ratt_finkel

So I'm at the point where the HVAC is next to be removed in the Pikes Peak car. Should I keep it or ditch it? Keep in mind the car will be raced here in Texas. And being cool in the pits, etc would be nice.

Last C5

Dump it! I don't want to be the only one setting on the hot grid in a pool of sweat.

Airconditionless on the West Coast
LAST C5

LateBreak

I'd ditch it, then buy/build a coolshirt system for on the track. Removing the hvac unit from inside the car frees up a lot of space for roll cage construction, and getting the compressor and plumbing out of the engine bay makes working under the hood more pleasant.

ratt_finkel

Windshield fogging is a big issue too. My friend ran a air hose connected to a naca duct and it blew air on the windshield. Still ended up being an issue on cool mornings.

On facebook I'm getting a mixed bag of responses.

Bad Karma

They make electric heated window defrosters with built in fans, hook up one or two of those and that should take care of some fog when it's cool out.

LateBreak

We race in the rain so that's a valid concern for us as well, but I've not had an issue even after our first race was in 6 hours of downpour. Dish soap rubbed on inside of the windshield as a polish works great as an anti-fog because it is a dispersant.

Rather than simply hooking up to a NACA duct outside the car, you should hook up a bilge fan inside the car and draw air from somewhere warm and dry. I haven't done this on mine yet because it hasn't been a problem, but I plan to pull air from the side of the tunnel inside the car where it's heated by the exhaust. The defrost diffuser is a separate piece when you remove the dash and the mounting suds are on the firewall, so I'm planning to hook this ducting to that diffuser in order to help spread the air across the windshield.

rbl

Why jump through all these hoops to accomplish what you already have, that works fine and cost nothing - plus it can keep you cool?

Sure cool shirt .. what a PITA to deal with and there goes your weight savings (and money) !

If the tiny bit of space gained or the weight loss is that important I believe you need a new sport ... just sayin.

I will never understand all these folks wanting to butcher up the cars ..........

LateBreak

Easy tiger, this is for a full-on racecar that won't have side windows, so the AC won't help anyway, especially with no insulation on the floor and the driver in a thick Nomex suit. Trust me, we tried it once

The coolshirt is far more effective for controlling your core body temperature, which is important because the interior on these cars typically runs 130+ degrees on the track so heat exhaustion is common and a major health risk.

Weight savings of about 25 pounds, give or take, that's free horsepower

ratt_finkel

Yes, our goal is to get the car down to 2800lbs w/o driver. So every pound counts.

I think I'm going to leave it in for now. Simply the system for ease of use, etc. And we can always yank it all later.

rbl

Roar .... cool shirt is a PITA ... had one and it sucks for all practical purposes. It won't help a drop with the windshield. It will keep you cooler for sure but I'd have to call a BS about your internal temps of 130° + unless you have literally gutted the car to sheet metal and run the exhaust through the cabin. Put 5#'s back and cut the heat 30° pretty easily. But it does indeed get pretty hot ... until you're rolling. All the more reason to keep the AC system .. it will in fact cool down the interior some and the clutch disengages on the compressor at WOT anyway so no loss on the power side.

25 lbs. weight reduction ... maybe, but that is only ~ 1, maybe 2 Hp ... no big deal when OP is saying Power goals will be somewhere in the 600-800whp range @ 9k feet

Roar off ....

Rexracer77

I wouldn't do it for weight savings. I would do it to make running roll cage easier, and cleaning up the engine bay to make things easier to work on.

Just depends on your priorities.

LateBreak

With the window net up, there's surprisingly little air movement in my car, and the temperature gets very high. I'll have to get a thermometer for my own curiosity, but that's the number seen by others I race with in their cars. Regardless, one of my drivers suffered heat exhaustion at our last race when the cool shirt system quit working (Wiring problem), he vomited in his helmet. It wasn't pretty, but it could have been much worse. One of our competitors had to be taken lights and sirens to the ER when he overheated in an E36 BMW without a cool shirt.

Yes, Cool Shirts can be a PITA, but I'll never race without one again, it's a safety issue if you're on the track for extended periods of time.

ETA: NASCAR says anywhere from 105-148 degrees....
http://sports.espn.go.com/rpm/nascar...ory?id=3454683

ratt_finkel

I plan to run a combination of window nets and lexan windows. FYI.

HVAC can be removed to help facilitate roll cage instillation. Not a big deal at all.

The real question yet to be answered, is how the condenser is going to fit in there without blocking air flow for other critical systems.

Bill Dearborn

Why not ditch the AC stuff but leave the heater core and air direction so you can move heated air from the windshield to the floor. If you run in cool damp weather that is a way to dry out the inside of the windshield and the heater also provides an additional engine cooling element. I don't know what weather you will be running in but I have been out in 32 degree ambient temps with snow flying. The heater comes in nicely then even with the windows open.

Bill

ratt_finkel

I've gotten a million different responses. And they all have merit. The plan is to keep both the heater and A/C for now. The old adage, I'd rather have it and not need it, then need it and not have it.

lefrog

I was planning to do just that, remove the AC condenser, pump and plumbing but leave the heater in. Without the windows in the car, I have had very mixed results in getting the fog off the windshield on colder hillclimb mornings during the familiarization run. The AC is nice in summer when sitting on the start line (it also triggers the fans to high speed to keep the engine cool) but once you start you can't feel the difference anymore without windows.
Given the configuration I think that removing the AC condenser should also help with the radiator cooling and prevent crap from sitting between the 2.

rfn026

The interesting thing is that when the Pratt and Miller corvettes were required to run a/c at LeMans the cars got faster. Of course they use a rather unique a/c system.

Richard Newton

stevensa

Just remember that the AC compressor disengages above certain rpm/throttle percentage. Chances are you will only be using the blower motor once you are actually moving up the hill. It will still have the benefit with the windows up at the start though.

Apocolipse

It may disengage but you loose airflow through your rad with the a/c installed. This adds weight but more importantly at speed requires a larger intake hole for air which creates greater drag.