so I have started tuning on my e85 setup and Im having some issues getting this thing fat enough. What fuel pumps are you guys using on e85/boost? I am currently seeing 77% duty cycle on e85 at 20psi (s480 bw). am i doomed to 2 pumps? weldon? what do you guys think? Am I really running out of pump? Im running a magnafuel mp4303 pump,the pro star 750 pro tuner...

thanks guys

 

I don't think the problem should be your pump. How big is your delivery lines? From tank to pump and pump to engine? Are you logging fuel pressure? A weldon will do no better. What injectors are you running?

 

I was really hoping youd chime in, but I didnt want to bother you with a pm. The delivery is -10 all the way to a y block, -8 dedicated to each rail, then the reg,-8 return. I really think its something in the tuneup, like im missing a global adder or something for the e85...i am tunning for gas ratios, trying to target 11.0 to start (since im new to this e85) and im seeing 13.0 and correction at its highest. i "cut" the injector as mentioned in other discussions and didnt seem to help at all. Injectors are bosch 1680s.

thanks for any advice

 

Brian, also, i have seen that injector offsets may need to be corrected but not sure how much to sway them with the 160s. current offset (opening times) are at .84...I am not logging fp, not aware that I can.

 

Your opening time at 12 volts should be 1 ms below 12v more above 14v can be less. To get the real numbers you would have to send your injectors to someone like www.injectordynamics.com

 

i multiplied the figure i started with x 33% which makes it like 1.14 and its fat now. is there a "wrong" way to do it? the lowest ive seen down the track is 12.7v. you think the 1.14 will work ok?

 

also, what about the fuel constant setting in bs3? what should it be set to? i cut it 33% initially

thanks again

 

You can use 1.14 but I usually start at 1.0 with everything. 160s have a wierd dead time between 1 and 1.5 then have more of a linear line. You can measure this with a osciliscope that would be the correct way to do it.

For the big stuff 3 there should be an exact fuel constant to use, it should be similar to the Fast but you need to check what that number actually is.

 

93wannabe, how do you like the MP4303 pump? How loud is it?

i am following this thread because i am planning to run E85 soon on my XFI setup. I just recently got it running on gas and local stations are starting to sell E85 on Long Island. Still learning to tune the XFI but i think i have a very good tune now and am getting the hang of it from reading, experimenting and asking Brian.

My 1000cc injector dynamic injectors should be up to the task for E85 but i think my fuel pump is going to be the weak link. I don't think the Aeromotive Eliminator pump is going to cut it. My prior setup with a blow thru, i used the Prostar 500 pump, that sucker was way loud. The Eliminator pump is not bad compare to the Prostar.

Did you completely drain your gas tank before filling up with E85?

thanks

 

Geddy, I cannot give you an honest answer on the pump just yet lol. My recent fueling issue leaves me undecided. I will say this...
The pump is reliable, I THINK its consistent and hopefully just my tuneup that weve been fighting. The pump is a little noisy, but what big pump isnt? Once it runs, you dont hear it much anyway. Overall, im pretty happy so far...They did offer very good support when I started fighting problems too. I really like their company for sure.

 

Brian, one last question and hopefully ill have something to report back tomorrow...Im going to go back to 1.0ms Inj opening time and start there. I see FAST has a specific constant (x.67) and that is what ive been trying with the bs3..after i change the opening time back, should i play with the constant to hit closer to my targeted a/f ratios? or set to a specific (which I have yet to find for the bs3) or is there someone you would recommend I call if it does need to be specific ? Thanks for all the help.

 

The constant is just that constant. You could call BS3 and ask what it should be, it is really for using the flex fuel sensor and BS3. Leave your injector time about 1ms and start tuning from there. In the XFI you would leave the injector size the actual size, change the fuel constant to the correct number and start tuning. I always use Lambda for something other than gas.

 

I called Bigstuff and they just wanted to tell me its not the correct way to do it with the constants, he said to just build a new a/f chart and roll with the e85 fuel selection...decisions,decisions lol...

 

Here is the "right way to do it"

Injector opening time, is an actual measured time it takes to open the injector. The 160s have a very funky spot between .8ms and 1.2ms. You can see more at www.injectordynamics.com. Most people usually start with 1.0 sometimes even to 1.2ms it will go from lean to really rich with a small change in opening time because of the injector voltage vs flow at idle.

The fuel constant should be set to E85

If it were me, I would leave my injector size correct, move my opening time to 1ms, tune with the Lambda value instead of A/F and be on my way tuning with the VE and A/F table.

 

built an af table tonight, changed the few things that we talked about...starts runs great, revs crisp, doesnt fog the garage out,even smells better! Ill tweak the ve tables tomorrow at the track and get it cleaned up closer. what lambda would you suggest for 20-30 psi (s480 bw)..ive got the timing rolled back for now until its all focused in better..