Thread: Quick question about increasing pulley size

Currently I'm running a 3.4 press on pulley and I'm seeing a max of 9* of knock. I tried using Torco and that barely helps, brings it down to around 7*. It's only a blip of 9* when shifting, but it doesn't want to go below 5* until I let off the gas. If I pulley up to say a 3.5 or 3.6 should I see a good decrease in knock and actually gain some hp back? I like hearing the scream of a 3.4, but obviously power is what I'm after and I just don't like to see that knock decrease my timing to below 10*. Please help me with some advice of what I should do. Mods are in my sig. Thanks Gents

I'd say it's not likely. The torca should have given you a ton of room if the knock was noise from predetonation. Almost sounds like you have a tuning issue.

The guy who tuned my car tried to lower my timing and it was still high kr. That's why I was going to replace my knock sensors because he thought they could be sensitive. I wasn't able to replace the rear one so I think it's either that or I have false knock somewhere. Although I only get knock doing wot pulls so idk whats up. Possibly a fueling issue? When I had a canned tune my kr was worse like up to 12.

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Knock sensor sensitivity is controlled by how tight they are in the block. They are supposed to be 14ft lbs. And if he thought that..then he should have turned down the sensitivity in teh tune for them.

To rule out fueling issue check your fuel pressure at the rail and depending on the last time you changed your fuel filter you could change that out as well.

Ok, I might have to have someone check my tune then cause the guy I got my tune from sold his GP and doesn't tune anymore, but there is another local guy I could get to look at it and try to find out what the other guy did. Heard he messed up on a couple other guy's tunes also so it really could be my tune. And I did change my fuel filter a little over a year ago, but I did use some seafoam and a couple other fuel system cleaner's since then so maybe it got gunked up again?

I don't remember how often the fuel filter should be changed.

Sent from A Galaxy Far Far Away........

I think it's like 50,000 or around there maybe 25,000.

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Yeah I can't really remember

Sent from A Galaxy Far Far Away........

I'd change the fuel filter everytime you change the blower fluid...around 30k~ miles.

my 03 gmc used to clog the filter by 13,000 miles, if let go it killed the pump. found that out the hard way. at around 12,000 miles off the line if i floored it and red lined it, it would bog and stall instead of shifting. first sign it was getting clogged up.

once the old filter was off you could not blow through it at all.

Also noticed peaking at 9* knock the past few days. Going to change up my intake tonight to see if it changes anything

Knock effing sucks dude!

Originally Posted by K Kraziee

Knock effing sucks dude!

I'll second that.. I've been chasing mine down for a while (also seen up to 9* at WOT). Installing some modded rocker arms here within the next week or two to try and get rid of some.