I've got a MSD/Carb setup in a 1800lb T-bucket.
The motor is as follows--Stock LS6 disp and compression, Ported 243 heads, 232/240 @ 609/595 cam, GMPP single plane intake, headers, 3400 stall convertor+ 350 turbo, 4.10 gears, basic heads/cam motor.

In the MSD box I've set a curve of 28* total in by 2300rpm, and 8* of vacuum advance above 6 inches of vacuum.
93 octane fuel. Seems to run pretty good, I'm in the process of dialing in the demon carb as well.

What are some of the timing amounts, etc that some of you carb/msd boxes are running?
Thanks!!

 

interested in this also, going to be running the edelbrock carb manifold with msd and a demon carb myself.
our petrol rating is slightly different to yours i believe , uk pump fuel being 95 octane regular and 97 octane premium.

 

ttt, anyone who can comment on LS timing needs?

 

Have you had any problems with detonation on the LS6? I am using the Edelbrock box right now but the timing is always too fast. I am going back to injection so I can get the timing where I want it. I plan on putting spray on my car and need to be able to slow the timing down some so I don't cook the motor.

 

I don't detect any detonation by ear but the car is so damn loud with sidepipes with glasspack muffs I can't tell. Thats why I'm looking for opinions on a "safe" level of advance with rpm and vacuum advance from anyone with experience, but there doesn't seem to be many of those I guess. Carbs=Dangerfield=no respect?

 

I bought the same setup as you Ionize but for an S10 and I won't be installing for probably another month or so. To be safe you could take it to a shop and dyno tune with A/F? As for anybody who bought the Edelbrock you might want to try the MSD instead far more ability to tune

 

These engine do not like a ton of advance and I wouldn't go above 32 deg total.That bucket must be scary fast!!

 

i've got mine 90% tuned, but don't remember exactly what it's at right off hand. it goes something like.........


10* @ 0 -800 rpm (starts easier when hot with some timing)
18* @ 800-1200 rpm
24* @ 1200-2400 rpm
28* @ 2400 rpm-redline..........flat line

MAP advance at like.....

0* @ 1-3 psi
2* @ 4-10 psi
6* @ 11 on..........for now....need to final tune for drivability (read below)

my tuner has been talking with Jim (Top Notch Tuning Guru!!!) @ Speed Inc and said that under WOT, a typical motor like my head/cam motor and even my tuners 408 ETP/BIG cam combo should see no more than 29* total. however, he said that while cruising, with more vaccuum, the tune on the MAP advance should head upwards of 40-45* total at like 20+psi. Jim told him that it would greatly improve drivability & fuel economy. so your MAP advance should be a constant rise from 0*- 40*+ @ higher manifold psi and your best bet will be to drive with your laptop connected to the MSD box to see how much manifold pressure you've got with your particular combo.

Example.......if your total timing is at 28* on your timing chart, and you want 40* total @ cruising (ie 20 psi MAP) then plot + 12* at 20 psi on your MAP chart. 28+12=40.


now, there will be some differences of course depending on altitude, fuel grade, engine combo, etc., but that should give you a pretty good idea based off of mine which is running soooo much better/stronger, and cooler now, not to mention it idles where it should. the edelbrock box is a great & easy setup for a stock to mild build where only carb tuning is needed, but it did NOT like my head/cam combo at ALL! my tuner also has another ls based hybrid that's using 243 heads & Z06 cam and it runs Perfect with the Edelbrock box.

hope this helps.

so Ionize, your's looks pretty darn close to what mine is at. i would try out the "drivability tune" mentioned above and see how that works out for you as i will be doing soon. sounds like a Mean ride!

 

Thanks, some great info there, I'm pretty close to that, but with a flat amount of vacuum advance 6" and up, I thinki will ramp it up higher as the vacuum builds. 29 total mechanical without any vacuum right now. I'll soon have a post showing the complete project..