Noname 08 OBXT Rebuild Thread

That's some big trailer for that car.

 

Glad you made the trip without any issues.

Uhaul is pretty bad with their trailers. They were like "you're aware you have a limited loading capacity of 1500lbs?" And I was like well that's 700lbs more than subaru says.

 

Averaged 13.15mpg across the whole trip (nearly 2k miles). Once I made it out of Wyoming we were doing 70mph unless it was up a hill. Then maybe 60mph on the worst ones. Above 70 and the trailer wanted to sway. Also had two bikes on the roof so not sure how much that impacted mpg. Probably not much by comparison.

 

Coolant temp I would guess didn't go above say 220? It did climb some going up parleys in utah. That was the limiting factor so I slowed down until the gauge stopped climbing. It stressed me out some. But otherwise temps were fine. I tried to stay out of prolonged high boost. Sustaining above 3500rpm caused temps to rise.

 

 

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I'll assume a oil change is on the plan for this weekend ?

From my experience, stuff on the roof really affects MPG on this car. It's amazing.

 

Here in St George, my engine really does not like intake temp above 100F. When it is the case, then I can't stay in boost for very long, especially with the AC on.

On a long climb, AC on, intake temp > 100F, bikes on roof+skybox, boost level between 1-5 psi, my coolant temp will climb a bit and easily reaches 217-221F. Even hit exactly 230F at one point . But it cools down quickly once you stop pushing the car hard.

 

 

The other day, on another long climb, nothing on the roof, speed > 70 mph, intake temp ~ 85F, AC on, coolant temp remained just fine below 200F. And after that trip, almost got 25mpg. Was really surprised. Once I put my bikes and box on the roof, mpg sucks.

 

 

FYI, the needle starts moving from its usual spot once it passes 215F. At which point, I also noticed the tune runs rich too, probably to cool down the engine as well or something. Performance sucks too.

Edited September 17, 2020 by xt2005bonbon

I'll assume a oil change is on the plan for this weekend ?

 

 

Yep! I'm gonna go ahead and do the trans and diff oil soon since they are already at almost 20k.

 

 

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From my experience, stuff on the roof really affects MPG on this car. It's amazing.

 

Here in St George, my engine really does not like intake temp above 100F. When it is the case, then I can't stay in boost for very long, especially with the AC on.

On a long climb, AC on, intake temp > 100F, bikes on roof+skybox, boost level between 1-5 psi, my coolant temp will climb a bit and easily reaches 217-221F. Even hit exactly 230F at one point . But it cools down quickly once you stop pushing the car hard.

 

 

The other day, on another long climb, nothing on the roof, speed > 70 mph, intake temp ~ 85F, AC on, coolant temp remained just fine below 200F. And after that trip, almost got 25mpg. Was really surprised. Once I put my bikes and box on the roof, mpg sucks.

 

 

FYI, the needle starts moving from its usual spot once it passes 215F. At which point, I also noticed the tune runs rich too, probably to cool down the engine as well or something. Performance sucks too.

 

 

Yea when I drove to Colorado with nothing on the roof, not even the bike racks, I averaged 28. I was pretty happy about that.

 

I've noticed similar. If the intake temps are above say 95, sustained boost causes the temp to climb fast. If they are below 90 I can basically hammer it up the same climbs no problem.

 

I've never let it get over 220 honestly. I get very stressed when that needle starts to move. Every cooling part on my car is new as well except the oil cooler which I think is at 80k now, the fans are original, and the radiator has I think 50k on it.

 

 

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every subaru ive owned became a complete slug when intake temps got over 90. The first time i lived in az when i had my sti, i thought something was wrong with it. I started doing data logs and realized the timing decay was pretty significant. Luckily there was e85 close so i was able to negate that to some degree.

 

I must be lucky with my outback, even when it was 117 degrees out i never saw coolant temp over 200 when ripping on it even up hill. In fact the only time i ever saw it get over 200 was in stop and go with the ac on. and it was hot enough that the ac couldnt keep up, we were all sweating out asses off

Yea when I drove to Colorado with nothing on the roof, not even the bike racks, I averaged 28. I was pretty happy about that.

 

I've noticed similar. If the intake temps are above say 95, sustained boost causes the temp to climb fast. If they are below 90 I can basically hammer it up the same climbs no problem.

 

I've never let it get over 220 honestly. I get very stressed when that needle starts to move. Every cooling part on my car is new as well except the oil cooler which I think is at 80k now, the fans are original, and the radiator has I think 50k on it.

 

 

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Don't worry. I was freaking out too when I first noticed temp reaching 217-219F. But then I got used to it .

 

 

 

I think I am going to upgrade the radiator.

 

 

every subaru ive owned became a complete slug when intake temps got over 90. The first time i lived in az when i had my sti, i thought something was wrong with it. I started doing data logs and realized the timing decay was pretty significant. Luckily there was e85 close so i was able to negate that to some degree.

 

I must be lucky with my outback, even when it was 117 degrees out i never saw coolant temp over 200 when ripping on it even up hill. In fact the only time i ever saw it get over 200 was in stop and go with the ac on. and it was hot enough that the ac couldnt keep up, we were all sweating out asses off

 

 

 

 

Were you pulling stuff though (or stuff on the roof) when you said you never saw the temp climbing over 200F? Mine is like that if I have nothing on the roof or hitch. I can be climbing, with the AC on at 80 mph no problem. But yeah, big disappointment when it's hot and you're loaded. You can't enjoy that 300HP+ engine.. In their defense, it was not really designed to carry so much weight and stuff for long distance..

Edited September 18, 2020 by xt2005bonbon

Never pulled with this one and nothing on roof, I pulled my jet ski with my last obxt but it’s a small trailer with a stand up so I don’t think it counts but it didn’t even act like it was there. I’m sure any added drag really destroys the out of boost performance if the 2.5. My friend complained about a huge drop in fuel economy with a luggage box on the top of his 96 outback.

 

When I moved to az, the wife drove the outback with the inside fully loaded and she didn’t complain and it did well on fuel but that was without anything hurting the aerodynamics. Since I’ve partially lowered the outback (haven’t had time to do the rear) I swear I’ve been getting better fuel economy

I agree on both counts: aerodynamic hurts fuel economy way worse than adding weight inside the car. And two, a lowered outback may get better fuel economy as well. I have a lowered outback too and she has always yielded slightly better fuel economy.

Lowered would theoretically reduce lift and reduce drag so that would make sense.

 

I think I'm also going to use this as an excuse to upgrade the radiator. To be honest though it's probably not worth it. The guys racing their lgt get away with the stock cooling system as long as they get clean air on occasion. I'm sure the main difference though is you don't expect a race engine to last 100k. I started a thread asking about it and it seems pretty consistent across people. Max capacity and boxkita both don't ever see temp raises. Max capacity runs around in the mountains in high temps and boxkita races a lot.

 

I'm also wondering if the temp raise is a boost issue though. I've got a stock intercooler and maybe it doesn't have enough heat capacity for sustained boost in 95f weather at full or near full throttle. Hot air means hot cylinders means hot oil and hot coolant.

 

 

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I would think the two row Mishimoto would be a good compromise. I find it hard to adjust the drive belts with the three row.

 

If you were thinking of going that route.

 

https://www.mishimoto.com/subaru-impreza-sti-performance-aluminum-radiator-08.html

 

I saw that mentioned in another thread a short while back.

Lowered would theoretically reduce lift and reduce drag so that would make sense.

 

I think I'm also going to use this as an excuse to upgrade the radiator. To be honest though it's probably not worth it. The guys racing their lgt get away with the stock cooling system as long as they get clean air on occasion. I'm sure the main difference though is you don't expect a race engine to last 100k. I started a thread asking about it and it seems pretty consistent across people. Max capacity and boxkita both don't ever see temp raises. Max capacity runs around in the mountains in high temps and boxkita races a lot.

 

I'm also wondering if the temp raise is a boost issue though. I've got a stock intercooler and maybe it doesn't have enough heat capacity for sustained boost in 95f weather at full or near full throttle. Hot air means hot cylinders means hot oil and hot coolant.

 

 

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Yeah but I don't think Max capacity is driving in the mountains pulling a trailer in hot weather. He has probably been driving fairly light and mostly during winter to go skiing I think. Could be wrong though.

When I drive light, I can push it hard in the mountains/canyons no problem. It's carrying all that weight/drag in the heat that is the problem. I probably need a truck

Correct, I don't tow.

 

What are your plans for towing in the future ?

Ah my comments towards max capacity and his car were more that I see the needle move on the temp gauge even when I'm not towing. That's what makes me think there might be some fin separation on my radiator or something.

 

Like if it's 95 out and I try to keep it at 75 up a 6% grade, the needle will start to move and I've seen temps as high as 220 when I monitored it. But it makes me real anxious so I just slow down lol.

 

I have a hard time justifying a dedicated tow vehicle until I have a dedicated race vehicle. I hate driving trucks anyway. Stage rally cars have to be street legal and the e30 is a long ways from stage ready so I just drive it to races. Also Michigan insurance is really expensive so a 3rd vehicle sounds like a nightmare. I don't really intend to tow anything bigger than a go kart trailer (next motorsports purchase) and only one more big trip but we'll be using the smaller 5x8 uhaul.

 

 

Edited September 22, 2020 by Nonamedude

I am curious if you can replicate the temperature going up in Michigan since you are at lower altitude. Cooling efficiency decreases at higher altitude (i.e Utah).

But then I'm not sure if you can find a road with 6% grade in Michigan..

Interesting I didn't know that. Makes sense though, air is less sense.

 

The ski places here are only like 500ft of vert. Apparently the highest point is in the up at a whopping 1979 ft. Maybe I'll just need to do a summer hdpe.

 

 

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yeah, basically flat then...

 

 

So, tuned for 93? I would if I were you. Oh yeah, you just arrived

You'll enjoy a lil more torque in the lower RPM range I would think.

That's the plan. I might actually just replace the dp and do a stage 2 tune. I'll be driving back to utah in it looks like November and I didn't get 93 until Michigan somehow.

 

But yea ultimately I'll get it retuned. Need to sort some mechanical stuff first.

 

 

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Yeah. I almost got depressed when I got to IL (moved from MD to UT) and had to put 91 in my tank. I then pulled my laptop and removed 2 deg of timing across the whole base timing map. I felt the lack of juice after that. And then, in CO/UT and the higher altitude resulting in less oxygen--> less juice again. My load average is noticeably lower at this time, although the difference in intake temp plays a big role too (used to peak at 3.3 g/rev in MD (50F -- 400F alt). At 2700F with 95F intake temp, barely peaks at 2.45 g/rev . It'll get better when it gets cooler though. And I need to work on the tune too.

I've only pulled to 2.5g/rev but I've only driven in utah. That was in winter too. But I'm on stock stuff.

 

I think the plan is to get a down pipe and then see if Dave can give me a 91 and a 93 tune utilizing SI drive. I think he can. Or if he even thinks it's a big concern.

 

 

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I installed a Koyorad Hyper V and a KillerBee oil pan. It did not solve my 100 degree days overheating up steep grades with the AC on. It was worse when I got stuck behind cars going too slow (not enough airflow).

 

Loaded car:

2 adults 2 dogs + camping gear. Sometimes a bike sometimes not. Adding an actual oil cooler and not just the in-block coil thing was my next step.

 

I bought a Sienna and now don't have any issues going up and over the Sierra's in the summer.

Edited October 1, 2020 by Rhitter

So you also suffered from this? I don't recall you complaining about overheating issues.

 

So the Sienna handles hot days just fine then? Good on Toyota. Bad on Subaru

Well I solved the problem by going way north and the average summer temp is 10 deg lower with thicker air and more humidity.

 

Still dissatisfied with the answers though lol. I feel like there should be a simple solution. At least I don't have a serious issue it seems.

 

 

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yeah. When I lived in MD, it was never a problem.