Clunk noise + jerk when taping throttle?
Roughy 65% of the time I'll hear a clunk noise and then a jerk (what feels like the clutches instantly grabbing) whenever I lightly tap the throttle. It doesn't matter what gear I'm in. I also normally drive in sport manual. I understand sport makes the clutches slip less and grab more aggressively but I don't recall the clunking noise being there. What could this be? My SST? Something else? I'm just confused since it happens irregularly.
My car has the following: Cobb AP Stage1+ 93 Octane LWG flash, Cobb SF intake, Corsa Catback |
When is the last time you changed the fluid in the SST?
Were you protuned for the SST or just an off the shelf tune? Has it always behaved like this? Ideally you should always drive in Sport + manual for longer clutch life - there should never be a clunk. |
Also, what year? How many miles?
Could be an engine, transmission, or other driveline bushing if your Evo's older or higher mileage.... |
Originally Posted by Napalm_Enema
(Post 11872564)
When is the last time you changed the fluid in the SST?
Were you protuned for the SST or just an off the shelf tune? Has it always behaved like this? Ideally you should always drive in Sport + manual for longer clutch life - there should never be a clunk. It's an off the tune shelf from Cobb, I'm not sure if their OTS maps even touch the SST. From what I can remember it hasn't behaved like this before, at least not as "jerky". I always drive in sport and manual mode while also putting it in neutral at stop lights. |
Originally Posted by splattj
(Post 11872622)
Also, what year? How many miles?
Could be an engine, transmission, or other driveline bushing if your Evo's older or higher mileage.... |
Is this not just normal noise from the transfer case? I feel like i get this "issue" all the time ha.
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Originally Posted by Haan
(Post 11872646)
I changed the SST fluid @60k miles which was about 3-4 years ago.
It's an off the tune shelf from Cobb, I'm not sure if their OTS maps even touch the SST. From what I can remember it hasn't behaved like this before, at least not as "jerky". I always drive in sport and manual mode while also putting it in neutral at stop lights. If you don't have that resource nearby, there are a lot of good ones that can etune. Kozmic Motorsports in Houston is one of the very best, and I live in Houston and can vouch for them. There are a lot of other great e-tuners, wtftuned is another, and some other are out there. Either way I'd change fluid first - see where you're at, but get that thing tuned unless you got deep pockets. |
Originally Posted by AdamDeMamp
(Post 11872679)
Is this not just normal noise from the transfer case? I feel like i get this "issue" all the time ha.
|
Totally normal for a DCT transmission/drivetrain to clunk, it's dealing with a lot of opposing forces and things are bound to slack over time. Don't see Kozmic until your transmission won't shift odd or even gears...then it's ready for a $4000 overhaul.
Why do people insist on putting an Evo SST into neutral at stops? Unless your ABS sensor and throttle positions sensors are broken, the car knows exactly when you're at a stop and tells the TCU exactly what it needs to do. Do a google of "Should I put my dual clutch in neutral at stops", read a few articles and learn why that's a terrible idea. One thing I'm learning about the Evo community is the amount of vapor-logic that gets tossed around. |
I think there was an issue with the earlier year torque damper. If it's not bushings, then that would probably be my next rabbit hole to jump down.
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Originally Posted by RevMaynard
(Post 11875794)
Totally normal for a DCT transmission/drivetrain to clunk, it's dealing with a lot of opposing forces and things are bound to slack over time. Don't see Kozmic until your transmission won't shift odd or even gears...then it's ready for a $4000 overhaul.
Why do people insist on putting an Evo SST into neutral at stops? Unless your ABS sensor and throttle positions sensors are broken, the car knows exactly when you're at a stop and tells the TCU exactly what it needs to do. Do a google of "Should I put my dual clutch in neutral at stops", read a few articles and learn why that's a terrible idea. One thing I'm learning about the Evo community is the amount of vapor-logic that gets tossed around. Kozmic knows a LOT about the SST, so I took their advice to put it in neutral as best practice for the SST. |
Originally Posted by Napalm_Enema
(Post 11875818)
On the neutral at stops - that was recommended by kozmic as the clutches don't have to sit there at the light applying continual force to stay there in gear. Interesting thing that corroborates that in my opinion is my M2 with a dual clutch puts itself in neutral at stops automatically so there might be something to that recommendation.
Kozmic knows a LOT about the SST, so I took their advice to put it in neutral as best practice for the SST. SST's don't just sit there and apply unneeded clutch-force, like I said there are several ways the car is telling the TCU to disengage at a stop and engage as soon as the throttle position is beyond a specific percentage. Putting and keeping your foot on the brake pedal and not creeping especially up a hill is however 100% valid advice. Believe what you will, nothing wrong with that but personally I believe 10% of what people write about these cars, especially the SST's in them. Cheers, RM |
Originally Posted by RevMaynard
(Post 11875824)
I know of and respect the hell out of Kozmic.. They have the market cornered, even as a Canadian MR owner my only proper path to a rebuild would be to crate my transmission and ship it too them.
SST's don't just sit there and apply unneeded clutch-force, like I said there are several ways the car is telling the TCU to disengage at a stop and engage as soon as the throttle position is beyond a specific percentage. Putting and keeping your foot on the brake pedal and not creeping especially up a hill is however 100% valid advice. Believe what you will, nothing wrong with that but personally I believe 10% of what people write about these cars, especially the SST's in them. Cheers, RM |
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