Bad clutch slip?

striktlysubie · 05-25-2024, 02:53 PM

New problem: Had the car at the dealer for some other maintenance work. The test drive by the tech noticed "really bad" clutch slip. The whole assembly has about 50k on it with 300whp from last year's bolt-ons and tune. It kind of answered why it felt like lately the car was falling flat at highway acceleration (namely in 3rd and 4th gear) with an rpm jump initially, and then would feel like it would stagnate, despite still gaining speed. Is this common? And if I now need a new clutch ***128548;, what have folks gone with for aftermarket?

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striktlysubie · 06-01-2024, 11:12 AM

No suggestions?

stoich68912 · 06-01-2024, 04:52 PM

If RPMs increase disproportionately from speed most likely clutch is slipping and needs replaced. It's a wear-n-tear item, so yeah pretty common to need replacement at some point. Just depends on how its driven and if its spec'd for the appropriate power output.

My 07 sti was on the stock clutch for about 120K, most of that on 93oct tune and bolt ons. Went flex fuel and the clutch went south quick on high E fuel. Replaced with ACT HDSS w/ resurfaced FW. Happy and holds great.

striktlysubie · 06-07-2024, 09:35 PM

^ Thanks for that feedback.

striktlysubie · 11-27-2024, 10:12 PM

The car is now in the shop to get the ACT HD clutch kit put in, as well as a slew of other work done to it. Fingers crossed....

Charlie-III · 11-28-2024, 12:50 AM

For the future, my usual clutch test is:
3rd gear, up at least a slight grade, RPM's 3000RPM or so, mash the gas.
If the tach jumps up but little or no real speed change, the clutch is slipping. You may also smell "hot brake" smell which is the clutch.
The gear reduces mechanical advantage.
The RPM's gets you near max torque.
The hill makes it work harder.

striktlysubie · 11-30-2024, 09:01 PM

Indeed, thanks. My burnt clutch smell was heavy.

striktlysubie · 01-01-2025, 07:06 PM

The car has the new ACT HD clutch with oem TOB and oem fork, so this issue seems resolved now. Other issues, not so much.

05-25-2024, 02:53 PM	#1
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	Bad clutch slip? New problem: Had the car at the dealer for some other maintenance work. The test drive by the tech noticed "really bad" clutch slip. The whole assembly has about 50k on it with 300whp from last year's bolt-ons and tune. It kind of answered why it felt like lately the car was falling flat at highway acceleration (namely in 3rd and 4th gear) with an rpm jump initially, and then would feel like it would stagnate, despite still gaining speed. Is this common? And if I now need a new clutch **128548;, what have folks gone with for aftermarket? Registered users of the site do not see these ads.

01-01-2025, 07:06 PM	#8
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	The car has the new ACT HD clutch with oem TOB and oem fork, so this issue seems resolved now. Other issues, not so much. Last edited by striktlysubie; 01-03-2025 at 11:55 PM. Reason: typo

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06-01-2024, 11:12 AM	#2
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	No suggestions?

06-01-2024, 04:52 PM	#3
stoich68912 Scooby Newbie Member#: 350291 Join Date: Mar 2013 Location: Chicago	If RPMs increase disproportionately from speed most likely clutch is slipping and needs replaced. It's a wear-n-tear item, so yeah pretty common to need replacement at some point. Just depends on how its driven and if its spec'd for the appropriate power output. My 07 sti was on the stock clutch for about 120K, most of that on 93oct tune and bolt ons. Went flex fuel and the clutch went south quick on high E fuel. Replaced with ACT HDSS w/ resurfaced FW. Happy and holds great.

06-07-2024, 09:35 PM	#4
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	^ Thanks for that feedback.

11-27-2024, 10:12 PM	#5
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	The car is now in the shop to get the ACT HD clutch kit put in, as well as a slew of other work done to it. Fingers crossed....

11-28-2024, 12:50 AM	#6
Charlie-III NASIOC Supporter Member#: 30669 Join Date: Dec 2002 Chapter/Region: Tri-State Location: USA, North NJ, 07456 Vehicle: 1998 Legacy 2.5GT Silver Sleeper BK, 5MT	For the future, my usual clutch test is: 3rd gear, up at least a slight grade, RPM's 3000RPM or so, mash the gas. If the tach jumps up but little or no real speed change, the clutch is slipping. You may also smell "hot brake" smell which is the clutch. The gear reduces mechanical advantage. The RPM's gets you near max torque. The hill makes it work harder.

11-30-2024, 09:01 PM	#7
striktlysubie Scooby Newbie Member#: 423516 Join Date: Jun 2015 Chapter/Region: NESIC Location: RI Vehicle: 2015 WRX Premium Lightning Red	Indeed, thanks. My burnt clutch smell was heavy.