Hi all. So, I put the car on the dyno today to see what kind of numbers she is making with my Burger Tuning JB4, which has been fantastic for the last 8 months. I have been running on map 2 most of the time to not have to add e85 (I'm in AZ where all we have is 91 octane garbage), but for the last 3 tank fulls I have been running 3 gallons of e85 and then 5 gallons of it on this current tankful which is what was on the dyno today. That's a 30% e85 mix. I did 3 pulls to log for Burger Tuning to review yesterday on map 3 with the 30% e85 mixture and the car ran flawlessly and threw no codes. Today though, only on map 1 (3lbs of boost over stock) to start, the car threw the code P0087 (fuel rail pressure too low) and cut timing dramatically at high RPM as it started to lean-out. Amazingly, even on only map 1 and pulling massive timing, it still made 500hp and 592tq. This was on a 4-roller dyno that notoriously reads about 5% low. That's not important lol. What the tuner said was that the e85 was causing this and that he has seen this on a few of these motors when on e85. That though doesn't answer why the car ran great when I did the 3 pulls yesterday and didn't throw a code or pull timing (I send the logs to Burger Tuning to review and they said it all looked spot-on). Acta in particular....any thoughts? Thanks.

PS....IAT's were very similar (cool) both yesterday running logs and today on the dyno.

 

Hi enj,

Acta is in Europe right now so I’ll answer more when I return (ha ha, always wanted to use 3rd person). I also want to write about dynos on here and another thread then.

keep in mind the delta in Stoichs between gasoline at 14.7:1 and E85 at 9.8:1. You need so much more fuel (volume) to satisfy complete combustion with the E. The ECU is trying to compensate for the lean condition coming from the O2s so you’re maxing out the fuel pumps and the pressure regulator is complaining with a P0087.

IATs break down on any ICE around 90*F and pulling timing is the standard way EMSs satisfy that. It’s physics. But E does run cooler than gasoline.

 

That's exactly it, Acta. Thanks mate. I think the solution here is just to get the Weistec water/meth kit. Then I don't have to worry about anything. Just put 91 in and go. The Weistec kit seems to be the only one that's a direct plug and play made for our cars, but it is very pricey. ($2,500). It's a shame that the kit made by Burger Tuning for only $600 (the makers of my tune) don't sell one for our cars, only the c63, so the silicon adapters won't work (where the nozzles are placed). Have a great time in Europe!