[Trochoidal]

Originally Posted by Joshinator99

GREAT stuff and very helpful. I think we settled at 365 SOI so I feel much better about our decision. Thanks again!

You said it Josh! Mike’s response will probably help many other people understand SOI and how more isn’t always better.

[Joshinator99]

Originally Posted by Trochoidal

You said it Josh! Mike’s response will probably help many other people understand SOI and how more isn’t always better.

Yeah, agreed! But not enough definitely costs some power, as I found out the hard way (as usual)…

[Trochoidal]

Originally Posted by Joshinator99

Yeah, agreed! But not enough definitely costs some power, as I found out the hard way (as usual)…

Ah, we all have the “found out the hard way” stories. It appears you’re getting it dialed in better. Maybe I’ll make it to Fall Brawl and get to catch up with you.

[Joshinator99]

Originally Posted by Trochoidal

Ah, we all have the “found out the hard way” stories. It appears you’re getting it dialed in better. Maybe I’ll make it to Fall Brawl and get to catch up with you.

Sounds good! Going to Lebanon Valley Dragway tomorrow for Test & Tune in Eastern NY if anyone wants to say hi. Or laugh at my crappy drag racing skills.

[KingLT1]

I don't necessarily think 370 is too much. I would of liked to see how the car would of responded if you leaned the AFR out when it richened up.

[toohighpsi]

Originally Posted by KingLT1

I don't necessarily think 370 is too much. I would of liked to see how the car would of responded if you leaned the AFR out when it richened up.

It dosen't richen as you change SOI, EOI follows SOI as it advances and the difference between them is the PW (pulsewidth).

You can go earlier, I just didn't find more power on the stock LT1 engine. Careful though, go too far and you'll start to go leaner, you just won't be able to tell from a Wideband because the fuel will make it out of the engine on the exhaust stoke - still showing the same A/F ratio as the Wideband is an average measure of all air and fuel passing the sensor - not an actual measurement of what's in the combusion chamber during the power stroke.

[KingLT1]

Originally Posted by toohighpsi

It dosen't richen as you change SOI, EOI follows SOI as it advances and the difference between them is the PW (pulsewidth).

You can go earlier, I just didn't find more power on the stock LT1 engine. Careful though, go too far and you'll start to go leaner, you just won't be able to tell from a Wideband because the fuel will make it out of the engine on the exhaust stoke - still showing the same A/F ratio as the Wideband is an average measure of all air and fuel passing the sensor - not an actual measurement of what's in the combusion chamber during the power stroke.

Yep I get that and thanks for clarifying!

Also how far is too far from what you have found? I have 361 commanded but it hits 386 and I think that is due to the alcohol adder. I am wondering if I should zero that out. Either way injector MS is staying around 5.5 on E60 and rail holds 2175.

[KingLT1]

So I played around with SOI a little last night.

First log is with the SOI @ 386, second log is at 361. The AFR actually richened up and gained headroom because if you look I am giving it another degree of timing and it's making a little more power. it looks like injector ms might be a touch less as well.

[radz28]

Does anyone have an option or insight as to SOI bring high? In a rough tune, on a stock cam LT4, my logs show SOI getting close to 380* My IPWs are holding at about 4.8ms, and rail pressures were holding at commanded. My SOI calculator shows I'm injecting before TDC, but after EVC. My EOI shows I'm at 193*, so I'm also not injecting into compression.

Is there a reason I couldn't inject some beyond 360*? Because this is on full pump E', should I try taking some SOI out of the alcohol adder? Maybe see if that brings SOI down and see what it does to IPW and rail pressure?

[Joshinator99]

Originally Posted by radz28

Does anyone have an option or insight as to SOI bring high? In a rough tune, on a stock cam LT4, my logs show SOI getting close to 380* My IPWs are holding at about 4.8ms, and rail pressures were holding at commanded. My SOI calculator shows I'm injecting before TDC, but after EVC. My EOI shows I'm at 193*, so I'm also not injecting into compression.

Is there a reason I couldn't inject some beyond 360*? Because this is on full pump E', should I try taking some SOI out of the alcohol adder? Maybe see if that brings SOI down and see what it does to IPW and rail pressure?

380 sound high to me. I believe the big boys are usually capping that around 370 (and I’m at 365 if memory serves). 365 was worth almost 30 WHP over 330-335 in my back to back dyno testing. But you should look at your cam timing and overlap to make your final decision.

[radz28]

Cool. Thanks Josh!

[KingLT1]

Originally Posted by radz28

Does anyone have an option or insight as to SOI bring high? In a rough tune, on a stock cam LT4, my logs show SOI getting close to 380* My IPWs are holding at about 4.8ms, and rail pressures were holding at commanded. My SOI calculator shows I'm injecting before TDC, but after EVC. My EOI shows I'm at 193*, so I'm also not injecting into compression.

Is there a reason I couldn't inject some beyond 360*? Because this is on full pump E', should I try taking some SOI out of the alcohol adder? Maybe see if that brings SOI down and see what it does to IPW and rail pressure?

Zero out the alcohol adder table and set the main SOI to around 370. Report back the results. I thought my post from above would give guys a better picture on what happens when you go above 370 on stock cam stuff. When I dropped my SOI back into the 360's it actually richened up even with another degree of timing. You just have to play with it and find what works best for your setup. My guess is somewhere in the 365-372 range will be optimal. On bigger cam cars you can get away with starting injection even earlier but stock cam stuff doesn't gain from it as Mike mentioned.

[radz28]

Originally Posted by KingLT1

Zero out the alcohol adder table and set the main SOI to around 370. Report back the results. I thought my post from above would give guys a better picture on what happens when you go above 370 on stock cam stuff. When I dropped my SOI back into the 360's it actually richened up even with another degree of timing. You just have to play with it and find what works best for your setup. My guess is somewhere in the 365-372 range will be optimal. On bigger cam cars you can get away with starting injection even earlier but stock cam stuff doesn't gain from it as Mike mentioned.

FWIW - I have read this thread several times, and you comments, too Where I was coming from what just that not knowing what, if any, effect the PI had on what the E92 was trying to do, and since, my calculator was showing I was safe- EOI-wise, if SOI starting before TDC would be a problem. It seems, by what you guys are showing, is that it must not be, because you're making more power starting just before, and I'm, perhaps, just outside of your-guys' envelope of data. I've gathered I shouldn't gain in power, but I'm just looking for RAIL PRESSURE/IPW to come under good control. I read Huggins or Higgs saying to command, like, 280 and leave it, because the ECM will compensate automatically anyways, but I just didn't know which way to start. That was a couple year old post, and understanding changes with time, so I'll go with the current logic, here, from you guys.

I did notice my adder was adding about 15* of timing, and I was going to pull out a handful, but I think I'm going to try what you suggest, and see what happens. I'm SO CLOSE to wrapping this up the way I was hoping to I can taste it. I'm only a stock cam, and I'm only trying to make sure it's safe and hopefully be reliable.

[radz28]

Originally Posted by KingLT1

Zero out the alcohol adder table and set the main SOI to around 370. Report back the results. I thought my post from above would give guys a better picture on what happens when you go above 370 on stock cam stuff. When I dropped my SOI back into the 360's it actually richened up even with another degree of timing. You just have to play with it and find what works best for your setup. My guess is somewhere in the 365-372 range will be optimal. On bigger cam cars you can get away with starting injection even earlier but stock cam stuff doesn't gain from it as Mike mentioned.

Because making multiple changes when tuning is a great idea (not... ), I tried a couple things, along with this suggestion, and seem to have a little ?success?.

I ZERO'd the ALCOHOL adder and commanded 370* in the last-top areas of the SOI BASE table. I also retarded my VVT back to where I usually run it (it was only 1-degree advanced from the last tune file), and SOI came down a little to almost 375* (EOI is almost 210*). Maybe this isn't too bad, because the OEM file commands 356* and the ALCOHOL ADDER commands another 15* for this area, so maybe I'm okay around 375??? And - I'm not looking for gains as much as I am just trying to make sure I'm safe, so if this is safe, then I'm fine. The car still sounds strong, and with that clean, staccato-type pulse (raspy-almost) from the exhaust (rather than a muttled/muted like when it goes too lean), and I'm a bit a ways from EVC, so is this "okay" (not optimal, but safe?)? I didn't really check if it richened up or not because the data capture from the REFLEX programming isn't the best/quick as HPTuners, but I didn't spend a lot of time trying interoperate it either (to be fair). I run my VVT a few/several degrees (RPM-dependent) more advanced than OEM, and am still trying to understand if that's better for this scenario (I can run more timing, too, which is why I left it this way for now), but am just trying to leave no stone uncovered. I've added some more SOI lower in the RPMs and lower in the AIRMASS to see if this will help when I'm pedaling the THROTTLE, raised the RAIL PRESSURES in lower RPMs/AIRMASS-areas (from where I had lowered them for other reasons), and pulled a few percent more E92 MAF in this area, too, and am hopeful the culmination will get this last little patch covered...

I'm so close to feeling like I did what I did, I can taste it. A WOT hit, from a roll, is totally fine (so far), but it's just pedaling (because of traction loss) that's the PITA now. Hopefully - with a few more small adjustments this will sort out. It takes so much time to interoperate what others post about SOI and this stuff, because I'm not a tuner (and I get that). Ugh... At least little tidbits are still dropped for the likes of people like me, and I continue to, ALWAYS, appreciate what anyone shares. Thanks for taking the time any of you do to share.