Originally Posted by jprelude92

the tuner called me today and said that he talked to someone from hondata and that he described what happend to the pistons and that the guy at hondata said that he's seen pistons like that before and that is cause by a lean condition he said that some injectors might work fine at 90% duty cycle but might not work well at 60% or 40% , i dont know yet what duty cycle my injectors were working at whent the engine blew up but the tuner is gonna let me know so i can send the injectors back to precision to have them flow tested at the cycle they were working when the engine fail

Originally Posted by Scott_Tucker

No, that's correct.

Abnormal combustion can generally be divided into two categories. Pre-ignition combustion and post-ignition combustion. Pre-ignition is anything that sets off the mixture before the spark plug fires and post-ignition is anything that sets it off in an area ahead of the flame front after the spark plug has fired.

Pre-ignition will show up as pock marks on the top of the piston and will eventually eat a hole in the center of the piston if it is allowed to progress far enough. As mentioned before it usually occurs due to a 'hot spot' in the combustion chamber. Continued pre-ignition will promotepost-ignition so sometimes you will have both types of damage.

Post-ignition (generically called 'detonation') occurs when the spark plug fires, the flame front begins burning, and the 'end gases' which are the unburnt air fuel mixture ahead of the flame front spontaneously combusts due to the pressure and temperature in those end gases reach the ignition temperature of the fuel. It shows up as damage to the ring lands on the edges of the piston. The reason it does this is because the spark plug is in the center of the cylinder and the flame front spreads out radially. This compresses the end gases which are at the outer edges of the cylinder. When the end gases explode the pressure in the cylinder in that area spikes high enough to damage the ring lands. The violent vibration of the two flame fronts colliding also increase the heat transfer which is why the ring lands may look melted.

I can not say why his engine detonated. It could be because the tuner had the ignition too far advanced or it's possibly the engine is built wrong. If there is not a proper quench area (meaning there is excessive clearance between the top of the piston and the cylinder head) on the edges of the piston it can cause this which would not be the tuners fault.

Originally Posted by tepid1

Tell you what.... I am still a mod over on the Neptune forums. You can post your file there or you can email it to me so I can take a look at it. If you want to email the cal file send it to: tepid1@sbcglobal.net

Originally Posted by jprelude92

we were on the highway when this happend so no we didnt check the plugs
last time when he set the mechanical base timming i swear he said that he set it to 30 degrees cuz i asked him and when i asked him today he said that it was at 20 degrees so right there i know that hes trying to cover his butt

Originally Posted by jprelude92

he just sent me the file but would'nt doubt he edited the file to make himself look good.
i want to post it but i dont know how to maybe some1 can tell me how its on my hot mail address

Originally Posted by ashb82

mechanical base timing are you talking about the distributor or the idle part of your tune

Originally Posted by oneludesol

Todd actually tuned my car as well... He is an EFI 101 grad, and been tuning for a long time. He is more than fluent in engine theory, and tuning. That being said, people make mistakes, but like I said before, I am curious to know if you are even able to set your mechanical base timing to 30deg... Through my experiences with him, I found that he is a good guy, and won't leave you up ***** creek (coming from a customer, not friend).

Originally Posted by ralph11sec

there could be a reason why the tuner set it at 30. reasons i dont understand.

first of all why does he say ign is at 30 at idle when his laptop shows 21 or so. doesn't he know he has to sync it? anyway it doest matter what ign you have at idle. it won't cause that damaga. as long as it's the same with the timing light and datalog.

what we want to know is how much ign do you have at 12/14 psi. you are using a 3bar map sensor i suppose.

Originally Posted by jprelude92

i know hes not a bad guy but i have heard more bad things about him than good

Originally Posted by oneludesol

what else have you heard? when exactly did this happen?

Originally Posted by oneludesol

what else have you heard? when exactly did this happen?

Originally Posted by jprelude92

it happend wednesday about a 1 ago

Originally Posted by jprelude92

also chech out my other thread title je pistons got melted and look at what happend he blame it on the machine shop saying that the piston to wall was too tight but now i dont think it was piston to wall cuz he was the 1 woho tuned it it cant be a coinsidance 3 times in a row something goes bad every time he tunes the car some thing happens

Originally Posted by oneludesol

Has the same machine shop been doing the work throughout these three separate occasions? I find LSVTEC to be harder to keep together than a stock b-series, I find h22 to be a little tricky than b-series, so I personally would be terrified of an LSVTEC h-series lol