Jump to content
SAU Community

Recommended Posts

Check the knock sensor loom for any splits / continuity and so forth and make sure that it is getting a proper signal from the knock sensor.

  On 27/01/2011 at 12:06 AM, paulr33 said:

use temp IGN adjust to back out -8 deg timing and floor it

if its does the same you can be pretty sure its not ignition related knock and some form of mechanical noise etc

yeh i have tried this its better but still manages to hit 70 very easy...

  On 26/01/2011 at 11:59 PM, battery said:

hey trent i have this "false knock" issue im trying to sort out perhaps you have some ideas...

i have a rb25 with a power FC making 200kw, basically i get crazy knock readings and i'd really like to fix it so i can have a go at tuning the car.

on startup it will read 20-40 and i can be driving along in any gear around 3000-4000rpm not much load and it will shoot up to 80-100. On WOT it can hit 200.

I have had 2 different tuners check the car out and they reckon its fine, its been in this state of tune for over 20000ks with no issues.

I have a 5 puk exceedy clutch, oil cooler and relocation kit, other than than that its pretty standard. I have tried changed the knock sensors but there was no change.

whats the best way to eliminate this problem??

Some PFC's have this issue we come across it every so often, its generally a knock sensor issue or a loom issue...

One of the reasons we like to use secondary knock detection when tuning.

  On 28/01/2011 at 11:26 AM, DVS32R said:

how long does it take to setup a kmon or similar for the 1st time? do you have to set it up for each engine and car?

2mins max, on big setups maybe 5mins as i prefer to get to a better spot on the block instead of the head.

Ive got an rb30 turbo with a really quiet exhaust. The car seems to drive perfectly, run really smoothly. Are you saying It could just pre ignite at any time or be detonating and i wouldnt even hear it? I thought pre ignition sounded like a marble or something in your cylinder, like a really pronounced bang?

Also what is the optimal spark plug to run in it. Its a standard N/a motor, high comp, n/a cam etc, with vlt injectors, vlt computer, stock manifold turbo etc. Will be installing water injection soon and trying to push it to 14psi. From what ive read if i get the water right i can lean it out a bit even on the n/a high comp motor. Only problem with doing that is if the water fails then almost certainly your motor will too. Its been going for 2000km and the sparkplugs have no signs of wear, this is a good sign of no detonation right?

And in your opinion how much longer (i,e a few seconds?) can forgies handle pre ignition for versus cast pistons?

Kind regards,

Jason.

Bad detonation sounds like marbles but by then it is too late, you can still get detonation that you won't hear unless you've got your head in the engine bay.

Pre ignition is a different thing that can destroy a piston with just one event. It is where it ignites on the compression stroke, basically trys to compress an explosion. Detonation is where after the spark ignites the fuel the shock wave causes some of the mixture to explode instead of burn, so there are different stages, can have a very small amount of the mixture explode or almost all of it.

Pre ignition will destroy any setup, detonation will be better tolerated by forged pistons but as its such a variable thing there is no way to say how long it'll last, avoid it at all costs.

Edited by Rolls
  On 28/01/2011 at 3:42 PM, Smegul said:

Ive got an rb30 turbo with a really quiet exhaust. The car seems to drive perfectly, run really smoothly. Are you saying It could just pre ignite at any time or be detonating and i wouldnt even hear it? I thought pre ignition sounded like a marble or something in your cylinder, like a really pronounced bang?

Also what is the optimal spark plug to run in it. Its a standard N/a motor, high comp, n/a cam etc, with vlt injectors, vlt computer, stock manifold turbo etc. Will be installing water injection soon and trying to push it to 14psi. From what ive read if i get the water right i can lean it out a bit even on the n/a high comp motor. Only problem with doing that is if the water fails then almost certainly your motor will too. Its been going for 2000km and the sparkplugs have no signs of wear, this is a good sign of no detonation right?

And in your opinion how much longer (i,e a few seconds?) can forgies handle pre ignition for versus cast pistons?

Kind regards,

Jason.

detonation is very distinct if you know what it sounds like. i'd never heard it until it was pointed out to me one day, and now i pick it up all the time, even just on normal cars driving in traffic that *should* be run on a decent fuel but are only getting fed 91oct.

spark plugs generally wont cop any damage from detonation, but will show some black specs, or even silver ones, around the porcelain.

hard to put a time constraint on how long each piston would last for. i've been caning a mates soarer recently while chasing what i thought was ignition braking down, which was actually a massive lean condition, despite being told by a dyno operator that it was flat at 11.5:1 (issue currently being rectified with help from trent), and its been copping it hard, and for a long time lol. still going strong though, standard cast pistons :)

instead of spending your money on water injection, get some GTR injectors and a nistune. cost a little more but the result will be about 487 times better

  On 29/01/2011 at 2:32 PM, VB- said:

detonation is very distinct if you know what it sounds like. i'd never heard it until it was pointed out to me one day, and now i pick it up all the time, even just on normal cars driving in traffic that *should* be run on a decent fuel but are only getting fed 91oct.

spark plugs generally wont cop any damage from detonation, but will show some black specs, or even silver ones, around the porcelain.

hard to put a time constraint on how long each piston would last for. i've been caning a mates soarer recently while chasing what i thought was ignition braking down, which was actually a massive lean condition, despite being told by a dyno operator that it was flat at 11.5:1 (issue currently being rectified with help from trent), and its been copping it hard, and for a long time lol. still going strong though, standard cast pistons :)

instead of spending your money on water injection, get some GTR injectors and a nistune. cost a little more but the result will be about 487 times better

haha those gas love that 11.5AFR dont they.... shit it was more like 16 to 1.... was lucky we checked their work.

leaning out an engine can be tolerated for a lot longer, especially if its waaay too lean. as long as it doesnt create hot spots such as glowing spark plugs that cause preignition

  On 05/02/2011 at 1:23 AM, Drift Motorsport said:

Engine Vids with knock sound on Youtube:

http://www.youtube.c...feature=related

Kabbom:

That was in the back the motor is in the front, so i dont think that this is det. lol.

The first vid was good the sound that det makes mate.

  • 2 weeks later...
  • 1 month later...

Rb 26 is impossible to mount onto the block. So have to mount to the engine head preferably near a coolant passage as the knock will travel through the water better than air.

Yavuz prefers to use his trained ears to listen for knock

Nope. And that proves it works fine.

He has a extremely good reputation.

The drag car he sponsors is tuned at the track using egt sensors and transducers in the spark plug to monitor cylinder pressures.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Latest Posts

    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...