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Old 02-19-2001, 08:54 PM   #1
Scooby South
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Post Front Mounted I/C...Who's running them

alooooooooooha...
Piecing together a forced induction system..
So Far I have a Turbonetics T3/T4
Turbonetics Delta Gate
Turbo Blow off Valve
Holly Fuel Pump
Thats about it...for now...
The question is....For those that are running front mounts...Is there any lag??? or is it about the same as a topmount..

The plan is to get a TRUST Front mount I/C and custom Piping...

Opinons please...
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Old 02-19-2001, 08:57 PM   #2
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Thats the best way to mount an intercooler in any car that makes mad power. I would also invest in a Gear Box filled with Legacy Turbo gears if I were you because they are suspected to be stronger than the RS gears and don't cost as much as a Hardened set of gears. I will eventually us a FMIC when I get another car to cut down on the wear and tear on my RS.
Zee
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Old 02-19-2001, 09:30 PM   #3
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i know a guy at jcsports has or had one on his RS the only thing i see that might be hard is the plumbing of pipes to get it to the front. although it looks really good, probably gets more air too
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Old 02-20-2001, 04:12 AM   #4
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Does it count if its not on a Subaru? I like the FMIC setups. Its not sitting atop a large heat source, I can use alot larger unit, I can always source a used aftermarket unit from Japan at a dman good price, after 1Bar of boost it just seems like a good idea and the opening in my bumper is alot larger then a hood scoop will ever be.
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Old 02-20-2001, 01:41 PM   #5
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Either use a top mount or a Air/water. I have said it many times a FMIC is flat stupid on a street driven Subaru. The motor and turbo are at the back of the engine compartment. Why are you going to add 10ft of pipe to put in a marginaly better IC??

Oh and the area the hood scoop gets air from likely gets as much air as a FMIC. The air there reall doesn't want to be there (windshield) and will go anywhere else that is convient. Yes you can get flow through a Subaru TMIC by mearly cutting a hole in the hood and sealing the front edge against the IC. Not a good idea but it would work.

The FMIC recall has alot of stuff blocking flow through it as well (condensor, radiator,fans, motor, etc). In many cases its also easier for the air to go around the FMIC than through it.
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Old 02-20-2001, 02:45 PM   #6
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Well then luckily for me I don't have that problem as mine isn't a Subaru. You could also install the water sprayer kit on either the top mount or the FMIC. If you do use a top mount then you might want to get some weather stripping to use to make a seal betweent he underside of the hood and the top of the intercooler.
Has anybody looked at ducting air down to the turbo like the older WRX's and Legacy's did? I'd like to know how much if any that lowered the temps of the intake air.
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Old 02-20-2001, 04:46 PM   #7
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XT6Wagon..So your saying you can get more power out of a top-mount???? Yeah ..OK...and I have 5 22b's in my garage too...

Heat Soak man.....

When I was in Australia...Everybody I talked to..said it was stupid to keep the top-mount and not get a front mount...and I rode in some pretty fast 300 hp standard WRX's...Thats what the Ozzies do..they buy a standard WRX that puts out 225 HP...and spend $3000 to upgrade it to 300 Plus HP...and they have been tuning WRX's Alot longer than we have...upgrades include:
-Ball bearing turbo
-front mounted I/C
-3in Exhaust..
Thats it...so if you think it is stupid to have front mount instead of a top mount..Thats your business..Thanks for your opinion anyways...Oh BTW..I still plan on a front mount...Thanks

[This message has been edited by Scooby South (edited February 20, 2001).]
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Old 02-20-2001, 09:10 PM   #8
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If 500 people say that you get a 18" penis by hanging a 45lbs wieght off of the end would you??

Also the TMIC on the subaru is over the TRANNY!!. If you put on hood vents to keep the air cool under there it isn't a problem
The biggest problem is the turbo being so close to the intake manifold, right head, and intercooler. So put a extra duct around the turbo to cool it like the old legacy turbo and you are set. oh and the duct will be a great way to keep the remaining heat from reaching the other items. If you are not on boost all the time get a turbo blanket and call it good.

Do you have ANY idea the pressure loss from 10ft of piping and a minimum of 7!! 90 degree elbows?? Thats a bunch of extra heat the turbo puts into the air keeping up the pressur ein the intake manifold. Then the Larger FMIC to deal withthe extra heat will create more of a pressure drop, thus demanding a larger FMIC.

I think what you are thinking of is the fact that it takes a huge FMIC longer to reach equilibrium temp under high boost than the smaller FMIC. This is a non event if you use a water spray, or racing (not drag racing) where ANY intercooler raises to a set tempature. In which case the larger FMIC will have a higher temp due to the hotter air reaching it.

To put it better would you run a FMIC on a MR2???
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Old 02-20-2001, 09:17 PM   #9
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Oh and the old air duct turbo coolers on the XT turbo, and the Legacy were worthwhile. They didn;t seem to do much for underhood temps, but atleast on the XT reduced the overheatign problem by alot. I think this is due to less load on the cooling system, less radiation heat trasnfer to the right head, and cooler oil being poured on the bottom of the right head. Needless to say the old turbos craked the right heads ALTO when overheated due to the much larger thermal loads, that were also centered around the #3 cylinder.

Lag may have been worse as the air would then dump over the exaust and likely cool the pipe , thus coolign the exaust inside and reducing the energy to the turbo.
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Old 02-20-2001, 09:27 PM   #10
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If you are using a T04 and running 20+ pounds of boost then I would use a front mount intercooler for sure. The pressure drop is there but who cares I mean you will be making 200 horsepower down low and 400+ up top. With a top mount you are limiting the potential of a turbo motor. Sure its easier and there is minimal lag due to shorter piping but its not the best when it comes to power in a TurboCharged monster and that is what our small displacement engines rely on to make power. We don't have 5000+ Cubic Centimeters of volume so pressurize the little volume we have and keep the pressurized air as cool as possible. Once you get over that initial lag there is little or no lag until you drop off into the lower RPMs again and you still will be making 200+ HP at the lower RPM's which is more than enough to get around town. Top mounts are simple and effective, little lag, those are factors that the Manufacturer have to worry about. We worry about Max Performance and a top mount is not Max Performance.
Zee (N/A by the way)
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Old 02-20-2001, 09:44 PM   #11
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Just to add to this.. it is possible to shorten the piping in a FMIC set up by turning the throttle body/intake manifold around. (like in the Rigoli car)

Also.. the top mount intercooler itself in the new WRX gets really warm, mainly due to the high underbonnet temperatures reached. I always open the bonnet everytime I get home..just so the heat can dissipate quickly. I guess a hot IC won't cool the air as much as a cooler IC.

And as Scooby South said.. a lot of tuners here in Australia recommend a FMIC set up if higher hp is wanted. With the scoop on the new WRXs, a big part of it is over the IC, but a small part is actually a vent over the turbo. I don't know how effective this is, but it does direct air over the turbo.
just my thoughts.
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Old 02-20-2001, 09:45 PM   #12
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I do agree that the longer piping needed for a fmic intercooler in a "stock" configuration might have some disadvantages but no one really knows whether those disadvantages are really negligible or not since no one has done any back to back tests here in the US.

Anyhoo, I'm planning on using a tmic until I get enough time this summer to fabricate my custom alternator brackets for my 180 degree manifold conversion. This will allow me to run a fmic and keep the piping as short as possible.

<IMG SRC="http://aspen.mwic.org/22lm/180.jpg" border=0>
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Old 02-20-2001, 10:41 PM   #13
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XT6Wagon...Appreciate the instruction...But I think you just don't like a FMIC on any vehicle....Maybe I will reconsider if I run less then 10lbs of boost..then I can see your point...(I was told to expect about A 3 LB Loss for a front mount). was just seeing if that figure held water..thanks again...

Adrian128...thanks.I met Rigoli at the Gold coast..He's the man...Also hung out with the the WRX club presidents 0f the Queensland chapter and the Northern Territory chapter..
Man their cars are fast...aloooooooooha..
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Old 02-20-2001, 10:44 PM   #14
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Ok, what volume of air do you think you are pressureising?? The volume of the combustion chamber is the SMALLEST portion of the whole thing. The Intercooler, piping, intake manifold all are larger than the 1/4 of the displacement. Note that since the motor is a batch mode, only one cylinder is gettign air at one time.

Lets see:

8' of 2" pipe is 678.58 cubic inches
(might be closer than the pulled out of my ... er... hat figure of 10ft)

A 12"X24"X3" Intercooler with say an void raio (space inside the "box") of 40% would have a volume of
345.6 cubic inches

No idea what the intake manifold holds, but the plenium itself will be larger than 1/4 the displacement.

So you see all that pipeing has a HUGE affect on the volume pressurised.

Next up you are forgetting that one 90 degree elbow is more of a flow restriction than several ft of 2" pipe. I estimate it would take 7!! 90 degree bends to make a FMIC work. (normal intake manifold layout)

I will now talk about your idea that a bit of pressure loss does not matter. If you are amkign 20 psi in the intake manifold (correct place to measure boost), the turbo will have to put out 23 or so with a decent IC, and minimal piping. If you add several feet of pipe, several bends, and a much larger IC you will likely need over 25 psi at the turbo.
The TEMPATURE of the air coming out of the turbo is a product of pre-compression temp, pressure ratio of the compressior, and the efficency of the compressor. So the extra pressure loss hits you two ways. The extra boost will lower the efficency of the compressor as it will be farther away from the peak efficency island, and the pressure ratio is higher.

Next up to bat is the flipping the intake manifold. I think this is a REQUIRED operation to make a FMIC worth more than takign a leak on an angry pitbull. However I have heard that the A/C must be removed, and the alternator and PS pump must be mounted different. This seems like a non-possiblity for most people with a street car.

I will end with a bit of REAL WORLD evidence of the effectiveness of the TMIC. Look at the two SCC Impreza'a. The 99 was making abotu the same power (peak), with far less lag, a healthier mid range, and less problems with a small top mount, in comparision to the 98 with the FMIC. I hope Shiv can slap a better rendition of the two cars here.

Oh and I don't CARE what the people in austrailia do, after all people here are stupid enough to use chips in a VW 1.8T that make the turbo glow for over 2min after a high boost run. Just because its popular or believed does not make it true.
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Old 02-20-2001, 10:54 PM   #15
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Actually a front mount on an MR2 has been done, but bye bye passenger seat. I don't doubt that it causes some serious lag. I don't have a subaru, but I have an custom turbocharged v6 audi with a huge front mount intercooler, and close to 8ft of piping, and 6 90 degree crush bends. With a T3/T4 on my 2.8liter engine, boost begins around 2000 rpm and I reach 10 psi by 2600rpm. Minimal lag, for such a crappy intake setup, and it is a similar setup to a front mount on an impreza. Has anyone done any testing on front mount vs. top mount intercoolers? Including pressure drop over, and just as important temperature drop over the system. These numbers would be even more useful, if two setups could be compared with similarily sized intercoolers. I personally believe that on a high power, high boost engine, a FMIC is a must.
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Old 02-20-2001, 10:54 PM   #16
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Oh, no FMIC have thier place. On my SHO a FMIC is a given. Not only is their no room for a TMIC, but the area behind the bumper is HUGE, and thats the only easy place to run a pipe anyway. Put the turbo on the passenger side, and you have it made.

On other cars it depends. The Civic is one that a TMIC is also fairly stupid. Its easy and not too long to pipe the IC in front. Here like the Subarus there is a sweet spot under the hood for a air/water IC of decent size so for all out applications that is what I would pick. I believe the Celica all trac had to use a TMIC due to the lack of room in the front, I could be wrong though. A "TMIC" might be a good idea if putting a turbo on a car with the exaust at the rear of the engine bay. Cars like the neon, celica, VW VR6 cars, etc. This would be placed off to the side of the motor where(if) room exists.

Subaru is the only one that I know of off the top of my head where a TMIC seems in my mind to be the only sane way to do it. There is a large area under the hood that isn't over the motor, the turbo is a LONG way from the front, and the TB is pointing the wrong way while also placed far away from the front of the car.

Note no one has talked about BMIC. I saw a Turbo Z28 with a BMIC. I have heard that its a fairly good way to do it if done right.
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Old 02-20-2001, 10:59 PM   #17
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Thanks again XT6Wagon...
I appreciate the feedback...but unless your moving..the topmount is useless...and it will take longer for the charge to get cooler..
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Old 02-20-2001, 11:39 PM   #18
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So is the FMIC. Also when you are not mocing you are generating no boost and most of the time the throttle plate is closed.

Oh and I think its a toss up on which gets warmer at idle if the hood has two open vents. Recall that the FMIC is not but 1" from the radiator. Where as the TMIC is farther away from items, but more of them. Natural convection is of minimal benifit, but it owuld be greater on the TMIC.
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Old 02-21-2001, 12:39 AM   #19
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My old Pulsar had a top mount when I got it. I changed it to a FMIC cause I got everything I needed really cheap. Also I was running enough boost that the temp was a concern. The Galant leaves me no choice since I can't fit a TMIC under the hood with a V6 and two turbos
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Old 02-21-2001, 02:44 AM   #20
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I love threads like this

J.
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Old 02-21-2001, 04:08 AM   #21
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I like the threads where people argue over which is better a turbo or a supercharger. Those are the funny ones. Then again the old thread Dumb Question was pretty damn good as well.

Oh yah Jay_UK do you still want the Evo6 repair manual thing? I lost your email address. I'll send you the copy I have as my CD burner broke a while ago and I'm not going to replace it.
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Old 02-21-2001, 07:43 AM   #22
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Howdt doody..

Sure...

email is jay@c-t-l.co.uk

J.
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Old 02-21-2001, 08:53 AM   #23
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Question

I have a question then
what does swrt use and why XT6Wagon? i know what but why then?
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Old 02-21-2001, 09:16 AM   #24
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I think swrt has a FMIC set up

<IMG SRC="http://albums.photopoint.com/j/View?u=1418522&a=10612127&p=41602960&Sequence=0&re s=high" border=0>
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Old 02-21-2001, 11:25 AM   #25
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Just to note about the two SCC Impreza's,

If you read both full articles completely, you'll notice that they have very different setups hence the differences in peak and broadband power. I can't remember all the specifics but it's documented in those SCC articles. Shiv?

No one has done any back to back comparisons in the US for the tmic and fmic so anything said by anyone including myself, is purely speculation based upon theory and should be taken as such.

Just to note,
I've been studying the mounting of the FMIC and besides having the extra piping, there are also routing and placement issues that can involve cutting metal and possibly using the lightweight front bumper brace. It will depend on your particular intercooler, piping, etc.

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