Welp, this honda pivic wanted to test me on the highway so when I hit about 130, the engine undercover ripped. . . like the new asshole the pivic has now. :naughty: All I hear while driving now, is that damn plastic rubbing the ground. VERY sexy sound by the way. Just wanted to know if I should replace this? I don't even know if toyota still carry this part. I'm sure this piece is useful somehow. But humor me.
anyone still have an under cover?
- Thread starter tonysupra
- Start date
The Undertray is a VERY important part of our cooling system.
There are 3 bolts securing it just below and behind the radiator and if even these are missing I see +10c temps at highway speeds.
Toyota should still have them in stock.
There are 3 bolts securing it just below and behind the radiator and if even these are missing I see +10c temps at highway speeds.
Toyota should still have them in stock.
They do have them, $140 ish. I made mine out of galvanized sheet metal from Home Depot, for about $10.
I also made one out of an aluminum sheet that keeps the air coming in from the bumper directed into the intercooler. I put a smaller piece on the drivers side by the oil cooler to deflect more air into the coolers and radiator.
Rushing air will always take the path of least resistance. Think about it... if you were air wouldn't you rather take the quick path downward rather than fighting your way through the fins of the IC then the AC Condensor and finally the radiator? The undercover makes sure that all air that comes in through the nose goes directly through the IC and everything else.
Isn't your cooling system worth the money?
Isn't your cooling system worth the money?
well here is neat way of doing
with it on you will not get that much drag on the front end
10 c diff as sated above witch is really nothing
bad part if you work on your car they suck drop a socket ring bell going under the car perid take off the under cover all the time sucks
but i had my car for many years wiht out that dumb ass cover
with it on you will not get that much drag on the front end
10 c diff as sated above witch is really nothing
bad part if you work on your car they suck drop a socket ring bell going under the car perid take off the under cover all the time sucks
but i had my car for many years wiht out that dumb ass cover
Adjuster
Supramania Contributor
The cover only really works at highway speeds where your car's high and low pressure areas really move the air.
Try this test. Turn your AC and Heat off. Fan off. Then drive with the windows up at about 75mph. Notice there is still air blowing in your vents? This air is coming from the high pressure area at the base of your windshield where the HVAC system draws in fresh air.
Some of the same ideas are used to help move air through the radiator/condenser and FMIC. The engine bay is a low pressure area, and the grille is high pressure.
As Keith noted, the high pressure air that goes into your grille, would just dump down mostly under the car if not for the cover. With the cover there, it is drawn through the core support area (Where your radiator/FMIC and other coolers are.) and then dumped under the car into another area of low pressure near the transmisison.
To have a properly operating cooling system, you need the undertray, and a good fan shroud. There are many people who have run the Supra with neither a undercover or a fan shroud, but at speed, or sitting in traffic with the AC on, they will start to overheat the car. (Might be why so many MK3's come down with the BHG? Don't know, but It does not help.)
The system is so effective, that most older MK3's have leaves, pet hair, and other debris packed up against the radiator. This crap was sucked into it as the air was drawn through the radiator core by this pressure change. (And the obstruction on older cars is another reason why so many have overheated in the past and wiped out head gaskets too IMHO.)
Best Idea I've seen yet was using plexiglass to replace lost or damaged undertray's. (Or just get another stock one.)
Helps with downforce too, but that's another post.
Try this test. Turn your AC and Heat off. Fan off. Then drive with the windows up at about 75mph. Notice there is still air blowing in your vents? This air is coming from the high pressure area at the base of your windshield where the HVAC system draws in fresh air.
Some of the same ideas are used to help move air through the radiator/condenser and FMIC. The engine bay is a low pressure area, and the grille is high pressure.
As Keith noted, the high pressure air that goes into your grille, would just dump down mostly under the car if not for the cover. With the cover there, it is drawn through the core support area (Where your radiator/FMIC and other coolers are.) and then dumped under the car into another area of low pressure near the transmisison.
To have a properly operating cooling system, you need the undertray, and a good fan shroud. There are many people who have run the Supra with neither a undercover or a fan shroud, but at speed, or sitting in traffic with the AC on, they will start to overheat the car. (Might be why so many MK3's come down with the BHG? Don't know, but It does not help.)
The system is so effective, that most older MK3's have leaves, pet hair, and other debris packed up against the radiator. This crap was sucked into it as the air was drawn through the radiator core by this pressure change. (And the obstruction on older cars is another reason why so many have overheated in the past and wiped out head gaskets too IMHO.)
Best Idea I've seen yet was using plexiglass to replace lost or damaged undertray's. (Or just get another stock one.)
Helps with downforce too, but that's another post.
Nash: 10c may not be much BUT if you're running a motor on the edge with timing and fuel that +10c as a start point before a hard top end pull may be enough to tip the motor into detonation and BHG!
I run a lower T Stat for this reason as it gives me a bit lower start temp before a hard pull.
I run a lower T Stat for this reason as it gives me a bit lower start temp before a hard pull.
I had a shit-ton of junk packed into the area between my radiator and condenser. about 3" worth...
What makes plexiglass the best idea yet?
What makes plexiglass the best idea yet?
I've never run my car with that undershroud, bought it without one. Now i'm not pushing a lot of horsepower but i've never run hot with ac going in South GA so its probably not gonna kill you to not use one.
Just bought a used one the other day, beyond the cooling benefits, I don't like stray crap potentially getting kicked up into my engine bay. Radiator took a stone and gave up the fight. D'oh.
-J
-J
I have yet to run an undercover on either of my Supras. I do plan on putting one on my current one soon here. I talked to Mike Donohue on this subject before. As I remember he mentioned he has owned many MKIII Supras and rarely if at all used an undercover and had no over heating issues, and that includes time at a road course I beleive. Since you guys mention AC, I think that is something that plays a larger roll in reducing cooling efficiency. Think of the large condenser covering the entire radiator.
Mine was trashed after doing the NA>T conversion. I had to buy one because the car was running real hot real fast at highway speeds. I can say that it runs a lot cooler with it on.