I previously had the distributor locked @23 with no timing control. I installed a megasquirt2 to control ignition timing and converted to e-85. The problem is that after setting up the system so i can datalog boost i am seeing very high boost ie 20psi. I am running about 20 degrees@7psi and 16@12psi 383sbc s471 jgs50mm wg with a light(7psi) spring iron heads 8.5:1 compression. I think my problems are that i dont have enough ignition timing with the e-85 and it is causing the exhaust coating to burn and also is giving the turbo to much pressure from the high egt. i never really noticed the boost guage going this high before i changed to the Megasquirt and ethanol. I am headed to the dyno next week and would like to get this into control before. I am going to try and pull less timing out. I have it set to 36@no boost and dropping linear to 20@7psi. Am i on the right track in my thinking. It seems that with the ethanol i should be able to run as much as 30 degrees@7psi??? Thanks again! Eli

 

Where are you reading boost from?

And yes too little timing. The lack of timing will make a lot of exhaust,
volume, temp, etc....

 

Boost is read from the map sensor coming off of the intake below the carb.

 

Try from under the carb or throttle body.
That is what the motor is seeing not just back pressure.

 

The only pressure line I have above the throttle plates is the boost ref for fuel pressure reg. Everything else comes off the intake plenum. IT looks like it controls the boost for a split second then when the rpms come up it just raises. Im pretty sure its from the exhaust heat overcoming the ability of the system to vent pressure. It has only seen boost 4 times for a few seconds each time. I understand that above the throttle plates boost will pile up when they are closed. This is not the problem. You havent had any problems with the jgs wastegates i presume.

 

The timing is way to low. You should be able run 30+ deg of timing with 16psi on E85.

 

Every engine is different but I feel your timing it too far retarded. I usually run 28-30 at that boost level (up to 15). I pull it down to 24* for 20-22 psi.

I don't know if it would make a difference but all my wastegate lines are off the carb hat side. Since you are hooked below the throttle plate you would be shutting the wastegate if the throttle is closed even if there is alot of boost above it.

 

The larger JGS's can have the top port run to the manifold and the bottom to a control and/or compressor pressure.
the JGS can handle the vaccum and upon throttle close pull the gate open.

Is this your set-up?

Also, with the very limited timing the fuel is getting burnt in the pipes not the motor. So instead of creating rotating energy it is just wasted energy in the pipes spinning the turbo.

 

No, I've been running a line from the carb hat to the bottom of the wastegates. Then another line of the hat to the boost controller and to the top of the wastegates. The map for the electronic never sees engine vac so if I screw up and turn it on with the engine already running it won't effect it at all. Before it would think 14'' was atmospheric pressure so it controller was really confused. I haven't had any issues yet running it this way. It will go 7psi with the controller off and follow the cuve nice all the way to 25psi.

 

Just a little update. I ended up working on my timing curve a little and it resolved the problems. The boost is tamed back down and i can only imagine that the egts are lower. Going to take the car to the dyno on wed the 16th. Sould really be able to dial it in then. Any pointers on what to take care of first on the dyno? I figgured i would get the timing set if i can and then do jetting unless for some reason it is to far off. Thanks again for all the help. On a side note i would reccomend that anyone with a holley style carb should move their idle feed restrictions to the bottom of the main well. Most carbs run them in the top of the idle well. After trying to chase down carb tuning info it was highly reccomended so i done it and it seems to have made the idle much smoother. This has to do with the fact that it meters much more consistently when submerged in fuel than it does at the top of the metering plate. Look up ifr relocation on the innovate forum for more info.