turbos and timing

[carreraboat]

What if my dist is locked out? i have a msd btm and 6m2?

[TurboNova]

I lock out everything we do, it is more accurate that way. The BTM is the way to go unless you have EFI. There is also several MSD boxes that have laptop programs that let you enter a timing curve based on time, or pressure. I have never seen an engine that needs more than 1 degree of retard per psi of boost. Maybe we just haven't seen it but that is a pretty conservative set up. I would lock your timing at whatever base timing you can handle, 34-40 degrees and then pull timing out from there. Start with something like 2 degrees per psi and work from there. You will not be able to hurt anything with that. I am running about 28 degrees at 14psi on my engine but I am also using C-16 fuel.

[carreraboat]

turbonova would you mind if i called you to talk about my setup

[texas-19]

Turbonova,you don't have any starting problems even when the engine is hot?
Great info,keep it comin.

[ttmott]

The way I would look at it is if you are setting up for competition lock it out at some point where it likes to run like Turbonova does because the motor will live at WOT. But, if used for a recreation boat, weekend on the lake, skiing or whatever curve it. There are two reasons for having a curve 1 easy to start, and 2 setting up the carb(s) so you can get a good idle. Don't know why you would want to lock it out if you have a good dist. My MSD Pro Billet is dead nuts on and repeatable; the only thing better would be a crank trigger with a RPM retard module and BTM.

[TurboNova]

I like to lock out the timing because I have found that the timing seems to be more stable at high RPMs. Also by locking out the timing you will be able to achieve a higher horsepower quicker because of the higher timing. I have no starting issues at all but I do use a gear reduction starter. Another thing that can be done if starting is a problem is a MSD start retard box it is built into some of the 7 series boxes. One thing that I did find is make sure your BTM is working correctly by putting some pressure from an outside source like an air compressor regulated down to the boost pressure you are going to run. Then re-check your timing. I did have a MSD box that didn't work correctly.
carreraboat you can call any time.

[HP350SC]

I like the features on this product. Ignition module with individual cylinder retard, done automatically from one knock sensor. Seems like it would be ideal for a turbo'd carb. deal.http://www.jandssafeguard.com/index.html
From the website:
It is simply amazing that in this age of megahertz decision making that people want to "crank back" their timing either through dash-mounted knobs or by actually "retarding" their distributor. Even if you have an aftermarket ECU that allows PC-programmability your decisions are exactly the same because you must decide on degrees of advance or retard which are invariable once set.
The J&S SafeGuard harnesses the power of the microprocessor to allow your modified high output engine to run normal ignition advance for optimum responsiveness. Since the SafeGuard is a closed-loop control system using modern knock sensors as a feedback mechanism you no longer have to turn dash mounted knobs, twist distributors, or even second guess the future with a PC programmable device. Hundreds of times per second your J&S Safeguard will both monitor and adjust your engine's ignition timing on a cylinder by cylinder basis. If you think you can twist a dash mounted knob to retard the timing in cylinder number four at eight pounds of boost with a coolant temperature of "x" at 6385 rpm on a day where the temperature is 92 degrees farenheit and the relative humidity is "y" and the car is in third gear on a 6% grade at 1600 feet altitude....well, you're first in line for the next Superman movie. You probably "get" the idea, it would sure be a lot easier to let the microprocesor retard cylinder number four a very specific two degrees, six degrees or whatever and leave the driving to us.

[HP350SC]

They also sell this combination A/F and Knock guage. Unfortunately it does not appear to be wideband A/F.
http://www.jandssafeguard.com/images/dualmonitor.jpg

[TurboNova]

I like the features on this product. Ignition module with individual cylinder retard, done automatically from one knock sensor. Seems like it would be ideal for a turbo'd carb. deal.http://www.jandssafeguard.com/index.html
From the website:
It is simply amazing that in this age of megahertz decision making that people want to "crank back" their timing either through dash-mounted knobs or by actually "retarding" their distributor. Even if you have an aftermarket ECU that allows PC-programmability your decisions are exactly the same because you must decide on degrees of advance or retard which are invariable once set.
The J&S SafeGuard harnesses the power of the microprocessor to allow your modified high output engine to run normal ignition advance for optimum responsiveness. Since the SafeGuard is a closed-loop control system using modern knock sensors as a feedback mechanism you no longer have to turn dash mounted knobs, twist distributors, or even second guess the future with a PC programmable device. Hundreds of times per second your J&S Safeguard will both monitor and adjust your engine's ignition timing on a cylinder by cylinder basis. If you think you can twist a dash mounted knob to retard the timing in cylinder number four at eight pounds of boost with a coolant temperature of "x" at 6385 rpm on a day where the temperature is 92 degrees farenheit and the relative humidity is "y" and the car is in third gear on a 6% grade at 1600 feet altitude....well, you're first in line for the next Superman movie. You probably "get" the idea, it would sure be a lot easier to let the microprocesor retard cylinder number four a very specific two degrees, six degrees or whatever and leave the driving to us.
Those seem to work pretty well but not in something with a solid roller cam or anything with excessive valve train noise. MSD has a box that you can control timing baised on pressure, time and other factors that works great. It also has timing per cylinder tuning available but then you need to know which cylinders really need the retard in timing. Personally I wouldn't trust a knock sensor with a preformace race engine but for a stock type smooth idle type engine that is a different story.

[ttmott]

Boy, I agree with Brian on the knock sensor. Several years ago I tried to adapt a knock sensor with an Electromotive EFI system and went through probably six different GM sensors and was all over the map on how to read them (never could tell if it was knock, valve train noise, turbocharger system effects, etc). And on top of this mess knock sensors with a carb setup like you have is out of the question IMHO. Keep in mind knock sensing is a "make play" fix for deficient elements on your setup. Always build to the environment you will operate.
What is needed is what you are trying to do (race, cruise) and what your combination is. The right way to do it if you want to lock it out is to go with the 7 series MSD and set up a start circuit; sitll doesn't fix the carb issues you will have to deal with (having full advance at idle). Also the 7 series is not designed for continuous useage. Otherwise to advise on lockout or curve would be a guess. I have a curve setup in by combination and it gives me the best of both worlds.
Tom