Fun with troubleshooting leanness (and 5th gear cruising temps) |
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Fun with troubleshooting leanness (and 5th gear cruising temps) |
emerygt350 |
Mar 15 2024, 03:37 PM
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#1
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Advanced Member Group: Members Posts: 2,144 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
So I have been playing with adding resistance to the cht to bump my mixture. Messing with the mps was not getting me to where I wanted to be I wanted something a little more global. Anyway, bought a 10 dollar Bluetooth relay. Set it up so one channel was clean the other had 50ohms resistance in it. As I am driving I can switch back and forth and watch the results on the cht and AFR. 50 is really working well (this is all in addition to my 250ohm found on 73s). Now I have added another 20 ohms to the alternate so the relay will switch between 50 and 70. It ain't pretty but it's only for troubleshooting.
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emerygt350 |
Mar 25 2024, 10:34 AM
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#2
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Advanced Member Group: Members Posts: 2,144 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
I would love to hear how PMB handles it but I suspect with a good cam grind most of this goes away. At least that is what I have heard. I have the stock cam.
djet, original 2.0 heads, 96mm piston/sleaves, 123 non-bluetooth dizzy. Mine is a little warmer than yours. Mathematically I was shooting for 8.5 compression but I suspect I am closer to 9. I suspect the combustion chamber was a little smaller than my measurements (oil and clay both). And yes, a couple degrees advanced is where it likes it, and the impact of reducing the advance is quite a performance hit (I will have hard data on that once I get to the Dyno) with little effect on temps at cruise. Right now I am at 8.5-9 (at 950rpm) so about 30 at 3400 (how accurate can we possibly be?). Idle for me is very good though, not sure why that would vary much, I do notice idle is terrible at 7 (at 950rpm), inconsistent, engine rpm dropping too low frequently etc but a soft landing would idle ok. That is with tuning the ecu and idle control etc. Apparently around 330-350 is where these heads like to be if I remember correctly, so anything around there doesn't bother me. It's when it climbs past 380 that I get a little nervous, and mine will do that in 5th cruising at 72 on a pretty relaxed incline if given enough time. Town driving 280-300 depending on ambient temps. Oil is nice and cool (180-200). Even 60 in 5th (which I know many people don't do) is getting there near 360 at level cruise over long periods. I took it through the twisty's yesterday pushing it real hard and the engine never got over 314. My son was asking me why they just didn't make the fan go faster on the highway, so we had a discussion about physics.... Also, the seating of the ring on that 3rd plug really matters on what temperature you get on the gauge. |
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