Nova 404

iTrader: (5)

I am helping a friend with his Carbed LS1 with the MSD timing control and have a few questions.First of all which timing curve would be best to start with?We put # 3 in for start up.Car is a Nova wagon,3.55 gears,700R4 with a slight increase in stall.It should be less than 3400 lbs.

Next question is Accelerator pump(Quick Fuel 650 vac secondaries),we added a 50cc pump and was thinking of a 31 shooter but not sure which pump cam would work best.I have read these like a lot of pump shot.

Pop N Wood

iTrader: (1)

The carb data base in the stickies has a lot of info on timing curves. for initial start up the #3 will work. Most guys start with the #1 just to be safe. Once you get it going you will want to install a custom tune. Judging from your set up you will want to run a MAP sensor to boost the idle timing.

Your Quick Fuel carb should have adjustable air bleeds. Also correct me if I am wrong but that looks like a dual plane intake. If you adjust the air bleeds than you shouldn't need the 50 cc pump, expecially with a dual plane and that undersized carb.

Most guys fix the single plane bog with the larger accel pump and more agressive cams. I did too at first until I put in smaller air bleeds. That got rid of the bog and made all the difference in the world how the motor ran below 2200 RPM. It really flatens out the AFR on the wideband. I am about to pull the 50 cc pump off and see if still runs as well.

But from what I have read the dual planes aren't as prone to bog as the single. And like I said with a 650 instead of the more common 750 I don't see you having a problem with bog.

ZONES89RS

iTrader: (25)

It seems if that is a LS1 with a stock cam, it should have a high signal to the carb and like above mentioned, a 30cc acc pump should have worked great, i am running a 30cc pump on my 5.3 with a cam and no stumble at all since it is on a 114 LSA, i think it helps get the right signal to eliminate the off idle dead spot and it is a vac sec as well, so that helps.

cody161

iTrader: (18)

If the motor is not over carbureted then it should not have a flat spot off of idle. The 30cc pump should be good.

Nova 404

iTrader: (5)

Ok we have had this thing running for 5500 miles,it drove from California to Ohio recently.We had to drop to the #1 timing pill at sea level in California to stop it from pinging.While out east it was even pinging on #1 pill.It does have a slight bog at tip in which I hope we can resolve with Acc. pump tuning.We will not have a chance to add the map and tune due to other issues in the next few weeks.The car will be doing some tight course Auto-X type testing and I was wondering if we added better fuel(100+ octane) if one of the other timing curves would be better for low end torque to help pull it out of corners a little quicker.The motor is a stock 97? LS1 with later #243 heads and stock cam.,headers X-pipe and fee flowing exhaust.
Thanks

GNCLONE

I'm curious about an answer too

3pedals

iTrader: (3)

Have you connected the MSD to a laptop and tryed to make a timing curve of your own?
Might be worth your while

Pop N Wood

iTrader: (1)

It also sounds like a MAP curve would help with your pinging problem. Let the vac advance take out some timing under load, but still have good advance for cruise.

It might take you a whole 2 minutes to hook up the MAP and have it working. I believe even the pills have a vac curve in them.