Thinking about heat under hood of my Outback XT - Phenolic Thermal Manifold Spacers

[Nuclear]

Hello, Subaru`s brotherhood members!

As you know, I have 2004 (2005 model year in BL|BP|B13) Subaru Outback XT with 2,5 turbo, AT

Stage is something like Stage 2,5 - full catless, 3" exhaust, equal length headers (Tomei), Grimmspeed top mount intercooler (TMIC), fuel pump - Deatschwerks DW65C.

 

Intake manifold is stock plastic one.

 

During last half of year i am thinking about heat under the hood of my car.

As everyone of us knows - a lot of heat comes from engine block to intake manifold, so - there is idea in enthusiast brain to change engine block-TGV gasket (OEM partnumber # 16272-AA001, 2 pieces) and TGV-intake manifild gasket (OEM partnumber # 14035-AA490, 4 pieces) to something more thicker

Of course, first of all looking to the Phenolic Thermal Manifold Spacer made by Grimmspeed.

 

Did any of you use it already?

Any issues with setting up of 8mm spacers made by Grimmspeed?

There are not a lot of manufacturers of such type of product, but ---->

In my country we have equal product but it`s 10mm height.

Do you think i will have any issues with this size?

[Dujo]

Yes, I think you might have some issues with that size. So I got 8mm phenolic spacers from IAG, which I believe is pretty much the same thing as the Grimmspeed one. I did indeed have a problem closing the hood! Keep in mind that the intercooler is located in the engine bay by it's connection to the turbo and also by it's connection to the driver's side bracket which attaches to the intake manifold.

 

If you raise the location of the intake manifold by 8 or 10 mm, it will raise the intercooler by approximately that amount as well. The clearance problem isn't with the intercooler itself so much as it is with the BPV/BOV. That was the part blocking the hood close, but you see how it all flows from the top deck of the head on up. There are solutions to this problem and not all combinations of parts will necessarily have this problem, but it's an issue that I did not think would be an issue and it turned out to be one.

 

I have a Process West intercooler and a Forge BPV. That Forge unit is not short by any means, but anything is going to be pretty close. I solved it by changing the location of the bracket mounting points from on top to be underneath with a through bolt, but a shorter BPV like a Turbosmart shorty might have solved my problem as well, but I didn't want to replace my perfectly good, great performing BPV. So monkeying with the mounting points was required. It's worth noting that my intercooler does not really sit quite square to the hood and it looks a little canted in the engine bay, but it functions. Not saying this will be a problem for you for sure, but definitely something to consider.

 

 

The other side of things is whether or not you really need a phenolic spacer or will make good use of one. Your plastic intake manifold is actually kind of a good thing, believe it or not. The plastic does not heat soak like the metal ones do. A phenolic spacer is really more of a tool used with the metal sti intake manifold where it is a lot more valuable. You don't gain nearly as much value from adding a plastic spacer in between an aluminum head and an intake manifold that's already plastic. There is some minimal value and I thought it would be a fun addition to my project, but in your case (and in mine too really), it's probably not worth the headaches it will cause, which are admittedly solvable, but it's another layer of complexity to an already tough swap on doing the TGVs. Good luck!

[Gex]

I am running the 8mm phenolic spacers with the STI manifold as opposed to the larger plastic manifold found on the LGT/08+Wrx. The spacers were necessary for me to fit a 3" turbo inlet. I'm sure they do help take some heat out of the manifold, but the sti manifold gets inherently hotter due to the metal heatsoaking more. As for hood clearance. Once again I am running a STI fitment Grimmspeed topmount and I had to entirely remove my underhood shroud to close the hood. I'm sure you could trim it to fit. I also believe the engine sits slightly higher in the obxt.

 

Either way the spacers are a nice product that do what is intended.

[Nuclear]

I am running the 8mm phenolic spacers with the STI manifold as opposed to the larger plastic manifold found on the LGT/08+Wrx. The spacers were necessary for me to fit a 3" turbo inlet. I'm sure they do help take some heat out of the manifold, but the sti manifold gets inherently hotter due to the metal heatsoaking more. As for hood clearance. Once again I am running a STI fitment Grimmspeed topmount and I had to entirely remove my underhood shroud to close the hood. I'm sure you could trim it to fit. I also believe the engine sits slightly higher in the obxt.

 

Either way the spacers are a nice product that do what is intended.

 

 

Is metal STI intake manifold are smaller and less in height?

[Gex]

Less bulk and less in height. It is definitely not worth the labor and parts needed for the swap. Keep the plastic manifold.

[Max Capacity]

Just saying, its a street car, not a race car. Are those spacers really going to be that much of an improvement ? After sitting at a traffic light or in stop and go traffic on the highway...

[Rhitter]

Just saying, its a street car, not a race car. Are those spacers really going to be that much of an improvement ? After sitting at a traffic light or in stop and go traffic on the highway...

 

I asked M Sprank about this when I was getting my rebuild done. He mentioned the only reason to install them on the plastic manifold is to get more space for a different intake (if needed). They do nothing on our cars.

 

On the OEM STI manifold the spacers help separate the metal STI manifold from the heat of the engine, this isn't needed on our cars.

 

If you want to cut down on heat focus on the turbo (blanket / heat shield) or the hood (extractor vents - done right). Raising the plastic manifold up will do a whole lot of nothing.

[bigleben]

Also they don't seem to like freezing climate. From my mech's experience, every spacers he installed/saw at his shop cracked and leaked after couple of winters.

[Dujo]

^ Didn't know that one. Thanks. Will keep an eye out for that.

[Tuning Alliance]

If you are worried about heat, get a front mount.

 

-Brian

[Dujo]

Which is a whole other ball of wax.

[Nuclear]

If you are worried about heat, get a front mount.

 

-Brian

What for if i already have TMIC by Grimmspeed, that is not worse:eek:

[Rhitter]

What for if i already have TMIC by Grimmspeed, that is not worse:eek:

 

A TMIC will always be at a heat disadvantage. It's sitting on top of the motor, hangs over the turbo, air is forced through a small hoodscoop, heat rises.

 

A FMIC sits out in front of everything. The only heat you have to worry about is coming off the pavement(which can be hot, but not like a turbo)

[Nuclear]

A TMIC will always be at a heat disadvantage. It's sitting on top of the motor, hangs over the turbo, air is forced through a small hoodscoop, heat rises.

 

A FMIC sits out in front of everything. The only heat you have to worry about is coming off the pavement(which can be hot, but not like a turbo)

May be you right, but i think that GrimmSpeed product was

breakthrough, judging by the results of tests and reviews

But, lets not begin holywar here about TMICvsFMIC

[scoobyscoodle]

I drive a lot in a pretty hot climate, max around 115 or so and consistent 100+ for 3 months of the year.

 

I switched to a FMIC and never looked back. Zero disadvantages from my point of view.

[kzr750r1]

Nice part about the STI or GS TMIC is uncoupling it from the turbo with a silicon hose. Your still going to get heat soak in bumper to bumper traffic from the motor.

Some of us need to go back to a stock apperance and tune every two years. Going full front mount is more work than I would be willing to take every time.... And no you can't leave parts hanging for re-fitment later.

Glad I passed on the spacers during my build.

[tocinoman25]

Those of you that have the phenolic spacers how drastic did the Temps drop? I considered this mod too but for now I has turbo heatshield, turbo and dp blankets and gold tape to help keep Temps down lol. Makes me want to consider fmic...but no because sleeper

 

http://uploads.tapatalk-cdn.com/20160829/e9b217475bc6576932f1275668876b5c.jpg

 

Sent from my SM-G935V using Tapatalk

[scoobyscoodle]

If you have the plastic/composite LGT manifold the phenolic spacers will not do anything to reduce heat at all. They are mainly used to space the manifold up to fit a larger inlet and for more room under the manifold in general.

[Tuning Alliance]

What for if i already have TMIC by Grimmspeed, that is not worse:eek:

 

It will still heat soak, there's no avoiding it. Your best option would be to sell it, and buy any fmic (if you are worried about higher intake/charged temps).

 

-Brian