964 RS engine mount advice on 987.1 S

[Edmundo2]

Hi,

 

My 987.1 S is booked in to have Wavetrac LSD, LWFW, GT3 mc etc fitted in early Jan. Whilst it’s in I’ve decided to get semi solid mounts fitted as seemed to make sense whilst the box is out and on the basis I’m wanting to build the best weekend drivers car I can..

 

Obviously there’s lots of conjecture around what the best options are but after much reading I’ve plumped for 964RS mounts with a power flex yellow front mount insert. 

 

I’m a tad concerned it might be too harsh but then I’ll read other reports of similar combos with owners saying there’s very little extra NVH and it’s  all worth it etc..I want a road racer and will be happy with a bit more mechanical noise but don’t want something that’s trying to shake itself apart

 

My dilemma is now whether I return the 964RS mounts and swap for RSS or Dtek 987 trans mounts, ( as they seem popular ), or just stick with what I’ve got and see how it feels?

 

A couple of questions if anyone can advise....

 

Q. Does anyone know the shore rating of the 964RS engine mounts vs the dedicated 987 RSS or DTek gearbox mounts? Are they similar in stiffness?

 

Q. If I stick with the 964RS engine mounts fitted as gearbox mounts, do I need a different/adapted bolt? I think I read somewhere this was the case but I can’t find anything definitive. They came with fitting hardware inc bolts but for their intended 964 engine application as opposed to dedicated 987 trans fitting. ( this is the kit I have inc bolts https://type911shop.co.uk/964-/-993-/-996-/-997-RS-Engine-Mount-Set-Aftermarket )

 

Thanks as ever for any advice..

 

Ed

[extanker]

if the car is going to spend MOST of its time on a track yes on the semi solid mounts .....if most of its time is street just put new oem mounts in. 

[Edmundo2]

Thanks. It will spend most of its time on the street but having read what I've read I just wanted to know if anyone can answer the questions raised...cheers

[Lennym1984]

I've had the RS mounts on a 986 and have DIY 85a mounts on my Cayman. Personally I did not notice much additional NVH with the RS mounts (or indeed the 85a mounts - I actually think they're better but hey ho) but in each case I ran these with a new OEM engine mount. From the feedback I got, it is the engine mounts that cause the most NVH. The perceived wisdom on the 986 was to stiffen one but not both (some claimed that it set off the knock sensors)

 

In terms of the bolts, I fitted that Type911 aftermarket kit to my old Boxster and the bolts that came in the kit were fine (I even bought shorter ones just in case... they're still sat in the shed)

[Edmundo2]

3 hours ago, Lennym1984 said:

I've had the RS mounts on a 986 and have DIY 85a mounts on my Cayman. Personally I did not notice much additional NVH with the RS mounts (or indeed the 85a mounts - I actually think they're better but hey ho) but in each case I ran these with a new OEM engine mount. From the feedback I got, it is the engine mounts that cause the most NVH. The perceived wisdom on the 986 was to stiffen one but not both (some claimed that it set off the knock sensors)

 

In terms of the bolts, I fitted that Type911 aftermarket kit to my old Boxster and the bolts that came in the kit were fine (I even bought shorter ones just in case... they're still sat in the shed)

Hi Lenny. That's really useful info thanks. I'm thinking my best bet might be to do both whilst its in and if too harsh then remove the powerflex insert which should be a quick and easy job, ( as it's an insert rather than a full bush ). If as you say it's the engine mount that is thought to add more NVH than gearbox mounts then this process would allow me to work backwards most easily I guess.

 

Cheers 

[Lennym1984]

I'm not totally familiar with the insert but I don't see how you could remove it without removing the engine mount again... Which is the time consuming bit. 

 

The gearbox mounts are much easier to get at on the Cayman and so it would be easier to experiment with them

[Beanoir™]

I've just fitted the 964RS engine mounts in my 996, they do help keep the mass of the engine a bit more controlled, and the gear shift has improved quite noticeably.  The 964RS mounts are a rubber bush, simple but appear to be effective.  There hasn't been an increase in NVH.  

 

I have driven a 996 with the RSS engine mounts, which are a semi-solid design, they do make a noticeable increase to the NVH and vibration through the car at certain revs, I wasn't keen on that particularly on a road car.  

 

What has made a big difference to the NVH in my car is the gearbox bush, I fitted a poly bush.  After fitting that, at 4k revs the noise and vibration feels like the crankshaft has gone out of balance! 

 

[Edmundo2]

Thanks Beanoir. Based on yours and Lennys comments I'm now tempted to try just the 964RS trans mounts whilst box is out and see what I think. If I then decide it could take more I can add the yellow insert in the engine mount at a later date..