GQ Patrol Carbies and Cold/Altitude

[Throbbinhood]

Went up to the vic high country over the weekend and had a few issues with my rb30 carby patrol, and a mates tb42 carby patrol. Both would struggle to hold idle at times.

Is this normal for carby cars? Does altitude affect them that much? We were generally from 700m to 1500m for the weekend, and it was pretty cold. EFI cars had no issues.

[Irish]

Yep, EFI vehicles can adjust for the altitude for the mostpart(maf sensor/afm tells the ecu how much air is going in), whereas carbies can't. So if your carbie is tuned in a lowland area, it'll struggle when it gets up where the air is thinner and will meter too much fuel for the available air.

Example, see pg 9:

http://www.edelbrock.com/automotive/misc/tech-center/dl/carb-owners-manual.pdf

[Irish]

You'll also find that your carb might miss when you're at extreme angles. Something to do with the float bowl. 4x4 carbies are made to compensate somewhat but they're not perfect.

[Throbbinhood]

Thanks mate, figured that may be the case. While running with the revs up, car was ok, just idle/low rpm was affected. Is there a mixture screw on the carb to adjust this when I'm up in the hills?

[Irish]

Thanks mate, figured that may be the case. While running with the revs up, car was ok, just idle/low rpm was affected. Is there a mixture screw on the carb to adjust this when I'm up in the hills?

This is for the TB42, not sure if the RB30 carb is the same?

http://i121.photobucket.com/albums/o234/Irishpete/carbieTB42_zpshfabyipy.jpg

[Throbbinhood]

Thanks Irish. Simply a case of adjusting the screw until she idles nice again?

[Irish]

There's a procedure for setting it up properly but a quick fiddle might get you out of trouble, just remember to take note of any changes you make so you can undo them if you stuff it up.

[Throbbinhood]

Thanks mate.

[GQ TANK]

tb42 and rb30 carbys are basically the same.

The rb30 is known for running out of fuel on step hills, I have not experianced this on the tb42