NNBD

hi,

Im sorry to ask this noob question that probably everybody asks and is covered like a million times but the search still does not work.

My question is, plain and simple..how does detonation really sound ? I've been told that its like a metal-like crispy rattle, but i've never actually heard it. Is there any soundtrack on the internet that resembles detonation ?

Why i ask this, simple...i just added my first turbo (at least on a NA car), never tuned before and i don't want to blow ---- up (if i did like that...i would be in the militairy).

There are just so ------ much rattle's, cracks, noises in my car that i'm afraid that i won't detect detonation and just think its one new normal noise.

and please...be gentle...

skittersk8er

remeber that time i beat your *** with brass knuckles well the few times i hit your braces the metal on metal contact thats wat it sounds like

NNBD

oke, now maybe a bit less violent desciption ?

4.3Lsofrage

sounds like a ------ hammer hiting the block of your engine, like.... the piston mashing up on a valve in other words a loud metalic knock that increses with rpm. use higher octane gas is the best way to prevent that and checking your ignition system and retarding timeing is your best bet if you do have some detination

NNBD

the reason that im asking this is because when i hit like 5000rpm, I hear this rattle...not very very loud, but cerainly noticable. Im only boosting like 4psi at the moment (just added my turbo), i use 7grade ngk spark plugs (gapped at 0,75mm), using 95 oct gas at the moment (could use 9, have a convervative timing (as said by xenocron since im using a bin that he tuned on a dyno for about the same setup). Using a starion intercooler, and AFR's are like 10.5-11 (set it really rich since i wanted to make sure i don't happen to hit a lean spot).

So its logically very unlikely that this rattle is detonation (i think) but just a resonation (new noise/rattle in the car..like the dozen other rattles...but louder).
But as i said before..i never heard detonation as far as i know.....so as im not sure...im worried.

4.3Lsofrage

what car is this were talking about? what motor as well

NNBD

its a 1990 DOHC D16Z5 engine (european crx). comp ratio 9,5:1
Td04 turbo (3000gt)
starion intercooler
NGK grade 7 plugs regapped at 0,75mm
PM6 ecu (orgininal is PM7), with a PM7 bin (from xenocron, tuned on a dyno for a similar car)
95 oct gas (cheapest...still about 6-6,5 dollar a gallon)...can use 98 (bit more expensive)

Thats all the info you might need right ?

Ravage70

,75mm
you must be on crack

ochizon

Honestly, if you cant tell, we def wont be able to understand from a description.

Knock doesnt always have to be loud and consist, either. It can be a low level clack, inconsistent and infrequent through the rpm band, but also can be consisitent, or very loud an rattly. I would try and find someone that knows what they are listening for to take a ride with you.

Tom-Guy

The detonation you hear is a best case scenario, and something is hugely fucked with your tune.

Fix every rattle, creak, squeak, noise, etc, and run a decent resonator and muffler with dumptube routed into the exhaust so your car is very very quiet... and it's the detonation you don't hear that breaks ringlands or shoves a rod through your block.

Using your ears to detect detonation is not the way, grasshopper-san. Go stalk SOHC_MShue on HT, search his writeup on det-cans. That's the only way you'll "hear" jack ----, and you CAN tune ignition correctly with them! Go son, get with it!