One of the most fun parts of a new platform is experimentation — not with just the innards of the ECU but testing various fuels. We entered for the foray with the 2017 EX-T turbo 1.5L “base” Civic in December 2016 and started making great power with a completely stock car. What we didn’t disclose publicly are what fuels or fuel blends (more on that!) we were using to make power.
We have D/I experience dating back over 5-6 years and a lot of that carries over to the new Honda platforms. This isn’t something that can be said of the general Honda performance community as D/I for Honda is very fresh (and it’s an exciting change!).
To test the various fuels we needed proper ECU control to do so and to make sure the vehicle drivability maintained perfect — KTuner was able to provide us with rapid development and table access to get this done, and in that time we’ve helped countless customers make not just good power, but also clean, smooth pulling power curves.
So what’s the trick?
It’s really quite simple — ethanol. E85 is all the rage, however it is not needed in large quantities on D/I motors. A couple gallons actually suffice just fine. The optimal blend is actually around 25-30% ethanol content in the fuel to reach an MBT timing map (timing map for best power), after that the benefits of ethanol is actually outweighed by the stress on a limited fuel system on most cars — you get a tad more charge cooling (most of it is already realized in the 25-30% area). What’s that come out to? 2.5 gallons of “E85” mixed with 7 gallons of 91-93 octane works superbly (we actually went so far as doing 2.5 gallons and 7 gallons of 87 octane, which also worked just fine!)
The next step is to be able to bump direct injection pressures a bit — the stock CivicX D/I fuel system runs at about 18MPa of fuel pressure, and you can safely raise up to ~21.5MPa which gives you a significant amount of injector overhead (have to be careful — ~22MPa you start hitting the pressure relief, and it’s not something you want to hammer on).
On the ‘base’ EX-T we were able to make ~245-247whp & 300wtq safely on a COMPLETELY stock car and a stock clutch before it slipped — and we got on the horn with ClutchMasters very early on to have a clutch developed for this platform — which was ready for us as soon as we picked up our 2017 Si first week of June!
Si? Yes yes!
Once we got the Si and a clutch we repeated the same tests — making 255whp on a safe level, and ~275whp on a very aggressive level (33psi! — can’t do this long term because the map sensors max out at 29psi) using the same ethanol blend.
But that’s not all, there are better blends of ethanol. Ignite Red or what we really liked — VP’s C85. Using the same blend ratio of C85 we were able to SAFELY (without pegging the factory map sensors) make another 10-12whp.
The little 1.5T in these cars is very potent — torque levels as high as 350wtq can be attained easily, but caution is advised as who knows how long the rods will handle that kind of torque level in the low end/mid range, especially if you like lugging this motor in high gear.
And before you ask — yes, you can do this on the CVT, but KTuner is highly advised as they are the only ones to offer a fully “unlocked” solution for tuning the CVT as we see fit. We can bring down the torque levels and get the cars another ~20whp easily and safely.
Also — expect to see roughly ~10% higher figures in other locations as we have a fairly conservative reading dyno, historically (stock 8th does 172, 9th does 160-170, on and on).