Quote:
Originally Posted by 66 II
GregWeld,
I am looking for information on how the eight stack works without an IAC valve (new to fuel injection). How is idle quality and how does the engine react when the AC is switched on?
I saw your post on FAST where you described a problem you were experiencing recently and you mentioned not having an IAC. The FAST tech seemed confused (I assume these are the same folks giving tech support for the Inglese system with the FAST controller...)
Thanks!
Todd
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Todd,
I don't have an IAC - don't need it. Motor was built with EFI in mind - to wit - we did a custom Crane cam with a wide LSA (114* I think) to get some vacuum and smooth the idle a bit. Another thing with 8 stacks that people don't understand is that you have ZERO "reversion" (pulses inside a normal open/common plenum manifold)... so an 8 stack will "eat" a bigger cam and tame it a bit.
The problem I was experiencing was I couldn't get it to idle down.... and this was AFTER I had it running super! But it - as most of these things seem to be - was OPERATOR ERROR.... I had gotten the stacks out of sync! From side to side they were off.... IT was completely my fault. I had disconnected the side to side linkage - and adjusted the idle in the meantime - and then failed to reconnect the side to side linkage = and then the more I messed with it the worse it got! UNTIL -- in the middle of the night -- I had an AH HA moment! Re-sync'd the TB's --- with the manometer -- and all was smooth as glass once again.
NOW for your other questions RE: A/C -- This isn't much of a load on a motor that is making a bunch of TQ and idles at 950 rpms.... I also have a "loose" TQ converter... 2800 stall -- so when I drop in gear - there is no discernible RPM loss. This motor made an AVERAGE of 478 foot pounds of TQ from 3200 rpms to 6000... so I think that's why the load of the A/C compressor just isn't a factor. I also run electric fans so there's no load there either. I get a bigger rpm "reaction" when I turn the stereo on! I'm serious! That puts a momentary load on the high output alternator. I use a SPAL PWM fan controller - and that is designed to not turn the fans on when you switch the A/C on... it waits about 20 seconds or until the trinary switch reaches a preset head pressure. I think this also takes that A/C load off the motor... as most hammer the alternator with the fan load (radiator and the cooling speed fan).
I drove to Portland on Wednesday just because it was supposed to be 90+ degrees.... this EZ EFI works so dang well -- it's just amazing. This morning when I got up (down there) I decided to change the cruising A/F ratio from the 14:7 I was trying out -- trying to see how it'd run a bit "lean"... and simply plugged the little hand held in -- changed the cruise number and drove off.... The motor seems to "like" a bit fatter A/F and the torque seemed a bit flat with the 14:7 I tried on the way down. The beauty of this is that there are only 3 numbers -- Idle -- Cruise -- WOT. Just pick one -- and the rest is all done for you. No tables to mess with... nothing. GAWD -- the thing is so simple and it just works!
BTW -- My idle doesn't vary 25 rpms.... watching the dash tach -- it doesn't move. Watching the hand held programmer -- it varies 50 at most.