Mappable ECU tuning

[DuncS3]

Right then, has anyone got experience of mappable ECUs, you know the ones that replace the motronic ECU and eliminates the need for a MAF etc?

I'd also like to know why or if you have/have not looked at this route Andy for your RS4 (since I take it you dont care about warranty [img]images/graemlins/grin.gif[/img])?

My thinking behind this is based on good input from Crafty and also taking the generic v custom remap further

Dunc [img]images/graemlins/s3addict.gif[/img]

[Joules]

I ran a GEMS for 18 months on a scooby. Good manners other than having to wait for the fuel pump to prime the system before starting... other features included...

Registered 1999(S) STiV (Version 5) Model Code GC8F4ED.

Details of Extras

* Full GEMS engine management system - Mapped by Steve Simpson

Dual switch selectable maps for 95 and 98 RON UK

Launch control/anti-lag system (switch control)

Shift change light

Optional centre diff control

ECU Does away with poor lambda sensor and air temp/flow sensor


Joules

[DuncS3]

Did you rate it as a system? Would you go down that route on your S4? What sort of approx. price did that cost you (if you dont think Im being rude asking)

Launch control - is that good fun?

Dunc [img]images/graemlins/s3addict.gif[/img]

[Joules]

Hi Dunc,

The launch/anti-lag is only a gimic really!!

If you used it for serious driving you would be likely to burn out the exhaust headers!!!!

Car park demos ONLY for spitting flames from the rear [img]images/graemlins/FIREdevil.gif[/img]

I would not consider the GEMS for the Audi. IMHO it is a fine system that was developed for race cars. It has been re-worked and worked fine on the scooby. However due to the mods on my scooby it never was a smooth runner. Rough idle and the odd starting. The audi is a far more refined piece of KIT and it just doesn't seem right to install the GEMS. Put another way ..imagine how much money AUDI spent developing the ECU/Code for the S4 specifically. Then imagine the money GEMS would have spent doing similar ??? simple answer they probably never did. I view the GEMS as being more generic controlling specific tasks i.e. Boost, A/R, Retardation etc etc... and smoothness is not the highest priority. Plus the mappers had vast experience of working on the Scooby... I don't have enough confidence in them doing the same job on an S4.... this is just my opinion and I know that the variables are the same. BUT a new engine/build on a Scooby versus S4 does not bare thinking about [img]images/graemlins/033102bad_1_prv.gif[/img]

Price is around £1600.....

(In any case for Scooby STi units orignating from Domestic roads in Japan I would always recommend a GEMS or MOTEC or LINK ecu to be installed by a reputable mapper)The latter det like mad on even 98 with a booster. If people say otherwise then they should get some det cans on and listen to their engine.... scary I assure you [img]images/graemlins/suicide.gif[/img]

Joules

[Crafty]

Anti-Lag is purely for showing off as Joules says. You don't really need it on a road car and can be damaging to turbo/downpipe if abused.
It is good though [img]images/graemlins/grin.gif[/img]

Launch is *very* useful on a 2wd car at the strip. Nothing to stop you using it on a 4wd car but TBH unless you are running *lots* of torque you shouldn't need it as you'd have to push the car hard to make all four wheels spin.

Imprezas can be awkward to get a decent idle on, mostly because people try to use the stock stepper motor which is a PITA as far as getting a decent idle goes. There are other ways to make the car idle nicely.

The biggest advantage of going mappable is the fact you'd then have a speed density system, i.e. load would be based on boost/vac rather than air metering. This makes a night and day difference to how the turbo spins up and the torque curve. You also have so much scope for further mods and exploiting these mods to the maximum by tweaking the map. Not sure about others but Autronic has built in correction for injectors, so say you mapped a car on a 270cc injector and decided to put 360cc ones in, rather than having to start from scratch you just tell it the new injector part number nad it adjusts the fuel map to suit. Needs checking of course, but takes alot of work out of it..

[Joules]

Year idle stepper!! that was what I was trying to think of. [img]images/graemlins/biggrin3.gif[/img]

Oh and the GEMS does allow trimming of each cylinder. GEMS key measure is the air temp into the throttle housing directly after the Intercooler.

Crafty what are your thoughts for this as a replacement to the stock ECU. Stock/Fast Road or Race/Track Day focused...IMHO the latter???

Joules

[Crafty]

Oh and the GEMS does allow trimming of each cylinder. GEMS key measure is the air temp into the throttle housing directly after the Intercooler.

Yup most systems use TPS, MAP for load, air temp is used for environment correction.

Crafty what are your thoughts for this as a replacement to the stock ECU. Stock/Fast Road or Race/Track Day focused...IMHO the latter???

All of the above really [img]images/graemlins/grin.gif[/img] although it costs more the advantages of speed denisty, the aux outputs, the adjustability for me outweighs the cost.. especially if you are going big power route.
As you say on the grey Imprezas its practically a necessity.

[Joules]

Yeah! but getting down to it ....would you have a replacement ECU on a mildy tuned S4 (Stage 1). I'm not keen???

Joules

[Crafty]

Sure, why not.
future proof against any more mods
no compromises, don't have to work around the OE system.
Buy the mapping software as well and YOU can check its running right & do extensive real time data logging
Its not "dead" money, unit could be taken to your next car.

Plus.. IMHO if its mapped right I reckon you'd get a better drive out of a speed density system, especially on acceleration..

[Joules]

Perhaps, I have no issues with the performance driving aspect of the replacement ECU... but the cruise and idle never seems as good.

Still.... i'll mull it over ....

Cheers,

Joules

[Crafty]

Joules, thats just down to how good the mapper is.

Remember Imprezas don't exactly idle well anyway! [img]images/graemlins/smile.gif[/img]
I'd abandon the stepper motor, there are other ways of getting an idle [img]images/graemlins/smile.gif[/img]

[Joules]

Remember Imprezas don't exactly idle well anyway! [img]images/graemlins/smile.gif[/img]

Ah! So true I'd forgotton...

That being the case we could do with hearing from someone who has had one of these on their AUDI??

Joules

[Andiroo]

Hey Dunc, totally reasonable question, and I have to say Crafty is spot on regarding the benefits of changing to an aftermarket ECU [img]images/graemlins/wink.gif[/img]

I will still be running the Motronic for the next few months. The development will then take it the Motec/Autronic (thanks Crafty [img]images/graemlins/wink.gif[/img]) route as I fully agree this is the way to go for maximum power and flexibility

The reason for the delay in going straight to Motec is that it supposedly has a complicated "front end", and I didnt want any initial delays. AmD are fully conversant with the Motronic, although admittedly the Motec is the ultimate route to go (££££££) - we will have to wait and see.

If I can get 520bhp ish [img]images/graemlins/tongue.gif[/img] with the Motronic, then it gives me another level to aim for before further compression ratio changes (with further possible gains)which I guess would definitely need a different ECU.

This is when we will start looking at the gearbox change (she will have over 60k miles and be out of warranty soon, so a smart change may be to go racing box - Getrag/Hewland maybe even sequential for almost the same cost as OEM [img]images/graemlins/smile.gif[/img]) and carbon fibre prop and driveshafts [img]images/graemlins/laugh.gif[/img]

Looked into Noz long and hard, unfortunately the only RS4 in the country (so far) has had the jets fitted in the wrong place - and this is by the leading expert in the UK [img]images/graemlins/crazy.gif[/img] Some of the US/Japan stuff is pretty cool, but most seem to be dry systems (just Noz and no fuel) so I'm waiting for someone to enlighten/convince me on this. After all it would be quite nice to bolt an extra 300bhp on just when you need it [img]images/graemlins/cool.gif[/img]

Seems to be the logical and sensible route to me anyway [img]images/graemlins/roflmao.gif[/img]

Andiroo

[Riz_RS4]

If I can get 520bhp ish

feck! thats monster performance! 0-62 in 4???? 200mph+???

Woooooooosh......... [img]images/graemlins/clap.gif[/img] [img]images/graemlins/s3addict.gif[/img] Maybe we can have another Northern meet once your beast is ready [img]images/graemlins/bowdown.gif[/img]

[Andiroo]

4.1 secs before she went in, so who knows [img]images/graemlins/1syellow1.gif[/img]

Andiroo