General Attention High Compression E85 Users-Ignition timing questions

[Kapok6]

Feels considerably better than it did before I upped the timing, but i'm not convinced yet its a 130+ trap car again. But FWIW, it's been two years since I did the 128 and 130.75 pass, so my memory certainly could be a bit skewed. I do plan on hitting the same track on the 28th if the car stays together until then, so I should have some concrete results then, unless it blows the HG or something on the first pass like it did that last time I was at the track, ha ha

 

[henrysan]

Lets see your equation..

Injectors were flow tested at 1425cc, and I use e85.

.83 * 1425 = 1182
1182 * (43/43.5) = 1167
1167 * 4.4 = 5138
5138 * 12.5 = 64229
64229/1000 = 64.22lb/min?

 

[Stew Pidaso]

Is the 12.5 from targeted AFR or from your gauge?

 

[bastarddsm]

Your probably severely low on fuel pump and your IDC's are inflated because of it.

 

[henrysan]

Gauge afr, and running a rewired jay racing 340 pump. I dont want to sidetrack the subject too much, I may PM you guys about it more. Glad that the OP was able to make improments to his knock situation.

 

[Kapok6]

I'm surprised that Jay pump is working for you on E85. I had 2 crap out on me with e85. Went walbro 450 and haven't had an issue since. Maybe I just got unlucky.

 

[henrysan]

The jay pump has been on e85 since february 2015. I also read about the pump failing on e85, after I already bought and installed it.

 

[Kapok6]

Update:

Did some pulls this morning and i'll try to put the results in nutshell. Also, I got a little bit of e85 this morning beforehand. Tested at 82%.

Pull 1: I haven't touched any of the settings since the last pull referenced earlier in the thread. I just wanted to make sure I could replicate the results as sometimes there are flukes. To my delight, the pull was smooth, no knock registering, etc, so results replicated.

One thing to note, I checked base fuel pressure and its actually 42psi, so my lbs/min referenced earlier would actually be a little lower than originally calculated. Lbs/min calc based on @bastarddsm formula on this pull and the rest are taken at 8500rpm.

This pull 24.6psi, timing 11*, lbs/min resulted in 49.95lbs.min.

Pull 2:

I upped the timing across the board in this boost area 2*.

As per previous pulls in the 5400-6500 area it did not like that. (7*) in that area. It got 5cts on knock and pulled timing and it slowly disappeared by 6500. After 6500, nothing.

Boost was 23.9psi, timing 13*, resulted in 48.36lbs/min

Pull 3:

I pulled -1deg 5000-6500 but left everything the same the rest of the way up since there were no issues on the previous log.

This time no knock, so it seems like the car wants 6deg 5000-6500, then ramping up from there.

Pull 4:

Being knock was gone, I upped the boost.

I had to let off early though due to other vehicles pulling onto the "track" in front of me.

Pull 5:

Boost 26.7psi, timing 13*, resulted in 51.5lbs/min. So I got about 1.5lbs/min at 8500 by increasing boost 2.1psi.

In regards to airflow I don't seem to be seeing much difference with timing changes, whereas boost seems to be where the differences are.

As usual, boost his 30-31psi by 5300ish, but tapers down to 26.7psi by 8500. I think if this thing would hold 30-31psi across the board, it would really rock. I'll be doing a BLT this weekend to see if I am leaking or something, but if I don't find any significant leaks, my next best guess is turbine/housing is just not keeping up.

 

[Kapok6]

Just compared pulls 1 and 5 @ 8000rpm, and it looks like it should have been flowing 47.27lbs/min on pull 1 vs 52.18lbs/min pull 5.

 

[biglady112]

I have been preaching for years, make power with your turbocharger, not your ignition timing.

I also have not used lbs/min for anything, let alone tuning in over ten years. Mitsubishi guys seem to be the only ones who care about lbs/min. And as for your boost not holding, as the rpms increase your VE increases and your engine can ingest more air thus creating less resistance. That is why smaller turbos and turbine housings "drop off or lose boost" on the big end. They simply can't supply the airflow.

You need to be more worried about mass air flow rather than your boost pressure(which is just a measurement of resistance). You have a bolt on 54mm turbo. I am not sure what you are expecting. Be thankful you have got as much out of it as you have. I am guessing you are near the limit of the turbo.

 

[Kapok6]

I have been preaching for years, make power with your turbocharger, not your ignition timing.

I also have not used lbs/min for anything, let alone tuning in over ten years. Mitsubishi guys seem to be the only ones who care about lbs/min. And as for your boost not holding, as the rpms increase your VE increases and your engine can ingest more air thus creating less resistance. That is why smaller turbos and turbine housings "drop off or lose boost" on the big end. They simply can't supply the airflow.

You need to be more worried about mass air flow rather than your boost pressure(which is just a measurement of resistance). You have a bolt on 54mm turbo. I am not sure what you are expecting. Be thankful you have got as much out of it as you have. I am guessing you are near the limit of the turbo.

Well, I was expecting to beat my previous trap speed of 130.75 with a janky eagle/ross combo, smaller cams, stock port head, etc. I would have thought a better flowing head, higher compression, bigger cams, etc would have helped me go faster...but the way the car "feels" right now, I am not quite sure that's going to happen. I didn't expect to be slower on a "better" setup motor. Will confirm hopefully on the 28th unless something bad happens before then or weather does not permit me to run at the track.

What you are saying about the engine ingesting more air and essentially the turbo can't keep up makes sense.

On a side note, would it be bad then for me to turn boost up to peak around 34-35 and fall to 30 or 31? In other words, if boost tapering off is not necessarily a "bad" thing, I am all for cranking it up higher.

 

[donniekak]

I also have not used lbs/min for anything, let alone tuning in over ten years. Mitsubishi guys seem to be the only ones who care about lbs/min.

You need to be more worried about mass air flow rather than your boost pressure

?

 

[bastarddsm]

Crank it up as long as your seeing airflow gains.

 

[Kapok6]

Will do. I'm going to keep afrs where they are for now as well. 9.55-10. Car seems to like it so I'll just run with it.

 

[bastarddsm]

FYI, up here in Illinois it seems like they switched to E60 or so for the winter. I found a honey hole though. Seems like the only blender pump in town is still 85%, and probably made with 87 Oct instead of white gas.

Anyone's else notice this?

 

[bastarddsm]

FYI, up here in Illinois it seems like they switched to E60 or so for the winter. I found a honey hole though. Seems like the only blender pump in town is still 85%, and probably made with 87 Oct instead of white gas.

Anyone's else notice this?

 

[Kapok6]

Ummm, "caucasian" gas would be the correct term. lulz

 

[1990TSIAWDTALON]

My E85 has been low for over a month. Around 66%.
Caucasian gas.....love it.

 

[bling5tatus]

?

Seems to me like he was referring to the fact that airflow != psi on intake manifold. Makes sense.

 

[bling5tatus]

Well, I was expecting to beat my previous trap speed of 130.75 with a janky eagle/ross combo, smaller cams, stock port head, etc. I would have thought a better flowing head, higher compression, bigger cams, etc would have helped me go faster...but the way the car "feels" right now, I am not quite sure that's going to happen. I didn't expect to be slower on a "better" setup motor. Will confirm hopefully on the 28th unless something bad happens before then or weather does not permit me to run at the track.

What you are saying about the engine ingesting more air and essentially the turbo can't keep up makes sense.

On a side note, would it be bad then for me to turn boost up to peak around 34-35 and fall to 30 or 31? In other words, if boost tapering off is not necessarily a "bad" thing, I am all for cranking it up higher.

My friend Brian up in Dallas likes to use the term "your turbo is clogging up your motor."

 

[Kapok6]

Yeah, Brian told me that when I told him a few years ago about when I put a 16g on and couldn't make more than 23psi with the wastegate disconnected.

 

[donniekak]

Seems to me like he was referring to the fact that airflow != psi on intake manifold. Makes sense.

What he said was that he didn't use lb/min(airflow), but keep an eye on airflow.

 

[turboglenn]

I know this isn't completely relative to where this discussion is at this point. But back when I first made the switch to E85 I read a paper that stated E85 will like less timing when AFRS are richer, then when ran leamer, I have found this to be true in my testing not sure what others have found but just throwing it out there. But when I was tuning e85 in the 10.5 -11:1 AFR range, I had to seriously dial back timing compared to when tuning it around 12:1.

The theory was that when ran richer the flame front propagated much faster than it would wroth more oxygen in the mix. I forget the exact reason e85 behaves this way but I posted the paper in one of my threads years ago in the tuning section. Might be worth a little experimemtatiom

 

[1990TSIAWDTALON]

I need to read that. Mine seems finicky but I don't wont too lean and hurt something so it's kinda scary playin with 12.3 or more for me so I try to run 11.5-12 flat, of course it varies just a point or so most of the time.

 

[Kapok6]

I know this isn't completely relative to where this discussion is at this point. But back when I first made the switch to E85 I read a paper that stated E85 will like less timing when AFRS are richer, then when ran leamer, I have found this to be true in my testing not sure what others have found but just throwing it out there. But when I was tuning e85 in the 10.5 -11:1 AFR range, I had to seriously dial back timing compared to when tuning it around 12:1.

The theory was that when ran richer the flame front propagated much faster than it would wroth more oxygen in the mix. I forget the exact reason e85 behaves this way but I posted the paper in one of my threads years ago in the tuning section. Might be worth a little experimemtatiom

I am not going to refute what you are saying. I am sure there is a lot of truth to that. I will say however though that when we start getting deeper into making power and are beyond free mods and super afc's and downpipes, nearly everything changes in regards to what works on each setup. I think at this point, my setup proves that for now. On my setups up to this point, 11.5-12 was glorious. Well, that ish isn't flying now. I had to run 0* @ 5000-6500 and 8* up top. Car was slow, and I have the et and trap to prove it. After dumping a ton of fuel and getting it to 9.5-10, I am able to run 5-6* higher across the board. I am not the only one shocked by this, but this is another example of every setup being different I suppose.