What happens to the air after it goes through the top mount intercooler?

[Vansquish]

Originally Posted by Tokay444 You don't want any MORE air flowing under the car. That will create drag and lift. You want the air flowing under the car already, to be faster than the air flowing over the car.

Thanks for the correction. Of course you're right. We want to accelerate the airflow under the car to create a low-pressure zone and decrease aerodynamic lift.

I've got the supplies to fab up a sort of shitty full-length undertray and I've been meaning to do so for some time now (almost a year). This topic is something I hadn't really considered and now I'm having some pretty big second-thoughts about whether or not it's a good idea to do one without doing a bit more R&D into engine-bay airflow and stagnation.

I suspect that the reason that the stock MS6 undertray has its innate convex shape is to create a low-pressure zone behind the front wheels. This would help to draw air out of the engine bay and pull it under the car. If you look at the general shape of the underbody of the MS6, it starts low at the front (with the skid tray) and rises gradually towards the tail end of the vehicle. In essence, it looks a bit like an inverted airplane wing (no doubt intended to improve high-speed stability).

I wonder if it'd be possible to modify the skid plate such that it is still more efficient at drawing air down through the engine bay by creating some rearward-facing openings that hang into the airstream beneath the car, essentially sucking air out of the engine bay near the firewall.

[Tokay444]

With the correct placement of naca ducts, you'll still achieve the rearward draw from the engine bay.

[Vansquish]

Originally Posted by Tokay444 With the correct placement of naca ducts, you'll still achieve the rearward draw from the engine bay.

This is exactly what I was thinking, though I'm not so sure we even need to go to a full NACA-type duct. I bet that a well-placed (and shaped) set of louvers would have the same impact and might be easier to retrofit.

Edit:

I don't want to derail the thread, but what do you guys think about doing a mock-up/test for something along these lines using these as a starting point?:
http://www.walmart.com/ip/ATP-Extra-...p-Pan/16778234



It's 47.0" x 25.0" x 0.5", and I realize that it's paper-thin and won't last more than a few decently large rocks, but it might give us something to go on.

[fortressofcomfort]

I can be a guinea pig if you want for whatever.

So who's it gonna be; to fashion up a GenPu hood with scoop and louvers and send to me for a low low price. Black or carbon fiber please.

[ibcrusn]

This is a very interesting thread on a subject I tried to wrap my head around the first time I looked under the hood. I was surprised by a couple things:


·How much air is allowed to bypass the TMIC via the extra holes in the plastic hood ductwork. I understand the need to certain extent just not why it was designed to allow so much air bypass the IC.

·How close the TMIC is mounted to the valve cover hampering airflow at higher speeds.

While I think a tray below the IC as mentioned before is not an ideal design it’s not a bad idea. What I mean by that is rather than mount a tray to direct the air to the back side of the engine create composite ductwork to be attached to the sides of the IC and lower back side (rear bottom for lack of better terminology) which can be exhausted either through hood louvers/vents or via a gap created by removing the seal and raising the rear of the hood. This should work pretty well as the hood scoop will be pressurized by ram air and there will be a venture effect caused by the exhaust vents thereby helping draw more air through the IC.

Reversed NACA ducts can help create a significant negative air flow but they need to be placed on a surface that has high velocity air passing over them (side of fender, side window, etc). Mounting them to the rear of the hood is far from ideal as that area of the hood generally has stagnant air flow. As a side note I have a fantastic article on the development of the NACA ducts on my computer at home which I can post if anyone is interested.

[Chimmike]

I think you guys don't realize just how little air goes through the ducting to the IC, and the fact that it's not moving at 900 miles an hour, it still flows out through the back bottom of the engine bay.

There are several dozen more important things most of you could work on until this stuff becomes necessary. Shit, most of you don't even have 300whp, let alone are big turbo with built motors making significant power.

[Vansquish]

I hear you, but I'd still like to see my IAT/BAT/ and fuel economy improve. If better airflow through the engine bay can be achieved without an increase in drag...why the heck not try?

[Voltwings]

Originally Posted by chimmike I think you guys don't realize just how little air goes through the ducting to the IC, and the fact that it's not moving at 900 miles an hour, it still flows out through the back bottom of the engine bay. There are several dozen more important things most of you could work on until this stuff becomes necessary. Shit, most of you don't even have 300whp, let alone are big turbo with built motors making significant power.

I do, however, the 3071 runs so muh cooler than the K04 that even in Texas heat the heatsoak is not unberable... The only thing that seems to come to mind is that last test @fortressofcomfort and i did where we took all the obstructions and crap out of the front bumper:

Yes, an imidiate decrease in Coolant temps and Intake temps was noticed, however only at crusing speeds, lets call them 40+ mph. However, this is direct airflow to the front of the car which explains why an impat was seen on the radiator (IE: coolant temps) and only more so with a decent bit of speed. To get going fast enough where enough air would be getting drawn out the back of the Engine bay, youd be going fast enough, or have already been driving long enough that would you no longer be heat soaked anyways... The only way to reduce heatsoak im thinking is to reduce the stagnant heat/air that results from sitting / low speed driving.

[Tokay444]

No one said anything about putting naca ducts on the hood. Lol.
We were talking about a full under tray.

[CosmicArkie]

Yeah, NACA ducts at the rear of the front undertray.....

[HavasuSpeed3]

Originally Posted by chimmike I think you guys don't realize just how little air goes through the ducting to the IC, and the fact that it's not moving at 900 miles an hour, it still flows out through the back bottom of the engine bay. There are several dozen more important things most of you could work on until this stuff becomes necessary. Shit, most of you don't even have 300whp, let alone are big turbo with built motors making significant power.

Gotta agree with that. I'm gonna go with my bug theory... Back in louisiana we had really bad lovebug swarms and the few times I drove across Tx with the damn moth infestations... the amount of bug that collected within the "scoop" or dead on the IC were VERY minimal while the front of the car was covered. I figure due to aerodynamics, that most air is deflected over the hood anyway.

[vrspeed10]

Originally Posted by chimmike if you removed the tmic ducting, but still have tmic, you fucked yourself. Your BATs are guaranteed to be higher. The motor is water cooled, it does not need your help in creating more airflow in the engine bay. the TMIC, however, needs that ducting to function and not be a giant heat sink!

On a 90 degree day stopped bats hit 135. At a cruise 105 - 110

[Ray Danger 2020]

Im thinking there may be some way of incorporating something like this into the gentwo hood, on the sides of the scoop.



Would need alot of R/D but I think with proper placement, the high pressure going over the hood would pull sufficient air out of the hood so that it wouldn't cause unnecessary turbulence under the hood at high speeds. And with more air being pulled out from under the hood, it (in theory) should increase the amount of downforce generated by the aerodynamic shapes and styling of the car because the pressure under the car would, in effect, be less.

[Chimmike]

Originally Posted by vrspeed10 On a 90 degree day stopped bats hit 135. At a cruise 105 - 110

I find that extremely hard to believe with tmic and removed ducting.

[Ray Danger 2020]

Also, with the added venting, it would suck specifically the HOT air out from under the hood, which would lower the underhood temps and effectively lower IAT's as well. Lower IAT's = lower BAT's = MOAR POWAH!!

[vrspeed10]

Originally Posted by chimmike I find that extremely hard to believe with tmic and removed ducting.

When i get home i will post my logs

[anavrinIV]

Originally Posted by Ray Danger 2020 Lower IAT's = lower BAT's = MOAR POWAH!!

Not really. High air temps are caused by the compression of the air in the turbo. BATs can only be as cool as the ambient air (in a perfect world; in reality they will be at best 10-15 deg above ambient)...that's what the intercooler is for. Theoretically lower IATs will create lower boost temps pre-intercooler, but in reality the effect is minimal. And besides, with the IC the temperature of the air coming out of the turbo is irrelevant until you start stretching outisde of a turbo's efficiency range.

so yeah...Lower IAT=/=Lower BAT

[Ray Danger 2020]

@anavrinIV Quit raining on my parade...lol


Can't just let me have a moment? Maybe comment on the vented hood idea and how it could possibly positively/negatively effect the car's performance? Gotta pick one vague statement that's correct (only to a degree and not perfect) and pick on it...jeez...some people...lol

[ibcrusn]

Originally Posted by Tokay444 No one said anything about putting naca ducts on the hood. Lol. We were talking about a full under tray.

NACA ducts on the hood would look gay but I wouldn't put it past some Mazda owners that still have Honda rice blood running through 'em.

A full under tray? Wasn't there some mention about reasonable cost in previous posts? You're quickly getting back to installing a FMIC if intake temps are that high on your hit list.

[snailD]

Originally Posted by anavrinIV Not really. High air temps are caused by the compression of the air in the turbo. BATs can only be as cool as the ambient air (in a perfect world; in reality they will be at best 10-15 deg above ambient)...that's what the intercooler is for. Theoretically lower IATs will create lower boost temps pre-intercooler, but in reality the effect is minimal. And besides, with the IC the temperature of the air coming out of the turbo is irrelevant until you start stretching outisde of a turbo's efficiency range. so yeah...Lower IAT=/=Lower BAT

the plus side about lower iat's is the turbos ability to build boost. its easier than with hot air. lex has a full thread on it

[ASmith]

This is just slightly off topic...has anyone ever used an intercooler water spray system to reduce heat soak in a speed?

Nevermind...

Thoughts on Intercooler sprayer

[Tokay444]

Originally Posted by Ray Danger 2020 Im thinking there may be some way of incorporating something like this into the gentwo hood, on the sides of the scoop. Would need alot of R/D but I think with proper placement, the high pressure going over the hood would pull sufficient air out of the hood so that it wouldn't cause unnecessary turbulence under the hood at high speeds. And with more air being pulled out from under the hood, it (in theory) should increase the amount of downforce generated by the aerodynamic shapes and styling of the car because the pressure under the car would, in effect, be less.

Now we're on about ricer hoods and downforce?
Unsubbing.
Call me back in when the undertray goes to the wind tunnel.

[Chimmike]

Originally Posted by Ray Danger 2020 Also, with the added venting, it would suck specifically the HOT air out from under the hood, which would lower the underhood temps and effectively lower IAT's as well. Lower IAT's = lower BAT's = MOAR POWAH!!

I think you missed the whole fucking point of this thread. The engine bay has a specific airflow pattern to it. IF you disrupt it by adding various vents wherever the fuck you want, there will just be random flow out of the engine bay and likely won't have the effect you're looking for, let alone a well-thought-out system.

[Ray Danger 2020]

Originally Posted by chimmike I think you missed the whole fucking point of this thread.

I didn't miss it. I know the point. And after I posted I found myself realizing that what I HAD posted was off topic. I had good intentions though. Just poorly planned ones.