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seeing some knock retard



fry626 said:
Porting a supercharger correctly makes the blower more volumetrically efficient, not the engine. More air coming through the blower means more boost since the engine VE hasn't changed.
Headers make the engine more volumetrically efficient, that's why boost goes down.
Click to expand...

No one tests this.

And you can influence ve differently at different blower speeds.

Mostly changing the size of the inlet/outlet affecting "overlap" for lack of a better term.

A blower for a 2.8 pulley should look pretty different for one with 3.8.

Stock the blower hardly sees 10.5 krpm. 2.8 w/ 6000 rpm shift would be 14.5 krpm. Thats almost 40% faster than stock.

Youd never suggest a cam for an engine spinning to 7000 rpm for an engine only seeing 4200 rpm max.

So if the high rpm cam is used in the low rpm engine, you will see a loss in flow. Use the low rpm cam and youll pick up flow.

In the high rpm engine, with the high rpm cam, you will increase flow at high rpm. Down low will suffer, but the engine isnt meant to be run there.

So porting your blower if youre running a large pulley? Probably a waste of time. If you care that much, get a gen v or a larger tb. Even then , tb is a waste unless you go past a 3.4. That number is based on gen v inlet flow compared to estimated stock tb flow numbers. Gen 3 guys will probbly get away with less pulley before it becomes a restriction.

If you wanted to know for sure, monitor vacuum on the top vac tree during wot. 0.0-0.5 is probably fine, 1" hg or more means you could benefit from a better flowing tb/ intake. You can do the same test to your intake as well. Simply monitor vacuum just before the tb.
 
This is GPF, Matt.

Sad panda math...nothing true applies here.

So keep that in mind when you figure the volumetrically efficiency of any power adder.
 
so, i just installed the 180 t-stat. gonna do a couple wot runs tonight to see if it helped or not. just in case though, i have already ordered a 3.5 pulley from zzp
 


got my friend to hold my phone and watch the kr numbers this time. apparently it got as high as 6.1 degrees. so i will have to keep off the pedal until that 3.5 comes in the mail. i\m guessing living below sea level does not help lol
 
bought a new o2 sensor today. gonna see if that helps at all because the current one got a bit greasy when i came out for the header install
 
haven't done a wot run yet because, merging onto the highway today, i went like 75% and got 6.3 degrees of kr on the 3.5 pulley. i'm starting to think that it's false knock. gonna install the new front o2 sensor soon because i was skeptical of the old one and think it might be running lean. but also i noticed some points where the headers touch other metal components, gonna stick some foam tape on those components, see if that helps
 
blakgtp said:
haven't done a wot run yet because, merging onto the highway today, i went like 75% and got 6.3 degrees of kr on the 3.5 pulley. i'm starting to think that it's false knock. gonna install the new front o2 sensor soon because i was skeptical of the old one and think it might be running lean. but also i noticed some points where the headers touch other metal components, gonna stick some foam tape on those components, see if that helps
Click to expand...

Not false if you're merging on highway. -- Pulley up on the double mister.
 


i pulley'd up from the 3.4 to the 3.5 already and saw no difference in the amount of kr. but i just installed a new front o2 sensor today, so we'll see if that helps. it already seems to idle a bit smoother
 
i think im having a similar problem to you... I wasnt running an KR on a 3.4 SD headers n canned tuned from ZZP. With the colder weather, i was merging on the highway and did like 3/4 throttle n saw KR for the first time. I pullied up to a 3.5 and still seem up at higher RPMS n speeds, around 0.2 to 1.6 ish. Not sure if its false KR or what....I do know that when i go in reverse i can hear a loud grinding thats apparently coming from my front 02 sensor from the new headers n making contact with the body. So idk if thats the problem with false KR or what....any new info after the new O2 install?
 
still have 6 degrees at wot. but i think it might be the second crossover clamp for the headers. when i installed them, i couldnt get the fat band clamps down there and all that, so i just used the one that came with the headers, and didnt get it very tight. so i think there's an exhaust leak there. when the weather clears up i will be trying the get the better clamp on there and seal it up.
 
Ya that's the same for me, but I've never seen KR for te month or two they've been on until now...idk what's going on either
 
I just drove home half hour ago and with my mods I've never seen KR until tonight only see it when I'm cruzin at 60 and mash it to 75 and saw 2.9* but didn't see any from 0-60 launching off the lights... Thinking colder whether maybe??
 


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