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Discussion Starter #1
I have searched all over this forum and I am curious about swapping out the intercooler for an aftermarket unit. I live in Florida and it's only a matter of time before the summer temperatures become a pain. I am concerned about heat soaking the tmic with Florida's wonderful 95% humidity. Efficiency is my concern and I don't want to tune it.
 

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I don’t have a full answer as to tuning — past responses I’ve seen have been “tune is required to get full benefits of larger core”, but I don’t have the expertise to fully confirm that...

I’ve been super interested in the Mishimoto TMIC due to the R&D that went into it (the article says 08-14, but it has since been cleared up to the ‘19):
Subaru STi Intercooler 2008-2014 | Mishimoto Engineering Blog

They used a stock car, so I got the impression that it would not need a tune... either way, Mishimoto is great with communication if you wanted to drop them a line...

I have the same interests as you with our high MD humidity... I’m on a stage 1 tune, and I wouldn’t mind getting a cooler upgrade just for improved efficiency and more consistent power delivery in the summer months.
 

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A number of knowledgeable people have written that later model STI inter-cooler a quite good - in terms of a top mount. Search carefully before sinking a lot of money into a TMIC replacement.

My thoughts are that in closed loop (low speed and cruises) it will be corrected and be fine. if the inter-cooler really makes a difference, then in open loop you'd need to tune cause you'd have denser air and the car would run lean. It would have to be different than stock, not some little change for this to be true.

Finally, stock plastic tanks store and transmit litt le heat compared to AL. They are good, not bad! A truly larger inter-cooler can provide more cooling at speed. All will hurt response to some degree (even if it is very small), and if they are a TMIC how much larger can it be? How much more heat will that larger intercooler store at a light.

Note, my GD has an aftermarket TMIC, but it is quite a bit larger than stock, I'm pretty sure it has a smaller pressure drop than stock, and both were all AL.
 

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I had an aftermarket inter cooler on my Focus RS and the differences between the stock and ETS inter cooler were huge. The stock one would heatsoak after a single pull and even without a tune there were obvious advantages to the aftermarket unit. Running lean is the last thing that I want of course. My goals with this car is to keep it stock but to maximize efficiency.
 

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Tune is not required for an aftermarket TMIC, but you won't gain any benefit from it. The tune adjusts itself just like it does in the winter.

The stock TMIC is an awesome design. The efficiency of the stock STI TMIC is far better than any other stock TMIC on other cars. I would never replace a brand new TMIC with a brand new aftermarket TMIC. It'll be completely pointless on these cars.

On another note, a TMIC is a TMIC, it'll heat soak no matter what. There's really no point upgrading a TMIC on a stock car used only as a daily driver / weekend warrior. Then again, it's your money. This is coming from someone who is heavily modded with a ETS TMIC.
 

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Tune is not required for an aftermarket TMIC, but you won't gain any benefit from it. The tune adjusts itself just like it does in the winter.
Aren't the only stock charge measurements done at the actual intake MAF and Temp?
If so there will be no direct correction for a different inter-cooler in open loop. So it would compensate for colder intake, but never any form of heat soak . In fact this is one of the dangers of heat soak except in th form of fuel trim or other secondary settings.

Also realize/remember people call two different mechanisms of an inter-cooler getting hot heat soak.

* True heat soak occur where the curve of intake temp bend upward due to lack of capacity for any reason, which amount to "being to small or inefficient" under a given set of conditions.

* Many here call picking up heat from the engine at slow speeds heat soak.Nt good, but at least it dissipates quickly with forward motion.
 

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Aren't the only stock charge measuremnts done at the actual intake MAF and Temp?

IOf so there will be no direct correction for a different intercooler in open loop. So it would compensate for colder intake, but never any form of heat soak . In fact this is one of the dangers of heat soak.



Also realize/remember people call two different mechanisms of an intercooler getting hot heat soak.



* True heat soak occur where the curve of intake temp bend upward due to lack of capacity for any reason, which amount to "being to small or inefficient" under a given set of conditions.



* Many here call picking up heat from the engine at slow speeds heat soak.Nt good, but at least it dissipates quickly with forward motion.

Think of winter conditions. The intake temp is analyzed, but the flow through the intercooler is not, whether it’s the air that’s denser or the intercooler that’s more efficient at “cooling”. It’s the same effect.

Yes, heat soak or hot charge temps will happen in both conditions. I only refer to the later environment because the majority of people won’t use their cars on the track, and if they would, they would be pointing it out.
 

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Intake is not the same as charge .

Is charge temp measured? There is a module on the throttle-body. I didn't think that measured temp because people add temp sensors to throttle bodies. (Thought I'd read over and over that it isn't - but I don't actually know from my own knowledge. I should know though . . )

If not , the charge is not analyzed - you could block off you inter-cooler intake and your ECU wouldn't know the difference. It would just ping in some conditions and pull timing. It kind of sucks which is why hybrid MAF/MAP with added sensors has become the norm in significantly modded street cars.

Anyone with more knowledge than me, please correct me if I am wrong!
 

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The stock TMIC will shed heat / recover better than any aftermarket alternative. If you are worried about summer, work on heat shielding and retention. If you want to go further with heat soak, get a FMIC and get a tune.

A "better" intercooler will have benefit without a tune... Unless you don't think colder, more consistent air is a benefit?
 

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Because you are yamahaSHO I'm sort of taking this at face value but under all circumstances / levels of build the stock intercooler is superior to any aftermarket? I'd think every part is improvable - whether cost efficient or not is another story?

I'm personally banned from removing the crash bar so FMIC for me isn't an option and it seemed like my aftermarket TMIC has contributed to my build with my tuners agreeing and in fact requesting it originally. But I'd be curious if its worth the time and effort to swap in the stock and retune and see what happens. In the process of trying to make a shroud for my aftermarket but would be easier to simply swap back in the stock probably.
 

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- An aftermarket unit can provide more flow if you have a turbo that can take advantage of it. In that case, and efficient turbo at X boost level will make the most use of it.

- If the flow of the stock one keeps up with X turbo, it will be far more efficient than the mass loaded aftermarket versions, which are terrible at shedding heat.

- An aftermarket version does not have crimps to blow.

- The mass loaded aftermarket version might be better if kept cool when you initially get on the throttle.



During the last few dyno days I had, the dyno operator, who was trying to keep the cars cool made mention (several times) about how the stock intercoolers shed heat so much faster. He didn't know the were stock.
 

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Because you are yamahaSHO I'm sort of taking this at face value but under all circumstances / levels of build the stock intercooler is superior to any aftermarket? I'd think every part is improvable - whether cost efficient or not is another story?

I'm personally banned from removing the crash bar so FMIC for me isn't an option and it seemed like my aftermarket TMIC has contributed to my build with my tuners agreeing and in fact requesting it originally. But I'd be curious if its worth the time and effort to swap in the stock and retune and see what happens. In the process of trying to make a shroud for my aftermarket but would be easier to simply swap back in the stock probably.
Cobb's fmic has a crash bar, so there's that option if you need it. But I would think you'd want a higher flowing turbo to support the increased volume of the intercooler in that case. The stock tmic is a pretty good match for the stock turbo, but a lot of people do change it.
 

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Have you looked into turbo blankets/shielding and wrapping your downpipe? That may remove some of the heat that makes it up to the top mount.
 

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Discussion Starter #16
I actually ordered a turbo blanket which I intend to install this weekend. Everyone's advice was good and I would hate to waste money on an intercooler when I could put that money towards ceramic coating :lol:
 

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I actually ordered a turbo blanket which I intend to install this weekend. Everyone's advice was good and I would hate to waste money on an intercooler when I could put that money towards ceramic coating :lol:
Get a downpipe one too, with both blankets, you'll see a huge difference. I love mine, well worth the money.
 
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