Ive got an LS/Vtec engine with b16 head b18a block and b16b pistons. This setup that I am running is allowing my engine to either detonate or spark knock at mid to high rpm's depending on weather and elements. I am afraid of ruining my engine that I have put pride and joy into building, and I'm in no rush for that to happen. Mabey there is some others on this site that may have some good solutions that relate to my problem.

Let all that will shed some light on this topic for us all to learn about. Thankyou

 

3 things to try:
Use higher octane fuel, retard timing, go one step cooler spark plugs.

 

I have tried all three thing listed. It seams though when I reatard the timing the car really becomes a pig and is VERY slugish. How do you read an NGK spark plug cold to hot?

 

What's your static compression with that head/piston setup on the B18A crank? And are your plugs showing signs of running too hot?

 

I am pretty sure that the static compression of this setup is around 12:1. I normally run 93 octane fuel. I changed plugs today and the plugs that had been in there for about 8k miles looked a little white on the tip, and they had a slight buildup of ruff sanpaper consistantsy type around the bottom of the plug right near the threads.

Would running to lean cause an engine to detontate or spark knock? The engine didn't start doing this until progressivly until recently. The engine has aprox. 20k miles

 

Sounds like you're either running a little lean or just plain ol too much compression (or a combination of both). The first thing I'd try would be an adjustable FPR with maybe 5 extra psi of rail pressure for a slightly richer mix. While this will hurt fuel economy a bit, it's less detrimental to power than pulling out timing if it can fix the detonation. It'd be nice if you knew your a/f at these RPM points, but I doubt you have access to a wideband.

 

nice information, guys keep it coming.

 

It's weird, because today I have been reving all the way up to 8200 without any noticable sound of detonation. Mabey going to the colder plug helped some. Is this correct, the larger the number on a NGK plug indicates a colder one. Correct me if I'm wrong. thanks

 

Spark Plug : NGK BCPR7ES-11 this is a 7 plug.

LS use 5
VTEC use 6
i guess 7 for you.

you should be ok with 12 or 13 BTDC

 

cool dude I will put the plug info in my notes for further usage.

I have come to the conclusion that part of the reason for my detonation is because the use of the factory unmodified FPR . In the next day or so I am going to experiment with adjustable B&M unit and see what I can do with that. I come to believe that with the B16b CTR pistons, more air than the factory gsr pistons is being pulled into the cylinders and not enough fuel is being mixed causing detonation probs. I should of remided this problem long ago. Does this diagnosis sound practical? Please, those that know shed some light. thankyou

 

i think that is a totally feisable(sp) idea, give that a shot, what octane rating are you running right now?

 

I am running 93 octane

 

odd... i know people with if not exact . similar set-ups.... with no problems... i would recomend the NGK BKR7e-11 plug ... stock timing .... and a <U> good quality </U> gas stations 93 octane...

 

FYI, your compression ratio is in the high 12s. probably 12.8 or so.
you are probably going to have detonation issues. what ecu
are you using to control all of this?

 

i do these setup quite often and and in order to run them on the street with pump gas you need to invest in a fuel pressure regulator and gauge, and run about 50 psi at idle if your on stock injectors, or get some 310-370cc injectors and start at 40 and go up as you need to. run about 12-14 degrees of timing, get the coldest plugs you can find. ngk 8s or 9s will do ok. there are some better ones out there but im not sure what your budget is like. or you can just mix in some race fuel. 110 octane should do the trick. 1 gallon to 1-3 gallons of pump at most. good luck with it.

 

I am using a p30 ecu out of a jap siR. Today I changed to an adjustable FPR and advanced the stock fuel pressure from 32 psi to 40 and it was light night and day. I can't believe it would cause such a dramatic diff. I also changed to a BCPR7ES-11 plug and adjusted my timing a little (without a light). It only detonates occasionally now. The FPR helped with detonation some, but mainly helped botom end bog wich I was experiencing before. If I try a VAFC will this help with detonation at all?

 

Just curious, what kinds of cams are you running?

 

you need to run as much fuel possible. then you can fine tune it with the vafc. if it still pings. it may be detonating at high rpm. you might want to go up to 43 psi just to be safe.

 

read my third reply in this post
https://honda-tech.com/zerothread?id=379274

BTW, how hot are you running? perhaps a lower temp thermostat would help, but not sure to your specific case

 

If you are still running B16 cams that may be adding to the problem as well. You may not have enough overlap for the C/R you have. If you go up to a more aggressive cam it should be able to handle the compression better

 

mmm 12.1 compression

 

Fellow detonator here &lt;---

Im running 8psi on my stock D16z6 with Hondata and adjustable FPR

From reading this, i have a couple Q's :

What should i set my timing at w/timing light ?

What plugs should i get, i seem to be breaking the cermamics off normal ones ?

what should i set my Fuel Pressure at ? its at 38 right now...

Thank-you for your help

P.S. im using 94 octane and my detonation noises usually come on in 4th and all the time in 5 gear... 1st,2nd and 3rd i get no detonatoin noises...


[Modified by Tommyyy, 3:26 AM 2/11/2003]

 

BE EXTREMELY CARFULE.... i justy blew mine ls/vtec w ctr pistons. milled head. yileds 13-1. damn ALL I CAN SAY IS SUNOCO 94, RETARD UR TIMMING... (and my car run better in moist weather fer sum f*cking reason) and let ur car idle in morings... let it warm up... please u wanna avoid my problem... find my thread i recently posted... it will scare u

 

So you can help prevent detonation by lowering compression, right? Like in setups with forced induction?

 

damn i just read about ur piston #3 and engine, that blows, did you ever fix it and get her running again ?