I just got my swap finished up and am ready to put some boost to it. Currently running it on 93 pump gas just cruising around working the bugs out with no charge piping installed.

6.0 Gen 3 SBE
SS2 cam, LS1 intake mani
Deka 80s
ebay cast 7875, DIY truck manifold kit
80E/Circle D 3200/2.88s
Terminator X Max

Non-intercooled!

This is a 99% street car so reliability is most important. Don't care about a big number. Burnouts and chicken wings.

My question is, when I go to put together the flex modifier tables in Holley, I want to know some baseline safe timing and AFR values to start with.

I am currently running 25* timing and 12.5AFR at 0kpa. I'm told I should stay on the gas scale when adding ethanol. Plan on running 10-15 lbs boost until I can stuff an A2A IC in there next year. I stood by the old 14 lbs/14 degrees when on straight 93 pump, how much timing can I run safely as a baseline at 14psi on say, E70 so I can go and beat on it to read the plugs? Not sure what the local station has for concentration.

30% additional fuel at 85% ethanol concentration, and interpolate accordingly (0% extra fuel at 0% E)? 11.0 AFR at 10-15 lbs with E70-85?

I am a flex fuel noob so bear with me as I learn.

 

@Forced86 paging

 

I took a crack at adding the various modifiers under an advanced config 1D table (Fuel Multiplier, AFR offset, and Timing Offset), all based on Flex %. Also have a bunch of timing pulled out via Timing vs IAT.

The forum won't let me attach the file type but here's a link to the tune on google drive if anyone would like to take a peek and let me know what they think.

https://drive.google.com/file/d/10PA8wWguoG4_jRwuIx_HD5m6e-P3SFt9/view

The one thing I think is iffy is the base VE table - the y axis (MAP) scaling is really goofy and has poor resolution above 100kpa which is where it's most important. I tried to scale the y-axis to be more reasonable (fill values) but the actual contents of the table don't follow the axis changes. Appreciate any input on this.

Thanks!

 

On the 93 pump around here, they claim 10% eth, but on the 3 diff cars I built with the flex fuel, it always read 6%, so I used that as zero, since that's what it was tuned to, then go up from there. E85 around here goes from 55% to 85%, so unless your testing, the flex fuel setup is great.

 

I flashed the tune with my sensor all hooked up and got 65%. This was with pretty minimal "contamination" as I drained the tank before refilling with E. Car runs great on 8psi and seems more snappy out of boost. Response is so good that I'm tempted not to install an intercooler, lol.

 

My combo is very similar to yours but intercooled. You'll find E85 has a much wider tuning window.
Here is a link to the file at I went 9.90@135 (14psi) with https://www.dropbox.com/s/fgx1lzlgfp...3deg.terx?dl=0
It may or may not help you, I'm only doing a fuel multiplier with flex - no timing or afr offsets at the moment.

 

I will have to take a peek at your tune when I get home, no Holley software allowed on work computers.

Thinking I'll start to turn it up slowly (10, 12, 14psi) and run 12-13 degrees, then start checking plugs. The only question mark is the IATs, but from the reading I've done over the past hour it seems not to matter much since it's measuring in the intake manifold, not the combustion chamber where the ethanol cools the charge.

 

before i switched to just running corn squeezins full time I did my flex spark this way
eventually I did figure out a way to link a 1D table and a 2D table to get more resolution like a p59 computer would do, but the car became pretty much track only so it's dead-nuts simple now

 

You can go in and modify the Y axis for good resolution. In a non intercooled situation, I would not just jump on that 14/14 rule. I'd stay somewhere in the 9-12* range until you know how high your iats are and gobs of other data, unless you just don't care what happens. Once you get a solid gas VE, then move to E, and make adjustments. JMO

 

Plug check - pulled #2 and #3

8psi, 18 deg, E65. Some 2nd gear hits (20-80) by my house, got back to the garage quick and parked it with minimal cruising. Ambient temps were about 70F, IATs saw a max of 180F at the end of a pull but recovered to 120 pretty quick.

Looks decent to me, just a bit of speckling on the very tip of the electrode. Time to go to 12-14psi? Gonna keep timing conservative for now.

Probably can go a lot further timing wise. Still new to reading plugs, so I'm taking it slow.





Thoughts?

 

my thought is i need a new phone or maybe i need reading glasses, i cant see a timing mark at all on that strap

 

Doug, I believe his timing mark is down where the speckling is at.
OP, I generally pull #5. It seems to regularly be the leanest/hottest plug imo. Glad to see your pulling plugs. Just before our weather went to crap, the last night the track was open, a guy asked me to come out and maybe look over his tune. Long and short is, it kicked itself apart. It was on like E60, had about 16# of boost from a Procharged, and 14*.
Still not positive of what happened. It had been together for about a year. It had some nice parts. But I'm wondering if pulling a plug would have warned him. Sometimes timing isn't what it "actually" is, so pull plugs.

 

I have been working on the "old car things" in the form of replacing ancient ball joints, tie rods, brake lines, pads, rotors, typical safety items so I can cruise this thing without killing me and the kids. Finally finished up the majority of it, so I made some pulls on the street to collect data and figure out next steps. I'm on 8psi, 55% ethanol and bored already. Since I'm still learning to tune turbo LS's as well as work the Holley software in general, here's the play by play:

What is max boost?
154kpa, 7.9psi

What's the boost curve look like at WOT?
3000 rpm - 1.7psi
3200 rpm - 3.4psi
3400 rpm - 5.6psi
3600 rpm - 7.5psi
3800 rpm - 7.9psi (max boost for now)

So, boost builds quickly and holds steady at 8 lbs from 3800 to redline.

What is AFR throughout a pull?
12.8 @ 100kpa, 10.7-11.0 @ 155kpa. Gas scale

What is Timing throughout a pull?
27 degrees at 100kpa, 20-21 degrees @ 155kpa

What is IAT throughout a pull?
100F-120F cruising, 187F Max

What is max Injector Duty Cycle during a pull?
46-61% depending on length of pull (fuel pressure dropping but stabilizes)

Fuel Pressure during a pull?
Cruising 62psi, end of longest pull 43psi. From 5000-6500rpm only dropped from 46 to 43psi.

Flex composition?
55% ethanol

Current fuel setup is a -6AN feed to a stock LS1 rail and 80# Deka injectors. C5 filter/regulator and a single external AEM 50-1005 (rated 400lph but at 40psi though).

So, my thoughts: I should turn the boost up to 10-12 lbs, but in order to keep fueling in check I should upgrade to a boost referenced FPR. The C5 FPR probably isn't doing my fuel pressure any favors under boost. Any suggestions? Maybe run the adjustable FPR at 43psi to stretch the pump a bit too?

Are IAT's an issue yet? Wondering how hot they'll get with more boost, maybe figure out some meth (I mean -20F windshield wiper fluid injection system) based on a Hobbs switch or a Holley output trigger.

Where is peak torque? Trying to save Gen 3 rods. Burnouts, not heroics. Is there a way to tell without a dyno? Appreciate the input boys.Oh and I finally put new wheels on it. Looks awesome. Pics to come.

 

As far as I can tell, you have a fuel delivery issue. What you are logging is rail pressure, which is not nearly as important as the differential pressure across the tips of the injectors. This is why a vacuum/boost referenced fuel pressure regulator is so important with boost. You need the rail pressure to vary with vacuum/boost, which actually just maintains a consistent differential pressure across the injectors. So if it was me, I would ditch the corvette regulator for a boost referenced regulator.

On top of that, your rail pressure is dropping under load, which means a fuel delivery issue. Something is causing the rail pressure to drop under load. No doubt that closed loop is keeping your engine alive.

Andrew

 

Sounds like my hunch was right - still learning this stuff. Question is, how much of the rail pressure dropping under load is being caused by the lack of boost referenced FPR, and how much is a general lack of pump/injectors?

Which FPR is recommended for my setup? I currently have -6AN lines feeding everything.

Here's a log:

https://drive.google.com/file/d/17YW...usp=share_link

 

Vacuum or boost in the intake will not change the rail pressure, but it does change the effective differential pressure. Your issue is worse than you think...

Andrew

 

-06AN lines feeding everything with E85, yikes.
I was running out of fuel with -06AN lines and pump gas at low boost.
Get more pump and bigger lines yesterday.

 

Yes, I understand the concept of differential pressure. The FPR will fix the differential pressure issue but the system still is generally undersized for what I'm trying to do.

 

How does one get around the 3/8 inlet size at the fuel rail? I would think that'd be a restriction regardless of the feed line size (smallest orifice in the path of the fuel). I see folks all the time making way more power than I am on stock car/truck rails.
Also, given the fact that the factory rails are deadheaded (only 1 inlet), how much am I giving up mounting the regulator before the rails rather than after?

 

I don't believe you have a fuel hose size issue, unless there are a crazy number of hard bends in it. Stock LSA fuel rails look like garbage when taken apart. You should be shocked at the size of the orifices, and those rails are fine for 700rwhp...

My money is on something else. Perhaps a clogged filter...remember, new doesn't mean good.

Andrew