JayCar Electronics Fuel Computer

[Shuey]

Hey Crew,

I was flipping a few pages of the latest Jay Car Electronic's Catalogue and i noticed a kit that can be used to modified the fuel curve of injected cars... VERY cost effective little device... Has anyone seen one of these in action?

Here is an extract of it's description:

"Qty 1+ $79.95 Qty 5+ $71.95
Digital Fuel Adjuster
Ref: High Performance Electronic Project for Cars – Silicon Chip Publications.
This unit is a huge revolution in DIY automotive performance. It gives you the power to completely tune the air/fuel ratio throughout the entire load range, at 128 load points, providing incredible mapping resolution and brilliant drivability. It uses the Handheld Digital Controller – KC5386, so there is no need for a laptop, and it supports both static and real-time mapping. It can be used on 0-5V and 0-12V signals, so it is compatible with all voltage output airflow meters and MAP sensors. It can also be set to work with 0-1V signals, allowing modification of EGO sensor signals. This unit has been extensively tested on a wide range of cars including Subaru Impreza WRX and STi, Nissan 200SX, BMW 735i, Lexus LS400, and Nissan Maxima. Kit supplied with PCB, machined case, and all electronic components. Kit requires the Handheld Digital Controller – KC5386.

Any thoughts out there??? How about you KDog... ???

Notice the Lexus LS400 gets a mention...

Regards,

Shuey

 

[cribbj]

This is the kit that Julian Edgar of AutoSpeed helped develop. There were a few posts about it already on this forum. Search on the abbreviation DFA, and you'll probably find them.

Julian also just helped to develop another "interrupter" type device that sits between the ECU and a PWM operated output device, and allows you to retune the PWM output. Very handy for boost controllers, steering systems, water injection, etc. There's a writeup about it in this week's AutoSpeed.

John

 

[Zuffen]

Just so you're all aware.

We copped a big serve in Auto Speed as we "the self proclaimed Lexus experts" din't know the later LS400 didn't use frequency signals from the AFM.

Such is life. I guess we don't see too many real late model LS400's being modified.

I still read Auto Speed but naw I'm very carefull about commenting on it's contents.

 

[Shuey]

Hmm... Interesting stuff, huh???
I did the search as you recommended and had a good read.
I guess the upshot of those comments posted is that it is a very effective tool when used on the right application.
My understanding of piggyback signals is that it interupts the signal from it's source and tells the factory ECU a few lies in order to get a new effect. With this in mind, logic would suggest that the ECU would not try to go back to any factory settings because as far as it is concerned, it is running as it should be... correct me if I'm wrong here...
Ok, so the question, as far as the older type engines are concerned, is whether is will function with our older type AFM's, right???
Has anyone heard anything???

 

[Zuffen]

Shuey,

It won't work with our early 1UZ's.

The AFM we use is a Von Karman Vortex AFM. It works by causing a disturbance in the airflow going thru the AFM (the black bit hanging down from the top does that) and the turbulance (or vortices) cause a small mirror to vibrate. The mirror has a beam of light directed at it that is reflected and read by a light sensitive device. This sends the ECU a signal that varies the amount of turbulance. The frequency is a square wave that changes in length (or frequency) as the air flow changes.

Enough of that diatribe.

Let's just say it won't work on cars earlier than (I think) 1998.

Now when Julian reads this he willl know he taught us something.

 

[Shuey]

Well, there ya go... Real pitty that, cos i was real fired up to get one.
I have an Apexi S-AFC on my GTR Skyline and it works a treat. I figured for about 1/4 the price i could have done the same on my HiLux... oh well.
So... next question... is there a simple way of getting rid of the AFM and using something else whilst retaining the factory ECU???

 

[Shuey]

One more thing... If Julian is reading this... do you do a kit for the R32 GTR Skyline that adjusts the amount of torque to the front wheels...? I remember reading an article on it in an old Zoom magazine where you had put one together...

 

[Zuffen]

Shuey,

This is what you want.

http://www.performancemotorresearch.co.nz/

 

[Damien]

Shuey, check this out for adjusting the torque to the front wheels...

http://www.autospeed.com/cms/article.html?&A=0060

 

[Shuey]

Cheers Damien... I don't have a subcription to AutoSpeed, but from what I have read of the column it is the same as the Zoom magazine article... it was a series of articles that talk about Julian's previous car (Liberty) and it's cornering characteristics... then overcoming a few mechanically issues in the GTR... bleeding the hydralic lines etc... then crashing... then the rebuild... then the electronic adjuster that he researches, builds and develops... That's the electronic kit that I'm hoping to track down.

 

[SCV8]

I believe one could install a MAP sensor, and use the out put from that to run this inexpensive device.
It's all additional, and separate from the factory injection.
Finally, someone took the time to just make some nice kits, not rocket science, but takes time to get going when you're starting from scratch.

 

[hrforever]

Its been years since this thread's had any up-date and so was wondering if anyones tried or has been using one.

I had my Volvo conversion dyno'd on the weekend and discovered how rich the motor runs in standard tune so I'm now looking at a value for money piggy back system to improve things.

 

[sideshow]

motor only runs rich after 90 % or so throttle
ive had my 1uz tested with fuel air gauge and everywhere is perfect except for full throttle
same goes for 90% of jaaaappppp cars

these units are good for back yarders
ring around 50 professional dyno guys and see which ones use them
prob none

for afew hp gains they are prob ok
but i garantee u will never see them on a big budget build up

i have ideas about tricking the throttle signal to stop this running rich at full throttle but trying to find time to make a unit is hard

at end oif day nothing beats std toyota ecus
and to gain abit of hp u might stuff up the rest of the drivability
i guess its just for those guys who love their megasquirts and safcs
cant afford a motec or autronic but want to play with the tune