The VitR Does Meth

The legal kind, I promise you.

I finished development of the Water/Methanol injection control subsystem for our Honda Civic Type R MoTeC M142 firmware. The control strategy we’ve implemented worked quite well and tuning went quite smooth.

We *only* used “boost juice” during testing — a 50/50 blend of water/methanol and the results were awesome. Yes you can use this subsystem to spray M1 methanol without mixing with water (I know someone’s going to ask). Maybe it’ll even make more power.

Tooning

This was probably the easy part — roll my face on the keyboard, some numbers get plugged into the calibration, and the motor made power resulting in the dyno numbers going up.

How much? We’re safely 25-30whp and 50wtq over our best E35 ethanol blend numbers. Compare to stock, the power curve is amazing. We’re up almost 140whp over stock and 150wtq over stock. A 50% increase in horsepower and almost 55% increase in torque.

Tuning

Ok, now for the “real” tuning. What was our goal? To provide a safe and repeatable system to reduce fuel demand on an already hammered D/I fuel system…. and improve power. We accomplished both, and the extra power might actually be secondary for some people. You can use this subsystem to ease up on the stressed D/I pump on this car and opt for a more conservative tune that provides you with a more reliable car for the type of racing you do — circuit, etc.

 

To the right you can see the graph which lists our D/I pressures and injection available times. We have a slight pressure drop to 19MPa at 3800 rpm — which is not terrible as we have 6ms of injection time left in that area (and factory D/I pressure here isn’t even 19MPa to begin with…). This is done with the methanol portion of the water/meth we were injecting — the methanol is extra fuel and you can even see where it “hits” after engagement in the “Fuel Volume” graph. We’re providing about 15-20% of the fuel volume the motor is using under boost with the methanol system now, which has reduced demand on the factory D/I fuel system.

Now bear in mind — we have this slight drop because we cranked the boost up and went for 430wtq. Remove about 20wtq and you have no pressure drop at all. Or add a second meth nozzle — as we’re currently only using one.

Decisions decisions. Tuning choices all left up to you!

Now the curious will want to know how much boost we were running. The plot to the left shows the boost curve.

Yes 30psi peak — and then it tapers. We can still squeeze a bit more boost out of from 3500 to 4500 rpm to make more torque (probably see 450-460wtq — but I think the stock clutch deserves a break as we already pounded it with 430wtq today). The stock turbo is effectively “maxed out” — we’re seeing a lot of back pressure after 6000 rpm and it’s very visible in the boost plot. Attempting to make more than 25-26psi at 7000 rpm actually drops power due to the high back pressure.

Charge Temps

Probably the worst part of the turbo system on this car is the factory intercooler — trying to push the boost levels we push on our tuned Type R basically destroys the stock intercooler in one dyno pull. On customer cars with our MoTeC solution we’re seeing charge temps skyrocket into the 140 degree Fahrenheit area in a very short pull (with ambient temps around 80 degrees). This is no good for power, reliability and consistency.

PRL’s intercooler helped us a lot, and adding water/meth injection on top of that is just an added bonus!

You can see the temps to the left — Airbox temperature being what’s in the intake (ambient was indeed about 75 at the shop today) and Inlet Air temperature being post intercooler. You can see how cool the intercooler stays. Yes we’re using the stock intake. It has not proven to be a restriction for us yet.

Safety First

There was another goal for this subsystem — I personally do not trust methanol injection systems to be absolutely error proof. I know someone’s going to come in and scream “I’ve never had a problem”. While that may be true, it could literally be just your luck. The unexpected can happen and our methanol subsystem is designed to “take control” and take monitoring the methanol system away from you. How many of us can REALLY watch a red warning LED and lift the moment it illuminates? You’re lying to yourself if you think your foot is faster than a computer.

With safety in mind — we worked on developing a control system that could drop the error margin and add fault detection and safeties into running methanol injection. As such the ECU takes full control — it runs the methanol injection pump, monitors the delivery of meth with a pressure sensor and monitors tank level with the level switch that is installed in the methanol tank. It also monitors for electrical faults — pressure sensor failure, level switch faults and since it’s monitoring for pressure sensor issues — pump faults (if the pump doesn’t come on, no pressure will get built — and the subsystem will failsafe and warn the driver).

We actually got to see this in action on the dyno — you can see in the following graph that the meth system hit a fail safe (dashed graph) and deactivated going to pure “pump gas” (or whatever your normal tune is) so you can continue running the engine without a hiccup (other than the obvious loss in power). I actually lifted when I saw this warning pop up on my laptop as I was tuning the car — and you can see how long it took me to react. Mind you — this was with me *actively* watching for faults as I was tuning the car. Imagine the delay if you have a problem and no failsafe? Sure, the failsafe may not save you from every problem — but it certainly goes a long way in helping avoid issues.

The Subsystem

What does it do? Other than what I’ve already discussed above. Well, here’s a quick overview. The system is totally configurable — you can chose to configure it for how it suits you.

The system has activation parameters — once those are met it “arms”. During “Arm” it will turn on pump injection and “wait” for a maximum amount of time for line pressure to build to verify the system is actively injecting water/meth. If the target line pressure is not met within a fixed amount of time — it will fault and not activate.

Assuming everything is OK with the system, it will then activate and allow you to add additional boost, ignition timing and trim the main system injection fuel volume (as already discussed) based on how much meth you are delivering. The system is fully progressive — you ramp it in as you chose fit.

If anything goes wrong — pressure drops below a set target, or above a set target (clogged nozzle?), it will failsafe. Pump dies? Pressure will drop — failsafe. Pressure sensor dies — failsafe. Low level switch indicates tank is low? Failsafe. Level switch fault? Failsafe.

Anytime there is a failsafe we run on our “normal” tune that doesn’t require the additional fuel. So you can keep on driving the car without skipping a beat.

On top of that you also have the driver notification — we’ve repurposed the “Check Engine Oil Level” prompt on the dash to come on when your tank is low if you so chose. Or you can also chose to have the check engine light illuminate when there is a subsystem fault.

What more could you want? Well if you do — we can probably develop it into this ECU.

 

 

VitR — Scraping the Bottom of the Barrel

No the title isn’t a shot at the car — I’m finding it to be a great car and the motor is turning out to be pretty solid. There’s just one thing that’s quite annoying — Honda gimped the potential of the motor with the fuel system. The D/I fuel pump is pegged out very easily once you turn the power up, which in fact leaves you literally scraping the bottom of the barrel to make a clean power curve as you’re riding a very fine line with the fuel system.

This turns out to be even more true once we put on the PRL Motorsports Intercooler on the car and found out it improves cooling efficiency to a point we were making the power we had before while running less boost. Of course we wanted to make more power and run more boost — which proved futile given the limitations we kept hitting in the fuel system.

The car is 100% OEM aside from the PRL Intercooler and we used E35 blend fuel for this test (as we wanted to see how much more we could push the motor).

Intercooler

So what did the results look like? We were able to make a clean power curve and pick up more power before the fuel system maxed out — and make roughly the same top end with less boost.

But that’s not good enough! Let’s make more… and we certainly tried. The motor wants to make power — but takes a slump after 6000 rpm. Why is this?

Well here’s why — in our MoTeC programming we’ve added code that estimates how much injection time you have left before your spark event. You need a certain amount of time left over for a clean mix in the combustion chamber before the fuel is ignited. Do not leave enough time for this to happen the engine doesn’t make power or even worse — misfires. It appears that on this motor we want at least 1.5ms of “Injection Time Remaining” to get a complete mix.

But as fuel demand on the D/I pump goes up it skips a beat and we see a large fuel pressure drop — from a target of 22.5MPa to 16.6MPa (a 6MPa or almost 900psi drop in fuel pressure). As a result of the pressure drop the injector pulse width has to increase and now we’re running out of injection time!

Really Push It

How bad does it get if you REALLY push the D/I fuel system? Well take a look at this. Wow it’s just a roller coaster ride after 5500 rpm — we were making over 390whp and would of made well over 400whp if we had the fuel…

 

You can see how tapped out the D/I fuel system was on this 29psi pull as we dropped 8MPa of fuel pressure.

Injection time remaining was super low… and the motor even misfired at 6600 rpm.

 

 

So Did the Intercooler Help?

Absolutely. Here’s some useful data from actual hard acceleration runs on the stock intercooler and with the PRL intercooler. You should note — we actually used a bit less boost on the stock intercooler runs and the stock intercooler had colder ambient temperatures versus when we ran the PRL intercooler test. However the stock intercooler still heat soaked rapidly. For comparison are runs at WOT from 1st to 3rd gear.

First on the left is the stock intercooler. Note the following — “Airbox Temperature” is the temperature sensor in the intake BEFORE the turbo and the “Inlet Air Temperature” is the temperature sensor in the intake manifold. The sensor in the intake manifold tends to heat soak at idle/low air volume conditions (not much fresh air flowing through the intake manifold).

 

On the right is the run w/ the PRL intercooler. You can note that with the stock intercooler the Inlet temperature never touches the airbox temperature and in fact starts to climb almost immediately after dropping. With the PRL intercooler the aircharge is rapidly cooled and comes down to match the temperature at the airbox — and stays steady all the way through 3rd gear and would *maybe* start to slowly climb in 4th gear.

Clearly the intercooler upgrade is worth it — especially for our road course folks.

Some Fun

After having the car for a while and getting more comfortable with the clutch — I wanted to see if it would hold a bit more torque. I brought in 23-24psi earlier in the powerband, held 24psi through the top end — and made ~390hp and just a hair shy of ~400tq.

Is there more potential there? I believe so — I think we can probably make 450wtq quite easily — if we had reliable fueling. We had a 6MPa pressure drop and the fuel pressure just did not look that great.

 

 

Some Thoughts

Yes — this is E35 fuel (we had made 360whp on 92 previously), but there will be comparable gains from this intercooler on pump gas as well. The E35 actually doesn’t bring up fuel demand *that* much over pump gas (which is E10 to begin with) — it’s about 10% more fuel. So what’s that tell us? Where the hard limit is for fuel volume with this D/I fuel system.

How much can we do on just pump gas? Maybe 400whp before we need to do secondary injection. Maybe less, maybe more. We’ll find out once we have a the PRL downpipe on the VitR!

The other option is to use a race gas that reduces fuel system demand over pump gas….