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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,261
My dizzy only has one port. I dont think it is the standard one for a type 68 motor.
But it has to be the cause of all my problems in lack of low end response. Beyond the vacuum range, the boost timing centrifugal bits take over. These bits always worked OK. Hence the vicious wallop when it hit boost -everything came right - fuel dump correcting leaness, plus boost timing. But below that nothing was happening.
Had another track/race day y/day. I bailed on the one last month because the problem was not sorted and too hard to drive.
The race day y/day started in the rain. The car was easier to drive in the wet than the dry race day 2 mths previous. I have full range throttle response, and never lost it once - even when wheel spinning in 2nd off the corners. It is a different car.
The timing was correct at low end at top end with the previous dizzy set up, but the fact I could barely turn the innards on the vac port has to be wrong.
All the low end hesitation is gone. I could tune some out by dumping more fuel in, down to 2000 rpm, but it still was wrong below that. It now pulls without hesitation from 1000 rpm.
I just have to get some precise fuel management going now. I was running it y/day with the WUR boost port disconnected (dumping too much fuel). My AFRs in this mode went from 13.5 at boost onset down to around mid 11's at top end. Weird - it was getting richer with more revs, instead of leaning. Can't work it out. But the bit prior to boost is a bit lean. It always was, but with the dizzy not working properly, the engine basically failed to work. With the dizzy freed up, it tolerates these lean AFRs much better.
I am ordering a digi WUR now I know my only remaining problem is precise fuel ratio control.
The car is fantastic to drive now, and wicked under boost. I was nailing the throttle about 1 sec before I needed full power, instead of counting to 5 and wondering if anything would happen. I could control the back end just balancing it on the throttle. Brilliant. It is much easier to drive now than I ever imagined it would be.
Now to improve suspension, tyres etc.
Old 08-03-2008, 02:41 PM
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