Labonte MotorSports

iTrader: (9)

Richard -

I do have to give Aquamist credit and respect that you have people with real engineering backgrounds and design your own systems like we do, unlike copy experts that think R&D stands for Rob & Duplicate.

shaman

iTrader: (2)

Dan raised the point I was considering. Since the new style pumps don't pulse like the older shurflo pumps do, it seems the only thing that isn't handled is the PWM valve, and that could be easily handled by relaying the pump to turn on, and using the pump feed wire to control a PWM signal to a PWM valve.

Richard L

iTrader: (5)

It is a a great advancement evolving from the "pulsing-shurflo" to a "by-pass valve-aquatec". Shurflo does have a by-pass pump but the PPS system maker was very slow to adopt it. AEM only recently can their pulsing-shurflo system to a "by-pass-shurflo". It took them 2-3 years to realise it.

Since the first day (2006) we offered the shurflo based system, we have used the "by-pass" pump.


A pump is designed to run on a steady 12V supply. Since is a quite expensive to to manufacture a true variable 0-12V DC controller. A high frequence chopped DC is used instead to reduce cost. This is because the pump is very slow to react to fast pulses due to this large inductance and inertia, so all it see is a a pseudo-DC voltage.

A PWM valve is designed to receive a pulsed frequency between 30-80Hz, not a 0-12V DC ramp. So feeding the pump's PWM signal to a PWM valve is a total mis-match and will not work.

shaman

iTrader: (2)

Richard, from my understanding, most controllers on the market don't send 0-12V signals, but PWM signals. From the DO website

PWM output 30hz

http://www.alcohol-injection.com/pro...roller-14.html

Richard L

iTrader: (5)

A pump does not respond to high frequence PWM pulses in a way a PPS system makers lead you to believe. Rather it sees it has a blurr, as you watch a TV at a refreahing rate of 50/400KHz.

Instead of sending a 0-12V to vary the pump speed, a PPS controller sends a "chopped" 12V (400-1KHz) to the pump with varied duty cycle, emulating a 0-12V. For example at 50% dutycycle, the pump sees it as 6V; 25%DC = 3V etc.

The DO website has not published an accurate frequency. At 30Hz, the pump will walk, literally! If it is not bolted down.

Here is a screen shot of a post by DO at their own forum confirming the real operating frequency. It was posted very recently. Note the date.


This industry is full of misleading information, don't believe everything you read.

As an engineer, there are no "black art" to make a motor speed controller. I believe you can buy a motor speed controller on the net for $30.00, using the same PWM control technique.

shaman

iTrader: (2)

Then that kills my idea. I got a stainless steel clippard valve on my preturbo nozzle. Was thinking about using it.

Richard L

iTrader: (5)

You can make a pwm(Hi-Fq) to pwm(Lo-Fq) converter, reducing the pump frequency down to 50Hz for the valve.

There is also a flow mis-match problem you have to solve:

- at 20% DC: The pump will discharge ~50% of its total capacity through the jet
- at 20% DC: The valve will only discharge 20% of it total flow capacity through the jet (linear response).

It will save you a lot of time if you just go for a PWM-valve system. Since the launch of our HFS-2, it was at $450 last week at our introductory offer (now closed). Even at full MRRP, it is still very reasonable for this kind of technology.

shaman

iTrader: (2)

Well I was considering full 12v to the pump, and PWM to the valve.

Richard L

iTrader: (5)

I see. Thats is simpler.

The PWM frequency mis-match still exits.

Richard L

iTrader: (5)

Clippard does make a proportional valve that will respond to current (DC or chopped DC PWM signal). But it is not very precise without close loop control. It is very sensitive to line pressure ripples.

Richard L

iTrader: (5)

One thing at a time. I am not kdding.

Lets discuss the lack of lambda feedback.

The ECU have rather more sensors than your controller, signals are all raw data.
Plus they also know the volumetric efficiency (mechanical data). Mass air flow sensor, engine tempertaure, air temperature and ignition timing data, all being used to interpret the engine's fuel requirtement at any given RPM and load.

You should know that boost signal alone cannot be used to interpret load without air temperature correct and volumetric efficiency table.

I believe you claimed that your controller can add the correct amount of methanol/water mix and pegged the AFR at a steady "half a point" lower use on two signals "boost" and "IDC".

Based on this control algorithm, user just fit a Labonte system and no tuning is required, power will come automatically.

Am I correct up to this point?

dvldoc

Just notice this post pop up while playing around on the net. Hate to ruin your gotcha moment but I was in Iraq when postin this and was still talking about our old controllers that pulsed the positives just using the info I had prior. The newer ones use a different board and different frequency. 30hz is what they run at. Kinda hard to have all the up to date info when your tryin not to get blow up by IED's every day.

Just wanted to clear that up.