Do you really need that hulking Front-Mount Intercooler (FMIC) on your WRX/STI? It looks kind of cool, but does it really live up to expectations or are FMICs just for looks? Do they hurt the performance? Can you have a big turbo and not need a front-mount intercooler? Is Top-Mount Intercooler sufficient for cooling your intake air charge? Will it heat-soak on a hot day? Let’s discuss and then you decide.
In the Intercoolers 101 article we talked about the basics of intercoolers – what they do, what kinds of intercoolers are most common on the market, and common installation location. The two most common intercoolers you will see on WRX and STI cars are Top-Mount Intercoolers (TMICs) and Front-Mount Intercoolers (FMICs). Subaru uses air-to-air intercoolers versus air-to-water intercoolers, which are less efficient.
Intercooler efficiency is measured by intercooler’s ability to cool air passing through it. In case of air-to-water intercoolers, the efficiency is only about 55-60%, meaning that the air passing through is cooled by 60% in the best-designed air-to-water intercooler. Air-to-water intercooler efficiency can be greatly increased with a separate closed water system using ice chilled water. Not usually practical for a daily driver.
Air-to-air intercoolers are more efficient. 2002-2006 stock WRX intercoolers are about 70% efficient. An upgrade to a 2.2 times larger aftermarket TMIC will yield about 78% efficiency. The best designed air-to-air Front-Mount Intercoolers have an efficiency of about 80%.
Intercooler efficiency drops dramatically on hot days, especially as the intercooler becomes heat-soaked. This heat soak is apparent on a hot summer day in slow moving traffic.
An aftermarket intercooler upgrade is highly recommended when you modify your car. A larger aftermarket intercooler will be able to cool more air and cool it more efficiently than a stock intercooler. Also, better air flow through the larger intercooler tubes results in less air pressure drop within the intercooler. This offers an increase in performance potential. But which intercooler should you choose – Top-Mount Intercooler or a Front-Mount Intercooler? Let’s discuss which one is a better choice.
FMIC by Perrin Performance
Front Mount Intercoolers
Both FMICs and TMICs have their advantages and disadvantages. Advantages of FMICs are:
- FMICs, due to their location in the front bumper, can have exceptionally large cores, 3-4 times larger than the stock intercooler core. Larger intercooler core provides for better cooling efficiency and for less pressure drop;
- FMICs look race car “fast”.
Disadvantages to FMICs are:
- increased turbo lag – although the FMIC core may be 3 times larger than a stock TMIC core, FMICs have much longer piping. Air has to travel the whole length of piping with more pressure loss. And, the much greater volume of air to compress in the whole system takes more time. This is the additional turbo lag;
- FMICs make your turbo spool slower / about 500-1000 rpm later than if using a TMIC;
- most aftermarket FMICs are incompatible with stock fog lights – fog lights will have to be removed;
- added weight – FMICs weigh quite a bit more than the stock due to sheer size and length of piping. The weight difference is made up in part by removal/cutting of your front bumper beam – this is necessary to install a FMIC on a WRX/STI;
- greatly reduced driver/passenger safety – installation of a Front-Mount Intercooler on a WRX/STI requires complete removal or cutting of the front bumper beam. Outfits that market FMICs insist that the removal of the bumper beam does not reduce your safety, since those bumper beams “are rated for only 5mph anyway”. Yes, JDM lightweight bumper beams are available for some FMICs, but they don’t meet US DOT crash standards. Now using your best judgement, think about it for a moment… Would you rather have a factory-designed safety device, in this case, a steel bumper beam, be an extra protective barrier in an accident? Or, would you rather have a soft aluminum FMIC, with or without a non-DOT safety spec beam to protect you?
Bumper beam will protect your engine from the impact in case of an accident. It will also help protect the engine from going through the firewall and into your legs and possibly save your life (see example photos below). A front-mount intercooler, even in a minor frontal impact situation, will be disintegrated, along with your engine. Plus there is a greater chance of bodily injury without the front bumper beam.
It is probably OK for track-only cars to have FMICs. In daily driven Subarus we highly recommend to choose a large aftermarket Top-Mount Intercooler over the FMIC. Also, rotated turbo setups cannot be fitted to a TMIC in most cases, so they require a FMIC installation. However, for an ultra-high-performance daily driver WRX/STI you do not need to have a rotated turbo setup – you can have 500-600 whp with a stock-location, large turbo and a Top-Mount Intercooler. Or, you could go intercooler-less, but that’s a topic of another article.
Overall, FMICs potentially* offer better cooling than TMICs at the expense of weight increase and greatly reduced safety. Looking cool is not worth getting injured or losing your engine.
* potentially because with alcohol injection, TMICs perform the same or better than FMICs in cooling!
TMIC by Perrin Performance
Top-Mount Intercoolers
Disadvantage to TMICs is:
- TMICs are more prone to heat soak than FMICs. This is because TMIC is located right on top of the engine close to the turbo, and rising heat heats the TMIC up. TMICs are cooled by the air coming through the hood scoop. The large aftermarket TMIC pressure drop is not significantly higher over the FMIC, so that’s not considered to be a major disadvantage.
Advatanges to TMICs are:
- aftermarket TMICs can also have very large cores – up to 2.5-3 times larger than stock core, thus they provide much better cooling capacity than a stock intercooler;
- TMICs, even the largest aftermarket ones, are lighter than FMICs;
- much less turbo lag is experienced with TMICs over FMICs, your turbo spools much quicker;
- lesser cost than FMICs;
- no reduction is safety, no cutting or removing of the front bumper beam.
The safety advantage makes the Top-Mount Intercoolers more preferable to FMICs for daily driven Subarus.
Solution to TMIC’s only disadvantage
TMICs can be almost as efficient at cooling as FMICs, and even more efficient with the addition of alcohol injection. Since alcohol injection nozzles are placed in the TMIC itself, right by the throttle body, the pressurized hot air coming into the intake manifold at boost gets tremendous cooling from the alcohol. Here is how it works:
- at normal, no-load driving, the outside air temperature is almost equal to the air temperature that is coming out of the turbo, and gets some cooling from the intercooler;
- at throttle, at load, the turbo spools, building pressure and heating up the air coming out of the turbo. A real-life temperature readings using a 4-channel temperature sensor, taken on a 2.0L WRX with a 16G turbo and a 2.2 times larger-than-stock intercooler show that at 70 degrees F outside air temperature, at 19 psi boost, the temperature of air coming out of the turbo was 225 degrees F. So the turbo heated up the air by 155 degrees F;
- the hot air goes through the Top-Mount Intercooler, receiving about 78% cooling. In the above WRX example, temperature readings were taken at the intake manifold without alcohol spraying. Temperatures in the intake were about 120 degrees F;
- the alcohol/water mix sprays pretty much right before the throttle body, where there is good air turbulence;
- alcohol and water evaporate rapidly in the hot air, thus enormously cooling the air;
- cold air goes into the intake manifold. In fact, alcohol cools the air so well, that the total cooling efficiency of the TMIC rises to over 100%! Temperature reading taken at the intake manifold on the above WRX indicated that with alcohol injection, the air in the intake was only about 63 degrees F. That’s over 100% cooling efficiency! YES, the air going into the engine was actually colder than the air outside.
It is possible to achieve even more cooling. In the example above, 10 gal/hr alcohol spray nozzle was used. If you are injecting more alcohol, the cooling efficiency will increase due to the evaporation of larger amounts of alcohol and water. Read about how much alcohol you can inject.
In fact, the hotter the turbo outlet temperature and the hotter your intercooler is, the faster will alcohol and water evaporate, thus cooling the air even more than at colder temperatures.
Quickly pop your hood after a few runs with alcohol injection and put your hand on your TMIC. If you inject enough alcohol, your TMIC will be cold and wet! It literally freezes over when alcohol and water quickly evaporate inside.
In addition to the alcohol injection, you can prevent the heat-soak of your TMIC by heat-shielding everything you can. For example, put a heat shield over the downpipe and turbo hot side, so the heat doesn’t rise up from it but goes under the car:
- Take 2″ thick fiberglass pipe insulation (the white stuff, it won’t burn or melt), approximately 1 foot wide by 2 feet long, put the heavy-duty aluminum foil around it and attach the foil with aluminum tape;
- With aluminum tape facing up, put the insulation over the downpipe and turbo hot side, all the way up to the turbo. The insulation should be thick enough to stay in place and not slide down the downpipe. You may have to trim to fit;
- Then put a second layer of pipe insulation, prepared in the same way, over the first layer, covering any remaining space where the heat can rise up from the downpipe or turbo hot side.
- Air flow through the hood scoop on GD Subarus can also be modified to direct more air between the turbo and the TMIC.
What did you just do? You put an excellent heat barrier that will keep the heat from the downpipe and the turbo hot side from coming up. Instead, since the bottom part of the downpipe is exposed to air, the heat will dissipate under the car. You just done your intercooler a great favor.
It would be pretty hard to fully protect your TMIC from the engine heat, and you do not need the full heat protection. The intercooler will be doing its own cooling just fine during normal driving and at boost the alcohol will help your intercooler to be efficient beyond 100%.
To sum it all up, on Subarus:
- Front-Mount Intercooler is absolutely NOT necessary unless your rotated turbo setup requires it;
- FMICs for daily driven Subarus are not cost efficient;
- FMICs add turbo lag;
- FMICs are not safe, if the US DOT safety spec front bumper beam has to be removed or cut to install an FMIC;
- FMIC supports marketed by FMIC manufacturers are not a replacement for the stock bumper beam and are not safe;
- Large aftermarket TMIC with alcohol injection is more efficient at cooling than a largest FMIC without alcohol injection;
- FMIC with alcohol injection is not more efficient than a TMIC with alcohol injection;
- Stay with a large aftermarket Top-Mount Intercooler and a stock location turbo – other than looks and turbo setup requirements, there is no sane reason to install a Front-Mount intercooler on your car.
Keep in mind what you’ve read in this article when selecting an intercooler, don’t get sold on FMICs unless you absolutely need one, use common sense. Yes, you can get a big stock location turbo and have lots and lots of power while still staying with the TMIC.
Here is a technical article on Intercoolers for your further research.
TIP: to show you what happens in an accident and why the front bumper beam is important, view the gallery below. This 2005 STI ran into a guardrail – spun out on black ice at about 55 mph and slowed down a little before hitting the guardrail. Guardrail post was totalled. So was the STI. The STI had to be stripped and parted out. The engine was saved by the front bumper beam – the driver is thanking God he didn’t remove the bumper beam and install a Front-Mount intercooler – he would have lost a LOT of money and may have suffered serious injuries.
This article is a joke. Are you from garageGT?
Ohhh Man….This Is fully what i was looking for….i hope Alot of others get a gain out of this post,and dont simply skim read it…thanks so much
I dissagree.I have a fmic on my 2006 wrx. Stock turbo,tuned,full tbe.I have no turbo lag problems,not much different than stock and running the same boost 15psi, I got 4 extra horsepower over stock tmic,and when I get a bigger turbo I can run more boost.so depends on your preference but no problems here.
tom, are you kidding? Did you read the article? View the pictures? Damn. It’s all proven, right in your face and you still think you made a good choice going with a front-mount? Hell dude, when you’re ready, and your car is at that level of power, just put alcohol injection on your car with a bigger top-mount or go intercooler-less – why would you want to make a dumb decision and install a front-mount? Guess you should have read this article first
OK- I hear the points of the article- here are my counter points.
#1 reason to ditch the top mount…heat soak.
I hated heat soak, my fmic doesn’t do that.
#2 I’m short- the 4 inch hood scoop was hard to see over. I deleted that when I went front mount. And now I don’t have heat soak.
#3 I bought the car to go fast, not to be a lame ass daily driver, even if that is what it really is. When I run it balls out on the weekend, I want it ready to go, without 6 hours of work to prep it. If subaru didn’t know that the tmic was a failure, they wouldnt have put the stupid “I/C Spray” button in the car. Band aids are not fixes.
#4 The bumper beam in my kit was not completely removed, just replaced. with a steel beam…and an intercooler. probably a pretty close trade off.
#5 fog lights are dumb. who actually uses them specifically for driving in the fog? most cars aren’t even wired correctly from the factory to make that possible. removing them probably saves the weight that the fmic adds over the tmic.
#6 More boost at lower temps without more mods. (AKA heat shielding everything AKA band aids)…ever wonder about the added stress you put on those parts but not allowing them to release heat properly? who cares my tmic is cooler! dumb logic.
This is informative, but not completely…and not fairly. stop trying to scare people.
#1 usdm wrx’s dont come with tmic sprayers
#2 you had heat soak because the stock tmic sucks, it takes no phd to know that fmic = lower/heat soak
#3 water alcohol injection could have saved you all that extra piping, lowered the charge of air temp into the intake manifold, and provided a broader knock threshold with out a fmic.
#4. They are driving lights, not fog lights and in relation to weight savings that fmic is shaq to mugsy bougs. If you really thing that your driving lights weight as much or near the weight of your fmic core you are either smoking 1/2 crack and 1/2 pcp.
#5 heat shielding is not band aiding anything, its preventing heat soak to your tmic. How is that a band aid? If you claim subaru is “not stupid” then the tmic was placed as a tmic for a reason.
#6. 4 hp over stock could have been achieved at 3/4 of the cost of that huge fridge in the fnt bumper. kidiots jjjjjjjjeeeeesh
Most you ricers are not even tuned, and ots maps ant tuned.
[...] Not Ranked : +0 / -0 0 score this was for subies, but I still think the article was good. i dont think you have to cut the front beam off for the speed to fit a fmic, but they still made some valid points and I dont see the benefit of spending a G no matter how sweet it looks Why you don't need a Front Mount Intercooler on WRX STI | R U Subaru? [...]
All these posts go back and forth arguing which is best, when in actuality if you start modding your subie your trying to get SOMETHING more out of it which means bigger better parts than OE-For instance im running cobb stg 2 w/tune , perrin inlet tube/intake, walbro fp, 550′s, ACT stg 2, cobb bellmouth dp, 3 1/2” tbe, perrin lightweight c p, perrin mbc, AND A PERRIN FMIC…
With that being said coming from a STI tmic with these mods and going into a fmic- boost is like night and day- run 20 psi daily and u tell me how many times u push your i/c button…lol ME? Ill take my FMIC WRX and no spray yet still whoop up on 90% of sti’s on higher boost with these tmics….So continue to dog out my fmic it wont matter u cant see it from behind anyways… if u tune for extra piping and pressure loss-whats the loss seriously? You know everytime you see that fmic, you wished you had one also….just my 0.02….
Water / Methanol is damn good.
Think outside the square people
Amen
This article allows people to make an informed decision nothing more nothing less no wrong or right better or worse. Just comes down to personal preference and what your’e doing with your car.
Great article
learned a lot in a few minutes, thanks.
PS: You can tell by the comments above who already has a front mount and doesn’t want to admit they failed.
I bought my 04sti with a front mount should I change back
Recently purchased a wrx….. Been doing research on both tmic and fmic…… This is not the 1st article I’ve read saying tmic is better…. N the price is big difference…. But I’m still not sold lol it’s like I got a angel on 1 shoulder n a demon on the other….. Who do Iisten to
Reference the air to water intercooler. Agreed the heat exchange efficiency is slightly lower but water can take more heat away than air to air per square inch of cooler core. The result, you need a lot less core size. So dream this setup on a Subaru. A top mounted air to water cooler that due to size has the cooling capacity of a front mount. Yes you need a condenser (radiator) at the front of the vehicle but it needs to be no where near the size of a FMIC. Consequently you don’t need to cut and shut the safety stuff at the front which helps stop your airbags going off at less than 5mph!! Obviously it’s never a featherweight set up and hence whilst it’s fallen out of favour with most modern race teams (who run horizontal mounted coolers with extreme levels of ducting and bonnet vents due to having the ability to relocate engines up against the firewall) but it does share weight similarities with FMIC and the 10 foot plus of aluminium pipework from Home Depot. And as for anyone who claims they don’t get lag with long runs of pipework… its fact that the shorter the intact tract to the throttle the easier the turbo and engine have to work to draw in air. How the heck do you think a cone filter betters the complex OE airbox!
I love all the know it alls here. I’ll speak from experience, as opposed to what I read somewhere or heard from someone… there is a limit to the TMIC configuration. Its high, but there is a point where if you want to make more power you need the extra surface area a FMIC offers.
That aside, this article is pretty obviously biased. It’s full of conjecture and assumptions, like the idea that the author somehow “knows” that a steel beam has better crash protection properties than a 3″ thick bar and plate aluminum box.
If the article hadn’t been so biased it may have been a decent source of information since there is some truth in it. But the fact is the lists of pros and cons are incomplete at best. And the difference in lag is nowhere near as bad as the article makes it out to be, especially with an experienced tuner. Just my $.02, but coming from a guy who’s owned and built multiple turbo subarus with just about every various combination of TMIC and FMIC there is.
The article isn’t saying that a FMIC is worse than a TMIC period.. It’s simply stating that if you are only looking to make <600whp, a thicker top mount with a stock (location) turbo will suffice.
If you're going big, then yeah, a FMIC will be the best choice.
Top advice their fella. I aint really bothered about an extra 4bhp or whatevet. As stated you can run 5-600bhp on uprated tmic so what is the point. How many scoobys do u know personally that run that kind of power anyway? Exactly. Main aspect for me is the safety and how you have to cut out the front beam. Thats stupidity an as i work in road safety tests in vehicles i think common sense must provail however you will find most subaru drivers are know it all a***holes. Yes i do have a subaru as a daily driver which is what led me to this article but the amount of penises who drive subarus and think they arr vehicle scientists is beyond me.
The best way to decide wich way to go is either what kind of driving or what anciliaries or supporting mods you have on the car. For those that do drag or auto cross top mounts are fine because the short runs dont tend to heat soak the intercooler. For track or circuit racing front mounts are better because of their location. Good cool air all the time. No mater how big the core is on a top mount it is vulnerable to heat soak. There are things you can due to cool the charge such as water meth injection. But i personally wouldnt want to use that wild card for that. Most people use wwater meth to controll predetonation. Also keep in mind that all of these things have to be tuned in. If the intake air temp is still a variable after the tune due to heat soak you could have big problems getting performance out of that setup. Especialy if you run speed density. The ecu cant make changes due to ambient air pressure and density. It must be tuned for where you are going to use the car. Most people are still utilizing their MAF’s. This means that the car can make subtle changes according to altitude and intake air temp. The fewer the variables that are involved the easier it is to tune and the more reliable the tune is. Look at F1 cars they have the cars tuned for every corner that they will encounter on the trak that they race. That way they optimize performance. There is trully no end to the debate. I really dont see why there is a debate anyway they are both very viable options. Depending on what you want to do either can work. On a side note. Subaru does not use a top mount strictly for performance. Production is faster then you can build the motor as an asebly and install it in one procedure rather that have to pay someone to route boost tubing. Also subaru was not the first to use a top mount . It was FORD! They put it on the siera cosworth in like the 80′s. And odly enough they stopped uing it. I wonder why?
it’s a proven fact that if you drive a subaru, you are of the gays
As an engineer who can stand 100% behind my statement I think this article is about selling “sometime”!! First the fact that a water to air intercooler removes 14x more air than air to air garauntees that it is more efficient!! Air to water is more work to install and maintain but it is FAR more efficient than air to air… Especially at low RPM…which are exactly the RPMs ur at during daily driving….duh!!! Secondly The intercooler does not cause the turbo to spool slower….EXHAUST DETERMINES turbo rpm…duh!!! A bigger intercooler system makes the turbo have to pressurize a larger area than stock and that’s what contributes to the increased lag….duh!! That’s why as a car turner… “F” what the sales men say…. By the book maximum boost and it will explain ALL u need to know to setup a nice turbo system and intercooler set up on any car!!
{quote phil} “it’s a proven fact that if you drive a subaru, you are of the gays”
…ummm that would be a Miata Phil, someone has scooby envy.
YOUR COMMENT WAS EDITED AGAIN TO REMOVE PROFANITY. ONE MORE OFFENSE AND YOU ARE BANNED:
WHERE IN THE WORLD ARE YOU GETTING THIS???
WHERE IS YOUR DATA TO BACK ANY OF THIS UP???
i wanna see dyno charts, IAT graphs, data loggers.
i have spent hundreds of hours on our company dyno, with tons of intercoolers.
YOUR COMMENT WAS EDITED TO REMOVE PROFANITY:
before any of you think “oh man FMICs suck my TMIC is good to 600WHP” read their ‘disclaimer’
i would love to see ANY subaru making 500-600WHP with a top mount!
call your local professional tuners. (ones with a real dyno n all)
ask them about this. see what they say.
@motor_chad You should do your own research and call your professional tuner. Top mount intercooler is a much lesser of a limitation front-mount intercooler sellers make it out to be. Alcohol injection mitigates heat issues. In fact, our top mount intercoolers ice over under boost with enough alcohol injected – achieving at least a 110% cooling effect. Pressure loss is not a big issue and the spool is much faster (there is much less turbo lag to be technically correct) than with a front mount intercooler.
It is a fact that you can do just about everything with a top mount I/C and alcohol injection that you could do with a front mount I/C – all while maintaining stock location turbo, less lag and other top mount benefits, such as front bumper beam for safety. On an all out race car benefits of a front mount outweigh safety concerns. On a daily driver, no matter what power level – a top mount intercooler is the only way to go.
It is worth noting that with the top mount intercooler the size of the stock location turbo is limited and efficient placement of the rotated mount turbo is not feasible, although it has been attempted. If you are looking to put in that huge turbo, you will have to go front mount.
We advise to take your frustrations to the person who sold you on the front mount intercooler.
@motor_chad We have all of the data to support the cooling claims and power claims and all of the data supports the fact that the top mount intercoolers can be just as efficient as the front mount intercoolers. Performance numbers, temperature sensor data, years of datalogs and any other data you can think of – we got. It is outside of the scope of this website to get into detailed technical discussions. However you are welcome to share your technical data and findings with us via email editors-at-rusubaru-dot-com.
On this note, we always welcome a civil dialogue. We do have an open mind when it comes to hard data and we love being proved wrong. However profanity, libel, or any other misconduct on our website will not be tolerated.
Here is the fact from real world. No need to say something
http://goo.gl/9Z2uq
590 CFM – 37lb/min turbo@1.5bar(22psi), STI TMIC
Max engine load.
Ambient temp= 21c degree(73F)
ACT=28c degree (82F)
Roger clarks and scoobyclinic fit fmic over380bhp. nuff said
is it safe to run alcohol/water injection on a DD?
engines are watercooled because water can transfer heat 3 times faster than air. step into a room @ 60 degrees with a fan going, then try stepping into a shower with 60 degree water and tell me what gets cold faster. anyone that thinks air/water setup is less efficient either a. has never had one and just reads bs online, or b. has run an undersized heat exchanger. Here is someone that did it and gathered temps before/after. Trust the facts not opionions. If everyone listened to opinions then there would be no such thing as a good car. ford vs chevy/dodge etc. it’s all the same till you drive one.
If tmics are so good.. Why doo Subaru use fmic on the classic wrc car and v-mount on bugeye, blobeye, hawkeye and newshap wrc cars? And why do you think Nissan gtir was changed from tmic to fmic in their rallycar and gained 30hp and 20nm on that litle mod.
I would love to see a 600whp subaru with a top mount. hahahahahahahahaha
This article is definitely biased. I ran a fmic set up on my 01 Jetta and actually had a homemade replacement bumper. Wouldn’t you know a month later someone rear ended me and I hit the car in front of me. Totaled the car and for the homemade replacement bumper….held up fine. The car hit me at about 15 mph…now of course my VW was slammed to the ground and that helped a great deal because the hood took most of the hit from the tow hitch.
Has the author of this article thought about the cost to maintain the I/C injection on a tmic set up? Over time you would spend considerably more on the alcohol and water set up. And what happens when you run out? If that were to happen? And wouldn’t the tune have to be on a constant spray?
Look at race teams…for some odd reason they use…you guessed it!!! FMIC!!!
Guess their wrong to though..
Wow! You guys are seroius…I have a 2011 sti with Turbo back exhaust,Cobb SR intake and Cobb AP with pro tune. I have a turbo blanket and my intercooler is much cooler than My 06 Outback XT is. Outback is Stage two for the last 180000 miles. All origional except mods done when new. My car has idled and creeps around under 30 mph for the last 15000 miles for my job. I still kick it in of course. I want to comment on the 0 to 60 times of 4 seconds and a 10 second quarter mile time, they were talking about on the mods that I have done. It is just not going to happen. It take more than that to run that fast. Just my view. I have had over 40 cars and that is unrealastic. Anything in the 12s is a fast street car. Think I will stay with my top mount for a few more ponies. If I do inverted turbo I will definanaty go with FMIC. Sorry if I am not contributing
TMICs are awesome for what Subaru designed them for……rally stages where the average speed isn’t more than about 100 KMPH or 65 MPH. They are really awesome for that specific purpose to be able to mount the turbo high in the chassis and keep it away from the elements so you can prevent completely annihilating the hot side of the turbo while staying close to the intake manifold so that boost pressure is almost immediate with very little turbo lag. Good job Subie on the rally side. Now, for the daily driven, lets see about some factory FMIC’s so that I can stop spending roughly $2k every time I get a new STi….shall we? I hate to say this being a Subaru fan, but the EVO is FMIC from the factory. Oh, and USDM STi’s from ’04 to ’07 ( I think those are the years) DID come with a sprayer on the intercooler…..FACT!
Also, for the admin, is the excess parasitic drag worth it to save some mula? I’ve had my ’11 STi sedan up to 140 mph on the track and the fact that the hood looks ready to take flight is enough for me to want to go front mount with a regular, slick Impreza hood. Who knows, with the loss of the parasitic drag you might even see increased fuel economy on and off the track. With sooooo much air coming in the front and the top, it has to go somewhere…. you can only move so much air. As for the turbo lag BS that you refer to, if you’re putting on a front mount, the turbo mod may not be far behind… food for thought. For the safety concerns, I don’t PLAN on running my car into anything. If I did, I might actually have paid attention to that portion. It was clearly just there to scare people into thinking they would be complete morons for going FMIC. I’m not an anal retentive purist, I want the best and if top mounts were so awesome, then why in the world did Porsche go away from it? Inferior design maybe?
This article is a joke. FMIC’s always end up making substantially more power up top than TMIC’s do and never seem to show the “1000rpm later spool”.
Author needs to spend less time in the interwebs and more time in the shop and on the track.
I recon ima argue about this too! ….. Wait lets not nit pick each other. If you think someone is retarded let them be and dont tell them. Someone has to come in first and if your not first your last. 7 years with subaru professionally and I wont tell you a think without some big heads. So if you “know” whats better then do it. It gives me something to laugh at in traffic. There are two types of people in this world. Thoughs with load guns and thoughs who dig…. You dig
Great article, but I’d say 200-300rpm later spool, not 500-1000. I barely notice it, and I have a big enough intercooler core and enough cooling with meth that I can run massive amounts of timing and boost. I get enough torque from added timing that lag doesn’t even matter.
I also know that my setup is ready for whatever turbo I can throw at it. If you know you’re going to be outgrowing your TMIC someday it’s more economical to buy an FMIC first than buy a TMIC then have to sell it for a FMIC later. If you never plan on going that route a big TMIC w/ meth is probably the ideal situation.
I still have a bumper a bumper beam too.
It is funny that people like tom say I got 4hp more buy going front mount. Imagine what you would have gotten spending half the $$ on a top mount. I bet you would have that 4hp or more and quicker spooling time.
[...] if your planning on bigger turbo down the road. As for the TMIC vs the FMIC this is a good read. Why you don't need a Front Mount Intercooler on WRX STI | R U Subaru? – Tuning Forced Induction Cars… Seems like they are abit biased and some of the info seems outdated, but overall a good starting [...]
I do not hold any bias towrd FMICs or TMICs, yet one thing I would like to add is that with a rotated manifold you can cut down on roughly 2ft of intercooler piping on a FMIC, which basically negates the turbo lag argument.
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If you think you would prefer the front mount then go for one if not stick with the STI top mount.Quite simply really
I would like to see some numbers on a chart for temperatures for the meth. inj. TMIC and FMICs on this article. It would be a great deal of help for credibility.