Now that warmer weather is here I thought I would sort out my meth/water injection which is not working.

I cannot obtain a mechanical boost reading to activate the controller.

Initially I chose the tubing to the SC bypass actuator however that is vacuum operated by the look of it.

Next I chose the inlet/outlet pipe at the base of the "spreader" where air exits the SC on its way to the intercoolers.

That reads a vacuum up thru 3,000 rpm. I did not rev higher.

I know the Eaton is an air "pusher" not a compressor but where the heck can I get a mechanical boost reading?

This has me wondering if my SC bypass valve is working properly.

Edit: Ok so some research on this seems to indicate that reading a vacuum at low revs is just normal. So how high do I have to go to get a positive pressure? Do I need to put it under load?

 

Do you need a boost reading or just a signal activate the pump?

If you just need a signal tap into the airbox flap solenoid

For the actual boost you will need to mount your sensor after the supercharger.
Im guessing you drilled an taped the intercooler bridge.
This would be reading the actual boost

Id would look at the boost readings under load. Ie go for a drive
As the bypass is vac operated reving wont see the load you will on the road as the engine is in neutral.


Cheers
34by151

 

The Snow controller that I have is boost activated and requires a physical, not electrical, connection.

The intercooler bridge on my car has insufficient room as the aluminum inlet sits quite suggly on top.

I ended up tapping the lhs charge cooler, very carefully, above the internal matrix.

Thats what I was hoping/thinking in your last paragraph.

The air box solenoid tapping for an electrical signal is a great idea for an electrical activation tho.

 

As long as it is after the supercharger any place that suits will do.

From JTIS
************************************************** ********
The supercharger by-pass valve assembly is part of the intake elbow. The butterfly valve inside the assembly is opened by a diaphragm actuator operated by vacuum feed from the elbow. At closed or partially open throttle positions, the butterfly valve opens, allowing the airflow from the two charge air cooler inlets to be directed back to the supercharger inlet. This action inhibits the supercharging effect and reduces engine torque. Progressive opening of the throttle causes the by-pass valve to gradually close.
************************************************** ********

In other words the high vac at idle/low loads will open the bypass. So in theory disconnect the vac line and block the hose will disable the bypass but I haven't tried it.

Cheers
34by151

 

I have thought about doing that and may try it to see what low to mid range power feels like.I do not think I can do any damage just make fuel consumption worse.

 

Ok so studying up on this a bit and maybe not such a good idea.

At low rpm deactivating the bypass valve can apparently cause cavitation in the super charger and possibly damage as well as poor fuel consumption.

 

Yeah I cant see any damage occurring.
Fuel trims will adjust to the boost at idle increasing consumption.

With bypass open the inlet and outlet of the supercharger will be close to the same pressures. The result will be to see vac at the boost gauge.

If your test works out, you could also put the vac line back in but add a vac solenoid. It would be easy to wire this to the same power swith for the meth injection.

This would give you stock with the meth injection off and no bypass with meth enabled.

Cheers
34by151

 

I cant see how as most installs dont use a bypass at all.
Added to that you have done the pulleys so your already in effect developing more boost lower down

Cheers
34by151

 

That is an interesting idea.

I have ordered a solenoid valve. It will take a while to be delivered. Also an adjustable rpm switch to activate the solenoid valve.

My objective is to use the solenoid valve to close the vacuum pipe to the SC bypass actuator at about 2000 rpm 100%.

The reason I am experimenting with this is because of the following:

The 2005 XJR has a compression ratio of 9.5:1, for obvious reasons. However with the SC "inactive" that is a very sub optimal performing engine compared to say my Range Rover with 11.5:1 compression ratio.

So I want the SC boost to come on immediately instead of gradually at a start point of say 2000 rpm instead at a much higher rpm.

With the car as it is now I am wasting money on 93 Octane gas most of the time!

I am sure someone will poke holes in my logic.

 

I have actually implemented your suggestion 34by151.

I have plumbed in a vac solenoid in the vacuum pipe to the SC bypass actuator and electrically linked it to the water/meth system.

The water/meth system is programmed to activate at around 5psi and will also now activate the vacuum solenoid to close completely starting at 5psi.

I have yet to take a test drive as the weather has been so bad here for days.

I am guessing that the bypass valve is normally still partially open at 5psi.

I will be looking for any difference to the "feel" of driving and also at fuel consumption.

 

Let us know how it goes

Cheers
34by151

 

From a previous post of yours.

From JTIS
************************************************** ********
The supercharger by-pass valve assembly is part of the intake elbow. The butterfly valve inside the assembly is opened by a diaphragm actuator operated by vacuum feed from the elbow. At closed or partially open throttle positions, the butterfly valve opens, allowing the airflow from the two charge air cooler inlets to be directed back to the supercharger inlet. This action inhibits the supercharging effect and reduces engine torque. Progressive opening of the throttle causes the by-pass valve to gradually close.
************************************************** ********

I am wondering whether or not I will feel any increase in torque at relatively low rpm.

 

I doubt it

Id still take a signal off the air cleaner bypass.

IE Wire the SC bypass solenoid in parallel with the air cleaner bypass wires
Put a relay on the ecu side of the air cleaner bypass and power the meth injection from that

IE under normal conditions the meth injection is enabled but not pumping
You put you foot down, the air cleaner bypass opens. This disables the SC bypass giving you boost for that RPM and the meth injection starts to pump

You may find that the Disabling the SC bypass is not needed. It just depends on the crossover between the air cleaner and SC bypasses. That something I have never tested


To put another way there are 3 states
SC bypass open
SC bypass closed
SC bypass partially open

With the bypass open means high vac or low load.
Here you dont need the meth injection pumping and boost is not needed reducing fuel consumption

With the bypass closed you will be at WOT, the air cleaner bypass will be open as well. Here you want the meth pumping and all your boost

What is not clear is the space between these 2 states.
Is the bypass linear or logarithmic on mature? I dont know but I suspect the latter.

What by forcing the bypass into a closed state you are getting removing the space between open and closed bypass top on and off

How much effect is created will probably depend on driving style.
On the Dragstrip will probably show no change as you so from open to closed right away.

At the track is where you will probably see some effect as you will be between open and closed at various times. How much that changes your lap times is again a function of driving style


Cheers
34by151

 

Quote 34by151:
"Both the Coils and Injectors are negative triggered
IE they have positive power all the time and triggered by the ECU connecting to ground

The module needs to be set to "negative trigger" to work
You should be able to use pin 1 on any of the injectors or pin 4 on the coils

If you send me a copy of the module's manual I can give you some more specific advice

Its a little different for the MSD module as it is senses current not voltage
For the MSD 8913 you need to put it inline with the coil power supply.

The easiest way to test it is to remove F30 from the front fusebox. This will give you a break in the power supply for the coil harness.

Put a blade fuse holder on the MSD red wire and insert F30 into that

Now put a spade connector on the fuse holder and insert into the fusebox on the power supply side. This will read 12v with the ign on)

Put a spade connector on the MSD Red/Green and put that into the coil side of the F30

Put a lug on the MSD black wire and mount under the fusebox bolt

That will give you your signal from the MSD Grey wire

If that goes well you can then make it more permanent by tapping into the injector harness (Pin 30 on PI41) or under the fuse box (Pin 2 on EC36)


Id think the air cleaner solenoid valve trigger will be all you need though".

Cheers
34b151 End quote.

Will look at this after test driving initial set up.

Will focus on just this thread now.

 

No luck!!!!

Took a couple of test drives with an idiot light hooked up to the meth/water injection system.

At a programmed 5psi it did not come on even at 3,500 rpm. Tested the idiot light and at 12 volts it worked fine.

Dialed the w/m system down to lowest point and still the idiot light did not come on.

The w/m system is progressive so I am assuming that it starts at a low voltage output when initially triggered and ramps up as the revs ramp up. I have max set at 15 psi so assume full 12 volts at 15 psi.

Anyway am now thinking of trying to get a signal with the magnetic pick up from the crank position sensor.

Maybe that has similar "issues" to the coil/cop leads I have tried?

Failing all that will try the F30 route.

What worries me about using the airbox solenoid is that I bet it does not activate until in the higher rev range?

One thing I will try next tho is disabling the SC bypass valve completely just to see what happens.

 

It would be worth testing the airbox signal using a light just to see where it triggers

Cheers
34by151

 

I do plan on doing that.

 

Ok so I went for a test drive with an idiot light hooked up to the airbox flap solenoid, which flap I removed a while ago, and it did not light up even at redline.

Also disabled the SC bypass valve actuator for same test drive.

No discernible driveability issues at all. IF anything at all there might be better throttle response at lower revs however that may simply be wishful thinking.

Normally around town I get anything from 14 to 17 indicated average mpg. On this trip I got an indicated 16.8 mpg average.

On a fairly hard take off from stop, no where near wot, I did spin wheels. They spun then gripped and then spun again.

The only way to really test this "theory" of mine is if someone were to do a few runs on a track with the bypass valve actuator disconnected and vacuum tube blocked obviously.

I am going to leave the bypass valve actuator disconnected.

 

Strange behavior on the airbox solenoid.
Was it still connected to the solenoid (without the flap) or just to the light?

Did you get a better boost guage reading?

Cheers
34by151

 

I did not check the boost gauge reading. Will do that.

The solenoid is still connected even tho no flap.