What are you using for a timing controller, or an add on box to retard timing? i've heard very mixed things about the MSD BTM boxes...... are people primarily using boost referenced retard setups (i.e. pulls 1deg. for each psi, etc) or are people using single stage retards, (i.e. above 20psi, pulls 15 degrees) im not to worried about race fuel, but when the car is running on pump gas i want to run as close to the edge as possible around 20psi. right now i just have a 6al box, so i was looking at the msd boost timing masters, but alot of people say they make shyte for power.

I just went through reasearching all of this...If Money is no concern then the MSD Digital series too much $$$. My final choice was the Mallory HyFire 685, $175 Factory redconditioned on Ebay. Has 20 degrees of retard vs 15 0f the MSD...
http://www.malloryperformance.com/Pr...inselection=14

anyone have anything to add??? TTT

Well, Im running the msd6al with the btm connected to it and man what a difference! Before I had to lock out my timing with a lot of retard in order for it not to ping like hell on pump gas, and it would really kill my acceleration. But now I run good timing and it starts to pull timing at 4 psi. I love it because if my knock detector senses a knock, I just turn up the knob a bit which is next to the shifter. Its very simple thats why I like it.
I am sure the others are probably better when compared, but the simplicity of adjusting while driving is great for me. I picked mine up on ebay used for $70.00.
It makes a difference in letting you run regular timing till boost builds. When I run 110 octane which is most of the time, I set the knob to nearly 0 and I dont have to even pop my hood.
Again, if you ask me, I say go for one. If you are going to buy it new, then just go with the one you want. Hope that helps some. Just my

I give everyone running boosted V-8's

ya, the only thing that worries me, is can you set the thing to not start retarding the timing until like say, 12psi? and then only pull a total of 10 degrees or 15 degrees etc?

Yes, how do you make it only pull timing above a cerain boost pressure??

Well, If you want it to pull timing only above 12 psi, then thats easy. Install a pressure relief chech valve on the vacumm line which goes to the BTM. In this case, the check valve will not let any boost thru until it over comes the spring which would be set to open at 12 psi. The btm would not recieve any boost until 12psi, so it wont start to retard until 12 psi.
If I wanted to pull timing higher than i do know this is what I would do. Just make one out of a booster check valve or buy one already made.
Hope I explained how it works.

An example, if you unplugged the boost vacumm line to the BTM and left it unplugged it will not retard. Now build boost and plug it in at 12 psi and there you would have what you want. The pressure relief check valve would accomplish this. I dont know why MSD designed it to go as high as a 4psi setting to start retard. Hope that helps.

When I was running the stock MAF and MSD-6AL, I used the programmable MSD-8977. It allowed full timing advance control via software:

http://www.msdignition.com/tc_11.htm

It worked great. Since converting to the 749 ECM, I no longer need the 8977. BTW, it's for sale.

If you're running big boost, you'll need to take care of your fuel as well, so most likely you'll end up going to either an aftermarket ECU or using a custom calibrated forced induction GM ECM prom, all of which let you map timing vs boost. The Gen6 DFI's seem to be going for downright cheap these days. That being said, lots of folks are running the MSD BTM's with an FMU, and it is a good starting point, although slightly crude.

its carbureted, thanks though