Speed Density tune, easy?
11-28-2007, 05:53 AM
#31
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BTW, for some reason, my ECM would revert to 35 deg of timing at full throttle despite all efforts to put values around 20 into the table at 100 kpa. Never could figure out why and almost blew up an engine trying to do so. I eventually put a HI6TR on it.
Mike
11-28-2007, 05:56 AM
#32
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I still say you aren't using enough timing.
BTW, for some reason, my ECM would revert to 35 deg of timing at full throttle despite all efforts to put values around 20 into the table at 100 kpa. Never could figure out why and almost blew up an engine trying to do so. I eventually put a HI6TR on it.
Mike
BTW, for some reason, my ECM would revert to 35 deg of timing at full throttle despite all efforts to put values around 20 into the table at 100 kpa. Never could figure out why and almost blew up an engine trying to do so. I eventually put a HI6TR on it.
Mike
11-28-2007, 06:02 AM
#33
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On the dyno using FastBurn heads (which should require the least amount of timing of any SBC head), we gained nearly 50 hp by going from 28 to 30 deg.
Mike
11-28-2007, 06:22 AM
#34
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Then I'd say there's something wrong with the test. Traditional SBC chambers need alot of timing. You don't have Vortec or LSx heads. Did you scan the run? How many times did you back it up? I bet it continues to gain power beyond 30 deg.
On the dyno using FastBurn heads (which should require the least amount of timing of any SBC head), we gained nearly 50 hp by going from 28 to 30 deg.
Mike
On the dyno using FastBurn heads (which should require the least amount of timing of any SBC head), we gained nearly 50 hp by going from 28 to 30 deg.
Mike
I need to get it on the dyno with a full tank of race gas again to see what it does. Although I think I am going to go E85 here soon so then I will for sure bump the timing up.
Back to this two bar map tuning, I'm liking this idea a lot. I might even ditch the megasquirt I was going to put on it, sell it and pay for some low impedenance injector converters, throw in some 96's, and go to town on the stock pcm.
11-28-2007, 08:20 AM
#35
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Then I'd say there's something wrong with the test. Traditional SBC chambers need alot of timing. You don't have Vortec or LSx heads. Did you scan the run? How many times did you back it up? I bet it continues to gain power beyond 30 deg.
On the dyno using FastBurn heads (which should require the least amount of timing of any SBC head), we gained nearly 50 hp by going from 28 to 30 deg.
Mike
On the dyno using FastBurn heads (which should require the least amount of timing of any SBC head), we gained nearly 50 hp by going from 28 to 30 deg.
Mike
Justin, I was also thinking about this and perhaps the tranny was just to damn overheated and sloppy by the time you up the timing. The results could have possibly been alot better. Eitherway, when the tranny is rebuilt, I would redo the test.
11-28-2007, 10:24 AM
#36
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So you say the LT1 PCM uses the TPS and RPM alone for fueling? I'd think the VE tables have to be right for this to work... VE uses %TPS under 340rpm it's probably extended out for the higher rpms with MAF and MAP disconnected.
I'm not sure about the VE tables not being used, what I was suggesting is that when I was playing with it there seemed to be a factor outside of the VE tables that was contributing to the pulse width of the injector. Such as a MAP/RPM TPS/RPM blend. I finally gave up and went to a mega squirt system.
I'm not sure about the VE tables not being used, what I was suggesting is that when I was playing with it there seemed to be a factor outside of the VE tables that was contributing to the pulse width of the injector. Such as a MAP/RPM TPS/RPM blend. I finally gave up and went to a mega squirt system.
Last edited by sean-k94z; 11-28-2007 at 10:27 AM. Reason: typo
11-28-2007, 06:06 PM
#38
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2 Bar tune + Speed Density + Closed loop on stock PCM - Just keep in mind I only took it to ~5 psi (5500rpm), been waiting for the weather to clear so I can finally hit ~7psi @ 6500rpm (never was able to go beyond 6200rpm with the 1 bar + MAF since it started leaning out so fast after the MAF maxed out even with PE set at 30+% at that point) 7psi is all Im capable of right now... since it sounds like not many people have done this I just want those who try it to be careful if they're running more psi's since a simple tuning error or other unknown problem could really mess something up (there I feel better now).
One more thing, I noticed some lean surge (slight power loss too) under light throttle right around the 2000rpm mark (Speed Density mode) and after looking at the VE tables I noticed the 400-2000 rpm table and the 2000+ table didnt match up, both tables have a 2000rpm table but VE master didnt make them the same so at one point there was a sharp drop... I went in an manually smoothed it out by copying the one 2000rpm table and pasting into the higher 2000rpm table and the surge went away.
11-30-2007, 01:10 AM
#39
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2 Bar tune + Speed Density + Closed loop on stock PCM - Just keep in mind I only took it to ~5 psi (5500rpm), been waiting for the weather to clear so I can finally hit ~7psi @ 6500rpm (never was able to go beyond 6200rpm with the 1 bar + MAF since it started leaning out so fast after the MAF maxed out even with PE set at 30+% at that point) 7psi is all Im capable of right now... since it sounds like not many people have done this I just want those who try it to be careful if they're running more psi's since a simple tuning error or other unknown problem could really mess something up (there I feel better now).
One more thing, I noticed some lean surge (slight power loss too) under light throttle right around the 2000rpm mark (Speed Density mode) and after looking at the VE tables I noticed the 400-2000 rpm table and the 2000+ table didnt match up, both tables have a 2000rpm table but VE master didnt make them the same so at one point there was a sharp drop... I went in an manually smoothed it out by copying the one 2000rpm table and pasting into the higher 2000rpm table and the surge went away.
One more thing, I noticed some lean surge (slight power loss too) under light throttle right around the 2000rpm mark (Speed Density mode) and after looking at the VE tables I noticed the 400-2000 rpm table and the 2000+ table didnt match up, both tables have a 2000rpm table but VE master didnt make them the same so at one point there was a sharp drop... I went in an manually smoothed it out by copying the one 2000rpm table and pasting into the higher 2000rpm table and the surge went away.
I was going to go megasquirt, but I think this will work for what I want to do. I want to have multiple psi on the fly, run 7lbs, 11lbs, 14lbs, and 18 or so lbs. This will work great, I can dial in everything up to 14lbs, then trick the pcm in a way I came up with to add the fuel in for the 18lbs.
I would run the same timing for 18lbs as I did for 14lbs so it should work good.
11-30-2007, 06:33 PM
#40
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[QUOTE=1982z28with18s;5018346]What is your setup, you should have been able to tune it before without a problem, I'm running 11.5lbs on the stock pcm, stock maxxed out maf, open loop.
My parts include 83lb injectors and no FMU, 50psi fuel pressure holding steady, 7psi depending how high it's revved.
I was increasing the PE fuel above 5500rpm and was getting better but I switched to the 2 bar before I got it perfect. Im sure maybe the VE's had something to do with it, or also the fact that my injectors werent setup right even though everything I had said they were... my original closed loop lean tip in stumble (bad in closed loop, not as bad in open looop) was somehow linked to the injector size being too large because I lowered it considerably for the 2 bar tune and the problem is fixed.
My parts include 83lb injectors and no FMU, 50psi fuel pressure holding steady, 7psi depending how high it's revved.
I was increasing the PE fuel above 5500rpm and was getting better but I switched to the 2 bar before I got it perfect. Im sure maybe the VE's had something to do with it, or also the fact that my injectors werent setup right even though everything I had said they were... my original closed loop lean tip in stumble (bad in closed loop, not as bad in open looop) was somehow linked to the injector size being too large because I lowered it considerably for the 2 bar tune and the problem is fixed.
12-09-2007, 09:56 PM
#41
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Just FYI, one of the forum members (not sure if he wants his identity released) sent me a 2-bar SD tune. I converted it and stuck it in my turbo car and I'm absolutely THRILLED with the results. I've disabled closed loop, so it's purely a 2 bar SD setup with no MAF or O2 sensor input. It's running directly off the VE tables and drivability and tuneability are 5x better than they were. It's just like tuning a DFI or Commander setup, except without the RT tuning. I'm on about iteration #4 right now. I've even cleaned up the lean tip-in that I've been living with for years. It's actually responsive now.
As an experiment, I added 20% fuel to everthing on the table over 55 kpa (this is any time the engine is in boost). Sure enough, as soon as the needle on the boost gauge went past 0, the WB went rich to 10.5/1.
BTW, for the doubters, my jet ski is a Sea-Doo RXP with the supercharged 1500cc motor making 240 hp. The stock ECU is a 2.5 bar SD setup with no MAF, no OBD2, and no O2 sensors, and the thing runs great. I'm now running my car the same way. As long as the VE table is correct, it should work fine.
I'm like a kid at Christmas with this thing.
Mike
As an experiment, I added 20% fuel to everthing on the table over 55 kpa (this is any time the engine is in boost). Sure enough, as soon as the needle on the boost gauge went past 0, the WB went rich to 10.5/1.
BTW, for the doubters, my jet ski is a Sea-Doo RXP with the supercharged 1500cc motor making 240 hp. The stock ECU is a 2.5 bar SD setup with no MAF, no OBD2, and no O2 sensors, and the thing runs great. I'm now running my car the same way. As long as the VE table is correct, it should work fine.
I'm like a kid at Christmas with this thing.
Mike
12-09-2007, 10:42 PM
#43
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Mike, you must be talking about the 2bar file I sent? No problem here I'm glad it's working. Feel free to distribute it as well.. no point in restricting it.
It's really working good for me. The version I sent you ran pig rich for me under boost also, since then I tuned the VE's to about 13.5afr at WOT and have 0's in the PE enrichment.
No point in running MAF anyway, it seemed like more work than it's worth (delay plus maxed out early on boosted apps).
Aside from all the MAP, Injector, and VE #'s being all the wrong "scale" it's really a good tune... best I've ever had.
There may be some changes from Tunercat related to startup/crank AFR, I dont remember if I put those back to stock (LT1_Edit doesnt have all options that tunercat has).
It's really working good for me. The version I sent you ran pig rich for me under boost also, since then I tuned the VE's to about 13.5afr at WOT and have 0's in the PE enrichment.
No point in running MAF anyway, it seemed like more work than it's worth (delay plus maxed out early on boosted apps).
Aside from all the MAP, Injector, and VE #'s being all the wrong "scale" it's really a good tune... best I've ever had.
There may be some changes from Tunercat related to startup/crank AFR, I dont remember if I put those back to stock (LT1_Edit doesnt have all options that tunercat has).
