Anyone with a FMIC swapped in a non-scooped hood?

I was just looking through junked legacies and saw a 2008 with no scoop which made me wonder about making my car even more sleeper-esque by putting a diff hood on since I have a FMIC.

Anyone done this?

. . . and underhood temps will rise, and you'll get knock!

The scoop isn't just there to bring in fresh air to the TMIC, it's also there to vent heat from the turbo. Don't believe me -- look at the shroud -- it's got that diamond section where it vents heat from the turbo. In fact, I believe Subtle even makes a turbo chimney for it, ala 1st Gen SS. (90-94).

LIEK DIS: http://farm4.static.flickr.com/3478/3457605859_e263714667_b.jpg

The point is, until you go low-mount turbo, ala '15 WRX or FXT, you need the scoop for the stock location turbo to vent heat.

Yup. Triscuit is correct. My '92 Legacy Turbo has no intercooler in stock form. The underhood deflector directs all air coming in the scoop to directly over the turbo "chimney" to give it a blast a cold air when the car is moving and to let heat escape thru the scoop when the car is stationary. There is no other purpose for the scoop on that car.

http://images.tapatalk-cdn.com/15/04/21/a827d34f1ff48048c073e4d4ffd84b3c.jpg

Other cars manage without direct airflow to the turbo. Why are legacys any different?

I've wondered about this too, would be awesome to have a blacked out fmic and no scoop but I don't know if the lag is worth it without offsetting it with more power first.

Other cars manage without direct airflow to the turbo.

Like what? I believe MOST other turbos are either on the front or sides of the motor, not in the back.

Other cars manage without direct airflow to the turbo. Why are legacys any different?

 

I've wondered about this too, would be awesome to have a blacked out fmic and no scoop but I don't know if the lag is worth it without offsetting it with more power first.

you are not the first to think about this and im sure someone here has done it many years ago.

remember...most the people on here are not engineer or physic majors. there is so much on this forum that contradicts every word said. EVERYTHING.

http://legacygt.com/forums/showthread.php/loose-scoopi-222891.html?t=222891&highlight=scoopless+hood

and again...

http://legacygt.com/forums/showthread.php/need-help-deciding-go-scoopless-keep-my-hood-my-fmic-164285.html?t=164285&highlight=scoopless+hood

with some creative engineering, you could create duct work behind the FMIC to send air under the car or out the sides thru the wheel wells. And use cowl induction to cool the turbo. Not an engineer, so YMMV.

If you really want to do something like this, contact BAC2.5 (an engineer) or several other actual engineers on the forum.

Yup. Triscuit is correct. My '92 Legacy Turbo has no intercooler in stock form. The underhood deflector directs all air coming in the scoop to directly over the turbo "chimney" to give it a blast a cold air when the car is moving and to let heat escape thru the scoop when the car is stationary. There is no other purpose for the scoop on that car.

Well... Actually.. On the JDMs, that had the AWIC, that's what the scoop was for. All SS VINs begin with J, because they were built in Japan, unlike their NA counterparts, which were built in Lafayette, IN. Now, we mostly use those scoops for added WRX TMICs, and, in some cases, JDM AWICs. .

Like what? I believe MOST other turbos are either on the front or sides of the motor, not in the back.

Remember, folks, turbos use exhaust gasses and witchcraft to generate boost; most exhaust headers are quite a bit more upward of the motor than ours, which means their turbos are at least further forward in the engine bay, if not almost entirely front-mounted, where they don't have an engine and shit blocking their airflow. +1 to my man 'teaser.

the 07 has an aluminum hood iirc. lighter than a 2.5i. im not sure what year they stopped doing this.

In 2012, when they stopped making actual GTs. All GT hoods are aluminum.

the 07 has an aluminum hood iirc. lighter than a 2.5i. im not sure what year they stopped doing this.

 

 

In 2012, when they stopped making actual GTs. All GT hoods are aluminum.

Also, most Subarus have aluminum hoods. That includes 4th gen Legacy 2.5i. They do make cheapo steel reproductions that need to be watched out for.

What about if you wrap your headers, UP and DP, then put a turbo blanket and turbo heat shield, and in addition to a CAI?

Isn't the intent to keep the heat in all the pipes pre turbo, through the DP to increase the scavenging effect in the exhaust? It also takes a lot of heat out of the engine bay and keeps the air intake charge cool, seemingly.

All GT hoods are aluminum.

Triscuit, you gotta stop pulling misinformation out of your ass and selling it as truth. All GT hoods are not aluminum, ahem, 5th Gens aren't, and I don't think 3rd Gens are. My 2003 Forester however, does have an aluminum hood.

What about if you wrap your headers, UP and DP, then put a turbo blanket and turbo heat shield, and in addition to a CAI?

Isn't the intent to keep the heat in all the pipes pre turbo, through the DP to increase the scavenging effect in the exhaust? It also takes a lot of heat out of the engine bay and keeps the air intake charge cool, seemingly.

IMHO, you still need some sort of airflow to vent the heat that will build up under the hood. I think the idea is to limit the amount of turbulent air flow under the hood, so that air can flow SMOOTHLY through the engine bay.

Heat shields and wraps are designed to help dissipate heat, but you can't dissipate heat without introducing cool air somehow.

In the limited background I have in this type of engineering, I would not advise getting rid of the scoop. That is unless you were planning on cutting up the 2.5i hood a bit and adding some more subtle venting (more EVOish) for the engine bay.

No matter what you try to modify, you need more fresh air to flow under the hood to keep the temps down. Otherwise, you need an aftermarket bumper with extra venting options, and some custom duct work to get the air to the turbo. As Tris already said, if you don't compensate for the air flow from the scoop in some way, you are going to get knock.

I'm not sure how far you want to go with this, but if you really want the sleeper look, and don't mind deleting your fogs, you could probably turn your fog light holes into vents and create duct work to the turbo. (Don't quote me on that tho)

I still say just leave the scoop... It's not really worth the hassle and risk of knock.

Not sure if they make one but a carbon fiber hood, would probably help some.. I've thought about doing this quite a bit.. but always figured it wasn't a good idea.. what about putting a turbo chimney on.. would it knock then? Like from the scoop..

some one says it will knock but they dont show proof.

the logic contradicts itself. people are asking about scoopless but only few have done it yet someone says there will be knock. talking results with no testing does not make it a real result.

when making tradeoffs many people focus on what they are losing and not what they are gaining.

i was reading here on this forum about someone heat wrapping a ton of stuff and temps were very good. oil and coolant was in question but iirc there were no problems. ive read...heat wrap is bad etc etc...but have not seen pictures or read posts saying damage from wraps. not yet anyways.

people here do donuts in the snow and there is no real airflow when this is happening yet the cars dont catch fire.

theoretically if you can heat wrap a turbo and have no problems then why need a scoop? there is no airflow with a wrap but there may or should be some from normal driving. its not like the engine bay is air tight except for the scoop and skid plate.

we do have a heatshield above the turbo do we not? what kind of airflow is that impeding? what if the removal of the tmic increases air to the turbo? but if the turbo is heat wrapped who cares?

according to this forum the turbo will die anyways. haha.

with no data or experience i will state...heat wrap the turbo and do a 2.5i hood with fmic.

^have you ever monitored your underhood temperatures? I have and I stop and go I will see the temperature get up above 100*F and along with that notice my knock sum go up if I try to hit it hard after sitting in traffic for awhile. If you haven't monitored any of these things I could see your confusion but from my stand point wrapping the turbo, having a heatshield, ceramic coating are all forms of heat sinks, a place for the heat to go other then your charge air or engine block and heads.

Saying that a heat shield or turbo blanket or heat wrap blocks airflow is entirely inaccurate. When you think thermodynamically heat always needs somewhere to go so IT IS going to leave the turbo what the shield, blanket, or wrap do is provide that medium for the heat to go to then be dissipated once there is airflow again.

I've run my turbo with the stock heat shield, nothing, a turbo blanket, and a turbo blanket with a Cobb heatshield. As I added layers I noticed a substantial drop in heat soak at lights and a reduction in knock sum increases. Try it out for yourself and see what happens.

^have you ever monitored your underhood temperatures? I have and I stop and go I will see the temperature get up above 100*F and along with that notice my knock sum go up if I try to hit it hard after sitting in traffic for awhile. If you haven't monitored any of these things I could see your confusion but from my stand point wrapping the turbo, having a heatshield, ceramic coating are all forms of heat sinks, a place for the heat to go other then your charge air or engine block and heads.

 

Saying that a heat shield or turbo blanket or heat wrap blocks airflow is entirely inaccurate. When you think thermodynamically heat always needs somewhere to go so IT IS going to leave the turbo what the shield, blanket, or wrap do is provide that medium for the heat to go to then be dissipated once there is airflow again.

 

I've run my turbo with the stock heat shield, nothing, a turbo blanket, and a turbo blanket with a Cobb heatshield. As I added layers I noticed a substantial drop in heat soak at lights and a reduction in knock sum increases. Try it out for yourself and see what happens.

you are combining different ideas into 1 result which i did not do. if you cant repeat what i said without proper wording i will not reply.

a blanket is to completely surround an object is it not? if a blanket can keep in the heat of a turbo and reduce underhood temps how is air flow going to affect that blanket?

if you are sitting in traffic and temps go up it wasnt from the turbo was it? non turbos heat get lower when sitting in traffic? obviously heat will rise in any car idling in traffic. 100f doesnt sound too bad. ALL engines heat up when idling in traffic.

you are right. i have not monitored. i know the tmic is warm to hot so i always expect the car to behave as it should with heat soak.

explain to me how a fmic is getting hot like the tmic.

how is your idling with tmic comparable to idling with a fmic?

your last paragraph is a statement people need to hear. no one said temps would rise after wrapping etc.

you are on stock tmic?? seriously?

^have you ever monitored your underhood temperatures? I have and I stop and go I will see the temperature get up above 100*F and along with that notice my knock sum go up if I try to hit it hard after sitting in traffic for awhile.

This is meaningless. At a standstill you have all the engine compartment's hot air trying to rise through the intercooler from convection. This does not happen with a FMIC. In fact, you have the air the radiator fans are pulling to cool it down.

Lots of turbo cars (like most of those with factory FMIC setups) run without any vents in the hood whatsoever.

I was just looking through junked legacies and saw a 2008 with no scoop which made me wonder about making my car even more sleeper-esque by putting a diff hood on since I have a FMIC.

 

Anyone done this?

People are unnecessarily over analyzing this.

Just go ahead and put a scoop-less one on.

This is meaningless. At a standstill you have all the engine compartment's hot air trying to rise through the intercooler from convection. This does not happen with a FMIC. In fact, you have the air the radiator fans are pulling to cool it down.

 

Lots of turbo cars (like most of those with factory FMIC setups) run without any vents in the hood whatsoever.

My Cruze is FMIC factory but it is "Sammiched" between the Condenser and the radiator. My trim also has shutters that close off air in front of it for FE reasons but open up when engine bay temps reach a certain temp. ATS is similar but shutters cover the entire grille area.

some one says it will knock but they dont show proof.

 

the logic contradicts itself. people are asking about scoopless but only few have done it yet someone says there will be knock. talking results with no testing does not make it a real result.

Its the internet. No one actually has money to test many of these theories. So everyone is hoping someone else will. However, in the case of underhood temps, a bit of fear of nuking your engine goes a long ways.

when making tradeoffs many people focus on what they are losing and not what they are gaining.

 

i was reading here on this forum about someone heat wrapping a ton of stuff and temps were very good. oil and coolant was in question but iirc there were no problems. ive read...heat wrap is bad etc etc...but have not seen pictures or read posts saying damage from wraps. not yet anyways.

 

people here do donuts in the snow and there is no real airflow when this is happening yet the cars dont catch fire.

They do blow up, especially when doing CCW donuts, due to oil starvation. In proper conditions, this can lead to fire, when the spilled oil ignites. Ask me how I know.

theoretically if you can heat wrap a turbo and have no problems then why need a scoop? there is no airflow with a wrap but there may or should be some from normal driving. its not like the engine bay is air tight except for the scoop and skid plate.

 

we do have a heatshield above the turbo do we not? what kind of airflow is that impeding? what if the removal of the tmic increases air to the turbo? but if the turbo is heat wrapped who cares?

 

according to this forum the turbo will die anyways. haha.

 

with no data or experience i will state...heat wrap the turbo and do a 2.5i hood with fmic.

Sgt.Gator's racecar is a good example of this. Worth reading up on his thread.

Just because you haven't found it using search, doesn't mean its true. Nor the opposite.