Howard Coleman

iTrader: (6)

as usual, Digital Technology changes everything. compare swapping Weber carb jets to the X Y grid that currently controls your fuel to the millisecond. the Power FC/Datalogit provides 400 discrete cells in which to tune. stipulate timing to the tenth of a degree, anywhere. measure knock. measure EGTs. measure ANYTHING.

and so it is w AI. AI, as many of us know was used on the B-17, B-29, P-51 Mustang, the ME- 109 long before computers. and it worked well for it's application.

that'd have been a pump. some nozzles and a few switches. bingo. more boost, less knock.

this technology carried over into the racing/performance area and was the standard until solid state electronics impacted.

AI DELIVERY CURVES could now be set. pick your ramp at the twist of a dial or a few keystrokes. delivery was stipulated by changing the current to the pump. the term "Progressive" became common, referring to a "progressive" delivery ramp.

i call this the second stage in AI evolution.

how does it work? excellently. it allows you to run maximum boost anytime w pumpgas. it allows you to tune for knock and whatever AFRs you wish. i have found it to be accurate and repeatable. always. my AI comes on to the tenth of a PSI boost. thank you Digital.

welcome to 2008 and the THIRD STAGE of AI.

call it HIGH DEFINITION-AI



if the above X Y grid looks alot like your fuel map that's because it is. note RPM and BOOST (load). 16 X 16 generates 256 discrete cells. you just enter the % of maximum.

the reason the HD-AI can deliver (pun) in such an accurate manner is that the system is fundamentally different than earlier systems.

Low Definition AI delivers varying amounts of injectant by varying the pumpspeed. i am sure you are with me in understanding that an electrical pump can not be precisely controlled.

imagine if your gas map was controlled in such a manner. consider how precise the tuning of your base fuel is to arrive at a proper AFR. you are messing with milliseconds on injector ontime.... 'think a pump can do it?

HD-AI changes all this.

for the first time, ever, your AI is metered just like your base fuel. the HD-AI uses a digital module to run fuel injectors. pump speed is not used to control delivery. the pump, just like your OEM system merely provides adequate pressure and the AI fuel injectors "on-time" governs delivery.

not only can you now stipulate EXACTLY how much injectant you want but you can also do something really important....

note on the above table (which is the initial setup table for my system) that i reach max delivery (100%) around my peak torque. note that even though the RPMs continue to build after that my injectant delivery declines. this is because your engine loses Volumetric Efficiency after Peak Torque and uses less fuel.

you can't do this w the Low Def 2nd Stage AI system. generally the system reads boost and provide injectant volume off the boost reading. Progressive systems are incapable of lowering delivery after peak boost. generally most people trim base fuel to end up at a proper AFR but that is not optimum.

further, if you are road racing you are on and off the gas in a corner and boost will vary wildly. a LD-AI system can not keep up w the gyrations. the HD system will.

while there have been a few HD systems running in 07 the big transition will happen in 08.

there are, AFAIK, 3 companies offering HD-AI.

Aquamist
Coolingmist
FJO Racing.

i completed installation of my FJO system Nov 30 last year but winter arrived w a vengence so i wasn't able to get on the dyno. i expect winter to end soon, though no guarantees, and be on Beyond Redline's (Green Bay) new DynoJet Eddy Current dyno ASAP. the FJO HD AI system includes a 4 bar MAP sensor with it's own boost controller and it also interfaces w FJO's AFR module. various "safeguards" can be set relating to AFR or boost etc. general availability of the new units will be in late March.

Aquamist (UK) has an additional feature in that the unit can be keyed off of total (primary and secondary) injector duty cycle. we have a board member doing initial testing (Cosmo Kraemer). see the Auxiliary Injection Section for details.

Coolingmist also offers and has been in the forefront on the HD setup. CM has been an active member on our board and speaks rotary fluently.

here's how my HD AI is fixtured...

the injectors (2, each delivers up to 700 CC per minute. i run 100% methanol)




the business end

the modules (HD-AI w boost control and AFR) need to be near manifold as you will note a boost pressure hose...


FJO AFR gauge w low alcohol LED and J&S timing retard

AI relay near battery

perfect pump location



howard coleman

Zero R

iTrader: (1)

Nevermind I am a total idiot sometimes

A7X

thats bad ***... i have heard of the FJO products

arghx

iTrader: (3)

So these are basically duty cycle controlled? In that screenshot at the top, is the map then rpm x pressure, and the number in the cells the duty cycle? or is it tuned by milliseconds of pulsewidth?

Howard Coleman

iTrader: (6)

the map is RPM across and load (vacuum/boost) vertical.

in each of the cells you enter the desired % of full delivery. notice at max torque i am at 100%. w my injector size (700 CC/Minute) that's 1400 CCs of methanol.

i run 2 850s and 2 1600s so my max gasoline base fuel is 4900 CCs. i have cut back on the base fuel and run the entire methanol delivery since it delivers higher octane and immense cooling. no knock.

FJO offers 4 different injector sizes, the largest being 900 CC/Min.

if you run water you use less injectant and could easily run one 500 CC/Min injector.

to directly answer the question... by setting % ontime you are setting the milliseconds.


hc

AHarada

iTrader: (25)

Another Outstanding post howard. I've probably learned more useful information from you alone than this entire forum.

I'm definitely going to give this a try in the very near future.