MMS 220 heads....Info, Pics, and discussion inside
#266
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@Exidous - I tried to PM you, but can't attach to PM. Here are a few pics for you of my high octane table. Fuel quality here sucks, but these are the timing values that got peak results on the dyno. Lower than most postings I see. Hope it helps:
Line View of Timing Table
Surface Contour View
Nerd View
Line View of Timing Table
Surface Contour View
Nerd View
#267
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Okay your timing makes sense considering your "poor" gas.
LilJay, I'm approaching 30-35* cruising around at light load. I have not even touched WOT yet but it's perfectly happy at 28* now. I'll add more and see how it does later once I get the cruising stuff sorted.
I've attached my current timing. Pretty much everywhere under 3k seems like it needs more timing still. WOT is .92 g/cyl previous setup maxed at .88 g/cyl. That setup had the FAST 102 and this one has an LS2 so I think once I can get the scratch for a new intake I'll be quite happy.
LilJay, I'm approaching 30-35* cruising around at light load. I have not even touched WOT yet but it's perfectly happy at 28* now. I'll add more and see how it does later once I get the cruising stuff sorted.
I've attached my current timing. Pretty much everywhere under 3k seems like it needs more timing still. WOT is .92 g/cyl previous setup maxed at .88 g/cyl. That setup had the FAST 102 and this one has an LS2 so I think once I can get the scratch for a new intake I'll be quite happy.
Last edited by Exidous; 11-23-2015 at 02:05 PM.
#268
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I have read lots of posts about 28 degrees being fine on 93 octane. Have you verified your knock sensors? Just as a precaution?
#269
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I did have a low voltage fault but that was one of the sensors coming loose. Was fixed. They both ohm'd out fine and the continuity to the PCM is good. I'f had/heard knock before and I'm not getting any hint of it. Just a lot of misfires that feel like unburnt fuel. Yet WOT is just peachy.
#270
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Just thought I'd update. That and it doesn't seem right for these awesome heads to be on page three.
My misfire issues were plug related. I was running NGK TR6 V-powers(.045" gap). Moved to a TR5GP and ALL my issues went away. Thought that knock might start to be an issue with the hotter plug. Saw a little around 4000RPM but not repeatable so I decided it was false knock. I don't have a dyno to see if it's making a difference but I'm up to about 29-30* at peak torque. Have not tried higher. I lowered my timing just about everywhere else to see if I could get a little better economy out of it.
The fact that all my misfires were are low engine speed led me to believe the chamber was too cool and not all the fuel was being burnt. As confirmed by popping in the exhaust randomly. WOT was all perfectly fine once I got past about 3200RPM. One step hotter on the plug worked out perfectly. Hopefully knock won't be an issue in the summer as my IAT's are about 30-50*F.
I must say, I LOVE the heads. Throttle is super snappy. No sogginess anywhere. Pulls hard all the way to 6800. Have not tried higher yet. If someone is looking for a perfect mannered street car but still wants to get the most they can these are the heads for you.
My misfire issues were plug related. I was running NGK TR6 V-powers(.045" gap). Moved to a TR5GP and ALL my issues went away. Thought that knock might start to be an issue with the hotter plug. Saw a little around 4000RPM but not repeatable so I decided it was false knock. I don't have a dyno to see if it's making a difference but I'm up to about 29-30* at peak torque. Have not tried higher. I lowered my timing just about everywhere else to see if I could get a little better economy out of it.
The fact that all my misfires were are low engine speed led me to believe the chamber was too cool and not all the fuel was being burnt. As confirmed by popping in the exhaust randomly. WOT was all perfectly fine once I got past about 3200RPM. One step hotter on the plug worked out perfectly. Hopefully knock won't be an issue in the summer as my IAT's are about 30-50*F.
I must say, I LOVE the heads. Throttle is super snappy. No sogginess anywhere. Pulls hard all the way to 6800. Have not tried higher yet. If someone is looking for a perfect mannered street car but still wants to get the most they can these are the heads for you.
#271
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As you build up some confidence you'll find that it pulls to 7200 without any difficulty. I haven't gone any higher, and my rev limiter is set there, because of the SBE
#273
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I figure if it goes, I'll fix it. The repair will probably rhyme with "four-oh-eight". Maybe you could figure it out from there...
#274
When were using EFI Live, found knock w/ anything above 24* timing from 0.24-0.44 g/cyl up to 3200 RPM (part throttle) & again @ peak torque during WOT. Different heads though (AFR 205, 11.8 SCR, 8.4 DCR). Wanted to note this as an area to pay close attention to while tuning. Am not claiming that what has been offered on the tuning tables above isn't possible. Just posting so that you pay close attention to this area while tuning. Whatever the number turns out to be, the limit will be found within this area of the table; under the conditions noted.