tuning problem

[slimtastic]

ever since i got a caspers knock guage ive been all paranoid about the ammount of knock i get at wot (guage hits red bytop of second then stays) and was wondering if you all could help my problem heres my list of info

boost 13-14lbs
chip red armstrong 93
injectors 42.5
adj FP @53psi @wot
stock intercooler
stock turbo with minor port job
160 thermostat w/fan override switch

i was thinking about going to cold plugs and a powerplate to cure the problem but im not sure if im compleatly forgetting somthing. i wanna turnup the boost to somthing like16-17 but im worried about a headgasket failure. any help would be appriciated.oh also the knock sensor was replaced when i did the guage.

 

[daviss]

That's a lot of knock. With that low boost, I would start with the obvious. Make sure your exhaust is clear an not banging. I don't know how the Poston DP fits but anytime I do any exhaust work, I usually have a couple of clearance issues.

 

[TurboDave]

With that much knock at that low of boost, my suspisions would point to the knock gauge its self, or its hookup. Doesn't sound right at all. YOu should be able to hear that much knock. Did you adjust the torque on the original knock sensor maybe?

 

[Royal-T-Ltd]

You say 53psi f/p @ wot. that would be 39-40 psi stattic at your 13-14 psi boost level. turn the f/p up to maybe 43-45 psi stattic and see if you still get that knock. Just my thoughts.

 

[strikeeagle]

Is it REAL KNOCK or FALSE KNOCK?

Keep in mind that regardless of whether it's real or false knock, the ECM is pulling out timing, which will slow the car down, so if for no other reason than performance it must be addressed. Besides you can't leave a problem like this hanging.

The first thing I'd do is establish whether it's real or false knock by either draining the gas you have, or running it down, and blending in a bunch of at least 100 octane unleaded, if not leaded race gas (e.g. VP C16 - 117 motor octane). Don't use leaded if you have an unheated O2 sensor and/or are running a cat.

If the knock continues you can be reasonably assured it's false knock. There are a million things that can cause false knock, but do this 1st and tell us the results.

BTW, the knock sensor should be torqued to 14 lb-ft, and no tape or other thread sealer...

 

[slimtastic]

strikeeagle. well i dont think its the knock sensor because the old one did the same thing which is why i replaced it. for double checking couldnt i also disconect the actuator arm for minimal boost and check for real or false knock that way?

daviss .when i installed the 3" down pipe it didnt looklike a clearence problem would arise. i do have a loose bolt out on the passenger side back on the last hangar that holds the side pipe, thats been jittering around a bit latly but one would thing that its too far away to be heard by a knock sensor...could i be wrong?


turbodave. i dont think i hear any knock at all but at the same time its tough to hear knock sounds while that noisy cricket (turbo) is running.

royal-t .that was gonna be the fp under 17 psi

okthen.... check exhaust, drop FP

 

[BOOSTD]

The clearance might look alright but I would check the bottom part of the downpipe for any dents. If your engine mounts go bad, your downpipe will hit the a-arm and cause some serious knock. Thats just one of a $#!@ load of things it could be. Start there and see what you find.

BOOSTD

 

[slimtastic]

from what i can tell it looks like the down pipe was resting up against the crossover flange. and when i realigned the down pipe the wot knock seemed to go away. thanks for all your suggestions.