Having read of others concerns over the ECU settings for the STi 5, I thought that it would be wise to get mine checked out.
I took the car to Power Engineering in Uxbridge and got David Power to check the fueling / ignition timing etc.
Power Engineering have a very sophisticated piece of software that plugs into the diagnostic system and monitors every sensor that the ECU reads. This, I understand, cost Power Engineering in excess of £2,000 but the results are outstanding. My car was tested on the rolling road and at peak torque the car has timing of 31 degrees. The STi4 at similar peak torque is about 25-26. This produces detonation (pinking or knocking) and is obviously a weak point in the standard settings of the ECU. From the software we could see that knocking was being detected and was going off the scale. Until such time as Power Engineering fully develop the re-programmed ECU, so that the car can run on 95 and 98 RON fuel safely, I feel it is advisable to run the car with an octane booster. You probably won't experience much in the way of problems unless you take your car on a track day where the excessive heat and higher revs can produce problems but, better safe than sorry. My thanks must go to David Power for helping me diagnose the problems that my car was experiencing in terms of fuelling. I would recommend that any owner with an STi5 visit Power Engineering and get David to check their car over to make sure that it is running within safe parameters (£40 well spent).

Power Engineering 01895 46 46 46.

Kind regards

Tim

Tim,

Very interesting post. Sorry but I have a lot of q's! I'm sure the answers will interest a large number of people though.

I guess the software you refer to is a version of the Select Monitor which will cope with the WRX and STi variants.

Did you notice any problems with the car before or was your concern based purely on other cars probs? If you did - I think we'd all like to know what the symptoms were.

What fuel have you been running regularly?
What did you run on the day of the test?

Over what rev range did you see the knocking? You say that you saw it at peak torque - which on the StiV is between 3800 to 4200 revs - so are we to assume no reving above 3800 revs! Or is it the case that the ECU was detecting and preventing the knocking - by retarding the ignition for example.
But that raises another q! I thought that the point of the ecu was to gain max performance from any fuel ie doesn't this mean that the ECU advances the timing to just before the knock point at all times. In other words is it not just normal operation for the engine to behave as you described it?

Incidently does David think that the ECU is set up correctly for 100 RON fuel. If the Japanese market is seeing similar probs with their fuel then maybe STi will modify their ECU. I know this won't help existing owners like yourself - but maybe those still sitting on the fence (like me) will have an excuse to stay on a while longer. Or at least have a reason to get down on the right (STiV) side ;-).

Previous posts have talked about fuelling problems in terms of the ECU starving the engine of fuel in the high rev range 7000ish and above I think. Is this a different and unrelated problem to the timing problem that you saw?

As you can probably tell I'm out of my depth here. I'm more than happy for yourself or someone to explain ;-).

Did David recommend an Octane Booster?

There was a thread on here some time ago - but I think it was inconclusive about what would be safe and not.

Can't think of any more - over to someone else ;-)

Ricky T.

Ricky,
Thanks for your reply.
Let me try and answer your questions, one by one.....

The software that David Power used to check the outputs from the sensors around my car is called OBD2 (On-board Diagnostic 2). This plugs into the cars cicuitry under the steering column and is world standardised.

I hadn't noticed any problems with the car (but then I haven't taken it on a track day yet!) and my desire to have Power Engineering check it over was due to other STi 5 owners having problems. I was also keen to see the BHP and Torque figures for my car, as it is running a Scoobysport downpipe, back-box and RAM air filter.

I have always run the car on Super Plus Unleaded (98 RON), usually from ESSO. On the day of testing I was also running 1.5% Octane booster (Silkolene Pro Boost).
RESULTS : 304 BHP @ 7220 rpm and 273 lb/ft @ 3800 rpm.

The rev range that knocking was detected was between 6000 and 8000 rpm. ( at peak torque of 3800 rpm the ignition timing was at 31 degrees - obviously a problem, but detonation wasn't occuring until you got over 6000rpm)
The main reason for my car detonating more than an STi 5 does at these higher revs was because the oil from my RAM air filter had been sucked into the "hot-wire" air flow sensor and contaminated it. This was then giving an incorrect reading to the ECU and the CO levels for my car were at 4% between 6000 rpm - 8000 rpm. Any healthy car should run about 7% at these revs.
After the sensor was removed and cleaned and a replacement K&N panel air filter installed, all was back to how it should be (7% CO between 6000 - 8000 rpm).
Without Power Engineering helping me detect these problems I would never have known until it was too late!!
I strongly suggest all WRX & STi owners get in touch with David Power and get their cars checked over!
NB : Do NOT use a RAM air filter in a Subaru - they can screw up the air flow meter and there have been reports of them being sucked through the air box, into the inlet tract!!
Use a K&N or ITG instead.

I am not sure if Subaru Japan are improving the ECU in the WRX and STi, but if the do so it will still probably be set up for 100 RON fuel.
I will be first in the queue for the David Power re-mapped ECU (this should be ready in about 6 weeks time).
You will be able to have a choice of three upgrades : for the car to run standard 280 BHP on either 95 RON or 98 RON, or have the ECU re-mapped to give you +30 BHP and +40 lb/ft, safely! - You can guess which one I'll be going for!! - The cost of these upgrades will be £650.

You mentionned that other cars had shown a lack of fuelling at higher revs - this again could be due to problems with the air flow sensor. Check those sodding RAM air filters!!

Yes, David did recommend running on the octane booster, until the ECU upgrades are ready.
I use Silkloene Pro Boost at 1.5% .

Hope this is of help. If any one needs to talk to me directly they can reach me on : 0956 370340.

Best regards,

Tim King

Tim,

More info from you and more q's from me!

When you say-

'The rev range that knocking was detected was between 6000 and 8000 rpm. ( at peak torque of 3800 rpm the ignition timing was at 31 degrees - obviously a problem, but detonation wasn't occuring until you got over 6000rpm)'

I'm not clear on the link between the timing of 31 degrees at 3800 and the knocking at >6000 rpm - please explain?

Why is 31 degrees obviously a problem? Is it ok if you use 100 RON or are we saying that STi have made a fundamental error here which will show up in the Japanese market?

Davids ECU u/gs sound interesting - I'll contact him direct.

How do you think the remapped ecu will affect your insurance - have you spoken to them yet?

Ricky T.

Hi Tim

Thank you I will take my car down to P.E and spend £40.00 sound like moneywell spent.Post results ASAP

Cheers

Saj

Saj

Your motor pinks above 3000 rpm so save your money. Here's hoping for a cold summer.

Seriously, hope it goes well. We have checked a number of times for weak fueling, but the way it bangs and pops, I think you've a good one. But I would say that.

Jonathan

ex S3 WRC. Saj tinted mobile, plus lots more mods http://bbs.sidc.co.uk/smile.gif now.

To clear up a liitle more.

Tim had a superchip fitted on his first visit and the recorded detonation was so bad that it was outside of the control of the ECU. ie. the ECI was adding 10 degrees of retard but still it was detting like mad. We removed the offending (offensive) article.

The car still showed signs of det at peak torque and other areas in the mapping. It was also very lean on full load (rare fault).

He used the car not too hard for a few days and brought it back. Then the det was not showing at peak torque but higher up (just as dangerous) it was still detting even with 98 and octane booster.

Although it was showing det it was within the scope of the control function within the knock software, but it was still reducing timing by up to 4 degrees which means you are relying on the knock sensor to stop engine failure.

The mapping on the 5 is quite different from the 4/3 and is simply not suitable for UK fuel. Although Jap fuel is 100RON it is more complex than 2 points on the octane scale. Subaru have mapped this car to 100% perfection with very little room for safety even on 100RON fuel. that is the nature of development, you keep making it better, lighter, faster, until it breaks then you fix it. I think this is just evolution mapping from Japan.

Just to warn you, knock sensors are not perfect, nnor is knock detection software. We had an STi5 in the following day from Tim and it had audible knocking and nothing at all was recorded by the ECU, not a thing.

We are working hard to sort this for everyone, we are as keen as you, we do not want this car getting a name for problems, I expect to be going to Japan next week or 10 days for further testing.

Thanks for the update David.

Looks like I'll be on the fence for a while yet ;-).

Ricky T.

I get my new STi Ver5 on MOnday...Now what do I do ...CRY ??

Clive just enjoy and use your right foot progressively;0.

Woah boys - let's not spread hysteria here. Clive, don't worry, you've bought the best Impreza to leave Fuju Heavy Industries (trust me, I've driven a few). Yes, the car does have a mapping problem, but only when used to it's absolute extreme - my piston picked up after a heavy trackday, where I had been attempting to keep up with Darren Soothill (Type R, Leda suspension, Brembo brakes, slick tyres), but it would never happen on the road, at least, not the way I drive the thing, letting the torque do the work, short-shifting and rarely using the engine above 5,500rpm. The thing's awesome grunt permits very rapid progress in this fashion.

So, run it on SUL, a bit of octane booster if you're going to give it a good howling, and get the ECY upgrade as and when PE have finished developing it. And ENJOY, you've bought the best beast in the business ! (And don't take too much heed of "three cars a year Jonathan, he'll be slagging off the RB5 by October!")
PS Would you believe, RB himself is having to pay (cost of course, £14K-ish) for his one!

Imagine a MAP utlised by a Possum Bourne that plugs straight in to the wrx and your aie/fuel ratios are correct. Your inginiton timing is correct and you gain huge torque and HP.No fuel programming required it is already encoded.
Not promoting just imagining?


Greg

Greg,
No cryptics, how much?

Craig

Greg,

Can Possum Bourne provide a MAP utlised by the STi, WRX and UK models that plugs straight in to the car and your aie/fuel ratios are correct. Your inginiton timing is correct and you have NO change to torque
and HP.

This will be of interest to those whose insurance is already high and don't need an increase based on mods which improve performance.

Ricky T

Thanks for the speedy replies.. I can sleep again... But which octane booster to buy as I hear some can cause more problems with the sensors than they are worth ....??? and wher to buy it !! In London or Hertfordshire ??

OK Guys,

I had my Sti V in to Power Engineering on Saturday to have the det checked out. At 3800 revs I got knock correction of only 2.5 degrees, which quickly reduced to 1 degree, for most of the time the knock correction graph was flat.

Along side this, Mervyn pointed out that I was running with a very rich mixture (which explains all the popping and banging from the SS Backbox) and there was plenty of O2 (ITG Filter).

The car was producing 295BHP max and 265LBS/ft @3800 revs, with slightly reduced boost than most sti V's (havn't got a figure for this, sorry). Not bad in my book, very hot dry day, only got an SS backbox and ITG filter, can't wait to get the SS downpipe !

Are we getting slightly hysterical about this mapping thing. Only one Sti V has let go, and that was in extreme conditions.

I've got no worries about driving my car through the rev range on a day to day basis and don't feel there is an immediate need for the PE remap.

I hope this info helps all you worried people out there.

Cheers,

Dave.

I can go back to sleep now.....

er.......... sorry guys got lost

STI V gotta go for the extension (booooooooooooooooooring story)
in 48 hours, going to try to get some decent times (unlikely since I can't drive cars for toffee) at Folembray
lockyear tell me "it's one of the good'uns" and I want to keep it that way unteil I sell it.

so please, easy guidance:

1) octane booster? Y/N if Y, what?
2) back off at 5000rpm Y/N (please say no)
3) buy french "sans plomb super"? a better bet than UK nonsense?
4) get so worried about this blowing uo thingy that I go around the whole track at 30mph?

aaaaaaaaaaaaarghhhhhhhhh

PS it goes like sh*t at the mo and I wanna carry on if at all possible
4)

BPM, correct me if I'm wrong, but doesn't Possum Bourne use a 98 Impreza, and the problems here relate to the 99MY? PE have said that the ECU for 99 is completely different (and therefore mapping etc!)