What does a TMIC add?
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Isn't a "stage 2" TMIC just another top-mounted intercooler, and therefore not a drastic change, if any at all, from stock?
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103 Posts
My 02 is actually being held back by the stock tmic. I'm getting a process west one because it's more efficient than the stock, larger area, better flow, etc... and I don't want a front mount.
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6,611 Posts
If your tuner said a TMIC doesn't add power, I wouldn't use that tuner. A quality aftermarket TMIC will probably be superior to any stock TMIC. If your tuner doesn't know this, I'd not use them.
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331 Posts
Good top mounts are out there. .
Think of it like this: you have a radiator. There are much better than stock radiators available. Colder air =power.
Process west or ARC. If you have an Sti, you can pick up some power in other areas while still on the stock intercooler.
Though i hear small front mount intercoolers are where it's at.
Think of it like this: you have a radiator. There are much better than stock radiators available. Colder air =power.
Process west or ARC. If you have an Sti, you can pick up some power in other areas while still on the stock intercooler.
Though i hear small front mount intercoolers are where it's at.
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14,901 Posts
This.
The stock units are so small, they leave a lot of room for improvement. That and after 2007, they went to primarily plastic pieces, the end caps are known for blowing off as you approach 18-19psi. So a quality aftermarket TMIC is almost a necessity if you are getting to those numbers - which most good aftermarket tunes will do.
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103 Posts
That would be funny to see. I love watching cheap plastic crap fail spectacularly. Kinda like my stock radiator did with its cheap plastic top and bottom caps. It looked like my bugeye was blowing its nose when it went. Lol
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12,649 Posts
The quality of the TMIC will play a big role in whether it's a worthwhile investment or not...
Aftermarket TMICs can be evaluated in two ways:
1) Restriction (Pressure Drop). If the pressure drop over the core is 3PSI, to achieve a manifold pressure reading of 18PSI (which is what's measured by the ECU), you would need 21PSI at the compressor. If the pressure drop over the core is 1PSI, to achieve that same 18PSI manifold pressure, you would only need 19PSI at the compressor.
2) Cooling Ability. This is the difference between the temperature of the charge as it enters the TMIC (T-in) and the temperature as it exits the TMIC (T-out).
The whole purpose of an intercooler is to reduce the intake charge coming from the turbocharger. At the end of the day, cooler air is best (T-out), regardless of how it gets there.
A quality TMIC will balance restriction and cooling ability. There are two main factors in what makes a good TMIC:
1) Design
2) Fin Density
There are two types of intercooler design: tube/fin and bar/plate. Generally speaking, tube/fin are more efficient at cooling, at the expense of restriction (vs a comparable bar/plate design). Factory TMICs on Subarus all utilize the tube/fin design, where most aftermarket companies utilize bar/plate.
The whole purpose of designing a quality aftermarket TMIC is that you balance both restriction and cooling ability. By using the less-restrictive bar/plate design (the turbo isn't working as hard, and is therefore producing less heat, reducing T-In value), and utilizing a higher fin density to adequately cool the intake charge, you can achieve better results from the more efficient / more restrictive tube-fin design.
Let's setup an example using some numbers tossed around earlier (and some others to make the equation work)...
TMIC Efficiency = ((Tin - Tout) / (Tin - Tambient))
Manifold Pressure: 18PSI
Tube/Fin: 3 PSI Pressure Drop
Bar/Plate: 1 PSI Pressure Drop
° / PSI (T-in): 10
Ambient Temp: 50°
Tube/Fin Efficiency: 80%
Bar/Plate Efficiency: 75%
Therefore...
Compressor (Tube/Fin): 21 PSI / 210°
Compressor (Bar/Plate): 19 PSI / 190°
Manifold (Tube/Fin): 18 PSI / 82°
Manifold (Bar/Plate): 18 PSI / 75°
Despite the bar/plate being 5% less efficient at cooling, the fact that it started with a 20° lower temperature (from the turbo not having to work so hard), meant that the end-result was a 7° cooler charge once it left the intercooler.
All else equal, let's assume that the bar/plate efficiency was 70%; the outlet temperature would be 92°, which will ultimately mean that it is a performance downgrade.
Aftermarket TMICs can be evaluated in two ways:
1) Restriction (Pressure Drop). If the pressure drop over the core is 3PSI, to achieve a manifold pressure reading of 18PSI (which is what's measured by the ECU), you would need 21PSI at the compressor. If the pressure drop over the core is 1PSI, to achieve that same 18PSI manifold pressure, you would only need 19PSI at the compressor.
2) Cooling Ability. This is the difference between the temperature of the charge as it enters the TMIC (T-in) and the temperature as it exits the TMIC (T-out).
The whole purpose of an intercooler is to reduce the intake charge coming from the turbocharger. At the end of the day, cooler air is best (T-out), regardless of how it gets there.
A quality TMIC will balance restriction and cooling ability. There are two main factors in what makes a good TMIC:
1) Design
2) Fin Density
There are two types of intercooler design: tube/fin and bar/plate. Generally speaking, tube/fin are more efficient at cooling, at the expense of restriction (vs a comparable bar/plate design). Factory TMICs on Subarus all utilize the tube/fin design, where most aftermarket companies utilize bar/plate.
The whole purpose of designing a quality aftermarket TMIC is that you balance both restriction and cooling ability. By using the less-restrictive bar/plate design (the turbo isn't working as hard, and is therefore producing less heat, reducing T-In value), and utilizing a higher fin density to adequately cool the intake charge, you can achieve better results from the more efficient / more restrictive tube-fin design.
Let's setup an example using some numbers tossed around earlier (and some others to make the equation work)...
TMIC Efficiency = ((Tin - Tout) / (Tin - Tambient))
Manifold Pressure: 18PSI
Tube/Fin: 3 PSI Pressure Drop
Bar/Plate: 1 PSI Pressure Drop
° / PSI (T-in): 10
Ambient Temp: 50°
Tube/Fin Efficiency: 80%
Bar/Plate Efficiency: 75%
Therefore...
Compressor (Tube/Fin): 21 PSI / 210°
Compressor (Bar/Plate): 19 PSI / 190°
Manifold (Tube/Fin): 18 PSI / 82°
Manifold (Bar/Plate): 18 PSI / 75°
Despite the bar/plate being 5% less efficient at cooling, the fact that it started with a 20° lower temperature (from the turbo not having to work so hard), meant that the end-result was a 7° cooler charge once it left the intercooler.
All else equal, let's assume that the bar/plate efficiency was 70%; the outlet temperature would be 92°, which will ultimately mean that it is a performance downgrade.
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198 Posts
For a trusted shop, prime motoring in Wallington (JRtuned) or head over to Precision in Spotswood. I wouldn't recommend Ivey in Linden, seems to only wanna tune GTRs. As for the TMIC, it had its advantages and disadvantages. Ever think about going FMiC?
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Do you know any tuners in the capital region of ny? I'm ok driving to nj but would rather stay local if possible.
I'm just trying to get a better understanding of the mod progression and I don't understand where the tmic fits in and what type of power gains it achieves if any.
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331 Posts
What model subie is at the core of this discussion? A bugeye? A Grb? Parts availability varies.
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