Detonation!

Does all standard ECU on skylines are equipped with a knock sensor? I know there are two knock sensors on GTRs. Did anyone know how actually these sensors work? Do they prevent pinging 100% or they just take action when pinging occurs?

I believe thay take action when pinging occur at least it did on my rb20 when it was on the dyno it was noticable drop nin timing
meggala

I believe they retard the ignition timing by up to 4 or 5 degrees at the onset of detonation.

With the powerfc, your check engine light will flash when it's detonating - which I think's a far better option! :)

matt

Any ideas how much timing will the ECU retard? By the way, how much power less when the ECU retards the timing?

I'm fairly sure there are two of them in r32 gts-4's, green ends in colour from memory. I always thought of the knock sensor as just a device that monitors within the engine for a certain range of frequency, which means some times it can false alarm a little bit, but the law of averages rules and the ecu reacts according to the number of knocks the knock sensor picks up. Now that is quiet obviously a plumbers diagnosis of brain surgery, but it's along the right lines isn't it? Something I'm keen to know a little bit more about, so if there are any knowledgeable people in the house, any chance of enlightening me.

can someone please explain exactly what detonation is and if its good or bad? sory to ask such a dumb question but im realy new at this stuff...
thanks :bloated:

Detonation is VERY VERY BAD. Detonation is when fuel pre-ignites in the cylinder, causing stress on cylinders, valves etc. When intake temperatures rise or low octane fuel is present the threshold of the engine to resist detonation is lowered. For example, you raise the boost from 7 - 14psi on a standard turbo car, your intercooler is only capable of holding about 12psi. This is due to the turbo exceeding its efficiency range and also the size of the factory I/C. Once boost is wound up, the faster the turbo spins and hence the reason for excessive heat.

Hope this has been helpful. Anyone correct me if I'm wrong, I'm sure you will ya bastards. :finger:

Doc
(aka Ben)

Ahhhhh thanks man... I dont think my car is doing that (not that id really know what to look out for). My boost is only somewhere between 10-12psi (bout 6 1/2 ish on the standard boost guage).
So HOPEFULLY ill be able to resist that detonation thingie haha :flipa:

I fortgot to add, that you will hear a sound similiar to rattling coins, coming from the engine.

Doc

ahhhhh haha thanks AGAIN!! ill listen out for that. i usually have the sounds up but ill keep them off nxt time i go out and see if i hear it... is the noise real loud? also can this happen on a non-turbo? my x gf's r32 gts makes a noise similar to that but may just be her exhaust

severe detonation can be loud, but some times you would never the know the car was pinging.

It can happen to any car, N/A cars have a higher threshold than turbo cars, because of higher compression due to the fact that the dont have forced induction. Also don't advance your timing to much either, as it will cause pinging with out high octane fuel.

Doc

ok thanks,
I only just got the car a couple of days ago... the car yard was running it on 91 octane so im gonna run the tank dry (even tho i added some octane booster to it) and run a fuel cleaner thru it then run it on 96-98octane fuel... will that help?
also how do i advance the timing? is that a good or bad idea?

it's bad, very bad if it happens too much.

Dont advance your timing until you have cleared out all that other shit in your tank and run higher octane fuel. Like 98+.

Doc

how do i advance the timing and what will it do?
i must appologise again for asking dum questions ahha

Hey guys out there who encounter pinging, in which gear WOT do you suffer most pinging? Did you monitor the EGT too? If yes, at what temp?

Try running your car on BP 98 and also Mobil 98, some people / cars like one better than the other. You'll find also that not only high boost creates detonation. With older cars, they can have a fuel pump on the way out and not having enought flow or fuel pressure. Hence the car runs lean and can detonate even at slightly higher than standard boost.

Cheers
Zapf

and don't worry about advancing the timing drive the car on optimax or synergy and get used to it. you have a fast car already in a month or so then look at what you can do.
meggala

Originally posted by YCEE
Hey guys out there who encounter pinging, in which gear WOT do you suffer most pinging? Did you monitor the EGT too? If yes, at what temp?

If my car pings, it'll usually do it in a higher gear 3rd some times, mainly 4th (usually after a bad batch of fuel too), and usually after running it through the gears. It's not loud enough to hear, but the pfc makes the check engine light flash and knock gets above 60.

If your car's pinging, I'd imagine your EGT would go thru the roof? I haven't got a exhaust temp guage on my car to confirm this tho?

matt

Originally posted by meggala
and don't worry about advancing the timing drive the car on optimax or synergy and get used to it. you have a fast car already in a month or so then look at what you can do.
meggala

are you talking about my car? or someone elses...
I dont think id advance the timing anyway... im not that clued up and would rather leave it to someone who knows what they are doing so i dont fuck up the car :)

Originally posted by zapf
Try running your car on BP 98 and also Mobil 98, some people / cars like one better than the other. You'll find also that not only high boost creates detonation. With older cars, they can have a fuel pump on the way out and not having enought flow or fuel pressure. Hence the car runs lean and can detonate even at slightly higher than standard boost.

Cheers
Zapf

Is the octane rating of BP98 and Mobil98 98 octane? Right now I'm using Shell V-Power which is 97 octane, does it make real difference with 98 octane?

before i had my intercooler fitted i had some pinging after parking the car for 5-10 min on a hot day then driving it a little hard i put it down to heat soaked pipes :confused: :flash: :flash:

Originally posted by blacksky33
before i had my intercooler fitted i had some pinging after parking the car for 5-10 min on a hot day then driving it a little hard i put it down to heat soaked pipes :confused: :flash: :flash:

oh ok... haha all i have to say is you have a SERIOUSLY cool sig man! :)

My boost is only somewhere between 10-12psi (bout 6 1/2 ish on the standard boost guage).

hey, how did you get your boost up to that? Just an aftermarket boost controller??

Originally posted by Ethan_R33


hey, how did you get your boost up to that? Just an aftermarket boost controller??

nah when i bought the car it had a 3" exhaust system and a k&n m's filter.... im thinking my boost is actually at about 13.5 not 10-12..... i need to get a boost controller tho....
what is your car boosting?

geez if you have 12 or over thats pretty high????
mines got big exhaust, intercooler and pod filter and only has standard boost (7psi) it only goes about half way up the standard boost gauge. Which is roughly 7psi.

Howcome yours is so high?? i mean thats not a bad thing, i want mine that high too!!!!!!!

Originally posted by Ethan_R33
geez if you have 12 or over thats pretty high????
mines got big exhaust, intercooler and pod filter and only has standard boost (7psi) it only goes about half way up the standard boost gauge. Which is roughly 7psi.

Howcome yours is so high?? i mean thats not a bad thing, i want mine that high too!!!!!!!

if yours is going half way on the standard boost guage by chance its probably higher than 7psi.... check out the conversion tables in the performance section on how to read the standard boost guage.
Also what kind of exhaust have you got...
you have a front mount? lucky! :P

yeah it wouldnt be much more than 7psi though :(

i have a HKS super dragger 4 inch straight through with 5 inch tip. also HKS dump pipe with separate wastegate pipe.

And also HKS intercooler.

So yes a lot of nice HKS stuff.

I got it all when i imported it :)

Originally posted by Ethan_R33
yeah it wouldnt be much more than 7psi though :(

i have a HKS super dragger 4 inch straight through with 5 inch tip. also HKS dump pipe with separate wastegate pipe.

And also HKS intercooler.

So yes a lot of nice HKS stuff.

I got it all when i imported it :)

4" pipe is probably a bit excessive. Mine has a 3" racing exhaust (tuned turbo down pipes) GAB adjustables with HKS springs and a K&N filter...:flipa:

nah 4 inch isnt too excessive. its perfect!!!!!!
Gives it a really low rumble and screams at high revs. Also is less restrictive so it is good for it. And i also have a blitz pod filter with cold air induction, and zeal suspension.
I just want more boost!!!!!!!!!!!!!:cry: :cry:

Originally posted by Ethan_R33
nah 4 inch isnt too excessive. its perfect!!!!!!
Gives it a really low rumble and screams at high revs. Also is less restrictive so it is good for it. And i also have a blitz pod filter with cold air induction, and zeal suspension.
I just want more boost!!!!!!!!!!!!!:cry: :cry:
wow sounds like a nice setup! :)
sorry i cant help you on the boost thing im kinda new to this whole turbo stuff so yeah.. try asking someone who is a bit more clued up... i dun wanna tell you something and then find out im wrong and you end up blowing up your car haha so yeah... there you have it! :licker:

hey dont worry bout it mate, thanks anyway. im just jealous u have gots lotsa nice boost. :(

Im actually getting a boost controller soon to up the boost anyway. It is a 2 stage one, where ill set one stage at 8 psi and the other at 12psi, and theres a little switch in the cabin that lets you choose between them both. really nifty!!!!!!

nice REAL nice! what does the R33 handle and perform like? any different to the r32?

lovely red hat protected flick switch? I've got that in my car. When you install it try to keep the extra piping down to a real minimum as it can induce boost spikes if the piping is significantly longer than the factory setup. simply put I guess there is slightly more volume in the system to fill up with pressure before the wastegate actually sees the required boost to activate. hence more boost running through your turbo to build up to the wastegate operating threshold.

is an aftermarket wastegate or dump pipe a good idea at 13.5psi boost? or is it not reallly worth it :confused:

yep thats the one mrmeal. looks pretty cool i reckon.
And yep i will definitely keep hose length to a minimum.

Well ive never driven an R32 but i know my R33 handles REALLY well around corners and so on. It really sticks to the road and i can chuck it into corner at high speeds. Sometimes i can hear the tyres squealing but it has never slid out or anything liek that yet.
And yes it is really fast (even if it is only at 7psi!!!)

And i really dont know about an aftermarket wastegate. I am just using the standard one atm...

true the r33 handles real good!

i was doing bout 170km/h last night on the freeway around a tight corner and it felt real grippie, mind u i do have blistern suspension tho and nismo 400r front and side's :sun:

Originally posted by denjam69
true the r33 handles real good!

i was doing bout 170km/h last night on the freeway around a tight corner and it felt real grippie, mind u i do have blistern suspension tho and nismo 400r front and side's :sun:

yeah my r32 has GAB adjustables all round with HKS springs... she handles like a dream!!! how much did that 400R front and sides set you bak? i only have the R32 Type M front sides and rear but i want a 400R kit!

THUBLE

COST? I DONT KNOW, THE CAR ALREAYD HAS THE 400R FRONT AND SIDES WHEN I BOUGHT IT FROM THE IMPORTER:D

By far I know misfiring is caused by a lean fuel mixture, so as pinging, so which one will come first? If the car is misfiring, does it mean that it will detonate too?:confused:

Ycee:
the way i saw it, is that when your car is running too rich it fouls the plugs and causes the car to misfire. This is because the gap is covered or filled with the unburnt fuel which doesnt let it spark.

As for pinging and detonation i am sure that is from a lean mixture.
If your car was misfiring theres not much chance of it detonating. My car was misfiring for a few months because of a faulty AFM which made it run really rich. There was never any chance of it detonating then.

Detonation- ignition of the fuel before the piston reaches TDC. Thus forcing the piston and rings to push its way to the TDC point. As the piston forces its way up the heat and detonation increase. This is why we snap rods and blow the rings. Cause the compression has to go some where. Which will always be the weakest link. I have destroyed 2 engines now. Both times I welded the rings to the piston and damaged the block.

Every RB20DET has 2 knock sensors. No the ECU will not prevent detonation. The ECU might retard timing a bit. But it is never enough. The only way is to have an aftermarket ECU setup to retard timing a certain amount for the severity of knock.

I installed the MSD knock sensor which has a visual and audible alarm inside the car. It also tells you the level of knock occurring.

You shouldn't adjust your timing without a visual knock sensor or other source of tuning equipment. Never tune your car by ear. If your car is misfiring it could be more then fouled plugs. The plugs could be damaged do to detonation. This will cause a rough idle. Even more so then plugs fouled by a rich condition.

WD:devil:

Im not tuning my car myself id rather let someone who knows what they are doing touch my car... but is that MSD knock sensor thing a good item to have? Will it help? if so... how much are they and where can i get one?

The MSD knock sensor is a great safety thing to have. No matter who tunes your car there can always be some kind of variant to cause detonation. Really hot day, bad gas. With this installed you can always keep an eye on things. Go to WWW.SUMMITRACING.COM they sell alot of good stuff for our cars.

WD:devil:

How does a knock sensor work? What is it detecting exactly, does it work on vibration????:confused: Are they very expensive?

I believe it is a little microphone. It picks up abnormal engine sound.
I have seen some where people have recorded their engine sound and looked at the knock. Quite interesting.

Ben

Ah I got the picture, so the car will misfire if it run rich. I remember sometime ago I changed a fuel filter and set the fuel pressure to 3.2bar, and the car was misfiring, set it back to 3.0 and it is normal again. So does it mean than any richer point from misfire will cause the engine to stall too.?

If we get severe detonation, the EGT will rise up very high I guess, is that why we install a EGT gauge in our car?

By the way, what can cause the fuel to pre-ignite??

EGT is used to keep the mixture at a safe temp. What I mean is, if the A/F gauge says your running at a good percentage but your temps are to high. Then you need to get them down even if it means adding more fuel and running slightly rich.

Fuel can be burn early for several different reasons. Your cylinder temps are to high and your spark plug is getting to hot and igniting the fuel all by itself. You may need to go to a colder plug setting. Deposits built up on the pistons and valve train can cause detonation. Any sharp edges on the piston valve seats or head. Having your timing advanced to much. Running to much boost and leaning out the mixture. Bad gas. A really hot day when running the same amount of boost you would on a cold day. The list goes on but I'm sure you get the hint.

GET A KNOCK SENSOR

WD:devil:

Sorry I have been reading through this thread and I have come in late.
R32's (RB20DET's) can run more boost standard than the R33. From talking to others it seems that the R32 can run about 12-13psi standard to the 10-11 standard for the R33. I believe the R32 has slightly lower compression to facilitate this.
As for getting an aftermarket wastegate, this is only really nessicary on big turbos which don't have an internal one. I have heard about people welding closed the interal wastegate and using and external, but to do this you need a new exhaust manifold and generally big dollars.
Anyway that's my 2c worth.

Jeff.

Hey guys, just been wondering, ive just rb20de+T my r32, it drives fine while normal driving, but when i put the foot down itl start detonating ive been told, its some sort of blat blat sound., doesnt sound good too. just wondering if anyone else has had trouble with this too ? any suggestions ? ive changed to a gtst radiator, gtst injectors, gtst ecu, and got a front mount on it, havnt changed fuel pump yet but could it be a possible chance because of the fuel pump ?:uhoh: