madmike wrote: ↑Sun Sep 27, 2020 3:51 am
when 'cruising' it should not be in boost should be in vacuum
Well, cruising at a steady 75mph through the area I live in, it just doesn't happen. The hills in the pass are so steep that the rail line that goes through there is the steepest grade without cogs in the country.
If I let off enough to stay in vacuum I'd have to drive 35mph or something.
madmike wrote: ↑Sun Sep 27, 2020 3:51 am
when 'cruising' it should not be in boost should be in vacuum
Well, cruising at a steady 75mph through the area I live in, it just doesn't happen. The hills in the pass are so steep that the rail line that goes through there is the steepest grade without cogs in the country.
If I let off enough to stay in vacuum I'd have to drive 35mph or something.
You're going to need to keep a close eye on your water reservoir if that the case. It's prolly gonna need to be filled more often than not if your system is spraying during cruise.
Yeah, I check it constantly. Fortunately it's just when I need to get out of my little village to get groceries (about once every 2 weeks). Otherwise I just drive around the forest roads.
Come to think of it, it might not have actually been that high. I had the line for the gauge running from the turbo housing. I've since moved the line to get my signal from below the butterfly. I'll have to go for a freeway drive sometime soon and find out.
Alright. I got new needle and seat assemblies and it'll hold 12.5:1 all the way up. Even if the boost is turned up beyond what my water-meth can cool. (15psi)
Now I want to figure out why it goes 10:1 at the beginning of the main circuit. Basically if I'm toodling along at 55mph in 4th, it runs between 10 and 11 to 1 on the afr meter. Probably means more messing with the emulsion tubes.
Time to get this sucker put back together. Best guess for my last failure was actually oil starvation at high rpm. It's a little more complex than that, but that's what it boils down to.
I have meticulously checked and fixed every oil clearance, got everything very closely balanced, and just put the shortblock back together last night.
The new setup is going to be largely the same as before but with some minor fixes. I got some 2.0mm inlet valves for the Kadrons. I'm going to control timing with a CB black box. I've added in total seal second rings, gapped to .020" on both the 1st and second rings.
That's about it for now though. Eventually I'll have to bother you all for advice building an advance curve.
Holy cow! The black box is so easy to use I think I'm all set! It's so smooth and the display makes it really easy to see what part of the map needs adjustment.
Here's a 5houggt. Since I added the black box I now have an absolute kpa readout for pressure. The gauge I was using for boost was referencing atmospheric as "0". So now I'm seeing that at what I thought was 10psi is actually only about 147kpa at my elevation.
When i was using my old distributor to handle timing, it pulled the timing down to ~22° by 147kpa (10psi by my gauge). Do I need to handle timing based on absolute pressure or should it be based on "psi above atmospheric". Because technically I'm 3psi boosted at 100kpa.
I did some digging and I think I've figured something out. My turbo is probably putting out more heat to produce the same pressure at my altitude. So I really really need to tune based on IAT moreso than the "1 degree for each pound of boost" rule of thumb. If I run 32° N/A at 74kpa, I probably ought to retard that a bit even at 100kpa due to the added heat of boosting up to sea level pressure. My turbo has to work harder to achieve the same pressure.
But without knowing the heat in the intake charge I'm shooting in the dark. My "egt" sensor is really easy to repurpose as it measures accurately from below freezing up to above exhaust gas temps.
Coyotemutt wrote:I did some digging and I think I've figured something out. My turbo is probably putting out more heat to produce the same pressure at my altitude. So I really really need to tune based on IAT moreso than the "1 degree for each pound of boost" rule of thumb. If I run 32° N/A at 74kpa, I probably ought to retard that a bit even at 100kpa due to the added heat of boosting up to sea level pressure. My turbo has to work harder to achieve the same pressure.
But without knowing the heat in the intake charge I'm shooting in the dark. My "egt" sensor is really easy to repurpose as it measures accurately from below freezing up to above exhaust gas temps.
For a few wires more you could add injection and log your temps real time. No more guessing.