I have an lg4 with a carb/distributor setup. I haven't really put much thought into the changes in timing that I'll have to do with boost, and I don't want to overlook anything. What changes in timing will I have to make with the stock distributor? Thanks

 

What you're going to need is the ability to pull timing in the event that the motor begins to see detonation, something that the stock distributor/ignition cannot give you. The way Vortech gets around this is to unclude the MSD 6BTM with their kit, then along with that to take care of the timing, they also use a FMU and secondary fuel pump to take care of the fueling needs. The stock ECM in the car is "dumb" as far as the FMU is concerned, dosnt even know its there. But when the FMU senses boost it adds fuel. Many different ways to accomplish this, the example here was just one way (Vortechs way). Alot of guys here swap to the 749 ECM (or 730 w/ $58 code) which has the ability to take care of both timing and fuel by itself. There are also other wanys. I would do some searching to read more about what you're going to need to tune the car with boost. The stock setup is not going to be able to cut it.

 

As far as the fuel system, since I’m carbureted, I am going to replace the stock fuel pump with a Carter strip mech. pump. I’ll then boost reference the pump so that it will increase fuel pressure 1:1 as boost increases. I’m also purchasing an assortment of jets for the Holley carb and an air/fuel ratio gauge to get the right fuel pressure at different levels of boost. This should solve the fuel issue.

For less than 10psi of boost, will I have to worry about pulling timing? I’m also going to have an intercooler, which should help with detonation a little. Is there a rule that when boost reaches a certain level, the timing needs to start being retarded? Thanks again

 

Whether or not you have to pull timing depends on a ton of factors. If you have your timing optimized for off the boost, it will most likely be too far advanced when the boost comes in and may give you some detonation problems. The BTM may be a good way o dial your timing out as the manifold pressure goes possitive, but you will still need to listen for and check your plugs for signs of detonation.

I'm assuming this will be a blow-through application since you are boost referencing the FP?

 

Yes, I'm going to be using a Holley 600 double pumper for a blow-through carb.

Some of the guys at turbomustangs are just setting their timing back from the start and locking it there to keep it from detonating with the boost. I'm not really familiar with the BTM. Will I be able to do without it and just lock out the distributor at a happy median timing? I'm kind of getting low on funds.

 

Yes, but it will hurt response off boost. FOr street apps, I would prefer to not do that. For a strip car, it shouldn't matter.

 

The more I research, the more that I see you are right, especially since my car is a daily driver.

If I were to get a BTM, would there be anything else I'd need to encorporate it into the system?

Is this kind of what I want?
http://store.summitracing.com/defaul...D-5462&FROM=MG

edit: I talked with Summit, and they said that the MSD-5462 would be a good choice and it would be compatible with my system. Are there any other places that would be cheaper though?