Lemmy

Is there anyone out there who has a 02, 03 or 04 Sti tuned to around 300 hp and fitted with a knocklink. Does yours show an occasional det spike (green, amber and red lights come on one after the other and then go off again all in a fraction of a second) between 5000 and 6000 rpm on WOT like mine? Use of optimax plus octane booster makes no difference to the knocklink activity.

My 02 STi is fitted with a sports cat exhaust system and an ecutek remap giving between 299hp and 319hp on different rolling roads. It has been in this state of tune for 18 months. I took it back to the tuner after I fitted the knocklink a few months ago and he said that it was operating as intended. If it wasn't then the engine would have failed by now. He went on to explain that the ecu changes the timing etc constantly so that the engine is generally on the point of det. What I have been observing with the det spike is the ecu changing the timing, the factory sensor then picking up the det and adjusting the timing accordingly. That is why I see just a spike. He even showed me the ecu doing this on Deltadash. The tuner did spend an hour checking out and improving the map using the latest version of the ecutek software, but I still get the occasional det spike between 5000 and 6000 rpm. Evidently this rev range is where the STi engines are most prone to det.

Although I understand the above explanation I still worry when I see the big red light come on for a fraction of a second.

Alan

JohnD

iTrader: (5)

I've seen just that on my 03STi PPP but not nesessarily on WOT. mine will do it on part throttle- albeit, probably 75%, accelerating in a high gear (5th or 6th) so the revs are well below the figures you state but boost is quite high. I VERY rarely use WOT! I'm about to change to a colder plug (7) to make things a little safer. I'm surprised there is no recommendation to do this with the PPP - have you replaced yours?
JohnD

marklemac

I get the same. Again usually around 75-80% throttle, not really on WOT (what does WOT stand for - I know it means full throttle)

My knocklink light up full for a micro second.....

Must admint, its not been so bad since fitting a bigger intercooler.

Gidney&Knowlesy

wide open throttle.....

Lemmy

Definately only get mine on WOT. I tried 75% throttle tonight on the way home from work, but no knocklink activity. I find that if I am in 3rd or 4th gear at 5000 rpm and then floor the accelerator I get the det spike sometimes twice between 5000 and 6000 rpm. Above 6000 rpm it is fine. Then if I lift to let the revs drop to 5000 rpm and try WOT again, no det spike. I am told this is the ecu learning and adjusting its temporary map.

Marklemac - what intercooler have you fitted and what difference has it made to the engine performance?

Alan

TonyBurns

iTrader: (3)

I drive a JDM MY03 STi, 300bhp 310+lbs of torque and pretty much standard (except the sti panel filter), run the car on optimax and millers ob, no such problems, im lucky to get a second green, let alone det (set on max sensitivity).
I feel you have need of going to another mapper and seeing if they can find anything wrong with your car, you probably wont find it on a rolling road as you dont get the same sort of pressures you do whilst out on the open roads, but it does sound pretty much like a det spike what sort of boost are you running??

Tony

Lemmy

Isn't your Scoob a Spec C which has a twin scroll turbo and therefore the ecu map will be different.

The mapper who did my car is very experienced (works for Ecutek) and therefore I would of thought knows what he is doing. When I took the car back he confirmed on the rolling road that the spike was indicating det, but didn't think it was a problem. If it was the engine would have blown by now

The max boost I have seen is 1.43 bar although it is generally around 1.25-1.35 bar.

Alan

BretMan

I get this on the odd occasion on my STI7 (scoobysport decat/ECUTEK). It mostly happens when the fuel gets low and its been sitting in the tank a week or more.

I'm guessing the octane rating drops a bit and causes DET. The ECU pulls timing and you can notice a flat spot between 5500 and 6200 rpm. When you put in a fresh tank of 98 Octane, it all goes back to normal - no DET and no flat spot.

My boost is around 1.35 bar max.

TonyBurns

iTrader: (3)

Yup it is but its also designed to run on 100/102 ron fuel so more seceptable to det (but they do run very rich )

Id say speak to Bob Rawle, you shouldnt be seeing any det, det will put strain on your engine, which whilst it may not cause an immediate failure, can cause a stress related failure later on in life (both you and the car ).
I am no expert but it sounds like your leaning out too much, thus your getting a spike, not good

Tony