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alex yates
Shanghai
Shanghai


Joined: 06 Mar 2014
Posts: 10654
Location: Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat May 27, 2017 9:38 am    Post subject: Powerflex gearbox mounting bush insert kit - WOW! Reply with quote

I ordered myself some of the Powerflex gearbox mounting bush inserts the other day afterfinally deciding to have a go at them once seeing infrasilver had took the plunge.

There's always felt like something is a bit slack or wear with the drivetrain on my 996. Nothing bad but I've had the impression it didn't drive as factory standard. It's as though there was some backlash in the gears noticeable when you quickly release your foot off the accelerator or dump your foot on it when coasting. I changed my engine mounts some time ago as you could rock the engine under the car when swinging on the manifolds and as far as I'm aware this is the only other fixing point for the engine and transmission so thought it would be a good idea to 'improve' the stability of it.

Knowing that it's probably not that easy to remove the original bushing and fit a new one, then the ease of removing the gearbox carriers and slipping these inserts in, well that option won.

They arrived yesterday morning and I knocked off work at 2.30. Once arriving home I had a couple of hours to spare before meeting the lads for the compulsory Friday T-time pint so thought I'd give it a go at fitting them.

Took just under 2 hrs start to finish and wasn't too tricky. Hardest part was fitting the inserts in the original apertures.

Once on ramps and axle stands and everything removed ready to fit the inserts (I used this guide here linked half way down the page: https://www.powerflex.co.uk/road-series/product-details/Gearbox+Front+Mounting+Bush+Insert+Kit/12311.html) I could then inspect the original mount. You could tell it had sagged over the years as the inserts wouldn't fit in. The two lower 'ears' of the insert fell in to the lower apertures, but the top one wouldn't even look at the top aperture as the mount had sagged so much. You could easily rock the steel insert in the original mount back and forth as it was that worn. I soaped up the new inserts and then by putting a long screwdriver through the bolt holes on the steel insert I could lever the steel insert one way to enable to open the top aperture and slide the insert 70% in. Then the same trick the other way round to get the other in. Using a rubber mallet I nicely knocked them into there final seated position all the way in.
Refitting the carriers was pretty easy and they were a perfect snug fit around the outside of the inserts (I know Chris had mentioned this could be a bit tight due to the side walls being 10mm thick, but this wasn't the case).
Lining the bolts holes though the carriers and mount was a bit awkward but by placing a 6mm allen key through one of the holes then a bit of jiggery pokery with the jack supporting the gearbox, I managed to get one of the bolts in and then the other one.

All bolted back up, undertrays refitted, back on the floor, pack stuff up quick shower, it was time to head off to the boozer for a well deserved scoop in the sun.

Well, WOW! - what an instant noticeable difference. Not necessarily a good wow, but a big difference. Jury's still out yet as I'm not 100% convinced on all aspects and only covered about 8 miles in urban area (ish).

As soon as you turn the engine over you notice something's changed. I get what cobrars was saying about vibration as once the engine's running you can feel it right through the car.......but.......as yet I don't mind it. It doesn't feel over the top but does give a sharper fell of what's between you and the tarmac.

Once in motion, the car does feel more sturdy and sharper and more 'precise' on the throttle. I'll say this - it instantly felt great, to the point it was like I'd got in a different car. Everything just feels so much tighter when driving it, most noticeable when actuating the throttle just after gear changes and gear changes themselves. The correlation between what your foot it doing and what the car is doing feels so much more precise than before.

I accept my original mount was jiggered and not performing anywhere near how it should and these have taken it back to standard and a bit beyond so the difference I've experienced may be greater than others would. The 'vibration' mentioned previously, I wouldn't call vibration but more feedback through the chassis what the engine is doing. A bit like on a motorbike.

I'll update when I've done a few more miles in the car and as I said,, jury's still out, but I get the impression that there's 2 groups of members one here:

1. Those that love the interface between man and tarmac that the 996 perfectly delivers and want the most raw but precise feel between the 2 - if this is you - fit these bushes (only £30 and a couple of hours, what's not to like).

2. Those that love the comfort of the 996 but sometimes feel it's a bit harsh so let their tyres down to compensate, etc. - if this is you, don't bother wasting £30 and go to the pub for a couple of hours (on the A road as the tarmac is smoother Grin ).

Hope this write-up helps a few undecided members.

If I do find them a bit unbearable, I'll either wait till after my 1st St Tropez jolly with the lads and see if they bed in after 3k miles or I'll start shaving some material off the side walls and shortening the lower ears. Watch this space.

thumbsup


The image below shows the original gearbox bush but shown on it's side. The top aperture that had closed in due to sagging is the one on the left:


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EGTE
Nürburgring


Joined: 06 Jul 2015
Posts: 439



PostPosted: Sat May 27, 2017 11:48 am    Post subject: Reply with quote

I found these completely unbearable and gave them away (to another forum member).

But it probably comes down to just how balanced the drive-train is on each car. Mine had a new clutch and may be a tad out; it was appalling.
 
  
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Marky911
Imola


Joined: 04 Jun 2009
Posts: 850



PostPosted: Sat May 27, 2017 1:03 pm    Post subject: Reply with quote

I'm with you EG,

Glad you like them Alex, we found them absolutely horrible. Fine on a track car when you're so busy chasing lap times and hitting apexes to notice harshness, but they ruin a road car. And that's not because I don't like harsh.

A GT3 is arguably too hardcore for road use and you don't even get poly gearbox or engine mount inserts on those.

Like I say, I'm glad you like them but I think sometimes we all try and justify our purchases. The change in driving feel (which isn't actually much) does not warrant the increase in buzzing and vibration (which is horrendous).

Mind you I've only driven a car that previously had a good bush anyway. These were just an experiment, but if I had a car with a worn gearbox mount bush, I'd just fit a new standard rubber bush.

Good luck heading off through France with them. Although if you keep the roof off you may not hear the racket so much. Wink

Edited to add - Mods that make a car feel more racey, tight or keyed in - Single mass flywheel, dampers and bushes renewed, even bucket seats.
£20 rigid insert, nooooooo. nooo
Because like I say if your bush is decent anyway this insert will actually not make much difference to the feel at all. Only vibration and vibration doesn't = keyed in.
 
  
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alex yates
Shanghai
Shanghai


Joined: 06 Mar 2014
Posts: 10654
Location: Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat May 27, 2017 1:21 pm    Post subject: Reply with quote

Like I said - jury's still out for me. I wouldn't say mine is horrendous but there is an increase in NVH. I suppose this may differ depending on the original state of the original bush. Are these replaceable with the gearbox in situ?

If anything, I'll start removing material off the inserts until I get the desired feel. Although as yet, I'm gonna let them bed in and see how they go. Only done 8 miles so can't make a proper judgement.
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911munKy
Spa-Francorchamps


Joined: 26 Nov 2014
Posts: 314



PostPosted: Sat May 27, 2017 1:23 pm    Post subject: Reply with quote

Very informative Alex, thanks, looking forward to your future updates.
Also EGTE & Marky, your experience is valued.

I'm wondering if I should just get a set and try giving them a 'shave' before fitting, I'm thinking that the side walls probably transfer most of the NVH.

I'm in the first camp that you refer to but whilst firmer suspension, standard tyre pressures on wider tyres, upgraded engine mounts, SSK, loud exhausts etc make my car more fun to drive it's doesn't cosset you as much when you're tired!
Mind you I like my noisy fast bikes.

I was going to try filling the voids with 60 shore poly but I may try these mounts (modified) first as they would be easier to reverse.
I'll wait for Alex's & InfraSilvers feedback before deciding which way to go.
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Marky911
Imola


Joined: 04 Jun 2009
Posts: 850



PostPosted: Sat May 27, 2017 1:39 pm    Post subject: Reply with quote

Standard bush can be removed on car but a press is required to fit new, so not great. Not sure it could wound in with a large G clamp and plenty of lube.
I think Craig did about 100 miles on his with no change so it was removed.
Removed from material may work as everything is packed very solidly.

Munky some people appear to like them. There's a thread in the 997 section about them too, but there's also a few of the 997 lads who've removed them.

Funny mod it would seem and very "marmite". I just thought it ruined a sublime car in Craig's (Cobrars) as everything is new on his so it drove beautifully anyway. We just didn't feel it added anything positive to the experience and the cons far outweighed the pros, but it could vary car to car.

Anyway apologies for thread hijack Alex. I know you do enough miles to get a proper feel for it so I'll be interested to see if it goes ok. Thumb
 
  
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alex yates
Shanghai
Shanghai


Joined: 06 Mar 2014
Posts: 10654
Location: Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat May 27, 2017 2:04 pm    Post subject: Reply with quote

No problem mate. The more information we have the better Thumb
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poppopbangbang
Nürburgring


Joined: 25 May 2015
Posts: 450



PostPosted: Sat May 27, 2017 4:16 pm    Post subject: Reply with quote

I've got the black ones on mine (so the REALLY stiff one) and didn't find it made much difference in NVH - although mine is on RSS engine mounts and most bits of suspension are on spherical bearings so there is already considerably more NVH than a standard car.
 
  
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Phil 997
Yas Marina


Joined: 05 Dec 2015
Posts: 8921
Location: Bournemouth,Dorset

2009 Porsche 997 Carrera 4S

PostPosted: Sat May 27, 2017 5:26 pm    Post subject: Reply with quote

Alex, This is a very interesting and informative read mate, I like the fact that you being an engineer are looking at ways to overcome the NVH , I had read reports of the powerflex being bad so interesting to hear your view .
I went on my old gen1 with function first trans mount bushes in yellow(softest).
I know I know your thinking it so I will say it ,always been partial to a nice soft bush ) LOL.
Anyway initially they were quite hard but bearable and as you said made the car feel sort of mechanical and GT3ish . after about 5/700 miles they did bed in and feel ok and about 25% of the added nvh disappeared so I left them fitted for over a year . Then the vibration was back with a vengeance and more that when I first fitted them, not sure if through heat or something the compound had gone brittle but it was not a nice ride so removed them and the NVH was gone.
I did like the benefits that were gained from this mod so watching very closely at what you do re shaving etc. because if you can resolve the NVH while retaining all or most of the gains from fitting these then I will do this mod on my gen2 .
Happy to contribute to the cost of a spare set for you to work on and play with, to see what the outcome is. As its this type of research and thread that takes us forward at getting the best from these cars. Grin Thumb
Enjoy your pint mate Thumb Thumb Thumb
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alex yates
Shanghai
Shanghai


Joined: 06 Mar 2014
Posts: 10654
Location: Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat May 27, 2017 5:28 pm    Post subject: Reply with quote

I do love a soft bush, just maybe not in Yellow. What's the other colour? Question Embarassed
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jezgreen911
Spa-Francorchamps


Joined: 12 Dec 2012
Posts: 270
Location: Bucks


PostPosted: Sat May 27, 2017 7:12 pm    Post subject: Reply with quote

EGTE wrote:
I found these completely unbearable and gave them away (to another forum member).

But it probably comes down to just how balanced the drive-train is on each car. Mine had a new clutch and may be a tad out; it was appalling.


I fitted these (thanks again EGTE) along with RSS engine mounts, I really like the improved connection and feel between the car and drivetrain, I guess I would put myself in the wannabe GT3 camp, my car was standard when I bought it so I can appreciate the comfort and usability of a stock 996, I just wanted my car to have a sportier feel, Thumb
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alex yates
Shanghai
Shanghai


Joined: 06 Mar 2014
Posts: 10654
Location: Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat May 27, 2017 7:27 pm    Post subject: Reply with quote

Just been for a more 'spirited' blast down to the local Aldi (3 figure run). The vibration at 5k+ is a bit extreme and when decelerating from say 6-4k there are some very strange engine noises I've never heard before.

Like I say - jury's still out on these. Tremendous feel to the performance and handling but as a trade off for loosing fillings and wobbling my moobs, I'm not sure. Will give them a few hundred miles to see if they bed in, then after that, I'll start looking at reducing some of the material content........or just buy a new bush off Porsche and make some special tool for pressing it in in situ if needed.
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diverzeusy
Hockenheim


Joined: 10 Nov 2012
Posts: 717
Location: Doncaster UK


PostPosted: Sat May 27, 2017 8:57 pm    Post subject: Reply with quote

alex yates wrote:
I do love a soft bush, just maybe not in Yellow. What's the other colour? Question Embarassed

Alex the main thing is,
if you require a soft ride you need a well shaved bush, however, us northerners prefer a hard ride so I would never shave my bush, just have it as it was intended, black? yellow? who cares. Floor Floor Thumb
On a more serious note please let us know how you get on, shaved or otherwise Grin
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thecarfixer
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Joined: 03 Nov 2016
Posts: 87



PostPosted: Sat May 27, 2017 9:08 pm    Post subject: Reply with quote

alex yates wrote:
or just buy a new bush off Porsche and make some special tool for pressing it in in situ if needed.


You won't get a new bush separately from Porsche I don't think (the parts list doesn't show them separately!)

A 987 Boxster front engine mount contains the bush you need, well, it contains a better version of the same one, albeit pressed into the alloy housing that bolts onto the front of the engine. Lemförder make one too, to the 997 pattern. That was my plan..

Tool wise, yeah, a big tube and a washer that fits against the bush, and an end cap for the tube, with a large stud and nuts will do the job nicely - there's a fair amount of room under there with all of the mounting bracketry out of the way..
 
  
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Marky911
Imola


Joined: 04 Jun 2009
Posts: 850



PostPosted: Sat May 27, 2017 10:03 pm    Post subject: Reply with quote

Interesting stuff car fixer.

I also thought you couldn't get one from Porsche as I looked into this last year. However, looking on Pelican parts there's the usual Lemforder one plus a Porsche part apparently for more money? I haven't enquired any further though.

http://www.pelicanparts.com/More_Info/996-375-055-05-M69.htm

Nothing comes up in this country though.

Dont know
 
  
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diverzeusy
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Joined: 10 Nov 2012
Posts: 717
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PostPosted: Sat May 27, 2017 10:11 pm    Post subject: Reply with quote

All available here, unless I have read wrong Confused
http://www.design911.co.uk/pages/productList.aspx?search=gearbox+mount
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thecarfixer
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PostPosted: Sat May 27, 2017 10:15 pm    Post subject: Reply with quote

The later mount has a different shape of rubber and voids, and is distinguished by a more 'teardrop' shape of centre.

The 987 front engine mount was a big upgrade on my old 986, so I should imagine in the gearbox application of a 996 it'd help quite a lot too. Couple that with some RSS (or 964 RS) engine mounts, and I think you'd have a good package.
 
  
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diverzeusy
Hockenheim


Joined: 10 Nov 2012
Posts: 717
Location: Doncaster UK


PostPosted: Sat May 27, 2017 10:17 pm    Post subject: Reply with quote

thecarfixer wrote:
The later mount has a different shape of rubber and voids, and is distinguished by a more 'teardrop' shape of centre.

The 987 front engine mount was a big upgrade on my old 986, so I should imagine in the gearbox application of a 996 it'd help quite a lot too. Couple that with some RSS (or 964 RS) engine mounts, and I think you'd have a good package.

would you have the part number for the 987 boxster engine mountr bush?
thanks carfixer Thumb
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Last edited by diverzeusy on Sat May 27, 2017 10:24 pm; edited 1 time in total
 
  
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Marky911
Imola


Joined: 04 Jun 2009
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PostPosted: Sat May 27, 2017 10:21 pm    Post subject: Reply with quote

You're right diver, the D911 item is the same as the Pelican parts one.
Cheaper too at only £43+vat. Think I'll try one as my box is coming out soon.

https://www.design911.co.uk/mobile/#part;id=4744
 
  
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diverzeusy
Hockenheim


Joined: 10 Nov 2012
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PostPosted: Sat May 27, 2017 10:34 pm    Post subject: Reply with quote

lemforder is, as I understand original supplier to Porsche so should be good, but as carfixer pointed out is it better to fit boxster 987 bushes?? link
http://www.pelicanparts.com/catalog/SuperCat/4293/POR_4293_ENGMIS_pg2.htm#item6
and more importantly are we sure dimensions of this are ste same? i.e. it will fit??
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