Rown Hicks and Tom Bell on engine managment systems:

There was some negative comments, from Tom Bell, as this isn't a US product and no one can make anything outside of the (US hehehe just kidding Tom), his main beef was that the processor on board wasn't a 16bit processor (which I actually think it is) or something along those lines and that it could never do the same job as the stock computer. Or thats what I recall anyway. Fact is it can and it does.. the LINK computers are renowned for being a little rough down low driveability wise but I think thats the coarseness of the fuel mapping, and with a little tuning time will be pretty close to stock, sure it will never be the same as a stock unmodified TT, but neither will a JWT chip running big injectors. JWT chips are renowned for running rich infact it's not uncommon for JWT chips to be used in conjunction with an Apexi AFC to trim fuel out of the map (well thats not true but I'll get on to it). The biggest problem with a JWT chip is everytime you want to change something it costs, and it costs big time.. 

It is extremely uncommon in the US to fit fully programmable computers to cars, yet down under in just about every race car there is has an adjustable black box, and boy racers all round town fit programmable computers, just pick up your local Hot 4's mag.. You can buy a variety of systems, ranging from the "hack" MAS adjusters (Apexi AFC & HKS Vein Pressure converters) which "fool" the computer into seeing a different airflow than what is going into the engine (these black boxes sit between the Mass Airflow Sensor and the Computer).. consequently it's not a true adjustment as it's not fine enough and IMHO will not cater for Accel enrichment properly.. then it's on to the midrange systems such as the LINK, Microtech, 3D Wolf and Autronic, then upto the full monty high dollar systems such as the MOTEC M42 .. but you are PAYING..

So why am I always reffering to the LINK system ? Well it's the only one that I am aware of that has had it's internals specifically designed for a 300ZX, LINK have been, for some time now producing programmable computers, but a little different from the typical vein of producing a computer and you figure out how to wire it up (eg cut the loom and you actually wire the injector wires to the computer terminals), but LINK actually produces board replacements, so you open up your existing computer, take out the guts of your computer and replace with the new computer, then bolt it back uptogether. Much less painful. .... they took quite some time to get it right, as the 300 computer controls a lot more than just injector pulsing, it does things like telling the CAM timing when to kick in (kinda like Hondas VTEC),

Now whats the difference between the JWT and the link, simplistically, the JWT program has the MAP "hardcoded" into the EPROM, the LINK has these same values in the MAP which you can edit on the fly with a handcontroller.

Example (total fiction, just pulling numbers out of thin air):
In your grunter a "perfect" stoichometric a/f at Pressure 1.2 Bar Engine Revs 2000 is acheived with an injector pulsewidth of10ms (or whatever). Optimum power is acheived with a timing of 29deg BTDC This is specific to your engine because of your cams, your fuel, your compression ratio etc..

The JWT has the pulsewidth actually at 11ms and the timing at 28BTDC, so the JWT is not at the optimum. It's hardcoded, you can't do anything about it. You ring JWT and they tell you it works fine on every other car.

In the LINK on the other hand you pick up the handcontroller and dial up ZoneFuel 315 and enter the pulsewidth of 11, dialup ZoneIgnition and enter 29BTDC. Problem solved.
So what can you adjust in the LINK ? Everything you need too.. the CAM timing, you don't want it at 2000rpm, you want it later.. fine you can adjust it..

So whats better? Well if you're building up a car with known quantities, or you're not worried about squeezing every last drop out of it .. then the JWT/Sonic programs are the one for you. But if you're going for big turbos, big injectors, running it on special fuel, constantly playing about with it then get a programmable computer - as every new chip from JWT is going to cost you $$$, whereas on the LINK you just change a number.

The thing to bear in mind is with the LINK you need to dyno tune it everytime (unless you're willing or able to fiddle the numbers yourself which, for the sake of keeping your pistons in one piece, is best left to the professionals), which can end up costing you as much as a new JWT program... so that puts an interesting twist on things..

So yes you can adjust for a dual air intake, and theoretically all you do is halve everything in the map, but I'd do that one on the dyno :-) Better safe than holed pistons..

I am hoping to test out the LINK to see what it's really like, but I've been in a passenger seat in a 323 GTX which had a LINK and it behaved fine. Nothing untoward..

PPpppppphhhewwwww that was long.

Rowan Hick


From: "Bell, Tom" <thomas_bell@arvin.com>
Subject: RE: Chips [reply to Rowan's long e-mail]

With Rowan's opening line, how could I let this go by? Seems he takes after
the popular US comedy show Rowan & Martin's Laugh-In of some seasons back...

My point about computers for these cars is that, if the company doing the
work has not got the proper sequencing for the program, then the results
will make caca out of your engine. I did not imply, nor intend to imply,
that nobody does it correctly, or that it couldn't be done. Blitz and Link
are two companies who have been doing programmable boxes for 300Zx cars and
others for a long time - successfully. Jim Wolf's resident electronics
expert, Clark Steppler, did the same thing for the Nissan 300ZX race
computers a decade ago, when these ECU's were new and almost the state of
the art. And the 8 vs. 16 bit computer point is that the Nissan boxes were
8 bit controllers early, then went to 16 bits about 1994, AIR. No
intimation whether one was more capable than the other, just that they are
different, and they are not interchangeable.

Rowan is very right when he says that tuners in the US market very rarely
make a completely programmable engine controller. Our emissions laws make
it impossible for us as individuals to vary the parameters which regulate
our engine's operations. The manufacturers have begun to seal the brain
boxes so that they cannot be re-chipped, as JWT does for the older cars.
It's a Federal crime here to tamper with the emissions controls in this
country (many do anyway, such as gutting pre-and regular cat's). A sad day
for performance-minded people.

As for programming the computer on the fly, you could do so with the BLITZ
units as well. Nissan gives you some LIMITED capabilities here, using the
CONSULT units, but it would not permit you to alter parameters such as those
in Rowan's example. Other tuning can be done using a 'boost controller' or
other such secondary unit, but within the parameters of the engine's data
maps and programs. LINK and BLITZ do give you free rein - but I hope like
he## that you know what you're doing! Otherwise, Harvey will retire much
richer than he intends to from all the engine rebuilds he's going to do.

As a conservative car owner, I believe I'll opt for the longer life and
moderate gains achieved by the JWT ECU upgrades for now. Besides, I can
still kick a$$ with my Z, and haven't a burning desire for MORE POWER (yet).

Tom