Cayman GT4 upgrades

[Motorhead]

Just FYI Adam, a member on this forum (ralphmusic) had a Carrera 3.8L engine installed in his 981 PDK Cayman S by Ehresmann Automotive long before the GT4 was released. He's still running it and if you PM him he'll be able to give you more information.

You're probably correct in assuming that Ruf have a policy of steering clear of the Porsche GT cars.

Jeff

 

[Toppers]

Hi All

Seeing the article about the GT4 upgrades done by Sharkwerks in California got me wondering if Ruf do the same thing - they already bore out the 3.8 to a 4.2 which is what Sharkwerks did. On contacting them they were rather evasive and then said they do not upgrade the GT4 and this cannot be done as the Carrera 3.8 engine is not the same as the 3.8 in the GT4.... is this true? I wonder whether Ruf have a gentleman's agreement with Porsche not to touch any of their limited edition cars...

 

[ralphmusic]

Best bet for upgrade is Jens Ehresman In Dusseldorf.

The GT4 engine is the same as the 991.1 3.8L with relocated oil manifold for the different installation.

Jens Ehresmann is installing a different crank into his GT4 MR to get 4.0L and has a 4.2L project with different pistons.

BGB in Ormond Beach Fl and DeMann Racing in NJ offer 4.0L upgrades, parts around $18k plus it needs an ECU tune.

There are lots of ways to improve GT4 performance with exhaust manifolds, intake and tune, without going to increasing capacity.

Or wait for Gen 2 which will have 4.0L version of current engine (not GT3)

Search for BGB Motorsports, DeMann Racing and Ehresman and PM me if you want to chat.

Ralph

 

[spyderwhite]

Or wait for Gen 2 which will have 4.0L version of current engine (not GT3)

Ralph

Latest rumour doing the rounds is detuned Gt3 engine? I would like to believe it ? I can't see the point of boring out the old engine to 4.0 if all Porsche is going to give it 425hp better off using the 3.8 to 425hp!

 

[MrDemon]

might have a detuned GT3 3.8 engine to keep the gap to the 4.0l unit.

Also seems to be another gt3 coming ou sans wing and touring spec, unless it's just a test mule car testing engines etc.

 

[Toppers]

Thanks for the replies....and thanks Ralph for your contacts. Did he change the gearing ratio too?

Could it all amount to a GT4 RS in the pipeline...?

 

[MrDemon]

I doubt we will see a GT4 RS

but there are many options to make a GT4 even more amazing

420bhp tune

rear toe links to allow a proper geo on the car (bad move oem on Porsche part) to have fitted fixed units

Ohlins TXX shocks (just released nice proper 2 way passives)

yummy if my GT3 does not happen as nothing is set in stone, this is my route for my car having done the middle option in that list.

 

[ralphmusic]

Thanks for the replies....and thanks Ralph for your contacts. Did he change the gearing ratio too?

Could it all amount to a GT4 RS in the pipeline...?

There is a gearbox upgrade that replaces the poor 3rd and other gear attachment to the shafts and gives better overall hearing. Around €5k as I recall but I'm away from home at the moment so can't look up details. Try pff.de

Ralph

 

[tscaptain]

and gives better overall hearing. Around €5k as I recall....

Ralph

You can get something a lot cheaper in Boots...[]

 

[Motorhead]

Sharkwerks offer this transmission upgrade: http://sharkwerks.com/products.php?pid=464

Jeff

 

[MrDemon]

I don't get he sharkwerks hassle for this mod.

2nd is the issue imo, the gears feel shorter up top and no issue.

so keeping 2nd and making 3rd like 2nd seems pointless For the big cost it is.

give the car more power and it makes the stock gears less of an issue.

I forgot to add lightweight flywheel to the 3 GT4 mods.

 

[Motorhead]

In their opening paragraph Sharkwerks say:

The most common complaint among journalists and enthusiasts for the GT4 is that the gears are just too long for the 3.8L engine in this chassis. The ideal solution would be a complete re-gearing of 1st through 6th gears. However, that comes at an enormous cost for small batch parts and engineering 1st and 2nd gears will likely not be an option for years, if ever.

At the expense of top speed a cheaper alternative would be to lower the final drive ratio, maybe with a beefier Guard LSD in place of the stock item.

Although I'm not a great fan of DMFs due to their additional weight and complexity, they're primary function appears to be to reduce gearbox rattles at low speed. A lightweight (single mass) flywheel will definitely improve throttle response but will probably introduce minor driveability issues for everday driving as well as making the gearbox noisier. It's interesting to note that both the GT3 and GT4 feature DMFs, although that in the GT4 is lighter than the Cayman-series stock item; it's probably the same for the GT3.

Jeff

 

[MrDemon]

A lower final drive would also not be nice, 4th.5th and 6th gears feel too low as it, it's the worse car ever for any motorway or even doing 90 odd in 6th gear my revs are quite high !

I would leave the gear box alone and add power to over come 2nd.

I think it's been blown out of control as the GT4 only makes peak power at much lower revs so any road driving I tend to change gear at just over 6k, and you don't seem to go any slower !

It takes a few miles and a lot of playing though to realise this, having a go and red lining it the 2nd year feels LONGGGGGG.

 

[ChrisW]

Just to update on where I am with my car ...

9500 miles ---

I'm really enjoying the Manthey / KV Clubsport 3 way / Nurburgring set-up as fitted by JZM --- it is very confidence inspiring.

I've just removed for safe keeping the PCCB discs and have fitted Surface Transform --- and am bedding them in. The discs are so hard that apparently even running the pads down to the backing plates will not damage them, ST can simply skim the backing plate off the disc --- in fact the discs can be skimmed five times !

I'm advise by Steve that the main thing is to lap the pads in gentle use to avoid any hot spotting or glazing over 100 to 200 miles of general city type use, and then once bedded in work the pads very hard with however many big stops it takes to get the pads to the point where the paint around the edges of the pad burns off --- and then let them cool down.

After 100 miles I can say that they feel better than the PCCB's when soaking wet and I've just had first ABS chatter with very progressive pedal feel and weighting ...

I will post some pics when I get my image hosting question resolved !

 

[ChrisW]

ST front ...

PCCB removed for safe keeping !

And ST fitted ...

 

[MrDemon]

nice, a little more than I 1st thought as they prices are plus VAT.

I see they just bolt onto the non PCCB cars also so the £6k saved not spe3ccing them could be spent on the ST disks, worth noting if you have a new GT3 on order as they should be a straight swap.

 

[ChrisW]

First impressions, they don't have that "wait" moment from cold in the wet, they are quieter, similarly linear and powerful ... but after 200 miles of bedding in I am struggling to get them hot enough to burn the paint off the edge of the pads !!

I may have to finish off bedding them in on track ---

I'm anticipating that Porsche will keep the 410/380 disc arrangement on more of the cars that I will want to try --- so the ST's should be with me for a very long time !

 

[Steve Brown]

I know it's not an upgrade, but have you seen the 1:18 model yellow GT4 on sale at Mini Model Shop? I have no connection to them other than being on their emailing list!

https://www.minimodelshop.co.uk/diecast-model-car/porsche-cayman-gt4-diecast-model-car-schuco-00400?open&utm_medium=email&utm_source=updatecars&utm_campaign=cars210617