john banks

Si there comes a point where you just end up retarding the ignition and throwing in fuel and the cause is excessive boost for the situation. We found this to be about 1.4 bar on the road on Hoppy's car (which has uprated TD04 and top mount). In addition exhaust manifolds can sometimes affect ECU knock correction, and the 99/00 ECUs also seem a bit deaf to transient det which can happen on track - I don't like any det at all, but arguably some transient det is acceptable.

SiHethers

Thanks John

This may be a stupid question but is there varying degrees of pre-ignition from pinking through knock to full detonation or is it all the same thing.

Would seeing -0.5 to -1.0 degrees of knock correction at max boost be deemed dangerous or excessive? A lot of questions I know but holed pistons etc sound a tad expensive.

Si

john banks

Si, I keep my understanding on this one as simple as I can... basically as I understand it there are two types of detonation I am interested in...

1. Transient detonation

This is one or a few metallic sounding clinks of varying volume that ends abruptly

2. Detonation

This is a more continuous drilling sort of sounds which does not always end abruptly or when you take your foot off the gas

I have often heard 1 when finding the limit mapping a car. A knocklink will usually flash up suddenly to the 2nd orange or red and come down again. I usually set the fuelling and boost first and start with a conservative timing map. Then I advance the timing to find the edge. Information to find the edge is based on listening to the engine through a knocklink sensor attached to the mic in on my laptop, watching a knocklink, listening with naked ear, looking at ECU knock correction depending on circumstances. I then back off the timing for the safety margin, which depends on how the car will be used and also how competent the ECU is at knock correction.

I have only ever heard 2 on my car when fuelling was inappropriate with overboost and far too much advance. I never want to hear it again! I have found that the biggest cure for det on my car was mapping with a wideband lambda.

Maybe I am tame in just mapping around transitional det, but the knocklink and the earphones are more sparkly around this point, so I back off from there. I gather transitional det can be considered acceptable on some cars, but I just hate the sound of it. I can usually hear it naked ear if the knocklink shows 2nd orange - at least on my car. You can sometimes even hear it on track with a helmet on, but not if you have music on.

As well as changing the map, you can get rid of det by reducing exhaust back pressure, cooling the charge, cleaning up the intake of oil, broquets, increased octane, fuel additives, water injection, correct fuel pressure etc.

I have seen cars running 1 degree of negative knock correction, but they are still detting. The only thing to trust is a microphone on the engine block with ideally headphones to setup a knocklink, but the second best is a knocklink which is tested and working with a well sited sensor on maximum sensitivity. Get the idea of what happens at low boost first and then look if it is any different at higher boost. So I can't really answer whether your car is safe... better that it is running some knock correction in a way because at least your ECU is hearing something, but whether that is det and whether the response is appropriate should be checked out if you have extensive mods or suspect a fault.

The other method for mapping which I have found quite useful is to run at either higher boost or lower octane and find the timing limit. Then turn the boost down for safety margin or always use better octane. As it is when I put 97 RON in my car it audibly dets, when I use Optimax it is silent through headphones, so I can't be too far off the pace on timing. Does mean I drive out of my way to get Optimax, and I would turn it down a bit more for the track - I would throw in 0.5 AFR points, knock off a few degrees and drop the boost by 1-2 PSI compared with road use, AND use octane booster. Call me paranoid if you will, but you have to do several little things to make an on-edge road car safe on the track and not worry about it and enjoy driving it. In my case it will still torque steer everywhere with a conservative map Maybe that is a bad thing and actually I need some coilovers

[Edited by john banks - 12/9/2002 6:35:37 PM]

Hoppy

Thanks John

Si, I've just got in from a run as I wanted to see what boost I was getting as it's brass monkeys today - garden thermometer says below 2 degs C

At 4000rpm in top, gauge snaps straight up to 1.35 bar and holds. No peak at all. KnockLink quiet (and it's set on max sensitivity).

Richard.

R19KET

John,

"and I would turn it down a bit more for the track - I would throw in 0.5 AFR points, knock off a few degrees and drop the boost by 1-2 PSI compared with road use, AND use octane booster. Call me paranoid if you will,"

John you ARE paranoid

Mark.

john banks

Like everything it has its place at a price point But a proper FMIC is a different kettle of fish (or air?)

SiHethers

Cheers Richard, warning gratefully received.

That'll explain why I don't understand half the stuff you lot are on about, yet.

When should I start applying for new credit cards then?

Si

R19KET

John,

"Why do you think I need all this straight line performance"

It's ok, Alan told me about your driving prowess :P

Now you know why I need my engine !!!!!!!

Mark.

MorayMackenzie

But Mark, surely you are more interested in Lateral Performance?

EvilBevel

Mark, if that is how it works... can you advice me on a cheap, say, 900 BHP setup

R19KET

Theo,

Sure, mail me............

Mark.

pat

Theo,

watch this space... 900 BHP is possible, but you're talking very serious money at this point. To give you an idea, consider that the crankshaft alone will cost between UKP 2000 and 3000 It will need to rev to about 8000 RPM and run 2.35 to 2.5 bar up there to get your 900 BHP....

Like the man from Lateral Performance says, give him a bell, but please make sure that you're sat down at the time

Cheers,

Pat. ( who's speccing up a "lazy" 600 BHP engine )

R19KET

Theo,

To even contemplate this, it would help, if like Pat, you had....

1) At some point in your like, suffered a massive blow to the head

2) Have an inate ability to come up with "wacky ideas".....

3) Tread a fine line between being very bright, and totally insane..

4) Suffer from short term memory loss, and forget the whole idea...


I would just like to say that I have been involved in many discussions with Pat about this project, both in my capacity as a friend, supplier, and partner in crime. My advice has always been the same.........

Pat is in serious need of medical help

Mark.

[Edited by R19KET - 12/13/2002 4:43:53 PM]

Pete Croney

LMAO at Mark

Mark even more so today. He has serious belly rot and is more in need of a vet than a doctor

EvilBevel

mutant_matt

Pete,

That was more information than we required thank you very much!!

Matt

wacky.banana

Congratulations Tim.

WB

Tim Taylor

BL

Tim

As you can see in my other post im planning on going ecutek as well.

Whats been done to your scoob.?? Looks very impressive (im jelous)

How does the car perform with ecutek in terms of fuel economy??

Tim Taylor

My car has the ITG panel filter, Scoobysport full decat including up-pipe with an Afterburner back box. The car is a different beast with the Ecutek done. Once it has found it's feet the car is great. Fuel...I don't look at that part but do expect to use a bit more.

...oh by the way I run mine on Sainsburys Super Unleaded.

Tim

Tim Taylor

Time to bring this back up again.

Just had my WRX tested at Power Engineering this morning and the figures went from 240 bhp & 218 lbs/ft torque to 285 bhp and 279 lbs/ft torque.

Here are the graphs:

Before:



After:



Comparision:



[Edited by Tim Taylor - 4/18/2003 11:36:49 PM]