Whats up everyone, I had my '04 G at Church Automotive this past weekend and while Shawn was tuning my car, we found that the knock sensor was throwing the timing. The car made ~390whp and 350wtq but Shawn de-tuned it so I could drive her home.

Shawn told me to look for external sources of vibration in the system as the SC kits tend to add a lot of extra vibration to the car. I think I may have found the problem, but I'm not sure, as this is my first time going FI with a vehicle, I'm turning to the knowledgeable folks on here for advice.

The Imgur album has the dyno sheets (hp/tq and boost/vaccuum) and a pic of what I believe to be the problem.
http://imgur.com/a/wAXpx#0

When I purchased the kit, the previous owner told me that when he took the kit in to have it polished, they couldnt get the 3.12 pulley off so they just polished around it. I have a feeling that the bearing might be starting to go as there is a bunch of black dust building up around that area.

Does anyone know where I can source just that piece? (The thingy that both the 3.12 pulley and the cog pulley bolt onto? No idea what to call it )

Also, if you guys think that isn't the problem and have any advice on what I should be looking for, that would be greatly appreciated. (I'm thinking it might be safer to switch back to the 3.33 pulley )

Some more info on the car:
2004 G coupe 6mt
Motordyne 5/16”plenum spacer
Vortech V3 Si kit
NGK 1-step colder plugs
DW 255 lph pump
DW 600cc injectors
Momentum Performance headers
Berk High Flow Cats
Greddy EVO-TT Catback
Uprev Osiris Tune


On a side note, I also picked up some torco for my next dyno session just to be **** safe and try and avoid detonation.

 

The pic's tell me nothing on the condition of the Blower.

What ever Fuel you normally run is the Fuel you should Tune with.

 

Thanks man, I'll keep that in mind, just wanted to try and minimize the chances of detonation
The blower itself runs fine, no real vibrating or weird noises

Do you tink it would be worthwhile adding an engine damper?

 

No, but if yo have bet slip, you'll need a Radius Rod Strut Kit.

Search my old post if you would like to see it.

TimRod

 

Thanks for the input tim, I've actually read through all your posts and that kit is pretty bad ***, but I'm not getting any belt slip at the moment

The reason I think the vibration is coming from that part of the assembly is because that is where I hear the noise when I listen to the motor. I'm going to pick up an automotive stethoscope and see else I can learn.

I have an osiris tuner license so I can monitor my knock sensor through cipher as I try and hunt down the source of vibration, just have to learn how to do that lol

 

The Bearings in the Jackshaft could be wore out. Take off the belts and spin it, if you hear any sound at all, they are done. Easy job to replace them, I did mine at about 20,000 miles. I don't think it could cause a knock signal, but who knows.

Don't go thru Vortech to get the bearing if you need them. talk to Superchargersonline.com He's a good guy.

 

I've had the same issues too with my Vortech setup, and I've read other FI setups that use the Osiris also have this issue, due to the inherently noisier nature of FI, and the sensitivity of the oem knock sensor...

It definitely could be the blower, but it may also just be the noise from the Vortech setup...

I just disabled mine since I knew for certain I was getting false knock readings (I also tuned at Church), but to be safe you probably should keep it on. WIth other standalone EMS you can also adjust knock detection thresholds as well...

 

If i may ask, How did you disable the K.S ?, Using Uprev, a resistor or what ?!!!

 

Thank for all of your help and advice guys!

I'm gonna remove the drive belt later and check for noise coming from the jackshaft and then the two idler pulleys. If I don't find anything there I'll drive around a bit and monitor the K.S. using Cipher and let you guys know what I find out.

 

My tuner did it, so I assume he used uprev to disable it...

 

that must be a pro-tuner option as its not defined in the standard set of Uprev features.

 

Roger that

 

are you getting any code?

 

Nope, no code!

Yesterday I took the belts off and no noise from any of the pulleys, I did however go about re-tightening the 4 bolts that mount the blower to the mounting bracket and that seems to have made a good difference in vibration. Gonna drive it a bit and re-torque all the bolts on the mounting plate as well.

The ability to monitor/change the knock sensor parameters is most definitely a pro-tuner option only, as str8 stated.

 

Just to update this, I haven't found any source of extra vibration against the chassis, or against the motor, other than the vibration the Vortech unit is known to make at low RPM's (haven't adjusted my idle up yet).

So I'm thinking the knock sensor wasn't malfunctioning and it was probably sensing detonation. So, I'm thinking a stage 0 RFS and swapping down to the 3.33 pulley should be a good solution.

Any thoughts?

 

if its true knock, prolly better to address the source, ie the tune, instead of changing anything else.

otherwise dump in some race gas and see if it goes away. I