Front Skirt / Ground Effects - Is this causing overheating?

[BigFrog]

After dealing with overheating problems for years and replacing the water pump, radiator, etc etc... I found this post ( http://www.ls1.com/forums/f6/rk-spor...00-z28-177753/ ) about a front skirt causing overheating.

This is what my 2002 SS has had on it since I bought it (used), photographs lightened so you can see the shape of the skirt and the amount of exposure to the air dam behind it:

A.jpg

B.jpg

The car gets very hot when climbing even mild inclines at freeway speed if the temp is in the 80 F or higher range. Living in the southwest it is now 90-100 or higher every day. When the temp goes up on the car if I turn on the heater in the cabin it is enough to cool it back down within a couple of minutes (but make me hot as hell and very unhappy).

Around town it runs nice and cool even when it's 105 outside and the A/C is on full blast, even in stop and go traffic or when sitting at a light for some time.

Going from the other thread, I am wondering if this front piece is the one previously discuss, or similar enough that the turbulence at 50+ MPH is keeping air from passing through the radiator. I was going to remove it recently just to test it, but most of the screws appear to be INSIDE of the body work, not from below. I don't want to take the entire front end apart for a test.

I wanted to see if anyone has tried a series of 1" or so holes across the center of the front skirt (tastefully done, of course) or if the extended air dam under the radiator works well enough. I don't mind a part designed to scrape the ground now and then scraping the ground, it's better than having LS1 parts exploding through the hood.

Any and all comments, suggestions, and experiences appreciated, esp with Photos, Diagrams and Instructions

THANK YOU

[SMWS6TA]

Yes, the chin ground effect does cause air flow issues. Our cars are consider "bottom feeders" meaning the air is diverted up into the radiator and into the air box from the bottom via the air dam (it's the flat plastic that goes across under the nose of the car). The effect blocks the air flow like you are thinking.

You should be able to remove it and see if this will help.

Other things that could help are:

Swapping over to a 165* thermostat, have a tuner adjust your fans to come on earlier, and most importantly have your coolant purged, flushed out and replaced. Should be done every 3 yrs. If it's the stock water pump you might want to go ahead and swap it out too. It's going on 12 yrs now.... It might help to have someone look at the relays that control the fans too.

[BigFrog]

The water pump has been replaced (did it myself, good excuse to buy a torque wrench) and the radiator is an aftermarket high capacity job (I forget the brand). I know both fans are coming on (and staying on after the car is shut off some days). Do the fans shut off above a certain speed? I can't see any harm in having them run when the car is moving fast as the air flow would spin them anyway (If I had air flow, that is).

I would like to try extending the air dam before I remove the front piece, it looks like a gigantic pain.

[pajeff02]

I would test it with a simple piece of aluminum bent and bolted in place of the rubber air dam. How are you determining your coolant temp? The stock gauge is an estimator at best and should not be relied upon. Either utilize a scanner or an aftermarket temp gauge to verify your actual coolant temp.

[BigFrog]

Thanks, extending the air dam tonight. Good thing the front of the car is so easy to get under and work on

[SMWS6TA]

Good plan on extending the dam.

[theorangeguy]

The water pump has been replaced (did it myself, good excuse to buy a torque wrench) and the radiator is an aftermarket high capacity job (I forget the brand). I know both fans are coming on (and staying on after the car is shut off some days). Do the fans shut off above a certain speed? I can't see any harm in having them run when the car is moving fast as the air flow would spin them anyway (If I had air flow, that is).

I would like to try extending the air dam before I remove the front piece, it looks like a gigantic pain.

just make sure whatever you use an extension gives like the stock air dam does...its designed to hit stuff and bend/flex to avoid being ripped off.

[SMWS6TA]

agree....

[BigFrog]

Ya, I have been brainstorming trying to come up with the right material. The other thread suggested an air dam of the same or similar design from a junk yard. I was trying to think of something I could get at Home Depot.

I would do the Dozen Holes In The Skirt bit if I knew it would work, I just don't want to take the chance on messing up the piece if it's not going to improve airflow into the "mouth".

[Firebirdjones]

Before you do something irreversable like drilling holes in things, have you actually verified the coolant temp with a scanner??

What your gauge is saying may have you worried for nothing. These cars aren't programmed to have the fans come on until around 220-230 degrees. Only other time they come on automatically is when the AC is switched on.

If it were me, I'd first install a cooler 170ish stat, and then have the computer tuned with fans programmed to come in in the 185 range. See how that works for you, before drastically modifying things.

If you still experience warm temps verified by a scanner, I wouldn't bother with drilling holes in that lower facia, I'd just knock that sucker off with a baseball bat

[BigFrog]

The air damn extension worked GREAT. I was able to get a piece of lower bumper trim from the salvage yard off of a Dodge Ram for free (I guess you could say it's a "Ram Air" now?).

It extends the air dam two inches. As you can see (below), I chose a piece that had a L-shaped lip so it would not fold in. I have screws in it for now but if the piece holds up for a few weeks I will bond it in place with epoxy. It scrapes going in and out of my driveway, but it WORKS!

I was on the freeway in 106 degree heat, AC on full blast, went up a 5% grade in 5th gear accelerating hard for half a mile and it barely climbed to a 225-ish on the "gauge". When I topped the hill it went back down to under the 210 marker within a minute. This same run before the modification would have had the temp at 240-250 and the CHECK GAUGES light on - and I would have had to back off the throttle, switch from AC to HEAT and wait about 5 minutes for the flow to cool things back down.

The other thing I noticed was the temp gauge was staying in the 200-210 range during "normal" freeway and surface street driving in this same 106 degree heat. It was always about 215-220 before if was 80-85 or more outside.

Last, though it is even LESS reliable than the Temp Gauge, it felt like the AC was working better - which it should with the improved airflow.

I would HIGHLY recommend this mod to any car with a front skirt. Just that 2" addition to the car's "top lip" had a large detrimental effect on the cooling system. Even if your vehicle is not overheating, if you have a big top lip, it should be matched with an equally extended lower lip. ...the "Bow-tie Botox Mod"?





Ya, 12 years and 100,700 miles is apparent in the front paint.

[SMWS6TA]

I have to worry now if my DSL will clear....So no chin botox for me...maybe a splitter.

[BigFrog]

I like the skirting on the car and think it would look odd (to me, at least) to have the sides and back without the front. Some day when I have lots of $$$ I may mod the front skirt and go with new paint, maybe be able to unmod the air dam.

[Firebirdjones]

I don't think I'd make it around the block with something like that on our 4th gen. Living in hilly terrain, every driveway and parking lot is always at some odd angle. Even at stock ride height the car is still a bear to maneuver in some spots. Even the stock front facia without the added RS panel will sometimes touch the ground.

I could see where that may help with cooling, but find it odd so many other 4th gens running the RS ground affects that don't complain about heat. I'd personally still invest in a cooler stat and reprogram the fans.

[KahanaReef]

I'm glad you were able to fabricate a fix. Looks pretty good as well.

[KahanaReef]

I could see where that may help with cooling, but find it odd so many other 4th gens running the RS ground affects that don't complain about heat.

That is probably because the extended air dam was installed with the RS package

[Firebirdjones]

That is probably because the extended air dam was installed with the RS package

Ah, well there you go then. This was apparently added at some point without taking that into consideration.