1991 R32 GTR RPMs dropping...

[Jjtxaz24]

Hey guys, just recently started having this issue where I press the clutch in and my RPMs drop. I thought the clutch booster was old and the diaphram inside it was torn so I did a clutch booster delete, swapped in a new clutch master and slave and plugged the vacuum source that came off the intake plenum that the clutch booster was using. 

Car still bogging when I press in the clutch. 

Aside from that I also have a "chirping" noise at idle, but it wasnt as bad as it is now. It was just every once in a while. I suscpect its the throw out bearing, and of course the "clutch chatter" when the clutch pedal is fully engaged, but I've had that ever since I got the car. 

Here's a link of what it does when I press the clutch in. 

Any help is much appreciated it. Thanks in advance. 

[Duncan]

Holy shit you've lost your steering wheel!

[Duncan]

Anyway...I've not seen/heard that before but something is pretty unhappy there.

Have you changed the oil lately, and were there any metallic flakes? Also, if you push the clutch in with someone watching under the bonnet, does the harmonic balancer move back and forward at all?

[Jjtxaz24]

On 6/17/2022 at 5:58 PM, Duncan said:

Anyway...I've not seen/heard that before but something is pretty unhappy there.

Have you changed the oil lately, and were there any metallic flakes? Also, if you push the clutch in with someone watching under the bonnet, does the harmonic balancer move back and forward at all?

I have not driven it enough to change the oil, but I can. Short answer. No, I haven't. I will need to give the harmonic balancer a once over. 

I'm confused as well, it idles fine. Only when I press the clutch init drops RPMs like that.

If it helps any I have now deleted both the brake booster and clutch booster, and both vacuum sources have been plugged. 

[joshuaho96]

That sounds horrific and unrelated to any booster. Like Duncan my first instinct is that the clutch may have be pushing on the thrust bearing hard enough to cause serious friction and slow the engine down. The other possibility is a clutch bearing has failed. Or maybe the transmission and engine aren't actually bolted together properly and operating the clutch is causing the input shaft/crankshaft/clutch to touch something it shouldn't.

Don't keep trying it until something more catastrophic occurs. I would check for crank walk and if that's not your problem it's time to pull the transmission and inspect the clutch.

[GTSBoy]

Yuh. They're ^^ correct. That is clearly mechanical friction happening. You do not want to push that pedal while the engine is running EVER AGAIN..... at least until it is all out on the workshop floor and you find out what is rooted.