? Can't edit my post

If you don't have a speed reference and can't use normal gearbox output it wouldn't be hard to cut a couple of trigger wheel segments to slap on the diff pinion or uni behind the box and glue a mount for a hall sensor on the diff snout/gearbox extension housing.

 

I'm actually running a water/meth mix now, and to be honest I didn't really notice much difference over straight water, possibly because every time I go on the dyno I'm always looking for more power and messing with several different things at the same time. If nothing else it's probably easier on the ignition system.

Tremec TKO's have a built in speed sensor which I'm using as a digital input to the ECU. I'm running spring pressure in first gear and full boost 2nd gear onwards. Spring pressure in first is still to high I feel so I need to do something there. The car gets a better 60ft time with the 2 step making 10psi vs 20psi. The problem is as soon as it starts to launch boost jumps up to spring pressure of 25psi. I'm thinking about going back to a soft spring and using 2x 3 port mac valves - one on the top side of the gate, and one on the bottom side. I have a spare pwm aux output and can set up a table for the 2nd mac valve. I just need to figure out the best way to go about it, when I have time. When I get this sorted I also have the option of time based boost control - the Link/Vipec ECU has this built in.

We have one more meeting left this season, and for now I've bumped up spring pressure so I should be able to get to 45psi, track condition, weather etc permitting. The higher boost pressure will probably generate more wheel spin in the first part of the track but at least mph will give a good indication of any power increase. We'll concentrate on boost control and improving traction to half track next season. We can also mess with the rear end to hopefully improve 60ft's.

 

We were having similar issues, to much boost in first, spinning tires.

Solution was a 6psi spring with a 4 port boost solenoid. Boost by gear since you have a speed input.

Use to have a air tank with a regulator plumbed to the top of the gate. Easiest boost controller out there. More boost was needed, just up the pressure to the top of the gate. Very reliable. Then the boost got to be to much in first. reason for going with the 4 port solenoid.

 

How does the 4 port solenoid compare to the 3 port? I have heard they are no better than a 3 port setup in some situations (possibly at high boost levels), but I cannot speak from experience yet. Can you still run the same high boost level with your 6psi spring?
What's your pressure range with the 4 port and what was it with the 3 port?

 

The 4 port only allows pressure to the top "OR" the bottom of the gate. So when building boost there is no pressure on the bottom of the gate, only top. Once boost is reached there is no pressure on the top, only the bottom.
With the 6 psi spring and with a good designed manifold, I have run 6psi with the controller off. And as much as we wanted with the controller on. It does take time to get the duty cycle correct but not to bad.

 

The 4 port cycles pressure to both the top and bottom diaphragm, not just the bottom, it uses boost the actually hold it shut until your boost target. They are obviously more sensitive to DC changes than a 3 port so it is best to run them in closed loop.

The 4 port allows you to run from a very low spring pressure up to very high target boost by forcing the gate shut, atmospheric only pressure on bottom side of diaphragm with boost on top, plus spring force, with the area ratio of the diaphragm to the gate valve means massive boost on a very soft spring is achievable. Anyone who says a 4 port is no different to a 3 port running an external gate obviously does not have it plumbed properly or has a gate spring stiff enough that it would not struggle with a 3 port anyway. Especially with that big turbine (relatively low EMP:IMP) you should get 50-60psi on a very soft spring at high duty.

 

Yep!

But wont you have a slight disadvantage during tip in or after gearchange as if you plot boost and emp curves the boost will always lag slightly behind in transient situations and there might be the risk the gate will be pushed open by emp during this initial high emp:imp ?

 

No issue guessing he would be flat shifting anyway.

 

Tried flat shifting with the 75mm turbo but not yet with the 80mm (only one meeting on the 80mm). Flat shifting actually made no difference to ET or trap speed vs conventional shifting. Transient response between gears is actually pretty good considering, and transient response of the 80mm turbo seems to be no worse on the track than the 75mm, even though it's quite a bit slower to spool on the dyno.

I think I'm going to try a 4 port solenoid before I try 2x 3 port solenoids. At least I still only need one boost table with a 4 port. I don't have much time to mess with the car full stop so the less I need to change the better!

 

So I fitted a 4 port boost solenoid and set it up on the dyno. Spring pressure is now a nice low 11psi and at 39% duty cycle boost was up to 43psi. I'm sure it will go as high as I want - or at least until the turbo maxes out. The turbo spools a few hundred rpm earlier too.

The solenoid is very sensitive - at 20psi adding another 5% duty cycle increased boost by 15psi. No problem though, I just have to remember to make small changes at the track!

I also found out once again how good water injection is. After a decent number of dyno pulls in a row the fuel level was low, and as I subsequently discovered, very hot. Halfway thru a 35 psi pull the fuel pumps cavitated and fuel pressure disappeared, gradually leaning the engine out until it misfired. No problem though, it didn't detonate and is somehow still fine. I dumped some cold fuel in the tank and continued on to higher boost.

Amazingly enough this engine just wont die - after 278 dyno pulls (over almost 2 years), two full drag race seasons (at 40psi), two Powercruise weekends, one dirt drags, and a lot of street driving.

 

so what where the numbers at 43psi?

 

Wow, that's bragging rights

 

I didn't actually pay much attention to power as I was pushed for time and only interested in setting up the boost. Was about 560rwkw but with wheel spin. Once the engine reached peak torque power just flat lined after that as the tyres broke traction. I didn't take the extra time to load it into the rollers properly this time. The previous time on the dyno with more grip it made about 630rwkw at 40psi and at that boost it trapped 162.5mph on the quarter mile.

 

wow amazing!

how much water are you injecting and at what psi do you activate it?

 

At 20psi it's around 1200cc per minute from memory. I'd have to assume it's almost double the amount at 40psi.

Activation point is 14psi.

 

The flow increase will be proportional to the square root of the relative increase in boost, so it is probably somewhere in the 1700-2000CC/min area.

Awesome to see how reliable and consistant your setup has been. I'm assuming you are only using dyno torque and wideband to set fuel and ignition timing, not something fancy like a combustion pressure logger?

 

Correct, I'm only using torque and an Innovate LC1 wideband. I can't afford anything fancy!

 

Good to see someone else having great success with WI.
I wish i got to race mine properly to see what it really had.

 

I find the older an engine, the more kms/runs it has on the board the stronger it gets.
Fresh engines are always very sensitive.
I am no engineer, maybe someone else could comment on the properties of seals possibly change with heat cycling etc?

 

This is insane. Great to see how much power you can make with such little.

What ECU are you running?

 

I wasn't able to burn that much water on my car. Most
I could burn was 12-1300cc of water at peak torque with an 11.5 mixture with the Crane CDI's

Those IGN-1A must be hellish strong to be pushing through 1700cc of water, are you backing water flow off after peak torque?

 

I'd say 1700cc of water /meth is likely easier to fire than 1200cc of straight water.

Either way it's amazing what a 13b can achieve on pump fuel.

 

Yes backing off flow with rpm, due to lack of ignition power at higher rpm. WI PWM control is thru a duty cycle table.

 

You running the mac valve around 50hz?

 

I set them to 40Hz.
Seems to work well.
It even worked Okish at 25Hz just abit slow to speed up and slow down I found.
40 seems to work really well.