Post by ebrowntaylor on Aug 15, 2018 12:26:44 GMT -5
This is my first post on the forum. I have a 65 chevelle with a 327 I run E85 on with a 750 DP carb w/o choke. Rob Mix built it, but I have had to make some mods to get this thing right (and still isn't right), and I am having a terrible time with a lean bog right now. It's also flat on the upper rpm range.
I have an AFR that I just installed.
My motor is built pretty solid with a cam with a little overlap, decked block, shaved/ported heads, about 12.5-13-1 compression, 4.10 rear th400 with shift kit. If you need more info on any of this let me know.
My initial set up from Rob was:
Air bleeds: 31/68 PVCR: .067 Jets: 89/99 (rear has extensions) PV:4.5 front (rear is blocked) IFR: .041 Boosters: 157 ( maybe a little small) accel pump(s): 30 cc squirters: 45 (I have tried 42's without luck)
Can't get the thing to idle without the following changes and I have to go in more than 3/4 turn on the 4 corner idle which gives me about .9 lambda and 13 inches of vacuum. I made the following changes, but left everything else the same:
Air bleeds: 31/67 Jets: 83/94 IFR: .035
Any of you guys running a similar combo that have had luck with your settings, or does anyone have any advice. Thanks
Post by bigydaddy on Sept 30, 2018 17:11:39 GMT -5
two things. 1) where is your timing at? 2) is this new motor or did you convert a running motor to E85. The reason I ask is mine did all kinds of crazy things while it was cleaning all the carbon off the piston tops befor I was able to work on just the tune. I used to run 1.13 lambda @ idle and everyone would pregnant dog that it was too lean. You're not going to have detonation problems at idle with no load. It was .82 lambda @ wide open throttle. bottom end gets more stable with the more fuel you throw at it. Other thing you can do is get it close to idle off the secondaries, then bring in the primaries for fine tuning.. This lets one of the circuts stay on the idle circut instead of uncovering the transfer slots in both primaries and secondaries. I had a huge flat tappet cam with only 5 inches of vacuum @ idle. Its a ball to drive on the street with E85, Been doing it since 2009. Good luck its the greatest fuel around if you drive on the street with a high compression engine.
Post by bigydaddy on Sept 30, 2018 17:18:38 GMT -5
with the IFR change oyou are back to almost the gas carb sett in. that is ok if you are trying to trim fuel out of the idle circut but be careful it will make it more unstable at idle. Kinda like a knife edge. It will be ok for awhile then fall flat on its face and want to die. If you run the smaller IFR try running a smaller idle air bleed to fatten the idle circut on the bottom end. bigger bleed more air smaller bleed less air more fuel. Sorry I didn't reply to this first. Just got back into town. I think most have abandoned this site unfortunately. Good luck. Post if you have any other problems I'll try to help.