Racing in Crappy Air Question

May 06, 2024, 07:02 AM

Was running this past weekend in some crappy southern air, I mean flat out bad air. Noticed my car seemed a little fat but was still able to get down the track. I figured it was this way because of the air and not being able to burn the fuel. I am one who tends not to make big changes so I left it alone. BUT then I noticed later in the day the idle was higher (I did nothing to it) by about 400 RPM. I cant seem to figure out why, the air was still the same as it was all day.

May 06, 2024, 07:38 AM

BD104X

You sucked an intake gasket.

May 06, 2024, 07:41 AM

SmokinChicken

quote:
Originally posted by BD104X:
You sucked an intake gasket.

If so would this also make a cars performance fall off?

May 06, 2024, 07:54 AM

wideopen231

while may not be gasket sucked in. If car was rich and then idle went up you have a vacuum leak somewhere. If a gasket leaks at top side of intake I doubt it would affect performance a lot. The old carb cleaner trick will tell you if you have vacuum leak if induction side. If under intake plugs will show signs of oil in cylinder.

Did not say if carb or injection. Guessing carb since did not state. There could be other signs with carb thaT I have no idea of.

May 06, 2024, 08:18 AM

BP758

quote:
Originally posted by SmokinChicken:
Was running this past weekend in some crappy southern air, I mean flat out bad air. Noticed my car seemed a little fat but was still able to get down the track. I figured it was this way because of the air and not being able to burn the fuel. I am one who tends not to make big changes so I left it alone. BUT then I noticed later in the day the idle was higher (I did nothing to it) by about 400 RPM. I cant seem to figure out why, the air was still the same as it was all day.

If it were me;
Put a wrench on the carb and manifold then clean your air bleeds and check the float adj.
So what do you call bad air there? Two weeks ago Vegas we saw 27.66 Baro, 9% Humidity, 5000’ Density Altitude and a 1.129 correction factor with 139 track.

May 06, 2024, 09:13 AM

BD104X

quote:
Originally posted by SmokinChicken:
quote:
Originally posted by BD104X:
You sucked an intake gasket.

If so would this also make a cars performance fall off?

Slightly, but you said it "seemed fat but still able to get down the track"... that sounds like it wasnt running great. Last time it happened to me, performance barely changed but idle came up and I noticed a very slight bit of smoke out of one header.

May 06, 2024, 09:19 AM

SmokinChicken

quote:
Originally posted by BP758:
quote:
Originally posted by SmokinChicken:
Was running this past weekend in some crappy southern air, I mean flat out bad air. Noticed my car seemed a little fat but was still able to get down the track. I figured it was this way because of the air and not being able to burn the fuel. I am one who tends not to make big changes so I left it alone. BUT then I noticed later in the day the idle was higher (I did nothing to it) by about 400 RPM. I cant seem to figure out why, the air was still the same as it was all day.

If it were me;
Put a wrench on the carb and manifold then clean your air bleeds and check the float adj.
So what do you call bad air there? Two weeks ago Vegas we saw 27.66 Baro, 9% Humidity, 5000’ Density Altitude and a 1.129 correction factor with 139 track.

Barro 29.98, 100% Humidity, 88 Degrees, DA 3120
17MPH Wind

APD MAX Speed Carburetor

May 06, 2024, 09:46 AM

S/C718

You call that bad air. Here in New Mexico we race with in crappy air. 24.80 Baro, 8000 DA, 20% humidity and between 85 to 95 degrees. But I agree with the others you have some sort of vacuum leak.

May 06, 2024, 10:04 AM

SmokinChicken

When coming from the last race that was 1200 DA, 25% Humidity and 67 degrees id say yea its bad air. Hell id take 20% Humidity any day at 95 degrees over 100% Humidity at 95 degrees. When you race in the South Central area to the South East area the weather changes quite a bit at times. From the heat and humidity in Texas, Louisiana and Mississippi, Florida to the dryer higher altitude north is a big step for some.

May 07, 2024, 01:18 PM

TOP38

quote:
Originally posted by BD104X:
quote:
Originally posted by SmokinChicken:
quote:
Originally posted by BD104X:
You sucked an intake gasket.

If so would this also make a cars performance fall off?

Slightly, but you said it "seemed fat but still able to get down the track"... that sounds like it wasnt running great. Last time it happened to me, performance barely changed but idle came up and I noticed a very slight bit of smoke out of one header.

It's either this or you got a carb issue. There is no reason for the idle speed to change by 400 rpms on the same day without an issue and it's not the weather!

May 07, 2024, 01:50 PM

CAD

Check to see if an idle mixture screw fell out.

Had that happen once.

May 07, 2024, 04:28 PM

Curly1

First off I would blow out all of the air bleeds with carb cleaner until you can see and hear they are all open. Bet you will find one clogged. Check your float level and check for vacuum leaks.

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May 07, 2024, 04:41 PM

Curly1

For your other question 3100 is about average here in Texas.

If your carb is set up right then you do not need to change jets for different air as you do on mechanical injection. The car (Carb) will run faster in better air but fuel mixture should remain the same.