rcdash

iTrader: (18)

Either your compression ratio is high in a cylinder (not possible?), intake air temps are high, fuel octane is low (from contamination with something like oil from crankcase - catch can on both sides?), air distribution is uneven (spacer?), fuel distribution is uneven (injectors changed?).

That's all I can think of. You could also try to improve cylinder cooling (upgraded radiator, evans NPG+ coolant) to ensure you are not getting hot spots.

Continuing to retard timing too far can lead to increased heat generation at the exhaust valves and manifolds and may not control detonation if there is an underlying issue.

tef629

Bad Gas??
How much timing are you running up on top? A/F's at 11's w/ meth?

athenG

iTrader: (2)

he said 17-18!! I don't really know the PSI on every pulley so question now is what PSI is that?

jpc350z

The 3.12 pulley is probably giving him about 10-11 psi, the 2.87 would likely be 12 psi ?

DMK

iTrader: (6)

Other than building the motor, you could put in some 100 octane (5-10 gallons or so, for every full tank). Not very cost effective if its a daily driver though.

athenG

iTrader: (2)

he's running 91 octane and even with 50/50 meth then it won't really get a huge octane boost. I'm only boosting 8psi and my timing past 6000rpm is just 16 and that is with 93 octane and Meth. Granted I have a turbo but it shouldn't be much different. He's boosting 10-11 psi so I think 18 deg up top on 91 octane is a little high.. just my .02.

SpoilsofWar

iTrader: (39)

How many miles are on this engine? This is a stock block, yes? If you have wicked carbon build up it can cause detonation for several reasons. The carbon could be acting like a glow plug in a diesel, or it could just be that theres enough of it that its effectively raising your compression. Just something else to consider.

If you are knocking with 11:1 a/f's while injecting 50/50 meth I have a hard time believing your problem is fuel related unless like rcdash said its from oil contamination or poor quality fuel itself. Unless you are maybe knocking on just one cylinder because of a bad injector?

There are a lot of possibilities here, I would start eliminating them one at a time until you find the underlying issue.

str8dum1

iTrader: (11)

easy way to rule out fuel issues is bite the bullet on 1 tank of race gas.

if it still knocks, you have other problems

c3 rolling

iTrader: (19)

600cc injectors had just been flow tested and they are perfect and are working with a walbro pump and a JWT Fuel management unit.

I have a MD5/16 spacer but i dont see how that can cause it really...

I ahve one catch can on the passenger side with a check valve. I guess I should buy one for the driver side.

on the timing, Sam didnt want to retard too much timing, since I was already running low timing for my setup as it is

c3 rolling

iTrader: (19)

We thought that might be it but I had the engine de carbonized and the mileage is 26,000. 18k was N/A bolt ons, about 5k on Stillen Stage 2

c3 rolling

iTrader: (19)

im going to try try a vented hood, oil cooler and maybe a radiator soon. I really appreciate all the help guys. Ill try get the utec graphs up

SpoilsofWar

iTrader: (39)

While it can't hurt, I would not spend your money on one for the driver side unless you just want one anyway, as I highly doubt that you are taking in sufficient oil from that side to cause knock. If you were for some reason, you have more serious issues, and a catch can would be a band aid at best.

rcdash

iTrader: (18)

Sam knows how to tune a car - I don't know why people are recommending modifying timing or fuel at this point. Sam's obviously done the best he can with that.

If you have oil in the upper plenum (around the neck), that would indicate blow by past the driver's side PCV. Oops - your FI - not sure of the plumbing in the Vortech...

Any chance one of the injectors is leaking? I hate to ask cause it's a pain to check O ring seating - any fuel smell in the engine bay while the car is running? If not, they are probably fine. What brand of injectors?

I guess I would bleed the coolant for air pockets first, as that is the easiest. Just follow the procedure in the FSM and make sure your reservoir is not empty when car is cold.

Next I would go after injectors...

There's gotta be a reason - just gotta find it.

athenG

iTrader: (2)

Process of elimination... We all know Sam know how to tune but adding a race gas or removing some timing is a lot easier to find out if it is tune related. Even the all mighty Sam can make little mistake, you can't replicate every possible scenario on the dyno and that is why you go back to your tuner to make minor adjustment. Next thing is look at the injector’s coz if it is not spraying properly (spraying droplet) then that could also lead to knock....

SpoilsofWar

iTrader: (39)

It would be very useful if you could find out which cylinder(s) were knocking. I am not sure how feasible that is, but if its just one, then I would lean toward a bad injector. I know you said they had just been flow tested, but things go wrong.

A single bad injector could leave your wideband showing your A/F as safe (Especially if its installed on the other bank!), but you could be seriously lean in that cylinder.

Also, is your fuel system otherwise stock beside the pump? As in stock rails?

c3 rolling

iTrader: (19)

I have the deatchworks 600cc injectors. speaking of fuel smell, my fionce has noticed that the interior smells a little like oil/fuel once the car has been parked for a while, not sure, smells kinda normal to me.

Reservoir is full and ill try bleed the coolant. The coolant was actually flushed/re filled when GTM installed the vortech the first time around.

c3 rolling

iTrader: (19)

Sam actually tuned it on dyno and then the street. I find it hard to beleive it can be inectors since they were just flow tested so its the second time they have been installed, even the first time around the knock was worse.

c3 rolling

iTrader: (19)

Is there a way to check if certain cylinders are running lean? Yes I have a stock fuel rail, only upgrades is the 600cc injectors, walbro pump and JWT FMU

c3 rolling

iTrader: (19)

any clue on why my startups has gotten difficult?. It was fine before with the first blower and no meth but once the car had the blower swapped, meth installed, injectors removed for flow test and a retune, the startups have become difficult once in a while. Sam doesnt know why, I was thinking its just unburned meth/water that makes it hard sometimes?

You guys think me mixing a couple bottles of 12 oz HEET with the gallon of boost juice to raise the meth content might help? Would it be fine with the current tune?

Also, if it is the fuel system thats the problem, why did my car knock so bad with the Stillen also? Stillen was run on stock injectors and pump....

sigh this truly is a headache, if it gets resolved I think im going to cry haha. Once again, thanks for the input. Really sucks drive this car so conservatively after spending all that moola

rcdash

iTrader: (18)

The actual injectors could be fine, but you could have a leak around an injector so it's not seeing full pressure. There is a little blue O ring that needs to be properly seated in the fuel rail. Sometimes on insertion, the O ring sticks out a little bit and can leak. If you're saying the problem was the same with the Stillen with stock injectors, then that's probably not the issue. You should not be able to smell fuel in the engine bay with the car idling. If you have a leak, the smell will be strong.

You're using 1 step colder plugs, right? For the summer, you could probably get away with 2 step colder if you want to try that and see if it helps. Now that I think about it, it would be interesting to see your old set of plugs side by side. If you do decide to pull plugs, keep track of which one came from which cylinder and post up pics.