DJChunter

i am doin a N/A turbo project, and purchased a MSD boost retard.. its adjustable between 1-3 degrees per psi all the way up too 20degrees total retard.. i was wondering what i would set it at.. like how much is the timing retarded per psi is all i really want to know.. thanks
Dave

ASE_Joe

um, normally on a piston car, its 2 degrees retard for every 50hp added. thats partially why the civic melted a piston, cause i didnt retard the timing.

DJChunter

BUMP

rotarygod

iTrader: (1)

The MSD will immediately start to retard timing as soon as boost hits. When you hit 1 psi it will retard anywhere from 1-3 degrees, 2psi from 2-6 degrees, but you understand this already. The BTM is not really the best thing to use on a turbo car. Will it work? Yes. If you want 10 psi of boost then you are going to have timing retard a minimum of 10 degrees but as high as the max at 20 degrees. The problem that comes into play is that you may only need 1 or 2 degrees of timing at a certain spot in the powerband. However, the BTM is going to pull timing back as long as there is boost and not neccesarily where you need it or want it. Every degree of timing it pulls off that you would optimally want there is hurting your power. The good thing is that it is better to be safe than sorry. The next problem that you run into is how are you going to wire it in? How many are you using? Just one box or three? If you wire it in standard to the leading side of the crank angle sensor you are only going to get retard on the leading plugs while the trailing are going to run standard timing. All you are doing at this point is changing your leading/trailing split according to boost level. Not a good idea unless you have a standalone ecu that can control how and when you want to do it. To get the full benefit of the MSD you need three of them. One for the leading side and two for the trailing. The reason for this is that both leading plugs fire at the same time always in a wasted spark configuration. Swap leading spark plug wires and start the car, you'll see. The trailing however each fire independently of each other and of the leading meaning you need control on each spark plug here. 3 boxes. Kind of a pain in the ***. I would contact or PM aaroncake. He added a T-II turbo to his n/a and it has been running for several months. Check and see how he did it.