Knock Values On Pfc - Hot Day

[benl1981]

Just wondering if it is normal to get a bit of pre ignition on the base map.

I have 10psi, R34 cooler, exhaust.

Today being about 30+ degC thought I'd take 2 deg timing out on the hand controller. Under a bit of load saw knock of 39.. thought I'd take one more degree out (so -3 deg) and I saw 56 under load.

So I took -5 deg out and thats when I was almost home so didnt get to see the effect of this but looked ok.

I'm wondering if I should see to this before I get the dyno tune or is this normal??

I might replace the fuel filter on the weekend.

I am running 15deg BTDC on the CAS

Thanks

[benl1981]

someone must know pfcs are pretty common

Cheers

[benl1981]

anyone

Should I be doing an engine decarb? I did a small dose of Redex petrol treatment routed through a vacuum hose while engine is running to decarb it but I only used about 100ml if that - I heard to do full decarb you should use close to 500ml.

I got a lot of smoke for about 5 mins. Car seemed to pick up a bit of responsiveness...

Is it worth doing some more?

I was reading in some of Sydney kids posts that he doesnt have a problem on the base map with 98 octane. Most of the time the knock is low but every now and then I get higher than 30 which is worrying. I guess a 35 degC day is a test..

Edited December 7, 2005 by benl1981

[benl1981]

bump

[paulr33]

have had you had the powerfc tuned yet? sounds like you haven't if so then it just needs to be tuned correctly some spots (or even possibly one or two) are too high and knocking a little, you can simply keep backing out the timing each time you drive it (the value gets reset when u turn car off) or have it tuned properly.

[Sydneykid]

1. Just wondering if it is normal to get a bit of pre ignition on the base map. I have 10psi, R34 cooler, exhaust.

2. Today being about 30+ degC thought I'd take 2 deg timing out on the hand controller. Under a bit of load saw knock of 39.. thought I'd take one more degree out (so -3 deg) and I saw 56 under load.  So I took -5 deg out and thats when I was almost home so didnt get to see the effect of this but looked ok.

3 I'm wondering if I should see to this before I get the dyno tune or is this normal??

4. I might replace the fuel filter on the weekend.

5. I am running 15deg BTDC on the CAS

Thanks

Suggestions follow;

1. Yes, the standard mapping is set for 100 ron fuel, so it is not unusual to see a bit of knock. The defualt maps are there so you can drive the car to the dyno.

2. 2 or 3 degrees is nothing, you won't see much difference under 5 degrees, 10 degrees is not unusual.

3. You can, or add some octane booster or add some fuel. Personally I would just use the throttle to control the knock on the hot days

4. Won't help unless the current filter is blocked, but then it would knock on cold days as wel.

5. That's standard, no problems there

The bottom line, get it tuned.

cheers

Edited December 7, 2005 by Sydneykid

[benl1981]

Thanks guys. Yes I will get it tuned - just waiting for Dyno Dave.

Sounds like it isn't anything out of the ordinary just a few areas where the timing is a bit too far advanced. Maybe Dave will be able to stop the knock with a tune.

Sydneykid - am I right in thinking this isn't something I should see to before the tune. I just don't want the tune to be compromised due to knock occuring

[paulr33]

it should be ok, i had mine knocking for a week or so.

as long as the numebrs aren't high, try and keep them low.

dont floor it in the high load areas cos it will knock a lot, this is bad.

light throttle and low load should be *ok* but again best to get dynoed as soon as possible, no doubt your ecconomy will be fairly average too

[benl1981]

Paul - so yours knocked a bit on the base map?

I have set the rev limit to 5500rpm and don't thrash it too much. I've had it on the base map for about 2 months now. Economy is ok until you give it a bit then it goes out to about 13L/100kms pretty quick.

[paulr33]

yeah mine did, and its expected to. you should really get it tuned. 2 months is probably a bit long

[benl1981]

Called the tuner - might get it tuned next week

Hopefully it goes a bit harder aswell...

wonder if I will notice the difference. Running 10psi R34 SMIC, exhaust...

[paulr33]

with the stock maps i made about 150rwkw

my 172 was the first tune

then to 181 for the second retune (reset to defaults) - a year or so later

once its tuned you may want to dicuss having the light load / low cruise ign points tuned, again your tuner may already do this. most of the tune's ive seen are max power and afr's but don't touch light load / low cruise area's

[benl1981]

Did you do any more mods to go from 150rwkw to 172 rwkw. Was 150rwkw on the base map of the powerfc?

Then onto 180rwkw did you add mods?

So you picked up 22rwkw - thats pretty good. It already feels quicker than the std ECU. I think this tuner will tune light load/med load but will ask him about it.

[paulr33]

the change from 150 to 172rwkw was a tune of the powerfc.

max power tune, lean out afr's and up the timing. basically a "tune".

an hour or so on the dyno, and 172rwkw is done.

yeah 150rwkw was base maps, basically plug in the powerfc and dyno run.

however at 172rwkw my fuel pump was leaning out a little on 0.90bar (they tried it, not my idea to run that much). 180rwkw jump was a gtr33 fuel pump and thats it. complete retune as my previous tune was a bit wierd and it was quicker to start from scratch. im now on 192rwkw but this is on a different dyno so it doesnt really mean much.

as long as you keep going the same dyno it should be fine. then they are comparable. there is a massive massive difference once the ign points have been tuned, the response difference is amazing

[paulr33]

i had adjustable cam gear fitted that kept the vvt solenoid (custom made) and that made no extra power, in the factory position was the best power

[benl1981]

nice to hear. Just wondering if Im already getting some knock can they really gain much by adding the timing (Wont I get more knock). Or do you think they can increase advance at different areas and retard enough in other places to make it quicker overall and knock less than on the base map...

Will be nice if it feels quicker

Edited December 8, 2005 by benl1981

[paulr33]

yeah there will be some areas where its retarded and could be upped easily and no knock or minimal knocking. and there will be some cells that are too high currently. the load areas if you had a look at map trace will drive those points will be quite low and shouldnt knock much. again knock is basically a micrphone so driving conditions may give more knock also

[benl1981]

Yeah I've had a look at map trace and most of the time driving fills up all the low load cells. I find when I've been getting knock lately its around med throttle in 4th at about 3-4000rpm.

Or even 2/3rds throttle up to 90km/h revving to 4000rpm.