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-   -   Rupert carb problems.. (https://www.racingjunk.com/forums/showthread.php?t=24217)

Birddog95 05-12-2009 05:16 AM

Rupert carb problems..
 
Here's some info I can share. Rupert 1150 carb came with 172 jets, enderly belt driven pump with bypass loop and (i believe) 180 pill up to carb. The car ran awesome in Ohio (Base of 800' corrected 1900) and has now moved to Canada (base altitute 2300' corrected 4300'). I had a hard time getting heat into the car. I'd lean out till 155 and as soon as I shut the valve temp would start dropping. Dropped the jets to 164 and can now regulate temp (leave at 150 finish at 170) but I am going through an average of 2 gallons a run (towing back). Even the original owner said that is double what he used. Any suggestions would be appriciated.

suicidebomb 05-12-2009 06:15 AM

It's just a bit rich.

hammertime 05-12-2009 06:15 AM

where is the idle screws set @ ?

Birddog95 05-12-2009 06:36 PM

The air mixture screws are out 2 turns and idle is at 1400 rpms

cepx111 05-12-2009 09:23 PM

I'm going with Earl, your WAY to fat for the altitude your at, go down at least 10 more jet sizes.
Monitor your fuel consumtion and re-adjust as necessary, no way you should be using that much on one run - JMO>Cp

hammertime 05-13-2009 04:33 AM


Originally Posted by Birddog95
The air mixture screws are out 2 turns and idle is at 1400 rpms

put them to 1 1/4, whats the fuel pressure ? also what size motor.

IMO your starting to get into a jet size smaller then I'd want, maybe a 1050 would be a better fit later on. Jet change will help it though.

Birddog95 05-14-2009 05:24 AM

The engine is a BBC 598. Now one thing I'm unsure of is when you say down 10 jet sizes your refering to numerical values right (currently a 164 down to a 154). I've alway been running gas and each steps down in increments of one where alky seems to step in 4's. (FYI I started at 172 jets). I'll try the idle mixture screws but with the bypass loop on the enderly pump at an idle I only have 2.5- 3 psi but as soon as I touch the throttle it jumps to 8. Should I be looking at changing the jet/ pill in the pump to limit the amount of fuel up to the carb?

hammertime 05-14-2009 06:21 AM

seems like a very small jet for that size motor, rule of thumb with a belt drive is 3@idle 8 on the transbrake.

Birddog95 06-08-2009 10:01 AM

Somethings F**ked! I went through 15 gallons of meth in 6 runs (including warm up) and we towed back! Runs were fairly clean 7.75 @ 170.3 Launching at 150 finishing at 170 degrees. I forgot to try turning the mixture screws back :roll: Air was really good here basically cause it was so cold (50F) corrected 2700 ft. Not sure what to do :?

dparker 06-08-2009 12:08 PM

You probably burned 3 gallons at warm up, your not that far off, You can save some fuel while idling with the idle mix screws. But you'll probably burn around 1 1/2 gallons a pass when its perfect. Are you milking the oil? If I don't pull my fuel cutoff back when I'm going to staging and to the line, Ill burn 2 gallons a pass also.


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