how does the intercooler flow work on an 818

[auburn2]

On an impreza a forward facing hood scoop flows air in and down through the intercooler. Looking at the 818 there are two vents that look to be over where the intercooler sits but I don't see anything indicating how the air will be forced or directed down through it. Does the 818 include an intercooler fan or anything?

[JeromeS13]

No fan. The two top vents are channeled inwards toward the intercooler.

[Mechie3]

It uses sheet metal pieces along with the top fiberglass piece to direct the air to it. The GRM build might have photos of it.

[Goldwing]

As I recall, reports from the open house mentioned the FFR guys found that the airflow was sufficient through the shoulder vents, through the intercooler, further aided by a vacuum from airflow underneath the engine. Time will verify that I guess.

[longislandwrx]

Capture.JPG

Here's a nice picture of how it works

[Mechie3]

Which reminds me....my aftermarket TMIC won't work with those....doh!

[305mouse]

AWIC time

[Frank818]

AWIC time

Right on!

[RM1SepEx]

Capture.JPG

Here's a nice picture of how it works

what is the purpose of the vent aft of the intercooler in the trunk panel?

[JeromeS13]

I would assume it's to create a low pressure area above the deck lid, to help suck hot air out of the engine bay.

[longislandwrx]

Which reminds me....my aftermarket TMIC won't work with those....doh!

Why not? The manual shows that they are trim to fit. Also, the R is running a larger intercooler.



also, how good does that carbon diffuser look down in there!

[Mechie3]

AWIC time

Translation: Spend more $$ time!

Why not? The manual shows that they are trim to fit. Also, the R is running a larger intercooler.

The R has the passenger headrest area cutout IIRC. What i meant was, I'd have to trim/fab up new stuff to make it work, not just bolt it in. Not a big deal, just something I'd forgotten about.

[Santiago]

also, how good does that carbon diffuser look down in there!

I just saw that! Sexy!

Maybe it's just me, but I can't seem to find any good pics of the carbon rear diffuser from the outside/rear of the car. Anyone have a good shot of it?


Best,
-j

[longislandwrx]

I think you have to trim it for the stock one anyway, it says allow 3/4 gap around the perimeter for engine movement.

See page 449 I'll know for sure tomorrow

[BrandonDrums]

Yeah, I hate to say it but there's just not enough airflow in this setup. Either a snorkel needs to be installed, the IC re-located to the rear mesh area of the tail or an AWIC needs to be installed. Heck, even some PVC piping routed from the front grill area would provide more flow. You know if the R version is getting heat soak with the entire passenger hump ducting air to the IC that the street version is practically un-ventilated.

Color me a little disappointed. Who wants to try to fit a pair of these to the humps?

[Mechie3]

I think they also mentioned on the R version that the turbo wasn't well shielded.

[BrandonDrums]

I think they also mentioned on the R version that the turbo wasn't well shielded.

True but still, that whole engine compartment is pretty closed in. I'd be interested to see the IC surface temps on a stock setup with the heat shield installed.

[BrandonDrums]

Actually, does anyone know if the fender vents get opened up at all or are people just painting them black? Looks like you could cut a hole and put some ducting in the top corner of those vents to incorporate more flow into the existing vents going to the IC. That would be more than double the flow....

[Mechie3]

They get cut open. FFR supplies precut mesh and trim rings for that area. Wayne just decided not to use it.

Here's an Exige with a shroud over the intercooler feed with the roof top scoop. Making a similar shroud fed with a hose from the side scoop is something I'd like to see someone try.

[Wayne Presley]

The air to air intercooler doesn't work as well as the AWIC, not close.

[Frank818]

The air to air intercooler doesn't work as well as the AWIC, not close.

Of course it doesn't!
All hails AWIC!

[Frank818]

Is that another one of your dog collection?

[BrandonDrums]

The air to air intercooler doesn't work as well as the AWIC, not close.

Of course not but this is an FFR we're talking about. There's gotta be some simple solution we can implement to allow as much if not more airflow to the stock intercooler than the donor vehicle had.

As it sits now, the 'pitch' of the 818 is the single donor vehicle and kit package. It shouldn't be a requirement to invest into an AWIC to have a reliable engine unless FFR is willing to include them with the kit....The target market for the 818 is the average joe who's going to buy a used stock WRX example and worry about upgrades later. If that means driving around with a glowing hot intercooler and tons of det then he might not even be able to afford the upgrades later because he'll be getting engine rebuilds.

By all means, I'd love to see AWIC be a standard feature. Otherwise, I think we're going to need a better setup to get more airflow to the intercooler on the stock unit. I really wish I had an example to work on myself.

I do think some intercooler piping routed from the side vents nozzled onto the intercooler will do wonders. Even PVC will work. I'm thinking take a 2.5 or 3'' pipe cut with an angle to fit in the top corner of the side vent routed up to the existing 'ducts' could help a whole bunch. Doing pipes instead of aluminum panel ducts from the top vents that are merged into a Y fitting with the lower vents would be probably about all you need if there's a nice fitting shroud. That would about as much airflow as you'd ever need.

Another option is to move the intercooler all the way back to the mesh opening on the rear of the car. That far back you don't have as much direct radiant heat exposure and the reverse induction effects on that vertical flat trailing surface would far exceed the stock hoodscoop.

[D K]

^
Longer piping = more lag

[Slatt]

It seems to me the existing FFR ducting to the intercooler provides an adequate path for cool air, but there is not enough differential pressure between those side inlet ducts and the engine bay outlets (there's a lot of outlet!) to create much flow. A pull-thru fan mounted below the I/C with a shroud would surely solve the problem. This was never a good option in a WRX (firewall and bobble-strut in the way) but surely there's room in the 818??? Yes, the shroud has to work around the I/C inlet pipes, so it'd be a little complicated to make.

Maybe a current kit builder could eyeball that option? I reckon a shroud could be mocked up / proven with kivex and, once you are happy with it, finalized in aluminum. There is that mount on the tranny where the bobble-strut used to be to create a metal support for the fan. I dunno, can't say for sure, my kit's gonna be a long time coming.

Edit: ok, bad memory, that bobble mount is not on the tranny at all, it's from the firewall to a bracket and then to some-kind-of-darkness-I-couldn't-quite-make out. Still, I think that bracket can be used to support the fan. You didn't throw that bracket out did you?

One last edit: I'm looking at a 2003 WRX.

[BrandonDrums]

^
Longer piping = more lag

Yeah but it's still relatively short compared to a FMIC kit on a stock WRX. Keeping it in the stock location and piping more flow to the IC from the side vents though....sounds like a probable fix.

I also like the fan idea, however it's hard to get a shroud to fit and seal well over all the pipes on the bottom of the IC.

[D K]

Top mount = short piping, no airflow
Front mount wrx = pretty short with rotated turbo, great airflow
AWIC = short piping, need a more complicated system to make it work.

Im personally going with AWIC because Im running a larger turbo and need the best transient response possible.
Im willing to put up with the extra weight, complexity and cost of the AWIC system.

Top mount in a mid engined car is a joke.

Only other option would be to mount an air cooled ic behind the passengers headrest.

Air cooled ic needs massive flow ro be effective.

[Xusia]

I also like the fan idea, however it's hard to get a shroud to fit and seal well over all the pipes on the bottom of the IC.

Radiator fans are effective and don't "seal" at all!

[longislandwrx]

Top mount in a mid engined car is a joke.

Only other option would be to mount an air cooled ic behind the passengers headrest.

Air cooled ic needs massive flow ro be effective.

I disagree, the new forester xt has no scoop and only a small inlet, which doesn't constitute "massive airflow" and does a fine job cooling 250 hp. Guys are already making good power with the stock IC.

[BrandonDrums]

Radiator fans are effective and don't "seal" at all!

...and they also aren't separated by 3'' worth of piping between them and the radiator surface. I was responding to another member's suggestion to have a puller fan between the IC and the rear mesh exit vent. A pusher fan mounted on top of the intercooler would work great.

The best shape for a top mount fan would be from a fireplace blower fan. You can get these for less than 100 bucks, they technically get their intake from the sides and come in all sorts of shapes.

I don't know how they'd stand up to weather though but they can easily be housed in an aluminium shroud directly on top if the IC. I don't know how much they'd flow without killing the alternator but could be a good route to take. I have a intercooler blower fan 'array' using 3 server cooling fans that held up to rain just fine. They didn't blow nearly enough to get the IC to ambient but they were great in preventing heat soak when I was sitting still. I have them mounted on aluminium rails that I just clip to the flanges in my IC during the summer.

This setup would be better though, I'm thinking of doing this on my WRX now. One of these 150 CFM units could easily fit in the hoodscoop and I could build an aluminium shroud for it that covers the top of the IC. With a little modification I'd still be able to get almost all the airflow at speed through the fan too I think.

http://www.electricmotorwarehouse.com/fireplace.htm

Here's a couple examples of these ranging from 12''-15'' long and 3.5 - 5'' high.

[RM1SepEx]

what good does a 115 volt fan do for you? You need to find a similar 12 volt model

[D K]

250 might not even need an intercooler.

500 however, is a different story.

I disagree, the new forester xt has no scoop and only a small inlet, which doesn't constitute "massive airflow" and does a fine job cooling 250 hp. Guys are already making good power with the stock IC.

[Mechie3]

250 might not even need an intercooler.

500 however, is a different story.

someone tried that. They also tried using meth to cool the air charge. In teh end they determine it wasn't worth the risk of detonation and the resulting lack of power from pulled timing and higher temp intake charge.

[longislandwrx]

250 might not even need an intercooler.

500 however, is a different story.

Guys are making quite a bit more on the stock fozzy IC. Most 818s are going to be making stage 2 power, and the FFR setup will be fine. Saying "Top mount in a mid engined car is a joke." is silly especially when you consider that turbo 911s have long used that setup and still use a variation of it.

For your 500 hp 818, a top mount might not be for you. I'll look forward to seeing what you come up with.

[flynntuna]

How about reusing the heater fan as a top mounted IC fan? build a shroud and have ductwork come from the side scoop. Would it be worth the effort?

[JeromeS13]

someone tried that. They also tried using meth to cool the air charge. In teh end they determine it wasn't worth the risk of detonation and the resulting lack of power from pulled timing and higher temp intake charge.

It was Perrin. Definitely an interesting read:

http://blog.perrinperformance.com/yo...rcooler-right/

[BrandonDrums]

what good does a 115 volt fan do for you? You need to find a similar 12 volt model

They sell units without motors. I'm not suggesting running a 115 volt unit obviously.

How about reusing the heater fan as a top mounted IC fan? build a shroud and have ductwork come from the side scoop. Would it be worth the effort?

Hey, that's an awesome idea.

[D K]

turbo 911s have long used that setup and still use a variation of it.

911 Turbo is a REAR engined car with a huge whale tail that houses the air to air IC to get the massive airflow necessary to make it work.

Perhaps I should clarify: a stock sized top mount IC for MY power goals in wheel to wheel racing would be a joke.

D

[BrandonDrums]

Guys are making quite a bit more on the stock fozzy IC. Most 818s are going to be making stage 2 power, and the FFR setup will be fine. Saying "Top mount in a mid engined car is a joke." is silly especially when you consider that turbo 911s have long used that setup and still use a variation of it.
For your 500 hp 818, a top mount might not be for you. I'll look forward to seeing what you come up with.

I believe all WRX based 818's will at least be making stage 2 power. Aren't the FFR guys supplying a reflash tune? I thought that was something they announced when they quoted the HP figures of their factory model. Maybe I'm remembering incorrectly.

In any case, TMIC is certainly fine given the airflow. If you look at any turbo 911 with a top mount you'll see that that the intercooler isn't only massive compared to the wrx/sti OEM units but it's under a giant mesh opening and located directly above the cooling fan. It's also over a foot away from the turbo, not directly next to it like in subarus.

I disagree, the new forester xt has no scoop and only a small inlet, which doesn't constitute "massive airflow" and does a fine job cooling 250 hp. Guys are already making good power with the stock IC.

BUT, it's in the front of the car. Big difference in the 'ram air' effect than behind the cabin where the car wedges through the air creating a turbulent bubble all around it. The 818 R lacks a full widnshield and allows more 'clean' air to go into the scoop on the passenger hump and STILL got heatsoak with a larger turbo. The street version will probably have this issue with a stock donor setup.

I'm not saying the 818 doesn't have access to proper airflow, we're just saying a bit more ducting needs to take place to get it close to the stock levels of airflow from the donor.

Another thing to consider is the lack of a scoop/opening above the intercooler. In the 818, the intercooler is close but not directly under the mesh opening on the clamshell. That means a lot more heatsoak will take place in the engine bay without a little more venting of some sort.

Lastly, The intake air temperature sensor on WRX's is located in the MAF housing which is pre-turbo. The ECU has parameters to reduce timing as intake temperature goes up but that measurement doesn't account for the intercooler's effects unfortunately. This is a big shortcoming with the subaru engine management system and contributes a lot to the failure rates of these engines. Keeping the intercooler near ambient temperature is the only way outside of a standalone engine management system to ensure you aren't inducing knock conditions that the ECU can't detect to our cars.

[longislandwrx]

911 Turbo is a REAR engined car with a huge whale tail that houses the air to air IC to get the massive airflow necessary to make it work.

D

Understood, the point being a non front engine configuration can still utilize a TMIC assuming proper airflow

Perhaps I should clarify: a stock sized top mount IC for MY power goals in wheel to wheel racing would be a joke.

D

Cool we are in agreement then. Not trying to argue, just thought you were saying that a TMIC was not a viable option.

I'll hopefully be putting 375 or so CHP through a coated Grimmspeed TMIC with coated header and uppipe, with a turbo blanket and heatshield. I'll be logging the data so I'll let you know what temps I'm seeing.

I'm not saying the 818 doesn't have access to proper airflow, we're just saying a bit more ducting needs to take place to get it close to the stock levels of airflow from the donor.

I can agree with this, however I do think the FFR supplied option will suffice for your basic stage two guys. Will there be heat soak? yes, will it be dangerous? no, the ots maps are very conservative and should be fine for most 818 enthusiasts