View Full Version : Detting for beginners

30th May 2000, 09:06
As many people know my car is detting on Powerstations rollers each time I run it.
The ECU has been interogated on a selectmonitor and no faults are reported - so I am not too optomisitic about subaru UK addressing the problem. I've got broquet so I can't see what the problem can be! http://bbs.22b.com/ubb/wink.gif
My question is, does anyone know if detting on a rolling road is indicative of a real problem in real world conditions? Ie when driving enthusiastically on an open road the engine benefits from a far greater airflow etc. also I have heard of instances where cars have not detted on PE's rollers but have on PS's - so is PS just putting too great an artificial load on?
I know it's probably a really stupid question, but I am just a really stupid guy http://bbs.22b.com/ubb/frown.gif .
I suppose I could answer the question by finding someone with detcans who fancies a blast around Essex - any takers?

30th May 2000, 09:41

sorry to see you car was not well on Saturday - mind you there seemed to be a few that had incomplete runs.

As I understand it, and I am sure that Bob or Mark will give a better answer than I will - detonation is load sensitive.

I also understand that Powerstation use a high load, even at higher revs - it is well known for some other facilities to wind-off the load at higher levels. (Does this explain the difference in peak power levels?)

Anyway, it may be that the load that the car sees on the PS road is like going up a very steep hill. So you will need to replicate this on the road.

Also the Select monitor will not read any knock events from memory after the event - knock retardation is part of the ECU function and is not a stored fault. Perhaps the LINK has something going for it after all (see Jonathan http://bbs.22b.com/ubb/wink.gif) as it stores the number of knock events recorded.

You will need to plug in the monitor as you do some power runs under high load to prove your case...

...or buy some Millars/Silkolene Pro Boost http://bbs.22b.com/ubb/wink.gif


30th May 2000, 09:53
FWIW. I'd much rather have my car tested/tuned/measured on a RR with a high load, simulating wind resistance/inclines etc. rather than low loads.

That way you can be more sure of having the car tuned for real-world application than simply rolling road figures.

30th May 2000, 12:36

Glad you could make it on Saturday... hope the rest of the weekend went ok to... http://bbs.22b.com/ubb/smile.gif

If det is a real problem on the road, where actual load is _greater_ but cooling is much better... water is cheaper than other octane boosters and you can get it at most petrol vendors, however "in the sticks" they are... so water injection might be worth considering... or maybe a replacement ecu... see what your warrantee says.

Or you could always arrange a convinient time to have the car detted to death, have the engine replaced under this wonderful warrantee thing... maybe this will get SUK's attention and give them an incentive to take your det problem seriously. http://bbs.22b.com/ubb/rolleyes.gif


30th May 2000, 18:16
Hi Chuckster!

You do seem to be running into problems with det at Powerstation..... probably due to the RPM slope they use. FWIW, if you're seeing det on the rollers, it will be far worse on an engine dyno.... anyway, back to the point....

Select Monitor will probably be most useful if out on the road. Just keep an eye on the amount of retard the ECU is applying to the ignition timing; any more than 0.5 degrees and you have problems! Of course this is a dynamic parameter, so you'de want to store it somewhere... perhaps a laptop, let me look into this (should be simple enough, famous last words!).

Broquet will cause subtle changes to the fuel, will help a bit, but if the ECU is still the Jap one, then you could have problems.... 97RON could be at the limit of its retardation safety zone....

Detting on the rollers can be indicative of real world problems... if you have similar conditions then you might expect similar results. With regard to detting on PowerStation's rollers but not PE's, well that would be down to the rate at which RPM is allowed to rise.... the slower it rises, the more time there is for heat to soak into the block and warm things up to the point where the charge temperature is getting too hot for the current amount of advance. Of the two, I'de far rather map on PS's rollers... after all you MIGHT be driving up a very steep hill some day and you really don't want det then!

With regard to running around Essex with det cans... OK, but I need to make up a set of det cans first. Hmmm, let me see, that should take all of about 10 minutes :)



30th May 2000, 19:53
Neither my or Richards 22Bs detted on Power Station's rollers. Get IM's position in writing http://bbs.22b.com/ubb/mad.gif

[This message has been edited by Anders (edited 30 May 2000).]

30th May 2000, 20:25
Tell me (or kick me) if I am wrong, but I was under the impression that Chuckster's car is a UK one and both Anders and Richard cars are Japs ?

If so, you would expect (all things being as expected) that Anders and Richards should be detting on the rollers or road (on 97RON) than Chucksters (on 97RON).

I would suggest that there is a real problem on Chuckster's car rather than just a fuel/rolling road use problem. The det was scattered at first then a very large (no det cans required) patch at around 4800rpm (IIRC).

Chuckster should really have SUK sort this out, sooner rather than later.

Of course, it could be something simple like a weak injector, semi-blocked fuel filter etc. there again, maybe not.....



31st May 2000, 07:05
Thanks for the feedback so far folks, I'm still waiting to see a dealer about it, darn work getting in the way at the moment http://bbs.22b.com/ubb/wink.gif . Hopefully get it looked at in the next week, meanwhile I've got the Escort 1.6L to get my kicks in, it too has aircon, alloys and a spoiler, so the driving experience should be similar http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/wink.gif .

31st May 2000, 15:05

Ian makes a good point - when my car was first diagnosed the main advice was to check fuel pressure - 'cause it may be that simple.