FINALLY; it runs with some authortity!!!!
Tomorrow (Sat.) we'll install a new O-2 sensor in the A/F ratio meter (the old one died) and do some more carb testing as regards mixture. if we can get that under control, it's ready to race.
I'll let you know. :happy1:
Today, we got the new wide-band, data-logging, (F.A.S.T.-brand), A/F-ratio meter's O2 sensor replaced (it was lead-poisoned, I guess) and did a test-run in the turbo car, and here is what I learned:
Strange things are happening...
At full throttle, (with 10 pounds of boost,) the A/F ratio is perfect at 11.6:1. That's with the water/alcohol BoostCooler spraying. Dunno how we lucked out and hit on just the right amount of enrichment crutches (BIG jets, float bowl vent extensions, and a boost referenced power valve,) but there it was; a brand new meter said it was 11.6:1 and I am lapping that up like honey!!! It's been a long and arduous road to this point. I'd bet we have had the float bowls off that carb (for jet changes,)
at least ten times! Probably more...
Here's the strange (bad) news:
All the time the engine is NOT on boost, the meter says the A/F ratio is 9.6:1.... Idling, or just driving down the road.
That is rich enough to wash all the lubrication off the cylinder walls... not a good thing. Adjusting the idle mixture helps the mixture richness at idle, but as soon as the throttle opens, it reverts back to a 9.6:1 ratio.
Now, we are stuck: It finally has the right amount of fuel (exactly, apparently,) to escape detonation under boost, but the mixture is so rich at all other times that driving it like that would wear the rings out, in short order.
I don't dare try to lean it out for fear of destroying the excellent A/F ratio it is showing to have under boost.
What to do?
It is so rich, that it runs noticably rough at part-throttle....
Tried a couple of stall start launches, today, and they went like this:
First one at 2,000 rpm... a disaster with probably a 3.5-second 60 foot time...
Engine had no power as soon as the brake was released, and it limped off the line, only to come on like Gangbusters two seconds later...
Second one: 2,500 rpm stall... left okay, but obviously needs 3,000 rpm to really haul the mail out of the gate, but on an un-treated surface like we have on the street, makes for too much wheelspin. I may have to install bigger brakes off a pickup (this rear end housing is a B-Body setup swapped out of a '69 Cornet.) The pickups have 1" larger diameter drums and wider shoes and are, I think, pretty much a bolt-in. The brakes we have now, don't hold the motor at a 3,000 rpm stall very well. Starts trying to spin the rear wheels...
It may not do that on a VHT-treated strip; we'll see.
I will go to great lengths to avoid the installation of a trans-brake, for reasons I won't get into, now...
But, at a 3,000 rpm stall, this thing moves well (when it hooks,) off the line... Better than my '72 supercharged, 360-Magnum, powered '72 Valiant (3,400 pounds.)
I am happy, but confused and don't have a clue as to what to do...
Ideas?????????????????:banghead:
