full management or piggy back??

[Guest lixid]

is there any piggy back has most the function as a full management system has (power fc)??

i am not aiming for any extreme big power. i just want to bring out the full potential that my mods so far...(fmic, boost controller, air filter, and exhaust) and stay as it is and run safe.. so do i really need a full management replaced??

or just a piggy back will do... as i don't want to spend too much...

any good suggesttions??

[d0p3y]

I was reading up on this the other day.. In High Performance Imports Magazine. Since i'm bored, i'll type out the article for you:

Article title: "R33 Tune"

Magazine: "High Performance Imports #21"

Page: 29

Story by: Martin Donnon

"There is a fair wad of power locked inside the R33 Engine-management system. We show you one way of getting your hands on it."

With the increasing popularity of the R33 Gts25t Skyline in australia, isses surrounding the tunring of these cars are becoming more prevalent. Where once it was almost accepted that these cars ran a little on the rich side and suffered from detonation with anything more than 12psi boost, the quest for further development has pushed the envelope further. Initially thought of as being nothing more than an RB20 with some extra capacity and some fancy valve timing, the RB25DET is now starting to show it's true potential.

Background

One key factor that has held back the development of the R33 GTS25t has been its lack of 'tunability'. Featuring a sealed computer with no form of adjustment possible(at least without chasing a Japanese daughterboard upgrade), most tuners have simply worked around the stock programming. If the engine pinged at more than 13psi of boost, the answer was usually to set the boost at 12psi and leave it at that.

Another concern has been the fuel-injector sizing on the RB25DET. It's not that the factory ones are too small for most applications, its just that the bigger than stock sizes that fit in the factory rail are extremely expensive. How does around $1800 for a set of six injectors sound? It's no wonder that there aren't too many who push these engines beyond their squirters 215 rear wheel killowatt limit. There is always the option of fabricating a complete fuel-rail assembly and using conventional bosch style injectors, but the engineering and expense involved here will be similar.

Turbochargers, too, have been an issue with these engineswith the stock device being capable of a smidgen over 200 killowatts at the wheels before needing modification. Being such a capable performer, and sporting ball bearing internals from the factory there has been some resistance to changing the turbocharger to something totally different (most simple stick with conventional high-flow items). All of these issues have conspired to keep the power output of the RB25DET engines in check, and to keep many R33 GTS25t Skyline in a stock state of engine tune.

Tuning Issues

As Delivered from the factory the RB25DET engine found in the R33 runs extremely rich. Not at idle, or cruise, where the oxygen sensor takes charge, but at wide open throttle where power production is at it's peak. There are several possible reasons for this though 'incorrect tuning by the nissan engineers" is the least feasable.

Most of the reasons would ventre on the engine maintaining a given exhaust valve temperate under extreme load condition, and the thermal control of the combustion process. Put in laymens terms, the additional fuel is more than likely added to stave off detonation when the cars are held flat out for long periods of time.

Ignition Timing control is also an issue with some near stock cars displaying an amazing propensity for detonation, even on the current brew of 98 octane fuels. The ignition timing curve of these engines isnt particulatly smooth and progressive either giving a distinct hump in the power curve which emerges once the engine revs rise past 5000 or so. For a while it was beleived that the stock boost control caused this surge in the power curve, but experimentation with boost controllers has pointed back in the direction of the factory mapping.

Potential Fixes

One sure-fire way of reducing the full throttle fuel mixture and gaining additional power on the RB25 has been via the fitment of a conventional fuel-cut defender. Being nothing more than a voltage clamp that stops the airflow meter from reading full voltage power at high boost pressures, the types of power gains you can get from the fitment of a fuel cut defender have their own drawbacks. The least reaslised of these is the effect the units have on the overall ignition timing. As the voltage clamp is lowered to reduce the amount of fuel on boost, the reported load signal to the engine management system is also altered. Not onl does the fuel map look up move to a lower load point, (yes, less fuel), but so does the ignition-timing map look-up.

The result is that, by optimiting the air/fuel ratios the engine is moved closer to its detination threshold. Whilst his may work fine when setting up the fuel cut defender on the dyno, there is no disputing that a hot day and some heavy boost application could cause serious damage. Fuel-cut defenders are best used for their intended purpose of removing the facotry boost cut and are best set conservatively.

Total Control

Getting the best from an RB25DET involves a total change of management system. Forget about the add-ons and patch up jobsm they are only of limited value since its the basic structure of the factory software thats less than optimum from a performance viewpoint. The management choices for the RB25DET engine are diverse with most, if not all, good aftermarket management systems able to interface directly to the Nissan crank trigger arangement.

How you achieve a properly tuned result is up to you. Personally i'd have trouble going past the Power FC from A'pexi, for two reasons: It plugs straight into the standard computers connector, and it contains a base map ready to fire up and run the engine instantly. Thats right - No mess, no fuss, just plug it in and turn the key. You don't want to leave it like that though, as the stock maps contained in the Power FC aren't ideal, with the fuel setting still erring strongly towards the "over-rich" side of the scale.

The improvement from this simple fitment - without touching anything else - is quite astronomical. The same boost pressure, the same temperature, the same day (infact both runs were only minutes apart) we gained something in order of 30kw at the wheels before the tuning process even began. Even a quick glance at the comparitive dyno graph will show the new and improved shape of the power curve. While that may be enough for some, the question for us was how much more would tuning improve the engine over the base FC settings?

Surprisingly, this particular car showed very little sensitivity to changes in the air/fuel ratio. Clouding black smoke towards the top of the rev range in stock form, we would've figured that getting the ratios back to somethign sensible would result in a worthwhile improvement. It did, but not as much as we thought with a peak gain of 11kW being recorded right at the top end of the power scale. We tried various settings, both richer and leaner, yet ended up with a air/fuel ratio of apprixmately 11.8:1 flat out giving the best results.

Setting the boost to 1.0bar and fractionally retarding the fuel-load ignition timing resulted in a final figure or some 202kW@ the rear wheels representing a total power gain of the stock management at 0.8 bar. There is also the massive gain in real-world on-road performance with the R33 coming alive in stark compatison to its previously sluggish ersponse. Whether you decided to go down the A'pexi path to nirvana or wish to fit a management system of your choise, the basic fact of the matter is simple; before doing too much to your R33 GTS35t, change the management system.

So there you go.. Power FC is probrably your best option.

Ryan

(p.s. i have rsi now haha)

[MaTBoY]

ryan has tooooooo much time on his hands!

[two40]

Originally posted by [ryan]

So there you go.. Power FC is probrably your best option.

Ryan

i could have told you that and saved you half an hour's worth of typing. :uh-huh:

[rev210]

e-manage has been used on some big Horsepower cars in japan. $415 from nengun's site, will give basic S-AFC features in this form. The optional software increases it to tune fuel and ignition maps and other things.

[PVL-747]

go microtech all the way or even Motec

[Guest Impul 25T]

Why not an HKS F-conV??

Used with std ecu...... a lot of high HP GTR's in Japan are using this set up..... I know of one near home running close to 650hp, running this setup.

[PVL-747]

simple, we make the best computers! period. the HKS car doesn't use a HKS computer.