75shot on built motor = burnt valve

[civicsi13]

i just threw my car on the dyno on my built 9:1 turbo ready motor who put down 160whp 120 tq. I have a gsr block and b16 head. I have a dry 75 shot zex kit and threw down 238 whp and 211 tq at 6k bc at 6k i burnt a valve and we let off. What do you guys think could have caused this. I am replacing the valves but wondering if i can still run the same shot without burning anything else. i was tuning on a vafc and was at 1100 psi.

[speedjunky01]

get some real tuning VAFC=OLD SCHOOL.

crome is free and tunes MUCH better then VAFC.

My though is the ignition timing is way off due to the VAFC(depends on how your tuning the VAFC).

[NationsMostWanted]

Originally Posted by civicsi13

i just threw my car on the dyno on my built 9:1 turbo ready motor who put down 160whp 120 tq. I have a gsr block and b16 head. I have a dry 75 shot zex kit and threw down 238 whp and 211 tq at 6k bc at 6k i burnt a valve and we let off. What do you guys think could have caused this. I am replacing the valves but wondering if i can still run the same shot without burning anything else. i was tuning on a vafc and was at 1100 psi.

wow those are some high whp numbers for a 75 with zex.

[TayloMade07]

Originally Posted by NationsMostWanted

wow those are some high whp numbers for a 75 with zex.

yeah... that math dosent make sense... 160 + 75 (which zex dosent even dyno to the wheels ) = 235... i guess that only 2 hp off... but still its a zex dry, i guess its possible

[festivagt]

Cooking valves can be a result (and it usually is) of either low fuel pressure or lack of fuel (running lean). Not saying timing didn't do it, but so many other things that are more likely you didn't mention. Fuel pump? is it stock? Stock honda pumps have barely enough pumping volume to cover the engine in stock form - little alone 75 hp extra worth. Your fuel filter? Is it old? Dirty? It will cost fuel volume and create a lean condition. What is your fuel pressure at? Is it holding steady? Lastly(before worrying about timing) your plugs - are they stock heat range and how did they look when you pulled them after the dyno pull? You should be running 2-3 heat ranges colder. Of course the AFC if tuned improperly will cause the issue as well. Of course you should dial out 2 degrees of timing per 50 hp but there are alot of guys on here pushing 75hp on here and not even dialing any out. Careful tuning and paying attention to details will bring you through this. Lots of variables and questions. More details so we can help out.
HENRY

[civicsi13]

i have a brand new oem fuel pump and the fuel was at 44 with the line off. then i broke an injector so the whole tip was shit.. that was the reason i ran lean in that cylinder.. ..i am putting it al back together just scared to go through all that shit again but my timing was not at all retareded in any way . and i had an awesome tuner that knows his shit but we sprayed twice and i had been spraying the 55 without a problem for over a month it was just the 75 that messed me up...

[festivagt]

Broke a injector? Were you taking a hammer to it? Just be advised that even though you have a new pump, you should be running a higher flowing unit like a 110lph or even a 255lph. The pump sounds like it was sustaining the 55 but ran out of legs for the 75. Your tuner should be aware of pump limitaions.
HENRY

[Clone]

your VAFC doesn't tune ignition timing, I dont think. Nitrous generally prefers to have retarded ignition timing... two degrees, maybe three for a 75 shot. If your timing has been advanced, and then you shove nitrous into it, that's probably a big problem right there.

and yeah, for power levels of that sort, and OEM fuel pump just isn't going to cut it. You should upgrade to a pump with higher capabilities, like a Walbro 255lph.

One question I have is why you bothered to build it for turbo, and then decided to run nitrous? Nitrous LOVES high compression motors... not the low compression a turbo is interested in. sounds to me like you're wasting a lot of money and time tuning that thing for nitrous... you should just ditch the AFC and the nitrous and finish the turbo setup.

[2PhastPrelude]

Ive burnt a valve and a piston using nos, but that was with a 50 shot. now Ive steped up to a 75 but Ive bump fuel pressure up to 45 at idel and I have the msd digital 7 box retarding timming 8deg. with colder turbo plugs and havnt had any problems on a h22. Even tryed 100 shot nx jets on 2 passes and still no problems... take you time with the tunning

bottle pressure is another thought.....

[VTECsqznN2O]

Originally Posted by Clone

your VAFC doesn't tune ignition timing, I dont think. Nitrous generally prefers to have retarded ignition timing... two degrees, maybe three for a 75 shot. If your timing has been advanced, and then you shove nitrous into it, that's probably a big problem right there.

and yeah, for power levels of that sort, and OEM fuel pump just isn't going to cut it. You should upgrade to a pump with higher capabilities, like a Walbro 255lph.

One question I have is why you bothered to build it for turbo, and then decided to run nitrous? Nitrous LOVES high compression motors... not the low compression a turbo is interested in. sounds to me like you're wasting a lot of money and time tuning that thing for nitrous... you should just ditch the AFC and the nitrous and finish the turbo setup.

as an aside..no..the vafc's dont tune timing...the vafc2's do the i-vtec cam phasing shit though


but back to before..change out the stock pump for a walbro unit..255 is my suggestion...get yourself an msd digital 6 ignition..you get a 2-step, high rev limit, and nitrous retard..

lastly..are you running a stock ecu? if you are running a chipped ecu then that may be advancing your ignition timing..since most ecu chips are for all motor and throw a lot of advance

[speedjunky01]

Originally Posted by VTECsqznN2O

as an aside..no..the vafc's dont tune timing...the vafc2's do the i-vtec cam phasing shit though


but back to before..change out the stock pump for a walbro unit..255 is my suggestion...get yourself an msd digital 6 ignition..you get a 2-step, high rev limit, and nitrous retard..

lastly..are you running a stock ecu? if you are running a chipped ecu then that may be advancing your ignition timing..since most ecu chips are for all motor and throw a lot of advance

thats rediculous for the price of the msd and the vafc its like 650 bucks, you could use crome pro and have a ecu chipped and buy a wideband for the same money...

[2PhastPrelude]

Originally Posted by speedjunky01

thats rediculous for the price of the msd and the vafc its like 650 bucks, you could use crome pro and have a ecu chipped and buy a wideband for the same money...

I dont see how... with the digital 6 you can runn around with the timming avanced and then when you wanna spray you flip a switch ad the timmngs retared as much as you want not to mention the 2 step helps alot on launches. I love it.

the only downside to a bigger nos shot is the retarded timming which you def start to notice. Why deal with the lag when you dont plan to spray?

[VTECsqznN2O]

Originally Posted by speedjunky01

thats rediculous for the price of the msd and the vafc its like 650 bucks, you could use crome pro and have a ecu chipped and buy a wideband for the same money...

nobody said to use the vafc...even if you go chrome..you will still need a good ignition box to light it..i agree..chrome is bitchin...but it cant do everything

and who honestly spends that much on a vafc and an msd box..i hope nobody..because they 1..arnt shopping around...and 2..are getting raped..with no lube

[speedjunky01]

motes 2 timer lets you tune 2 maps. nitrous cars run them all the time, you tun on one chip for an and on the second for nos. you hook up the 2 timer to a solenoid so that when you hit the nitrous it gets power and goes to the nos map.

crome has a 2-step and it works just fine. I usse it all the time, setup with the stop at a well tuned MPH it will work better then the msd since the miinute you get moving the MSD 2-step stops and you get spin if your on stret tires. I set it to 13mph so the 2step is still on untill that mph. its perfect 2.1 60ft over and over and over agiain for me with that setup( kumho 712's 205/40/16)

MSD ignition is a waist of money IMO.

bisi uses stock cap/rotor/wires/coil on his 9 second NA f22 SOHC.

the stock stuff is good to 400+, as long as you use the proper heatrange plugs the stock stuff is just fine as long as its maintained.