What happens in the carb & when?

[Chris Hebden]

Hi all! After this weekends RR session (which the car survived , and again big thanks to everyones help that day, helping me to understand the RR read out) I found out that the car is rich low down in the rev range at 2745 with a reading of 9.something and then on WOT leans out too a steady 10.4.

What i want to find out is at what stage something happens in the carb so i can pin point what i need to change/adjust to get the carb fuelling for 16psi and not the 22 which it was set up for!

I havent a clue yet as to what spec the carb is set to, i need to strip it and do some measuring i have only ever done this once on someone elses carb as well

[i l k e r]

New poster! (less than 10 posts)

the lower the number the richer the mixture is mate, so 10.xx is actually quite rich

[Nayls]

I'd check that you actually have a main jet in the carb!

[jantheeven]

New poster! (less than 10 posts)

the lower the number the richer the mixture is mate, so 10.xx is actually quite rich

that's what he said

Chris, do you have a group A carb?

[Chris Hebden]

Yea i now understand what the readings mean thanks to Adam and Bruce, but i wanted to know when each stage kicks in, in terms of RPM or another reference point!

Jantheeven i havent a clue mate, all i know is BB rebuilt the engine a couple of years ago and set the carb to run 22psi with an in car adjustable boost controller, which is set as 12psi-22psi

[UNICRONICUS]

Have a read of post number 2 in this article, it should sum everything up for you nice and easy! https://www.rtoc.org/boards/showthread.php?t=460

[Chris Hebden]

I thank you very much, i couldnt find any of the threads this morning, BUT key word there "MORNING"

[dj13]

Jantheeven i havent a clue mate, all i know is BB rebuilt the engine a couple of years ago and set the carb to run 22psi with an in car adjustable boost controller, which is set as 12psi-22psi

How can a carb be set to run at 12/ 22 psi and be expected to fuel correctley.

[Andrew Cooke]

give me a shout if you get stuck, I have a few bits kicking about. Do you have a wb lamda, or were you just using he RR one?

[Chris Hebden]

How can a carb be set to run at 12/ 22 psi and be expected to fuel correctley.

LOL thats why i was so keen to get to the RR and see how far out the car was running 16psi

Thanks Andy much appreciated, for now i am going on the graph that was produced at the RR but in the next week or so i will be (fingers crossed) owning a LM-2 that logs, so that i can reference back and cross reference to the RPM

[Mart]

How can a carb be set to run at 12/ 22 psi and be expected to fuel correctley.

Enrichment circuit mod's.

[dave j gtt]

Enrichment circuit mod's.

How exactley would you do that then Mart , please do explain , i was under the illuision that you can only have carb set up correct, for one boost pressure

[jantheeven]

How exactley would you do that then Mart , please do explain , i was under the illuision that you can only have carb set up correct, for one boost pressure

Me too! That's why I sold my in-car boost control kit... on advice of some members here