FlexFuel Tune for the Evo!

There’s a process involved when it comes to running the dual map tune that I currently run. First of all, when I want to run pump or E85, I need to drain the tank down as best as I can. Then, after filling up, I need to switch the key to “On,” and hold the throttle until the check engine light flashes. It will flash fast for E85, and flash slow for pump gas. Then you can start the car. When I go from E85 to pump, it struggles a little until it gets enough pump fuel in it. There’s also the matter of disconnecting the battery. If you disconnect the battery, the ECU will reset to pump gas. It’s not a huge deal, but it is something to remember.

There’s also the factor of contamination. Sometimes, it’s not feasible to get 100% pump or 100% E85 in the car. What then? This can be a painful process in which usually involves draining the tank or planning weeks in advance for fuel usage. The tune I had was also not good. I put some pump in the E85 tune thinking it would make the tune safer. It did the opposite, and now I have to put a little bit of pump in every E85 fillup to get the AFRs right.

Tired of this dance, I finally decided to seriously pursue a flex fuel tune. I’ve been told by the “top” evo shops in the midwest that the “ECU didn’t like it” on our 8/9s, or that it just didn’t run right. These are not true statements. Flex fuel tuning has been incorporated in tephramod for a couple of years now, and some time attack evos have already been running with it. I finally decided to do to the same, driving the Evo to Detroit to finally get it done.

I used the kit from Evolution Dynamics, which incorporates everything you need to convert to a flex fuel tune (https://www.evodynamics.com/products/evolution-dynamics-evo-8-9-flex-fuel-kit). The tuner, a guy named John working at Alex’s Automotive in Detroit was able to dial in the tune. He has tuned other time attack Evos on flex fuel so he knows the drill. No more worrying about what fuel is in the car, how much, where I can stop for E85, what kind of E85 that station has, etc. Of course, you still want to run pump when you can for the street for the best mpg and good cleanliness, and want to run as much E85 as possible for the most power – but no more of this map switching, tank draining, drive planning BS – it can just be filled, and driven. Especially with the evo going to NY, not being a trailer queen anymore, it really makes life a lot easier.

We did face a number of hiccups through the tuning process, mostly related to my car itself. Some wiring issues with the AFR gauge, which I forgot to mention to the tuner requires a slightly special formula in evoscan. The main issue was the knock sensor, which we think is bad. This has always been an issue with the evo, even before the engine went – this slightly oversensitive knock sensor, which randomly detects knock sometimes on certain pulls. Given this happened before with my old motor and with this one, we are pretty certain it is a bad knock sensor. I’m planning a trip back in about a month or so to take care of a few other things.

All that said, he spent hours dialing in the 93 octane map. Not just idle and WOT, but partial throttle and everything in between. The result is a car that runs much, much smoother than before. Pretty amazing how smooth and nicely it runs. As we suspected, the old tune was very bad, and knocked – a lot. That is only in part due to the knock sensor. The rest of the tune by RS was just a half-assed thing to get the car out the door. The new tuner went over everything, essentially starting from scratch. It literally took 8 hours to dial in the pump map, but that also in part due to the knock sensor.

I am planning to race both on 93 and E85. The 93 is used for SCCA time trials, while the E85 is for Grid Life. The rev limit is going to be set to 8400rpms, which really helps when I need to stretch 3rd gear. No power is made above 7k rpms and will probably experiment both with shifting early (6500rpms) and stretching out the gear. Also will help me preserve 4th gear. which is the weaker gear. I can stretch 3rd when I need to, and shift early from 4th as well. The tune also features a MIVEC map that I was told is quite different, so really excited there.

Looking forward to this next chapter with the Evo!


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