09

Project GD STI- Keeping Cool with Greddy, Cobb and Koyo!

By Mike Kojima

At this stage in the modding of Project STI's engine, it is time for us to lay down some base parts to support our plans for more power later.  One of the weak points of the Subaru intake tract is its top mount intercooler or interheater as some call it.  It is pretty ineffective at cooling the charge air as it sits in a heat chimney right over the engine.  It is fed by a large scoop but air only flows through it at speed.  This makes for irregular intercooler effectiveness.  The top mount intercooler is a legacy of the car's rally heritage where the Subaru engineers wanted to move the intercooler out of harms way.  Interestingly enough the last generations of Subaru's WRC car had front mounts.

Like the WRC cars we had to go with a front mount intercooler.  Greddy came to our aid here.  Since we are after balanced performance, we could not just stop with the front mount.  We had to add some peripheral things to optimize our intercooler install.  Since the intercooler impedes some airflow to the radiator, we installed a Koyo racing radiator to keep our temperatures in line.  We also installed a Greddy oil cooler and a Synapse adjustable BOV.  A Cobb intake also was used to make room for the intercooler plumbing.  Finally some custom fabrication was needed to clean things up as well.  The end result was a really sanitary set up that will support more power in the future and help reliability in track and other hard use.

Check out what and how we did it all!

Read more about Project GD STI here!

The Greddy front mount intercooler kit uses a high quality tube and fin heat exchanger.  It is moderately sized which is good for around 400 hp.  We have found that really large intercoolers lose power and increase lag in moderate boost, pump gas applications.  We generally like thin core tube and fin heat exchangers for applications where the car is in motion at higher speeds when under boost because they are lighter and work well with good air flow. They also allow more air through the core for the radiator. For applications like drag racing where the car is under boost at low speeds (like during burnouts and launch) bar and plate intercoolers work well due to their much higher thermal mass.  The Greddy intercooler kit comes with lightweight high quality aluminum piping and a new lower profile radiator overflow tank.
The Greddy kit comes with all fasteners, brackets, couplers, clamps, hoses and hardware needed for a clean installation.
Since oil is used to lubricate and cool the hot turbocharger, most turbo cars come with a large oil cooler from the factory.  Our Subaru surprisingly only comes with a small oil to water cooler that uses engine coolant to keep the oil cool.  We think that this is pretty inadequate for any sort of hard use.  We opted to use Greddy's side mount oil cooler kit.  The Greddy kit has a large high quality heat exchanger, braided steel lines, AN hose fittings, an air baffle, brackets and a filter adaptor bracket.  The Greddy cooler retains the stock oil cooler and supplements it.
Since the Greddy intercooler kit does not have a compressor bypass/blowoff valve, we used a Synapse DV.  The Synapse DV is a highly versatile and tunable valve that uses a multi substrate piston.  The substrates have different surface areas so you can tune the valve's response time by using different vacuum ports.  The DV has no diaphragm that can fail and has a super fast 25 millisecond response time.  The valve preload can also be adjusted.  The DV can be set up for push, pull and push/pull activation as well depending on how you configure the ports.  The DV is also highly leak resistant when subjected to boost pressure.
The DV has a large valve with a direct air path for good flow which can help reduce compressor surge when compared to conventional blow off valves.

  

 

 

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Comments
x01011000x
x01011000xlink
Tuesday, October 09, 2012 10:05 PM
Did you play around with the idea of a reverse intake manifold for the front mount? With the right setup, you can retain the AC.
Fly'n_Z
Fly'n_Zlink
Wednesday, October 10, 2012 7:17 AM
Wait, I don't remember the article mentioning that they had to lose the A/C. Or is it just that if you run a reverse intake manifold and FMIC that you might lose the A/C?

Does a reversed intake manifold setup result in less intercooler piping volume?
amp0412
amp0412link
Wednesday, October 10, 2012 9:58 AM
Typically on a Subaru when people run a reverse intake manifold setup with a front mount, the alternator is flipped on its bracket and is placed where the a/c compressor is to make room for he piping between the hood and the motor.

However if you buy the right kit or make your piping properly and run phenolic spacers between the tgvs and the heads. The phenolic spacers are supposed to help keep the tgvs and the intake manifold cooler by placing and insulator between manifold and the hot heads. However with the right piping and the right amount of spacing and some trimming of the under hood bracing its possible to squeeze the piping in there without moving the alternator and therefore allowing you to keep the ac. Also I would imagine that you might also need a slimmer fan on the back of the radiator as the stock ones don't leave a ton of room between them and all of the belts on the front of the engine.

In a typical suabaru front mount kit with the intake manifold in the factory position there is no need to remove the ac.

To answer your last question. Typically reversing the intake manifold leads the shorter cold side piping from the intercooler to the throttle body because the piping does not need to wrap around the motor the get to the throttle body.
Dan DeRosia
Dan DeRosialink
Wednesday, October 10, 2012 1:58 PM
Weird thing is I'm not sure when Subaru actually even did run TMICs in the WRC cars. Everything I've seen since at least '98 has been some variation of FMIC; usually v-mount setups.

Looking at my own bugeye though... I just can't bring myself to seriously consider an FMIC setup. Speaking as someone who used to do safety engineering and crash testing, the idea of cutting the bumper beam on something that's a daily driver that hauls not only me but my soon-to-be-wife around is just wholly unappealing, and it looks like pretty much all the setups require cutting it. Maybe an upgraded TMIC and water injection to bandaid it.
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 3:23 PM
I remember we tested an upgraded TMIC at SCC way back when and it lost a bunch of power. I forget whose it was though.
Dan DeRosia
Dan DeRosialink
Wednesday, October 10, 2012 3:58 PM
Supposedly the Process West piece is pretty darned good, at the very least up to the 400 whp range. Their setup also incorporates a purpose designed splitter and gasketing to make it flow air into it properly from the hood scoop. And Geoff at Full Race has a few turbo-in-the-same-place-it-is-normally (doesn't bolt up to the stock up-pipe so forumites threw a hissy fit over calling it stock location) setups for the small frame EFR out in the wild, including the new 7163, which looks attractive as hell. Which should all end up as a fun ride.

... yeah I know that at the very least, theory is saying that an FMIC is going to work better, and frankly I don't see any reason to doubt that in practice... I'm just (eventually) rolling the dice that it can be bandaided around at modest power goals because I'm not happy with the compromise.

Or maybe I should bite the bullet and get something to use as a mule to develop a v-mount setup or something similarly silly. Too many projects, argh.
spdracerut
spdracerutlink
Wednesday, October 10, 2012 4:44 PM
A possible option is a air-water IC. Then you can have a slim radiator up front with a pusher fan on it; so that can maybe be made to fit behind the stock bumper support.
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 4:51 PM
A possible option is to leave what we did alone because it works and it's easy.

I wish I remembered who made the TMIC that didn't work. It was a bar and plate that took up the whole hood scoop area. It looked real good.

It made less power even after Shiv tried to tune around it. I think it might have actually increased the charge air temp because it didn't seal up to the hood. Maybe Coleman remembers more.
Dave Coleman
Dave Colemanlink
Wednesday, October 10, 2012 4:57 PM
I can't remember it either. Three letters. Came from Australia. Anyway, it didn't lose a bunch of power, it simply didn't help. I stuck a thermocouple in the throttle body and measured charge temp in real world driving and found that it didn't cool as effectively as the stock one, and the extra mass of the bar/plate design made it retain heat much longer after being stopped in heat chimney mode.

The stock tube/fin intercoolers heat up a bit when you're sitting still, but they cool off remarkably quickly when you start moving. Everything is cool before you hit 2nd gear. Really much quickler than you'd expect.

Anyway, whoever they were (started with an A...) they were SUPER PISSED that we actually tested something and told the truth about it. Like most of the aftermarket back then, they didn't know the difference between the articles and the ads...
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 5:03 PM
The GTI-R TMIC would actually heat the intake charge. They were not vented as well as the subie IC though.
Dan DeRosia
Dan DeRosialink
Wednesday, October 10, 2012 5:06 PM
Oh; if there was any idea I was trying to second-guess what you guys were doing, that wasn't my intent - I'm just emphasizing different build tradeoffs. Maybe. Or fooling myself as to what's possible with the TMIC configuration and a really good setup, possibly. ;)

Part of me is just a little sad; I saw the opening image and got really excited thinking you guys managed to cram the Greddy IC in there without cutting the bumper beam.

APS for the TMIC maybe?
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 5:29 PM
Crawford and Perrin FMIC's don't require the bumper beam being cut so if thats important to you, those are good options.

I wanted to try the Greddy because in my current thinking, a thin tube and fin with a big frontal area works the best.
Dusty Duster
Dusty Dusterlink
Wednesday, October 10, 2012 5:55 PM
Doubled your oil capacity? Either that oil cooler is HUGE or that engine doesn't use much oil to begin with. What's the motor's stock oil capacity?
Dusty Duster
Dusty Dusterlink
Wednesday, October 10, 2012 5:58 PM
I really liked the oil cooler install, BTW. The Mustang is going to get some cooling mods in the future, and I'm going to steal some of your ideas. Especially about the heat shielding on the cooler lines!
Dan DeRosia
Dan DeRosialink
Wednesday, October 10, 2012 6:00 PM
Looking at the instructions, the Perrin one at least replaces the bumper beam with... essentially a hangar for the intercooler rather than something that will take an impact. The install instructions for the Crawford one won't download right now, but I'd wager they came up with something similar, or perhaps a clever way to mount the intercooler without something like that. Neither seems to require cutting the bumper beam, but I don't think they retain it either. If you know different, I'd be happy to be proven wrong; I certainly like your thinking with the Greddy.

It's all down the road anyway so maybe the market will be different by the time I'm ready to actually shell out; paying for wedding and honeymoon stuff is going to dominate my wallet for a good long time to come.
spdracerut
spdracerutlink
Wednesday, October 10, 2012 7:41 PM
Tube and fin is the only way to go for a road course car, IMO. Bar and plate blocks too much airflow to the radiator, and bar and plate tends to be heavier.
Dave Coleman
Dave Colemanlink
Wednesday, October 10, 2012 9:01 PM
Kenku, yes, it was an APS top-mount that we tested way back then. That was an important lesson that thicker isn't always better. I don't remember if that intercooler sealed properly against the scoop or not, but either way, a thicker core tends to reduce cooling airflow, and i suspect the top-mount position doesn't offer as much pressure drop to shove that air across the core.

Remember, that test was a loooong time ago. Not sure if that intercooler is still sold, and if so, not sure if they've changed the design.
Mike Kojima
Mike Kojimalink
Wednesday, October 10, 2012 9:29 PM
Wow, that's what Perrin means by no cutting of the bumper beam needed! Quirt Crawford told me that theirs fits under the beam.

Dave- I think that test was way before the STI.
Dan DeRosia
Dan DeRosialink
Thursday, October 11, 2012 5:06 AM
Really... hm. That's food for thought then. Even if the Greddy one is full of tube and fin sexiness.
x01011000x
x01011000xlink
Thursday, October 11, 2012 8:53 PM
The 08+ STi TMIC was an improvement over their past stock offerings, that and the scoop just worked much better. You "could" retrofit it on a GD, but it won't line up with the hood scoop opening fully. Not that most of the aftermarket TMICs do anyway.

Kenku, I think the Process West with the stock like location EFR setup would be a fun street car.

spdracerut, you may be interested in this air to water IC IWSTI thread:
http://www.iwsti.com/forums/water-meth-injection-nitrous-intercooler-cooling/199117-t-gs-air-water-ic-build.html
Dan DeRosia
Dan DeRosialink
Friday, October 12, 2012 6:36 AM
Found the install instructions on the Crawford FMIC ( http://www.crawfordperformance.com/docs//images/Front_Mount_Intercooler_Kit_Install_02-07_Version_1.00.pdf for the curious)... it's interesting how it mounts with the mount tabs integrated into the core, though it's using some of the bumper beam holes to mount the core and that makes me wonder. But it's obviously hard to be sure, and as Mike said, Quirt Crawford said it fits and he'd know.

I don't know, am I overthinking this and/or being a wuss? Having people important to me dying in an accident seems like a pretty big price to pay for even 30-40 extra horsepower on a DD, but a lot of people *do* cut bumper beams or remove them or the like, and it's not like you hear about lots of people dying as a result.

(again, I'm not calling anyone else's choices into question; more into 'shooting the shit' mode and trying to not overly focus on getting married in 7 hours)
Mike Kojima
Mike Kojimalink
Friday, October 12, 2012 8:01 AM
Its one of the reasons why we built the bash bar back into the bumper ends. The bumper reinforcement is a subsantial part. Removing it would change airbag deployment chariterisitcs for sure. I used to do testing for that and know what happens when you change the front structure. It would also affect chassis stiffness, especialy in torsion. It would also affect offset barrier crash results. A lot of racing subies don't run the beam and if this was a race car I would be running something less substantial for sure to save weight.

Don't let her eat the cake or it will be all over! They put something in it.
Dan DeRosia
Dan DeRosialink
Friday, October 12, 2012 8:36 AM
We have a bunch of cupcakes actually, instead of a single full blown cake, but we'll see if that makes any difference. I'm really looking forwards to it, just, you know, my adrenaline level is pretty similar to sitting in grid with the crash hat on.

Back to FMIC... packaging is just really weird with the boxer. I was trying to think of a better way to do things and it seems like most of the really good solutions would mean reengineering the whole cooling architecture, which is probably not optimal on a DD. I'll call Crawford around when I'm ready to see, but may just be stuck with TMIC; whcihever! At least I can comfort myself with the fact that it's nowhere near as bad as my soon-to-be-brother-in-law's Celica Alltrac.
x01011000x
x01011000xlink
Saturday, October 13, 2012 12:23 PM
There is also a JDM front bumper beam. It's lighter for sure, but I don't know if it will allow you to fit a FMIC without modification.
xeno_impreza
xeno_imprezalink
Wednesday, June 12, 2013 5:01 AM
Which version of the Greddy intercooler kit is this? There is a 28V and 28R intercooler available for the GD STI.
skets
sketslink
Friday, September 27, 2013 8:35 AM
Will you be looking to add water/methanol injection similarly to what you did with project EVO IX?
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