Heath, Thanks for the welcome. The Race on E85 site and this message board are very nice.
My decision to run a locked out distributor was prompted by my access to a complete MSD set-up (6AL, timing controller, and distributor) for a small price. My old ignition was a DUI HEI which worked well, but was worn out. The MSD stuff was new, thus the change.
My engine combination is as follows:
444 cubic inch tall deck BB Chevy.
4.35 bore X 3.74 stroke.
6.800” long rods
SRP 13:1 pistons
Cam is a tight lash solid roller from Racer Brown that was ground in April 1968! Intake .604” lift, 287 duration @ .050”
Exhaust is .604” lift 284 duration @ .050”. (I know it is over-cammed, but I am still able to run 10’s with the thing and it sounds SO good!)
Brodix RR-oval port heads
Weiand Team-G tall deck oval port intake
AED E85 1000CFM carburetor.
The engine is in a 1968 Camaro with a Liberty modified Doug Nash 5-speed, and 3.73 gears in the Dana 60 (soon to be changed to 4.30). I normally leave the line around 5,000RPM and shift at 7,400RPM.
My EGT’s with the DUI ignition (with centrifugal and vacuum advance) normally would run 700-800 at idle. My “idle” is at 1,600RPM. That was a rich air/fuel mixture at idle, but not too rich.
My wide open throttle EGT’s are right at 1,200 degrees. That is with 95 jets in the front (with a power valve) and 110’s in the back with no power valve.
Changing ONLY the ignition, my idle EGT’s went to 1,200 and I would experience a lean pop.
I changed the idle feed restrictors from a .046” to a .059”. That brought the idle EGT down to 850 degrees, and car sounded better at idle. Upon test driving, I found that my EGT’s would drop below 700 degrees at light load, partial throttle and the car slobbers all over the place(way too rich) except at WOT. WOT is still great; 1,200 degrees.
My thought is that I am using more throttle at light load due to the lack of vacuum or centrifugal advance, thus getting into the main jet (a #95) at cruise speed and load. I am not dripping fuel out of the boosters at idle, but I feel that I am too far into the transfer slot now. Can I correct this by opening up the secondaries some more at idle, or do I need to drill a small hole in the primary throttle blades?
So now, I am left with the question of how to tune for street driving? Yes, yes I know; it is a race car, but I do take the thing out on the street and drive it to work occasionally.
I do not even know where to start to be honest. I left the IFR’s at .059 and changed my transition restrictor from a .052 to a .046. That brought my idle to right at 1,000 degrees. It was at that point that I posted my question on the message board. I will take it for a test drive again tonight. If it is still too rich at light load, partial throttle cruise, I guess my next step will be to start bringing the front jets down in size.
Any input would be welcome. My thought is that I will end up with one tune-up for the street and a different tune for the track.
At the moment, my brain is short circuiting. Heck, I could have had bad batch of fuel…….I don’t know.
Here is a link to a video of my car at the track:
good-times.webshots.com/video/3059356640048907967mCgdFcMy old motor combination was much the same, but with a smaller duration cam. I ran it too lean at the track and melted a nice hole in #4 piston. That is when I bought the EGT!!
Thanks for your help,
Chris Smith
PS I have had great success with this fuel for the last couple years; Both on and off the track. I have endured lots of trial and error with E85, but in the end, I firmly believe that this is the fuel for high compression performance.
