what it takes to run E85
12-20-2008 | 10:57 AM
#21
Ok now I'm picking up what your saying. I realize that o2 sensors don't measure air fuel. Got that wrong on a couple test's in school they measure the amount of oxygen in the exhaust. Im just going to think this over for a while. My wideband can be calibrated for e85 of gas so this summer i will have to do some testing, just to make sure i understand this fully. So why do the ls1 guys change there stoich to 8.xx when they could just leave it alone. That seems to me like that would cause a issue changing it.
Last edited by Jditlfm; 12-20-2008 at 11:05 AM.
12-20-2008 | 02:16 PM
#22
When the LS1 guys change the stoich A/F in the PCM, they do that instead of lowering the injector constant like we do. The PCM will then change the fueling of the injectors to spray more fuel to the calculated 9.765. The LS1 guys still end up doing some tweaking after this, it is just the first step they do to trick the PCM into adding fuel.
I ran my LM1 to still display gas A/F, since that is what I'm used to seeing, so when it was reading 14.7, I knew it was really 9.765 and then I just shot for about 12.1 on the gauge at WOT or about .81 lambda.
Here's a forum with some racers running E85: http://www.e85performance.net/forums/
I ran my LM1 to still display gas A/F, since that is what I'm used to seeing, so when it was reading 14.7, I knew it was really 9.765 and then I just shot for about 12.1 on the gauge at WOT or about .81 lambda.
Here's a forum with some racers running E85: http://www.e85performance.net/forums/
12-20-2008 | 02:35 PM
#23
hey thanks for the info its helped alot but are there any tuners that you would recomend an its a 93 so it has that stupid chip thing and its never been tuned before
12-20-2008 | 04:51 PM
#24
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
Likes: 4
From: Decatur, TN (N-W of Athens)
Your o2 sensors will not detect a super rich condition and will not correct when your injector constant is set an appropriate amount smaller. Listen to me very carefully, your pcm tunes to stoich be it straight gas e10 e20 e85 e100 methanol propane etc it is hard wired to tune to stoich it gives less than a **** what the chemicals are going in right along with the actual fuel ratio its using, its looking for oxygen content that signifies stoich fueling.
What you do is if you have 30lb injectors, you tell the pcm that you have 30% smaller injectors ie 21lb. This will make it keep them open long enough to supply 30% more fuel than it would with gasoline for the same airflow or ve. This will keep your fuel trims right near perfect 128 but you may have to tweak the constant somewhat experimentally to get them back to where they were with gas, it kind of depends on the engine and the injectors and winter or summer blend of e85 (I find 24-28% is on the button most of the time, it is very easy to zero in). The blms will work exactly the same as with gas but it is up to you to get them into the ballpark with the injector constant so you are not banging up against the max blm and it can actually adjust itself.
You do not need any fancy gimics or resistors or any other quick fixes. All you need is a tuner who has been around the block a time or two.
What you do is if you have 30lb injectors, you tell the pcm that you have 30% smaller injectors ie 21lb. This will make it keep them open long enough to supply 30% more fuel than it would with gasoline for the same airflow or ve. This will keep your fuel trims right near perfect 128 but you may have to tweak the constant somewhat experimentally to get them back to where they were with gas, it kind of depends on the engine and the injectors and winter or summer blend of e85 (I find 24-28% is on the button most of the time, it is very easy to zero in). The blms will work exactly the same as with gas but it is up to you to get them into the ballpark with the injector constant so you are not banging up against the max blm and it can actually adjust itself.
You do not need any fancy gimics or resistors or any other quick fixes. All you need is a tuner who has been around the block a time or two.
Psycho maybe, but people seem to confuse the two with me 
