Since installing my SC, I hear a strange sound when the windows are down. I don't recall hearing it stock, but then again I wasn't listening for anything either like I did after installing the SC.

So basically the sound is like a tapping sound. At high RPM it taps very fast, and low RPM it taps very slow. It's not real loud and you can only hear it when the front windows are down.

It's not ping as I've used the URD 7th injector kit and tuned all the ping out.

I don't think it's an exhaust leak. I've climbed around all under the truck with it running using a 3/8" fuel line AND a mechanic stethoscope to listen to the exhaust flanges and I don't hear any leaks or feel them with my hands.

I've revved the motor with the hood up in my drive way, and had my girl rev it while I listen to the engine bay and I don't hear anything.

I can only hear it while the engine is under load and under boost.

For the rest if you SC'd guys.....is this normal? Maybe it's induction noise from the SC?

Mods are in my sig.

 

I was wondering do you think its the 7th injector? it only supposedly works under boost? maybe call urd and ask if its normal. I know I am really just throwing it out there but it seems logical.

 

I don't think so. The injector fires at like 2 milliseconds so I'd think it would go faster, but that is something I'll look into. I asked Gadget about this sound a while back and he said superchargers make all kinds of odd noises and that it could just be normal SC noise, or an exhaust leak. I've pretty much ruled out the exhaust.

I'm going to get a dyno run done in a couple of weeks. I'll try to shoot some video of the engine under the dyno load and listen real well to try to pin point the sound. On the dyno it should be pretty easy to find.

 

I have a similar sound and cannot pinpoint it either. I know it is not exhaust, almost sounds like a sticky or loud valve - but it runs perfect, afr's are right where they should be, and gets normal mileage. Let me know if you find out anything, I have been wondering about mine for about 6 months now...

 

Yep, sticky valve was my first thought too, but like you mine runs miraculously, good mileage, etc. I even listened to the valve covers with the mechanic stethoscope to see if I heard anything there and at idle or revving in the drive I don't hear a thing.

I'll update this thread if I ever find out.

 

Well i don't have a SC yet but i have a simular sound on mine, it seems to be coming from the heads like a valve or something but i have not had time to really track it down. Might be something differnt but could be the same.

Another sound i have been woundering about is when i go to get on the highway and the RPM's get up pretty high sometimes i hear a type of "grinding" sound but yet not a grind. The best i have come up with is something with the fan clutch. Is that normal? It seems to be worse when it is how out. Could it be something with the AC compresser?

sorry for the hijack...

 

its probably valve chatter.

mine does the same.