Friday Dyno Run Guesses....
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Joined: Jun 2001
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From: St Marys PA
Re: Friday Dyno Run Guesses.... (DiabolicalDave)
Ralph yes, I did play with the FP. I bumped it up to 55psi with the new walbro. I was surprised to see that even with the pressure up, the car still performed about the same, even with the 43psi tune :confused:
All my AFR were in the low to mid 12s, which I really wanted to play with, unforturnately I was sorta stuck with the little flexability I had. I really wanted to play with the fuel curve. The one adjustment I make, made a crazy change across the entire RPM range. I took out some fuel from about 3400-4400 and the entire RPM range went crazy lean! The car was ran during that run more torque than any of the other runs by a good 10-15 ft-lbs and HP was higher throughout. Still peaking at around 5100.
I will post tomorrow at work, the sheet I compiled them all onto. The weird thing about that run is 1 the entire RPM range when way lean, yet my scanner data showed the O2s well into the 900+ range...They should have been mid 600-700s with that lean of a WOT. So I made the guy go under to check the WB in the collector...maybe something shifted that skewed the results. Who knows, he said everything looked ok, but I didn't see it for myself.
I also tried moving the timing and as I found at the track, a decrease in timing of 2* yield crazy low TQ/HP numbers. So we went the other way and again they were lower than average. So I must have the sweet spot for the timing, but what scares me is the timing is unbelievably high. But I don't get any detonation, so I guess I shouldn't worry about it, as the dyno says I am in the sweet spot from the results.
Where I have the timing set right now the number just doesn' make sense that it would want that much. So I plan on doing some digging into the base timing. I am going to locate TDC, through the use of some timing tape on the balancer, mark TDC on one stroke, then reverse rotate the engine over till TDC come up again, then note that reading, and divide by two. that should give me a numberfor TDC. I need to then see where that locates with respect to my 0 mark on the indicator. I suspect that the base timing is where the error is coming in. And I am running around 34-38* timing. I seem to be off about 6* which isn't very uncommon to see when you get aftermarket pointer etc involved.
I am also going to check to see when at idle, where max vac is located with respect to SA. I suspect it right where I have it set.
Also as a side note I think my D44 is toast...tonight I drained some of the fluid out and added some more limitied slip additive, it seemed to make it worse! :cuss Well I figured it would be more than a $7 fix. I can't get that lucky. So I will have to probably pull it apart and see what the problem is. Corky said I probably broke the clips that keep the clutches apart and let there be some slip, in my case they are fully locked. He said I could probably be fine racing it since its a straight line. I just want to get by this nexy challenge and get my bar put in.
I also want to go all poly bushing in the rear and some other tweaks, don't know why, the next one will probably blow completely apart if I improve traction. :rolleyes:
This really sucks with these rears that there is nothing we can do to make them live longer behind one of these motors. Is there. My dad can get the stuff cryoed at his place, but I am very familiar with that and in come cases it helps and other it makes worse. I have been dealing with powdered metal tools and cyro for a good long time and as I said sometimes its beneficial, and other its not.
What is the material made of in these, as far as gears, he needs to know, so he can pick the cycle times if we try to do it.
But if its the clips there is probably little that can be done. I wish I had a scematic to show that that looks like in there in an exploded picture...hint...hint. :cheers:
Well thanks for listening to my rant....Dana rears suck....dana rears suck....I want a 9sec solid axle car...thanks Ralph! :D :lol:
All my AFR were in the low to mid 12s, which I really wanted to play with, unforturnately I was sorta stuck with the little flexability I had. I really wanted to play with the fuel curve. The one adjustment I make, made a crazy change across the entire RPM range. I took out some fuel from about 3400-4400 and the entire RPM range went crazy lean! The car was ran during that run more torque than any of the other runs by a good 10-15 ft-lbs and HP was higher throughout. Still peaking at around 5100.
I will post tomorrow at work, the sheet I compiled them all onto. The weird thing about that run is 1 the entire RPM range when way lean, yet my scanner data showed the O2s well into the 900+ range...They should have been mid 600-700s with that lean of a WOT. So I made the guy go under to check the WB in the collector...maybe something shifted that skewed the results. Who knows, he said everything looked ok, but I didn't see it for myself.
I also tried moving the timing and as I found at the track, a decrease in timing of 2* yield crazy low TQ/HP numbers. So we went the other way and again they were lower than average. So I must have the sweet spot for the timing, but what scares me is the timing is unbelievably high. But I don't get any detonation, so I guess I shouldn't worry about it, as the dyno says I am in the sweet spot from the results.
Where I have the timing set right now the number just doesn' make sense that it would want that much. So I plan on doing some digging into the base timing. I am going to locate TDC, through the use of some timing tape on the balancer, mark TDC on one stroke, then reverse rotate the engine over till TDC come up again, then note that reading, and divide by two. that should give me a numberfor TDC. I need to then see where that locates with respect to my 0 mark on the indicator. I suspect that the base timing is where the error is coming in. And I am running around 34-38* timing. I seem to be off about 6* which isn't very uncommon to see when you get aftermarket pointer etc involved.
I am also going to check to see when at idle, where max vac is located with respect to SA. I suspect it right where I have it set.
Also as a side note I think my D44 is toast...tonight I drained some of the fluid out and added some more limitied slip additive, it seemed to make it worse! :cuss Well I figured it would be more than a $7 fix. I can't get that lucky. So I will have to probably pull it apart and see what the problem is. Corky said I probably broke the clips that keep the clutches apart and let there be some slip, in my case they are fully locked. He said I could probably be fine racing it since its a straight line. I just want to get by this nexy challenge and get my bar put in.
I also want to go all poly bushing in the rear and some other tweaks, don't know why, the next one will probably blow completely apart if I improve traction. :rolleyes:
This really sucks with these rears that there is nothing we can do to make them live longer behind one of these motors. Is there. My dad can get the stuff cryoed at his place, but I am very familiar with that and in come cases it helps and other it makes worse. I have been dealing with powdered metal tools and cyro for a good long time and as I said sometimes its beneficial, and other its not.
What is the material made of in these, as far as gears, he needs to know, so he can pick the cycle times if we try to do it.
But if its the clips there is probably little that can be done. I wish I had a scematic to show that that looks like in there in an exploded picture...hint...hint. :cheers:
Well thanks for listening to my rant....Dana rears suck....dana rears suck....I want a 9sec solid axle car...thanks Ralph! :D :lol:
