Knock Level Increase...hmmm

[NSNPWR]

i can understand both sides, i.e:

1. ash with more O2 = leaner & subsequent higher boost (does make logical sense)

2. nsnpwr that higher air temp will cause pinging (i have experienced this in the past)

1. The potential increase in boost from the cold dense air is what causes mixtures to lean out not the fact the air is cold/dense.

[aerofocker]

in this case it could be a combination of a cell with high advance hot weather and maybe not the finest fuel,all speculation till you, retard the timming on the hand controller and give it a blast,if the det goes away,its likely the det was not erroneous and somthing needs fairly prompt attention,700 bhp is a fair few ponies and the thing is always going to want to det at that power

[wolverine]

1. The potential increase in boost from the cold dense air is what causes mixtures to lean out not the fact the air is cold/dense.

How is the boost increasing with cold dense air?

[Marko R1]

1 thing we all know is that heat saps hp

[NSNPWR]

How is the boost increasing with cold dense air?

Do you doubt that this actually happens?.....

I do not know and will not pretend to know the physics of it but the most logical comparison I can make is a big laggy turbo equipped car using NOS on the start line to bring the turbo on boost...clearly there is a link between a cold, dense intake charge and the way a turbo responds to it.

Heres a quick Google search for you-

'overboost in cold air'

And some comments of various experiences in relation to cold air and effects on boost levels...

The weather is getting colder here in Cincinnati. I've noticed by hitting the peak button on my boost gauge I occasionally hit 17.5 psi. The car is stock, running Stage1 MickeyD tune. In warmer weather the car hits about 15.5-16 psi.

With absolutely no boost controller your boost pressure will vary with ambient temps too, as will how quickly it can build boost.

I have experienced the same variance with climate changes on multiple other cars with various turbos. I've had a few turbo cars.

Edited April 9, 2010 by NSNPWR

[NickR33]

1. The potential increase in boost from the cold dense air is what causes mixtures to lean out not the fact the air is cold/dense.

cold (therefore dense) air means for the same airflow you get more oxygen as the molecules are less excited (more packed into the same space)... which can take you into areas of your mapping not previously seen when it was tuned... which can lead to some cells needing correction... its not a big deal but is very common with cars tuned during the day in summer and then thrashed at night in colder weather

[Marko R1]

you are right NSNPWR - my peak boost is higher by about 1 or 2psi in winter than it is in summer (according to my blitz controller)

[NSNPWR]

What NickR33 wrote makes perfect sense aswell and corrects some of what I was actually trying to say.

This is why most tuners will leave some extra fuel in the map to allow for these sorts of variables...unless youre running mega $$$ Motec or similar ECUs which may have the ability to auto correct...?

Edited April 9, 2010 by NSNPWR

[R31Nismoid]

No, it actually says you are wrong when you say colder temps could not/should not affect. Seems now though you've started the backpedalling as more and more people post up as such.

Fact is colder air temps can without question have an effect which is what many people have now been telling you.

However when they produce their own experiences - you call them an idiot.

Top work champ.

Well, seems the man can never be wrong and when a few people disagree with something he says...in come the Vic Club members...lol.

I know I'm not wrong on this. I've seen it on my own car as you'll see below, and on others cars.

One of my closest friends is also a well respected tuner and we've had lengthy discussions on various issues over the years as generally he's on the mountain runs with me in his own cars.

However, what you are saying is that colder air temps should not pose a problem, factually that is incorrect and you are unwilling to be informed as such for whatever reason.

For cool, dense air to induce knock the tune must have been right on the edge as it was and unless the car is making more boost from the cooler air then I do not believe it would cause lean mixtures.

Ive never heard of anyone retuning for winter or cooler conditions (maybe adjusting boost controller) but I have for hot conditions for obvious reasons.

I've had similar issues up in Olinda (Mt Dandenong) on a 8-10 degree ambient outside temp.

Boost pressure was the same, there was no spiking etc etc.

I would get a random trigger (around 60 knock on the PFC) under max load in 3rd.

It was nothing more sinister than a couple of cells that needed adjusting. No body has said anything about retuning for winter

[Dani Boi]

I remember one time when my car knocked at 252. I was like oh shi. Got a picture somewhere haha

[R31Nismoid]

lol wtf...

Although that said i saw 200 myself once. But it was my own fault, smashed the limiter stupidly on a missed gear whilst on the 1/4 mile

[NSNPWR]

No, it actually says you are wrong when you say colder temps could not/should not affect. Seems now though you've started the backpedalling as more and more people post up as such.

Fact is colder air temps can without question have an effect which is what many people have now been telling you.

However when they produce their own experiences - you call them an idiot.

Top work champ.

1 person 1 comment...If im back pedalling then where do you stand??? Your original statement was that inlet temps were not as important a factor as ignition or fuel? And now? Lets not forget what you posted to begin with...

Air temp in terms of intake temps is not as important as the amount of the airs vs timing vs fuel etc.

Cold air is inevitably denser....meaning theyre directly related and equally important...

And I called your lover an idiot because what he said made no sense.

Better make an announcement to all turbo owners...beware of cold air....your car will ping....

I stand by what I was originally saying in that cold air can create an increase in boost which can lead to a lean mixture...if youre tuner has half a brain in his head then he wont tune to 12.5:1 and the cold air shouldnt pose a problem...

Edited April 9, 2010 by NSNPWR

[R31Nismoid]

Assuming for a sec Marko is running good boost control - your cold air point is now high and dry (again)... as boost pressure is now out of the equation from the get go.

I'm fairly certain ole mate does have decent boost control and i read it in a previous post. (but CBFd trolling through posts to find it)

I mean come on, you don't build a 20k setup, 400rwkw and skimp on boost control now do you?

As i said, it's not as important. The issue is highlighted by the cooler air (potentially), however it is DUE to the timing/fuel etc.

If the tune didn't potentially have a wayward cell or two then the air would not be a factor in anything as there would be no PING!

[wolverine]

We seem to have gone around in a circle.

The original statement that

Cooler denser air = less prone to det....

has changed to

cold air can create an increase in boost which can lead to a lean mixture

So we agree that cooler air can cause detonation (even if the reasons are not agreed upon).

The fix is finding which cells are recording higher readings on the knock sensor and pulling some timing.

Can we close the thread until Marko has fixed the issue before someone pops a vein.

[paulr33]

cooler air can cause detonation???????????????????? what on earth??????????????????????????

not a million years

[skylinecouple]

My God but I miss the forums sometimes. This reminds me of my youth when I used to have a 56 Chev and a big block. There would be 20 of us standng around in the Shell garage at two in the morning arguing over anything from cams to carbs or does Mickey Thompson really exist. "ALL" the factors mentioned have an impact on tuning, cold, hot, or dense air. Cold, hot or dense fuel. What pistons or cams or ignition system one uses. Every engine is different and should be tuned as such. As the engine is broken in or accumulates the K's it will need a change in it's tune, it' OK, your both right.

[Marko R1]

Assuming for a sec Marko is running good boost control - your cold air point is now high and dry (again)... as boost pressure is now out of the equation from the get go.

I'm fairly certain ole mate does have decent boost control and i read it in a previous post. (but CBFd trolling through posts to find it)

I mean come on, you don't build a 20k setup, 400rwkw and skimp on boost control now do you?

As i said, it's not as important. The issue is highlighted by the cooler air (potentially), however it is DUE to the timing/fuel etc.

If the tune didn't potentially have a wayward cell or two then the air would not be a factor in anything as there would be no PING!

i run the blitz dsbc (dual solenoid) which is a very good controller

the colour display is pretty cool as well

[NSNPWR]

Assuming for a sec Marko is running good boost control - your cold air point is now high and dry (again)... as boost pressure is now out of the equation from the get go.

Excuse me good sir, but...

you are right NSNPWR - my peak boost is higher by about 1 or 2psi in winter than it is in summer (according to my blitz controller)

[Marko R1]

quick update guys.

spoke to my tuner this morning...his synopsis is that it could be valve train, piston slap or genuine knock due to fuel quality – he needs to go thru the motions to rectify which is booked for next week.

[R.3.2.G.T.R]

hope its nothing serious, my knock level is also ranging from 10 (idle) to over 60 at times at WOT, had the dyno + road tuned and conclusion was non-engine noise being picked up although I will be getting 2nd opinion

my clutch also upon engagment is noisy and i get spikes when moving car from stationary