Blackscooby

This is also my worry, I've increase the boost to about 17PSI but have reservations about whether the fuel is increased as well.

I'm looking into fitting an APEX-i Fuel control module and a boost controller so I can map low and high boost settings.

I was hoping this would guard against lean running at higher boost levels.

Any views.

Thanks

Mark.

Trout

iTrader: (1)

Rob,

you don't say what kind of car you have...

...even with light breathing mods my own car (STi) would run very lean. The modifications that you are talking about, combining significantly improved breathing AND increased boost greatly increases the risk that the car will run lean.

There are a number of solutions - very basic ones include air/fuel regulators of varying sophistication that will enable a gross increase in fueling. The best ones are the same price as replacement ECUs however.

Other routes include piggyback ECUs such as Unichip, or complete replacements, Possum Link and increasingly popular the MoTEC. Unichip and Possum are around the same price, MoTEC is twice as much.

These approaches will give better control of fuel, but also boost and ignition - all key parts of the equation.

Enjoy.

R

Trout

iTrader: (1)

Sorry, just in case I wasn't clear - running lean consistently and on boost will cause the engine to detonate and ultimately a combination of blown piston rings, melted pistons, blown main bearings will occur.

Blackscooby

mmmmm blown piston.....

Sounds all too familar. That was last month!
Rather not do it again.

Mark.

RobJenks

Finally I will have a BPM exhaust and enlarged air intake pipe fitted today.
I also have the resonator removed , a K& N air filter fitted and boost increased via a bleed valve.
So inlet and exhaust sides of the engine are pretty well optimised.
Now here comes the rub - since air flow /volume /quantity will have increased substantially can I safely assume that fuel will be increased accordingly to ensure a proper and safe fuel/air ratio?
Or should I discard the bleed valve now and look at an after market ECU ?

MorayMackenzie

A properly mapped replacement or piggyback ECU would get the best from your car. A Unichip piggyback ecu would be a better bet than a bleed valve.

RobJenks

I have bit the bullet and invested in a Possum Link.
It appears the risk of an engine failure due to leaning out combined with high boost is just too real.
Another $1600 I have to find - cheaper than a rebuild though!

Trout

iTrader: (1)

Rob,

I'll map if for free, I would just need my travel expenses...

...no where's my sunscreen

Good choice - great improvement!

Rannoch

Sam Elassar

i think the fact you can tune your ecu with a small tuning module at any time is one of the best features. it is not a bad as i Ian makes it sound. you can never blow your engine up if you change things by one or two, changing one zone at the time. while watching your knock and lambda links. so it is pretty safe i would say. even the boost you can increase it by 0.25 psi increments.

also its a good foundation for your map learning. for future cars, maybe in my next car i will get a motec

sam

sam

CraigS

Asking this question might be under the wrong thread topic but I too have am purchasing the BPM large Inlet pipe. Adding to the upgrades I would like to undertake at the same time I am stuck at what engine management system to use.

Why is it some ECUs have 96 zones whilst others have 200?

I have researched most areas I have undertaken thoroughly but this still escapes me. Is it a case of more zones , the better the engine management system is? (of course taking into account all other features)

I would appreciate any input and having stumbled on this bullettin board makes me happy since I cant check the Australia WRX egroups list at the frantic rate it moves.


Craig Smith
Most upgrades been thoroughly researched but he needs help with the engine management side

Sam Elassar

hi craig
i think when it comes to ecu it really depends on what you want to achieve from it. i have got the Possum link ecu which is relatively cheap compared to the other more advanced ecu's like motec and the like. link does have its limitations in some areas. however at the end of the day it depends on the mapper !!!. so find yourself some well proven mapper and see what he recommends link,autotronics,motec etc.

another thing you may want to take into account is your mapping knowledge. i did not know any thing about mapping before i got my ecu. ( i still don't know much ) but at least i can recognise when i am running rich (eg in the summer ) and adjust the fuel, advance and boost accordingly so the car is running at its best in the summer and in the winter, and believe me 96 zones are enough !!

thats my experience anyways, maybe for my next car i will get a motec.

sam

Trout

iTrader: (1)

Craig,

to enumarate Sam's comments.

A Possum will enable you to adjust fuel in zones of 0.4bar.

A MoTEC will enable you to adjust fuel is zones of 0.1bar.

So MoTEC would seem to be better - it certainly has greater granualarity. HOWEVER they are different - the Possum has closed loop idle control as standard (MoTEC does not although it can be done), Possum has knock control (necessary due to the wide areas of fuel control), MoTEC does not - although a bad batch of fuel...

Possum can be tuned in the car, MoTEC needs a laptop.

So they are different, Possum is easy to use, relatively cheap and works well. MoTEC, more sophisticated, harder to use and in the RIGHT hands will give very good results.

Think about your tuning priorities - basicallty with MoTEC you may be able to squeeze and extra 2-3degs advance with the fine control that you get.

R

IWatkins

Craig,

MoTeC and Link have been mentioned but another option is the Unichip (I'm sure is available over in Aus).

It is cheaper than the Link (in UK anyway) and actually has more granualarity than the Link but less than the MoTeC.

Why is this granualarity important ? Well, lots would argue that it isn't but common sense says that the more fine control you have over the maps the better the end results. Of course, just how many load sites you need is open for debate for ever

However, the Unichip is not a full replacement ECU like the Link and MoTeC, it is known as a piggyback ECU. It splices into the loom between the engine and the OE ECU and modifies the signals coming in and going out of the main ECU with regards to fuelling and ignition.

Other difference between Unichip and the Link/MoTeC is that the Unichip has to be mapped by the installer and doesn't have any end-user mapping ability. I.e. you need to go back to the installer should you need it re-mapping or even any small changes. Many people see this as a downside, but I know I would have blown my car up by now if I had a Link or MoTeC (Can't stop fiddling with everything else, why would the ECU be any different).

Just another option....

All we need now is Pat to jump in and say "Pectal, go on, get a Pectal"

(We really need an ECU FAQ)

Cheers

Ian

Trout

iTrader: (1)

Just to add a footnote - the Link does have fewer load sites - leading to a less granular map - however it also has interpolation. This does not make up for fine mapping control - but does make the car very driveable with apparently big steps betweens load zones.

It is horses for courses - the Unichip 'fools' the ECU into 'seeing' the sensors differently - so you retain many of the things that the JECS provides for you. Although (I haven't checked this) in the UK a fellow scooby owner told me his Unichip set up was going to be around £700, so much in it with Link.

A 'full house' Link set up will cost around £1,000 (including Knock Link, Lambda Link and a mapping session).

R

CraigS

Thanking everyone for the response. One question that remains open is in regards to the "load points". Is it a case that EVERY load point is looked at and adjusted or do some tuners just do the bare minimum.. A good mapper would use all load points?

When does the amount of load points become tedious and get to a state of no real benefit?

Is interpolation program used different by certain manufacturers? or do they use a mathematical equation that everyone shares?

Could you hypothetically have a excellent interpolation program that requires only 10 load points?


Craig Smith
Asking questions that might appear stupid...