[SeeTeaS-V]

Ok, so I know how to set up the sensor, multi vs comp, Flex Fuel adder table. I'm going to start with a maximum of 4 additional degrees of timing. See pic

I've read there are areas where I may need to actually pull timing for ethanol. Does anyone have a "known good" Flex fuel table that I can use to start with for the LSA?

Or should I just start with this?

 

[SeeTeaS-V]

Thanks to Mean Mike... emailed me a good starting file.

 

[specialp]

I am not sure why some people bump up timing in low airmass zones for e85. If you pull this table from a flex fuel sliverado tuned by GM you will find it pulls spark in most areas and adds spark anywhere where you'd be knock limited. (low rpm lugging the engine and power areas)

Ethanol burns faster contrary to what a lot of people think but is almost knock proof. The zones in boost look pretty conservative but you don't want to go too far without a dyno.

The stock table already has a lot of timing in it so I would not add more in normal driving areas. That is why a lot of tuners just tune the PE adder for alcohol. I did the the full table but pulled 2 degrees or so in low airmass situations


Edit: scholarly research article to back up that ethanol burns faster and achieves max cylinder pressure sooner Study of Flame Speed and Knocking Combustion of Gasoline, Ethanol and Hydrous Ethanol (10% Water) at Different Air/Fuel Ratios with Port-Fuel Injection

 

[SeeTeaS-V]

Thanks for the info. I see that my main spark table has already been reduced some by the previous tuner. I scan it often when I drive, and it seems to be happy and it feels great now that I've tuned the MAF. I'm seeing about 18 degrees in boost. I'm not very familiar with what the LSA likes, but that timing seems a little high to me for 13psi, but there is no KR, and the car pulls well. This is on 93

For Flex fuel I planned to use this FF table and reduce the high load areas down to 3 degrees as a starting point.

 

[07GTS]

the other thing is with flex sensor ur also using the ethanol virtual torque tables which can help as there is a torque difference using ethanol even just at idle so it helps correct for it, if u dont have flex sensor then u can use the flex spark table to lower spark in idle so its idle corrections are more in line with actual, makes a bigger difference with clutch and light flywheel

 

[specialp]

Thanks for the info. I see that my main spark table has already been reduced some by the previous tuner. I scan it often when I drive, and it seems to be happy and it feels great now that I've tuned the MAF. I'm seeing about 18 degrees in boost. I'm not very familiar with what the LSA likes, but that timing seems a little high to me for 13psi, but there is no KR, and the car pulls well. This is on 93

For Flex fuel I planned to use this FF table and reduce the high load areas down to 3 degrees as a starting point.

That table looks good. These cars have very high timing stock at low airmass. You could be approaching 50* with temperature adders. So pulling some timing out there for e85 is a good thing. You won't get KR on ethanol before you start having problems. The issue is it will not be knock limited, and sometimes people advance timing too much where your piston is fighting the combustion hard on upward travel. This will damage your engine. 3-5 degrees under boost is pretty safe for ethanol. I find when you increase the boost on these engines with a pulley, you are very much knock limited on pump gasoline.

The only way to truly tune e85 timing is to use a dyno and find the point where it is putting out the most power. With gas under boost you aren't going to hit that point before knock so you can street tune monitoring for knock.

 

[07GTS]

only thing i can say for the street and it takes a long time to do (dyno is way preferred much easier) is u can make up a pid to show acceleration rate so if u can log the same section of road under the exact same conditions each time then u can adjust the timing and see if u are actually going faster or not

 

[SeeTeaS-V]

only thing i can say for the street and it takes a long time to do (dyno is way preferred much easier) is u can make up a pid to show acceleration rate so if u can log the same section of road under the exact same conditions each time then u can adjust the timing and see if u are actually going faster or not

I was planning on using the dragy this weekend. If I get a nice bump in power by adding 5-6 degrees and the car goes faster, I'll leave it there. When I hit the dyno later I'll see if it picks up power with more than that.

 

[07GTS]

I was planning on using the dragy this weekend. If I get a nice bump in power by adding 5-6 degrees and the car goes faster, I'll leave it there. When I hit the dyno later I'll see if it picks up power with more than that.

try this maths in hpt u have to log undriven wheel speed ([8001.113.avg(-1500)]) - ([8001.113.avg(1500)]) u can adjust the (-1500) to give u a larger or smaller output value if u want to see smaller gains

 

[random84]

Ethanol has a faster flame front, which is why you need 4-5* less timing under light to moderate load situations.

But that octane resistance and oxygenation, tho....

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[SeeTeaS-V]

I run 18 degrees on 93. I'm slowly working my way up in timing. So far I do feel gains in butt dyno.
Looks like the stock fuel pumps will work for a while. Ethanol has changed my MAF error, so I will have to redo the MAF tuning process. LTFTs are also trimming 14% at idle. wonder why...

I also dumped the anti-freeze coolant and put in distilled water and water wetter, but I'm seeing higher IATs now. 140 when stopped. (talking about the HX/Brick/expansion tank.)

DSX Flex fuel kit was a breeze.

 

[random84]

You're only E60 and at 6k RPM are already losing line pressure. I'd suggest dropping your fuel pressure to 60psi in high flow and not going past E50.

It looks like you are right on the edge of what your fuel pumps can deliver, but have plenty of injector.

ETA... it's wild looking at 12psi. Been a loooong time since I was running 12psi.

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[SeeTeaS-V]

Me too 😁, but its just a daily.

 

[SeeTeaS-V]

You're only E60 and at 6k RPM are already losing line pressure. I'd suggest dropping your fuel pressure to 60psi in high flow and not going past E50.

It looks like you are right on the edge of what your fuel pumps can deliver, but have plenty of injector.

ETA... it's wild looking at 12psi. Been a loooong time since I was running 12psi.

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I dont know if its worth messing with. I just did some 60-130 pulls and its not dropping that bad. Its predictable, and like you said I have plenty of injector. I'm just gonna clean up the MAF and call it good.

[god its slow though 8.8 second 60-130] needs a cam and lower.

 

[random84]

I dont know if its worth messing with. I just did some 60-130 pulls and its not dropping that bad. Its predictable, and like you said I have plenty of injector. I'm just gonna clean up the MAF and call it good.

[god its slow though 8.8 second 60-130] needs a cam and lower. View attachment 159115

You're right. Your desired rail pressure is only dropping 18% in hot air.

What could go wrong?

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[SeeTeaS-V]

You're right. Your desired rail pressure is only dropping 18% in hot air.

What could go wrong?

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I live in Florida. All we have is hot air. I have plenty of fuel injector to cover the spread. Go smoke someone else cock with your sarcasm, douche dick.

 

[random84]

I live in Florida. All we have is hot air. I have plenty of fuel injector to cover the spread. Go smoke someone else cock with your sarcasm, douche dick.

A member of two months, talking the big game!

You want the reach around or...?

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[Jim]

Not cool SeeV! That kinda shit belongs on Facebook or somewhere else but here....

 

[Karch]

One more crack from him and he’s gone permanently


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[random84]

One more crack from him and he’s gone permanently


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Your glove is heavy, but fair.

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