daz_vx220

Im running a 56 plate sti spec D which is vibrating at low revs. All I can describe it like is as if I'm in the wrong gear, the vibration comes through the whole car but feels like it's underneath me. No slipping on clutch and engine and box run sound. Just had it serviced and been told nothing looks wrong although the garage isn't a Subaru specialist. If I keep the revs above 2k you wouldn't notice anything. Any experts around Doncaster?

greg320

iTrader: (15)

Have you checked the engine mounts

cster

I get this a bit in mine, but mainly only noticeable in 5th and 6th on WOT.
It all began when the clutch was replaced with a faulty item.
Clutch has been replaced, but there is still some residual low rev vibration.
I tend to drive around it.

moneys

iTrader: (5)

this is exactly what i get at around 3k in both 5th an 6th booting it, feels like its the diff but if you say the clutch it may be as i got the clutch replaced only a few months back and i know he struggled to get the correct one, you got any more info? i also suffer with a judder at 1500 revs in 3rd gear only, nothin mad but kind spoils the whole tootling around part of driving, i took it back to the mapper who simply said i was driving to slow, wasnt happy with that but what could i do

daz_vx220

Mines on original clutch 69k as it was one owner from new before me, so my clutch hasnt been messed with.

cster

Well it is all a bit mysterious to me.
My Spec D has done 110K so I guess their is a little "tired-ness" in the system.
Before the second clutch was replaced, I assumed the problem was coming from the rear. The problem with the second clutch was that the springs were loose. Perhaps this was permitting a resonance from a vibration originating from somewhere else in the transmission.
Perhaps the higher low down torque of the 2.5 litre engine is highlighting a weakness in the system that is not evident from the 2 litre engine.
F*cked if I know - I've pretty much given up, having had the rear diff and the gear box stripped and put back together - I have decided to learn to live with it.
I would be interested to get to the bottom of it if anyone out there knows any better though.
ps. I give 1500 rpm in third a bit of a miss for exactly the same reason. This was OK with the original clutch. It is annoying, because it means having to drop down to second more than I would like when I am in tootle mode as well.
pss. The 5th and 6th gear WOT issue was mainly between 2500 and 3500 RPM.
Maybe your mapper is right - don't let the engine see the wrong side of 3500 RPM!

moneys

iTrader: (5)

Thing is though mine was perfect before hand, it had a full rebuild as the HG went adn when the engine was out he replaced the clutch as well. i can drive around the low speed 3rd gear one but cant really drive round the high speed 5th and 6th one. i may give him a call next week an pop over. could do without any more big bills though

jazzyjembreaze

iTrader: (11)

The vibration you are feeling is torque goin through the drivetrain & shafts
Very noticable on the 2.5 if you are changing gear very low down
You should as a guide always try to keep the car over 2000/2500 more so from 4th up to 6th as it puts huge strain on the car
Keep the car reving you will notice the change & the car will be much smoother / if symptoms still persist higher up the rev band you have a engine mount or drivetrain issue /

99mrbe

iTrader: (1)

Daz is it whilst pulling of at low revs or just rolling along?

daz_vx220

Yes to be honest i didnt think there was anything seriously wrong and i can only compare to my previous 5 impreza's all being 2ltr engines. Ill just keep the revs up although ive done half a tank of fuel after 86 miles which also surely cant be right driving it steady

moneys

iTrader: (5)

can this be mapped out though?

moneys

iTrader: (5)

daz i find driving it 'briskly' is best. dont labour it or boot it just steady

daz_vx220

99mbre-to be honest its when i change gear low down while moving, like said previously if i use more revs, nothing at all.

99mrbe

iTrader: (1)

The only reason why I ask is the same happend on mine at low rpm but really only on pull of!
Which happened to be a distort (if that's how you spell it) flywheel!

DT-SPD

iTrader: (7)

I had a 5th and 6th WOT vibration on my Spec D ( now sold ) and think it was due to the limits of the std ECU software. The boost control can not be tweeked for each gear, so high load in high gears builds a lot of boost at low rpm, and because the revs dont rise as fast there is a lot of torque through the system and the vibration starts.

Be interesting to know if cars mapped on ECUtek ( with per gear boost mapping ) still have the same issue.

cster

Yes.
I'm not sure if it is possible to vary the boost through the rev range per gear, (except by using the right foot actuator).

DT-SPD

iTrader: (7)

I am pretty sure that ECUtek software allows per gear boost targets on the DBW cars.