Lean Or Rich On E-85 Maybe A Boost Spike

LANCEREvo9MR · Sep 28, 2009, 05:40 PM

On my zietronix W/B And Boost Gauge i looked at my peaks and i peaked on my A/F @ 9.8 And Lambda At 0.66, And my boost spiked to 30.7 when im tuned for 28.5 i havent touch my MBC why would it spike like that? And are my a/f's Safe?

97TSiAWD · Sep 28, 2009, 07:57 PM

Have the outside temperatures cooled down lately? Cooler temps generally cause a slight increase in boost when using an MBC.

And 9.8 A/F ratio is really rich and your sig says you're running dual maps; are you sure you're not mistakenly running your E85 map with 91 octane? Or that you don't have large amount of 91 octane mixed with the E-85 while running the E85 map?

LANCEREvo9MR · Sep 28, 2009, 11:52 PM

Quote:

Originally Posted by 97TSiAWD

Have the outside temperatures cooled down lately? Cooler temps generally cause a slight increase in boost when using an MBC.

And 9.8 A/F ratio is really rich and your sig says you're running dual maps; are you sure you're not mistakenly running your E85 map with 91 octane? Or that you don't have large amount of 91 octane mixed with the E-85 while running the E85 map?

i dont think so because if i was running my pump gas map i would only be boosting 24 lbs of boost so i shouldnt be worried of a 9.8 on e85? what is like dangerous a/f that i should look out for because i havent been knocking

LANCEREvo9MR · Sep 28, 2009, 11:55 PM

Jim in Tucson · Sep 29, 2009, 08:04 AM

I'm not sure what is going on, but this simply does not seem possible to me.

Do you know anyone with a portable W/B you could use to compare?

Might be worth a trip to a dyno.

97TSiAWD · Sep 29, 2009, 08:18 AM

Quote:

Originally Posted by LANCEREvo9MR

i dont think so because if i was running my pump gas map i would only be boosting 24 lbs of boost so i shouldnt be worried of a 9.8 on e85? what is like dangerous a/f that i should look out for because i havent been knocking

Since you mentioned that you are using an MBC, your boost is controlled by your MBC and not by the map you are running. And, since you say you're running E-85 currently, the running 91 octane with the E-85 map idea seems unlikely.

What A/F ratio were you seeing after the original tune?

GST Motorsports · Sep 29, 2009, 11:42 AM

Perhaps the tuner set up the fuel map to run much richer when it overboosts, like richening up the last load column a ton. 2 psi could jump a load column or two.

OP, have you asked RRE yet?

LANCEREvo9MR · Sep 29, 2009, 05:16 PM

Quote:

Originally Posted by 97TSiAWD

Since you mentioned that you are using an MBC, your boost is controlled by your MBC and not by the map you are running. And, since you say you're running E-85 currently, the running 91 octane with the E-85 map idea seems unlikely.

What A/F ratio were you seeing after the original tune?

im using two dejon tool mbc so when i flip the switch they switch boost controllers

LANCEREvo9MR · Sep 29, 2009, 05:19 PM

Quote:

Originally Posted by GST Motorsports

Perhaps the tuner set up the fuel map to run much richer when it overboosts, like richening up the last load column a ton. 2 psi could jump a load column or two.

OP, have you asked RRE yet?

wanted to ask u guys first before i go and look for my tuner hes only there tuesdays and thursdays want some opinion before i go? is it the alchohol content in the e-?? + the overboosting is whats making me rich?

LANCEREvo9MR · Sep 29, 2009, 05:27 PM

Quote:

Originally Posted by 97TSiAWD

Since you mentioned that you are using an MBC, your boost is controlled by your MBC and not by the map you are running. And, since you say you're running E-85 currently, the running 91 octane with the E-85 map idea seems unlikely.

What A/F ratio were you seeing after the original tune?

i was in the high 11's low 12's boosting a/f's before any overboosting

JJsEvo8 · Sep 30, 2009, 08:57 AM

I just got a similar tune last weekend. For E85, my guy has the boost A/F set to right at 12.0, and i have no knock at all. A 9.8 is definitely way way too rich, your spark plugs are going to foul out.

Jim in Tucson · Sep 30, 2009, 08:35 PM

Lance,

Are you seeing the 9.8:1 AFR all across the rev range when in boost? Or is it simply richening up right at the peak? Your screen shot does not show RPMs.

If AFR's are simply 'spiking' to 9.8 right at peak RPM, that is most likely the way your tuner intended. Seems too rich to me, but your tuner may have their reasons. This would not be a problem.

However, if your AFR's are 9.8 all across the boosted rev range, that is way too much fuel. You are washing the oil off your pistons. OUCH!

What are your AFR's at 4,000, 5,000, 6,000, 7,000, and 8,000 RPMs? Approx.