booger

iTrader: (6)

Jeremy....you tuned str8dum1 car ?

Audible Mayhem

iTrader: (48)

yes i did, there was something going on with it though. maybe it was the blower going bad, i am not really sure. it was making decent boost but not full boost. it also was knocking really bad when it shoudnt have. we even sent the guys out to go get 10 gallons of 93 octane to make sure it wasnt bad gas.


we run into this stuff all the time with self install stuff. sometimes it works well and sometimes it doesnt. its not that we are saying we can do things that people cant , its just that when you install sooo many of them, you learn little tricks that you wont learn on your first one. thats why we can save time and do it right the first time..

str8dum1

iTrader: (11)

when else was it knocking?

jpc350z

So , why does it make soooo much more than the typical Vortech with similar systems.. Single exxaust.. Higher boost but restrictive flow..What do you think accounts for the exceptional power..

Audible Mayhem

iTrader: (48)

honestly, some motors are stronger than others. we see this all the time.

we did nothing different from our normal vortech installs... the car was stupid loud , like undrivable but he liked it!!



rich, your car was knocking anywhere over 8 psi, it was weird. thats why we thought maybe it was bad gas or wrong octane.

we see that knocking usually when its a boost leak of some sort, its hard to explain but i sit on the dyno every day all day so i know what i see....

str8dum1

iTrader: (11)

Thanks.

I took of my plenum spacer and am now seeing 20inHg. I'm going to pressurize the entire system to make sure everything else is good.

As long as you feel that the knocking was due to something blower related thats a good step. I was concerned it was the car and something else that couldnt be fixed from just reviewing the blower install.

Thanks!

damojo2003

What plugs are you running and what is the gap? I would suggest a slightly cooler plug, tighter gap and maybe even a plug where the groung is cut back. Similar to autolites racing 103s.

Too rich would cause kr, but you have to be rich enough to cool the quench area and smother the KR. I would first pull the plugs and see how they are running. If any are lean, have the car programmed to give those cyl a bit more fuel than the others. If that is possible. I would also pull timing for WOT and slowly give it more timing until you see KR. Then back off. You want the car to start at a good AFR and slowly richen with rpm and time to prevent preignition.

str8dum1

iTrader: (11)

running 1 step colder copper plugs with .42 gap.

Does the UTEC distinguish between a knock and a misfire?

damojo2003

The computer should know the difference beween the 2. If there is a misfire, there should be a code that will come up. GM cars have the sevice engine light blink while the rapid midfire is occuring and remains on after the fact.

I think that before you really go hunting for a mechanical issue, you need to rule out the simple stuff first. The plugs tell the entire story for each cyl. It will tell you rich, lean and about the timing. First, do you have any type of scanner to hook up to the car and log certain parameters? Do you have anyway of programming the car yourself? How much boost are you runing? The plugs sound good for your setup, but I am still learning about 350Zs. I don't think the issue is boost, I think the issue is fueling and spark. What spark advanced are you commanding and how much knock are you seeing? What AFR are you commanding and what are you actually seeing? I am going to guess that up top you are not giving it enough fuel to cool the heated air from the supercharger causing preignition. That is just a guess, but I need more info. Can you post the link to the huge thread that we are now revisiting.


edit: 11psi and what compression ratio? Maybe a plug with a cut back ground might help.

str8dum1

iTrader: (11)

the car was pro tuned at Performance Factory. Jeremy knows all the details but didnt share what he was doing to tune the car. He does this enough, that adding fuel and pulling timing, I'm sure were addressed.

I can data log from my UTEC. I think bottom line is that I'm going to have to put the car back together when my blower gets here, run a pressure test to check for leaks and then redyno.

damojo2003

At this point it is still possible to pull the plugs and see if you have the common lean condition. It only takes 1 cyl to lean and cause preignition. I am not saying that the guy from performance tuning did not do a great job. IMO, you left with knock and he should have told you what it was or his best guess. Judging by his post, it is boost leak. Are you sure it is not spark blowout? or the common lean condition for these cars? Maybe some one can explain to me what boost leak is.

I know a mechanic that is an awsome mechanic for my engine. Has been dealing with this block since the grand national. Every car that he tunes runs rich, infact too rich. He got my car for a repair, he read the programming of my car for his personal benefit. This is a forever changing tweaks to my tune that I can change with my laptop.