Flex Fuel Tuning

[FFBOS]

Keep in mind there's a limit to how much power an engine will make with added timing. You get to a point where you add timing and the engine doesn't make anymore, so really it's about finding the right fuel for your setup. Those running 20+ psi and 21 degrees of timing probably need something like E98. Those running less boost need less octane. Dialing that in is where a dyno is actually useful.

The most common "900whp" packages are tuned with 20-21 degrees on pump E.

 

[fubar569]

I'd have to look but that ballpark has popped across my log more than a few times. I also want to say the straight E85 tune is slightly more aggressive timing-wise but it's nowhere near the 23-24 that some run with the more refined E fuels.

 

[Speedy!]

When referencing max timing, you should also quantify it with the aircharge associated. For example 1600 aircharge and 21 deg is one thing, 1900 aircharge and 21 deg is entirely different.

Looking at the Demon factory calibration, it has an MBT at 1.75g of aircharge of 26° in the standard MBT table and 28.5 in the HO table so an additional 2.5° at max aircharge and RPM. Down in the 2880 to 4800 RPM and 1.75g aircharge it's 4 deg more on HO at 28.5 to 29.

 

[16GoManGoHC2]

The most common "900whp" packages are tuned with 20-21 degrees on pump E.

My dyno charts of 10/20 where using this WOT timing map with sensing E77 I only got to 18.5 degrees in actuality.
Im hoping to get up to 21 degrees in the final timing table and with E85 and full timing end up around 950-975 wheel and torque up around 900 and I’ll call it quits and keep my fingers crossed it stays together. I’d be elated to crack 1000 but don’t want to crack anything else in the process lol. Next dyno visit is 11/5, we shall see!! 🤞

 

[FFBOS]

I'd have to look but that ballpark has popped across my log more than a few times. I also want to say the straight E85 tune is slightly more aggressive timing-wise but it's nowhere near the 23-24 that some run with the more refined E fuels.

Yes, 25+ can be seen with Ignite Red

 

[fubar569]

Yes, 25+ can be seen with Ignite Red

Holy balls.

Gimme some of dat!

 

[Hpindy]

Yes, 25+ can be seen with Ignite Red

Holy Crap cakes ! And here I am just touching 18 degrees at 1900 mg aircharge .

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[FFBOS]

Holy Crap cakes ! And here I am just touching 18 degrees at 1900 mg aircharge .

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They boogie.......

My pump ethanol tune clicks over to 21 degrees if I’m above e78 on my onboard gauge. I now carry a separate ignite tune that is rather “sauced” up when I am 87% or more on the onboard gauge of primarily Ignite Red. Came up short on that last time out so we had to clip it’s nuts a bit. Look forward to trying the full kill tune lol.

Ignite smells like “heaven” if I had to describe it. E90 and race fuel mixed....

 

[Hpindy]

They boogie.......

My pump ethanol tune clicks over to 21 degrees if I’m above e78 on my onboard gauge. I now carry a separate ignite tune that is rather “sauced” up when I am 87% or more on the onboard gauge of primarily Ignite Red. Came up short on that last time out so we had to clip it’s nuts a bit. Look forward to trying the full kill tune lol.

Ignite smells like “heaven” if I had to describe it. E90 and race fuel mixed....

I may have to try this " special sauce " next season after I get the injectors dialed in .

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[FFBOS]

It’s a strain on the fuel system for sure. We were 85% or so with 1300’s on my ported 2.4L on just e80 pump fuel. I wouldn’t of had room for ignite or if I did, it would of been right on the edge. Could of probably bumped up fuel pressure on the FORE system to keep up. Once I switched to the 2650, I had to put the 1700’s in, lot of room now.

 

[Hpindy]

It’s a strain on the fuel system for sure. We were 85% or so with 1300’s on my ported 2.4L on just e80 pump fuel. I wouldn’t of had room for ignite or if I did, it would of been right on the edge. Could of probably bumped up fuel pressure on the FORE system to keep up. Once I switched to the 2650, I had to put the 1700’s in, lot of room now.

How do the 1700's idle and cruise in pump gas?

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[FFBOS]

I haven’t blended much in yet, but my tuner has done a bunch others with it and they idle fine. I may play with a bit over winter.

 

[fubar569]

I think 1700's might be in my plans too...along with another fuel pump and a return line.

Keep us posted.

 

[Hpindy]

I haven’t blended much in yet, but my tuner has done a bunch others with it and they idle fine. I may play with a bit over winter.

Good to know . Thanks

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[coolblue]

Can anyone quickly explain aircharge etc. This is not necessarily pointed @Speedy! to explain, but anyone. I'm confused at the terms and abbreviations. Meaning aircharge (density? DA related? boost,temp related?)). At points it's described in what I assume is grams? (i.e 1.75g) and at other points an arbitrary number like 1600,1900. Also, what's MBT(max boost timing?).
I have all the mechanical knowledge but don't data log (yet) or know all the computer terms and abbreviations. Can some decode and explain.
Thanks in advance.

 

[coolblue]

I have the IE kit with twin 285's and FIC1200's.

I still have a bit of headroom left at inferred E90.

In retrospect however I may have done the ID's instead but any injector this size and up tend to become a little non-linear in the very low side of the ipw/mass tables. Some more than others.

So I assume that means these are less efficient on the low end of the duty cycle. So in reference to that, how's drivability/mileage on cruise with these on pump 93? Being these are still smaller than say 1700's, where would the street 'practicality' line be drawn in your opinion?
Thanks.

 

[fubar569]

It's really all in the tuning. Some take more time than others. They do become non-linear but most can be worked out on a case-by-case basis to within a certain margin.

Mine are wonderful on the street on 93 as are the 1300/1350's. 22.5 mpg or thereabouts as well.

I've done 16mpg on the E85 kill tune too.

 

[Hpindy]

It's really all in the tuning. Some take more time than others. They do become non-linear but most can be worked out on a case-by-case basis to within a certain margin.

Mine are wonderful on the street on 93 as are the 1300/1350's. 22.5 mpg or thereabouts as well.

I've done 16mpg on the E85 kill tune too.

As in ID 1300's??

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[16GoManGoHC2]

ID1300X2 where designed with flex in mind and idle and part throttle stability when on gasoline. It’s what I originally planned to use and had a set but sold them when I found a tuner that said by 1050X’s where plenty for E85 and 17 psi of boost I sold the 1300X2’s to fund the tune.

 

[fubar569]

As in ID 1300's??

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Yep. Those.

The ID injector data and their consistency is a big reason why they're popular. It makes that part of the process so much easier and in the hands of a gifted tuner the idle/part throttle is as good as you can ask for.