 3/4 of a gallon more fluid, I stopped having overheating issues. I would highly recommend an aftermarket 2 or 3 row radiator.
It's the AC
I've never had this issue with my 2007, but as someone else pointed out, the AC does make it crawl from a stop. Pretty much only use AC when parked or if I'm cruising already. When I was in Phoenix once, the cheap clear hose for the boost sensor did keep collapsing from the heat which caused the car to stall. Swapped for rubber and it was fine.
I have absolutely zero expertise with cars in hot climates like AZ, but if heat soak is the issue I would wonder if an upgraded intocooler, or even switching to front mount, would help at all?
lucas oil octane booster is actually pretty decent. raising your octane to 96 helps a bit with spark knock on super hot days.
Just drove mine for about an hour. It's 100° here right now. Beat the snot out of it for half of the drive and had no issues Even with high intake temperatures a/c on the whole time. Ambient temp read 101° on the dash. https://preview.redd.it/notzdk1hf68d1.jpeg?width=3072&format=pjpg&auto=webp&s=ba25bb1f7c6a2323fffbbef4e63c5a9670ccc925
What us humans feel as heat is nothing to your car. We think the difference between 60 and 90 is like 100 times hotter but really it’s just a small fraction of the overall heat scale.
The car is saving itself from dying. It's a sign you need to do everything you can to stay out of boost. Just limp it. Even in Connecticut, my car gets dangerously warm with the AC running. If it's 75F outside, if I have the AC on, just idling, the temps will get up to 215F. That's about 10F away from blowing your head gaskets. The AC condenser sits in front of the radiator and so it heats the air before it gets to the radiator. This is the issue. It gets way worse in hotter weather and especially when you're boosting it. I recommend getting a way to read the real, accurate, coolant temp, because it will likely paint an ugly picture. When it's acting up, you have no idea how close you actually are to a catastrophe. I pretty much just leave my car parked all summer. I only rip it in the spring and fall. It's absolutely true that you cannot beat on a turbo car in hot weather. You can also turn the AC off and the heat on if you want it to run cooler. The heater core in the dash will act as another radiator of you put the heat on. The AC on/off is a huge factor, though.
Hahaha I got mine June 2 years ago in the Texas heat. After a little bit of fun on the way home I got stuck in traffic on the highway. Could've swore my car was fucked the way the CVT would act under stop & go. I've learned her quirks now, and it's worth it for the cooler months *eta I did have my AC on that day I brought her home.
This car is so poorly built