Lotus Esprit V8 Aquamist Dual Water Injection System Upgrade
One of the most important items to consider on a turbo charged engine, is the temperature of the compressed (Turbo Charged) air entering into the combustion chambers (inlet temperature). Fact; the more you turbo charge the inlet air the hotter it gets. We are running in excess of 1 bar (14.7psi). The hotter the intake temperatures are, the greater the chances of in cylinder "detonation" becomes.
DETONATION DAMAGES ENGINES PERMANENTLY! On a Lotus Esprit V8, this could result in a monumentous expense. However, Lotus Engineers are not stupid, they have built in some safeguards against detonation. The most significant being an Engine "knock" sensor. This sensor is mounted on the engine underneath the plenum. It detects the smallest amounts of in cylinder detonation, relays the information to the ECM, (Electronic Control Module, The Computer) which in turn retards the engine ignition timing accordingly until the knocking ceases. While all this seems safe and wonderful, the more the timing is retarded, the less power the engine produces. Kind of defeats the object of turbo charging doesn't it?
When the engine detects high inlet temperatures, it signals the computer, which in turn opens up the fuel injectors, depositing more fuel into the cylinders. This performs a minimal cooling function as the vaporizing fuel cools, and the in cylinder temperatures are some what reduced at the expense of "dumping" unburned fuel into the exhaust. Not very efficient at the best of times. And one can actually smell it after a high boost run.
Remember when you had your old banger of a car in your younger days, and you got some bad fuel, you put your foot down in a high gear and you could hear that "pinging" noise coming from the engine. That was knocking or detonation, only then you did not care about it. (or understand the consequences). We bet you did not pay tens of thousands of your hard earned dosh on the car either.
Enter the Aquamist water injection system. What this does is introduce a high pressure jet of water (about 110 - 130 psi) into the intake manifold. As the latent heat of evaporation of water is 6.5 times that of fuel (2256 versus 350), as it vaporizes in the intake manifolds it absorbs heat, thus lowering the temperature of the air/fuel mixture, and significantly reducing the chances of detonation.
Why go through all this effort when "intercoolers" are designed to do the same thing? Well, We challenge anyone to locate and fit twin intercoolers into the Esprit V8. Without major body re-fabrication there simply is not any room. Lotus deemed an intercooler not necessary, as stock boost levels were not intended to go above 0.5 - 0.65 bar (7 - 10 psi).
We have been using the Aquamist ERL 3D Mapped System 2S with the MF2 controller Water Injection system ( www.aquamist.co.uk) with tremendous success and great results. It reduces fuel dumping, and as far as we can tell eliminates detonation. The all telling plug test shows all is well inside the engine. The plug test is simply removing the plugs and checking them for obvious signs of detonation and lean or rich fuel mixture IMMEDIATELY after a good high boost run.
All items listed assume the person(s) doing the modifications have a complete set of up to date Lotus workshop Manuals.
The steps we performed are as follows:
This procedure is very similar to the Turbine Bypass Valve installation procedure. In fact, we did both performance upgrades at the same time.
The left and right manifolds can clearly be seen here.
Once all the pipes etc. are out of the way, all the bolts removed, the manifolds can be coaxed off. This is a lot easier said than done, but they come off with the help of washing up liquid (dish soap) for lubrication (to help us get the attaching rubber joining hoses off). The main problem was getting the left (as seen) manifold off. The short 2" in diameter rubber connection hoses have a very small gap between the pipes, as you can see in the next photo, especially the lower one that connects the manifold to the turbo charger outlet (you cannot see that one). But with the mentioned washing up liquid liberally placed around the joints they came off quite easily.... considering. We thought they would be murder to get back, but the new blue silicone hoses we used were much more flexible and they just popped back on.
Here you can see one of the small gaps between the manifold and the throttle body
Here you can see the left manifold removed
Now the manifolds are removed you need to get the water injector threads welded on, drilled and tapped. The Aquamist ERL System 2S comes with a tap the correct size for the injectors. However, Aquamist provide only 1 of each sizes of injectors 0.5mm, 0.7mm, 0.8mm & 0.9mm., and one high pressure 1 way water valve. The final installation required 2 one way valves and a "Y" piece to feed both injectors from a single water source. We also added a pressure gauge. This installation needs 2 of which ever size jets you choose. We started with 0.5mm but found that we could get away with 0.8mm after testing, so 0.8mm is recommended. This next photo shows the manifolds all marked up with the most optimum places for installation of the injectors. We installed ours at the point marked 1 on the right manifold and 2 on the left.
Turbo charger manifolds, path of high speed airflow
Once the injector mounting ports were welded, the manifolds were re-installed on the car, with their new sparkling blue silicone couplers. The hoses were aligned and put back into place. Extra tie wraps were used where needed to keep the cables and pipes from fouling each other, and we were now ready for the injector installation. We routed all the pipes using a little of the 4mm pipe provided. On the Lotus we passed the pipe along the rear frame support and clamped it down using nylon cable ties and used silicone tubing at strategic points along the way to prevent the pipe chaffing on the chassis' rough edges. This is a little bit of trial and error, it is best to choose which location you are most comfortable with. We had to order extra pipe as the first routing was found to be not so aesthetically pleasing, so we re-routed them. The following photo shows the pipes being routed into the left bulkhead cavity. The blue pipe is the existing air valve vacuum. This came in handy to tie wrap the water pipes to. Notice the protective grommets in the fiber wall. This photo also has a nice shot of the water gauge. The thicker of the two white pipes is the reservoir to pump water feed, the thinner is high pressure output to the injectors.
Water pipes routed into the left bulkhead cavity to the solenoid and pump
ERL provide a super precision (and great looking) high pressure impact water pump. This has to be mounted somewhere quiet. This proved to be quite a task. Remove the left hand bulkhead trim from the rear of the car. (this is the same trim you have to remove if topping up the Power Steering Fluid) This is actually harder than it seems, it is a bitch to wiggle out after all the screws are removed. But it does come out eventually.
Remove the left hand flexible hose connecting the air intake to the air filter box. This is simple, undo the clamps and you are done.
Now, mount the pump in the position shown in the photo. We mounted it at first directly onto the wooden subframe Lotus installs to mount all the various sensors and solenoids on. But when the pump came on it vibrated the whole car and sounded terrible. In the end we finally found some insulated rubber mounts at Grainger Industrial supply. We used the smallest ones we could lay our hands on. Four 3-32 inserts were installed at the locations corresponding to the pumps mounting holes, (The pump was laid in position and marked) when the desired location was achieved. The rubber insulators were then screwed into the inserts. The pump was installed onto the protruding studs and secured with 3 - 32 nylon insert lock nuts. It ran as quiet as a mouse once this was completed.
Water pump final mounting position, intake air hose in place
Water pump installed showing input water pipe
Another water pump picture for good measure, after all it does look good!
Holes have to be drilled in the engine firewall and grommets installed to pass the water feed pipes through. We used standard rubber grommets and all was well. The main feed pipes goes from the water solenoid into the filter provided by ERL and then into the pump. The high pressure output of the pump goes into the pressure solenoid assembly. We mounted the solenoid assembly in the left hand firewall by drilling 2 holes and install 2 countersunk screws. The following photos shows the solenoid mounted and some of the pipes protruding through the firewall.
Water solenoid assembly in final position
Water Solenoid showing gauge outlet feed pipe
Water gauge close up, notice 130 psi standing pressure
A water reservoir is needed to hold the main water supply. We chose a custom fabricated aluminium reservoir. Mainly due to the fact it looked great and it kept the water cooler than the plastic one we prototyped. A BMW water level switch was installed in the reservoir so we could see when the water level gets low. The wires were passed into the cockpit through the firewall, (explained later) and connected into a spare fascia lamp socket. The water reservoir was mounted to the luggage compartment cover, on the left hand side to compliment the radiator header tank on the right. Here are some photos of the final installation.
Water reservoir and gauge final location
Water reservoir with breather tube attached
Here are some photos of the right hand injector and one way valve installed in the manifold. These clearly show the welded mounts that were threaded to size.
Right hand injector and one way valve final location
Right hand injector close up
Well, that sums up the mechanical side of the installation. The electronics was pretty easy. The ERL manual explains it in detail. What follows is our explanation, we apologize as photos are limited, as the car is all back together and the wiring has been re-wrapped so as not to look tampered with.
Remove the excuse for an inside glove compartment that is mounted to rear firewall of the driver's compartment. There are 4 screws, 2 on each side under the carpet.
Cockpit center glove box
Remove the small front center console switch cover. There are 2 screws in the front. This lifts off quite easily.
Remove the large rear center console cover. Be careful as these are all fine leather and can be damaged if not treated with care.
Large center console
We drilled a 3/4" hole in the firewall at the lowest point we could find, this was emotionally harder than physically, as drilling any holes in the fiber panels of a Lotus can be a stressful activity. The panel was double skinned so effectively 2 holes were actually drilled at the same time. A large tapered grommet was inserted both sided after it was drilled. These were hard to find. We ended up using 2 from a parts store that were normally intended for use for mounting EGR valves into valve covers. It took quite a few trips to the store and a lot of guesswork. Also, laying across the engine, probing blindly in the engine compartment, feeling ones way around proved quite interesting. the wiring loom was fed from the inside of the car into the engine compartment, and split up from there. The MF2 (Water control unit) sensor wires, (Blue MAP Sensor and Yellow Tachometer Pulse Feed) the Red power line, and the appropriate ground wires were routed into the right hand bulkhead cavity, while all the solenoid control wires were routed into the left hand cavity. All wires were coaxed into existing grommets with the help of washing up liquid for lubrication. All wires were also covered with a spiral protecting cover for extra protection.
Now for the fun part. The ECM Sensor Connections. We removed the ECM connector, removed the cover and unwrapped the loom to about 4 inches back from the connector. We located ECU pin 37 (MAP Sensor, Blue wire from the MF2), Pin 58 (Tachometer, Yellow wire from the MF2. We used this instead of the Coil wire for RPM, it worked a lot better, with less interference) and Pin 1 (Fuel Injector 1, this is used on the Boost Controller and is not applicable for the Water Injection System, but do it now and coil the wire up out of the way someplace). The wires from the ERL MF2 were then spliced into the ECM wiring loom and re-wrapped with the existing and additional wiring tape. (You can get old fashioned wiring tape from Home Depot or Home Base) Appropriate quantities of black tie wraps were used throughout to tie wires and pipes out of harms way.
The Solenoid wires were straight forward and connected exactly as the ERL manual stated.
The MF2 controller fits quite nicely under the front center console switch cover. We left ours open as shown in the following photo because final adjustment is a long process. Notice how the wiring loom disappears under the center console.
MF2 location in the center console
MF2 close up of all the adjustments
The Green wire from the MF2 to the Fault Light was routed to a spare lamp socket in the fascia the left hand side. We retro fitted some standard lamp holders and lamps we found at the Auto Parts store to fit into the spare "European" Brake light sockets. There are conveniently 2 that are not used in the USA or Europe, which 2 is based on where you are personally located. (Europe or USA) We used one for Fault light, the other for the Reservoir water level indicator. This worked out quite well.
Power for the pump and MF2 controller was taken directly from the switched side of the rear right hand fuse assembly. It has to be removed and a couple of wires installed into 2 spare switched power lines from the power relay. The relay provided with the ERL System was not used in this installation. This was not very difficult, as there were plenty of spare lugs on the relay output. One wire was routed into a 5 amp fuse in the right bulkhead cavity for the MF2 power, the other was routed to a 15amp fuse round the rear of the luggage compartment into the left bulkhead cavity to the water pump. All wires were easily concealed under carpet or in the cavities. We installed a ground lug (a screw, screwed into the left wooden mounting plate, where all the grounds could be tied together for the pump and solenoid.
Right rear fuse box
That effectively completes the installation. We hope you found this text interesting. If you have any more questions please leave email and we will be please to respond.