RPM and Load Dependent Screech/Whine Noise

Zbestest

Hi all, new to the forum and I've done my due diligence and cannot find anything similar to the problem I am having.

The problem: I am experiencing a screeching/whining noise under partial load, at 10%-40% throttle input in first, second, and third gear only. The noise happens somewhere in front of the drivers seat (Engine bay/ Transmission Tunnel) as I cannot recreate the sound while the car is still i cannot pinpoint location. Other gears may be doing it as well but the wind noise could be too great. The noises happen at 2100rpm and 3300rpm. The noises only happen when passing through these rpm's not when sitting in that rpm range. I did happen to climb a small hill steady at 3300rpm, and the noise did happen, this was the first time it happened stably, it sounds like a screech with some oscillation. This can be heard over my exhaust setup and is very prominent when it happens. Sometimes the car will produce the sound 90% of the time and others 30%.

Background on car: 2013 Nismo 60xxx mi., throws no codes. The car has stillen gen 3 intakes, INVIDIA HFC, FI CBE. I List because I've heard about some resonance frequencies from I/E setups but I don't think this is my case as the noise is far too loud and screechy for it to be a resonance frequency imo. Also the replicability makes me believe otherwise (Doesn't always happen)

Car has a aftermarket single mass flywheel and clutch assembly to go with, along with ZSpeed HD CSC. It does rattle but never makes screeching noise, I have a feeling this may be the cause, but it also doesn't make a screeching noise at idle and will not make it without engine load (dry revs do not recreate noise).

Now onto my other possible ideas the car is tuned and (1)I have heard of problems with the throttle bodies making noise (2) VVEL system issues? (3) water pump(never been low on coolant/antifreeze) (4) Alternator? (RPM dependent noise only makes me believe otherwise)

Kinda Stumped, anything helps. Thanks!

asht

Title says load dependent. If stationary does it do it in neutral / clutch depressed?



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SouthArk370Z

Check your belt. It may be worn or the idler may not have enough tension.

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Zbestest

I'll check the belt that was something I only did a visual and it seems tight but I'll try the deodorant trick and see if it helps then I'll tighten if needed. Thanks!

And more info for the other person, it will only happen while moving, downhill will not make noise but uphill will make it more prominent than flat. Uphill will also make the noise consistent if I hold the RPM which doesn't happen on flat.
Thanks y'all!

Dreadnaught

Try revving up your engine in neutral to see if the noise is present. If so, you can rule out the trans, diff and any other moving part. To me, it sounds like it you may have an exhaust leak. If you can have a friend help listen and try to pin point where the sound is with the hood up. Check to see you if you can see soot around the exhaust manifolds. You could have a stud that broke on one of the exhaust manifolds or any part of exhaust.

Also, put your car in gear and power brake it and see if the noise presents itself.

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