I have been setting up a pump gas (91) tune and I am going to switch to E85 after it is complete.
A little back ground before I get into the meat of it. I had a 8.5:1 347 SBF with AFR 205 heads and a HYD 242/242 @ .050" .576" lift at the valve 114LSA. This cam was easy to tune. Idle on E85 was around 12.5, cruise was about 13.1-13.5, 38-40 degrees, boost was about 11.4, 28 degrees. I have an AEM in the car. The engine made 710 wheel at 7psi load with an 88mm. 930 wheel at 12psi. Max rpm was 6500
Now with that said, I have switched to an NA set up. I'm looking to do some leisure road racing, autoX, and the occasional strip outing. I put some bore to the engine so now it is a 11.5:1 363". I switched to 225cc TFS HPorts ported by TEA. The cam is a solid 256/264 @ .050" .621" 110LSA. Obviously this cam is a completely different beast. The first thing I have noticed, on gas, Is the car will not idle richer than 13.0:1 and it is super dirty. I have the timing around 25 degrees. Rpm is steadiest at 1200. The car doesn't like to have much of a load under 2000rpm. The AFR is about 12.8:1 from 2000-5000 and the timing is 36-40. This is light load. At WOT the AFR is 13.0 from 2000-5300 and then I have it fattened to 12.5 from 5500-7700. Timing up top as near 34 degrees. No knock indicated thus far.
So what I'm wondering is...
1. Is the overlap in the cam sending so much fuel and oxygen down the pipe at low rpm that the O2 sensors (I have 3)are getting a false reading? Should I, theoretically, lean out the AFR? Like I said the car doesn't like it richer than 12.8-13.0:1.
2. Does the engine have less dramatic false readings when the rpm goes up? The engine seems to like the extra fuel up top (4000+).
3. If I were to advance the injector timing closer to the intake opening, instead of well before it, cut down on the amount of fuel going out the tail pipe?
4. As far as plugs go. I have a NGK 6's in it. I'm not sure if this is too cold for an NA engine or not and if E85 likes a different heat range.
I would like to finish the gas tune so I can switch to E85 and then head to the dyno to find the sweet spot
A little back ground before I get into the meat of it. I had a 8.5:1 347 SBF with AFR 205 heads and a HYD 242/242 @ .050" .576" lift at the valve 114LSA. This cam was easy to tune. Idle on E85 was around 12.5, cruise was about 13.1-13.5, 38-40 degrees, boost was about 11.4, 28 degrees. I have an AEM in the car. The engine made 710 wheel at 7psi load with an 88mm. 930 wheel at 12psi. Max rpm was 6500
Now with that said, I have switched to an NA set up. I'm looking to do some leisure road racing, autoX, and the occasional strip outing. I put some bore to the engine so now it is a 11.5:1 363". I switched to 225cc TFS HPorts ported by TEA. The cam is a solid 256/264 @ .050" .621" 110LSA. Obviously this cam is a completely different beast. The first thing I have noticed, on gas, Is the car will not idle richer than 13.0:1 and it is super dirty. I have the timing around 25 degrees. Rpm is steadiest at 1200. The car doesn't like to have much of a load under 2000rpm. The AFR is about 12.8:1 from 2000-5000 and the timing is 36-40. This is light load. At WOT the AFR is 13.0 from 2000-5300 and then I have it fattened to 12.5 from 5500-7700. Timing up top as near 34 degrees. No knock indicated thus far.
So what I'm wondering is...
1. Is the overlap in the cam sending so much fuel and oxygen down the pipe at low rpm that the O2 sensors (I have 3)are getting a false reading? Should I, theoretically, lean out the AFR? Like I said the car doesn't like it richer than 12.8-13.0:1.
2. Does the engine have less dramatic false readings when the rpm goes up? The engine seems to like the extra fuel up top (4000+).
3. If I were to advance the injector timing closer to the intake opening, instead of well before it, cut down on the amount of fuel going out the tail pipe?
4. As far as plugs go. I have a NGK 6's in it. I'm not sure if this is too cold for an NA engine or not and if E85 likes a different heat range.
I would like to finish the gas tune so I can switch to E85 and then head to the dyno to find the sweet spot
