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718 Cayman GT4 is here – at long last.!

Hi Jeff,

This LWFW is unique to the 718 4.0 and it's used with the standard clutch. It's produced for 9m by one of their suppliers, I don't know who. There are a few options for the 981 but they all need a replacement clutch to match.

Regarding driveability, it could have been a factory fit. No danger of stalling it and maybe only a fraction more revs required to pull away - and I mean only a fraction. Tickover is perfect with minimal extra mechanical noise and the auto blip function still works perfectly. Clutch action is now super smooth, and it wasn't exactly rubbish before!

The car is crazy now, it just leaps forward on the throttle. Much less engine braking is really noticeable and gear changes are fabulously slick. An amazing transformation [:D]

 
Thanks Dave, and I forgot to say well done for taking a punt on mods which are most likely to present some challenges if you need either engine or transmission warranty work. Fingers crossed that won’t happen; a bridge to be crossed if/when something happens. Meanwhile, just enjoy the upgrades.

I’m not a fan of the now seemingly common use of DMFs on multi-cylinder petrol rather than diesel engines. Heavier, more complex and costly than a solid flywheel, and I’m not convinced that they improve driveline refinement significantly, as your comments confirm. I’m surprised that 9m still use the original DMF clutch though, mainly because I suspect that it will be very different from that used with a solid flywheel where torsional ‘cushioning’ is provided in the clutch itself whereas with the DMF that function is provided in the flywheel. It sounds as though other than having to be a little more careful when taking off from standstill you’re not experiencing any other drivability problems in general driving, which is good to hear.

Keep us posted on your longer term experiences with the upgrades.

Jeff

 
Dave,

Congratulations on taking the plunge to modify your GT4 4.0. You are a brave man taking these mods onboard on such a new car and engine package, but one I wholeheartedly agree with. Both are entirely reversible which is important.

The lightweight alloy flywheel will as you say, transform the feel of the engine and transmission. I have past experience of LWAFs on Minis in a previous life. They have no doubt come a long way since the 1960's regarding manufacturing tolerances and quality of materials. The new 4.0 GT4 engine should cope fine with the lighter flywheel. It would be interesting to see if any changes in the torque graph range and profile result from the LWAF compared to the standard car.

Like Jeff, I am surprised the OE DMF clutch is still used with the new LWFW, but if it all works well, great!

The exhaust also looks amazing.

I'll be interested in you experiences with these modifications as they settle-in.

Well done.

Brian



 
Cheers guys. The 4.0 already has vibration dampening so the LWFW shouldn't in theory add any extra NVH, which I can confirm it doesn't in real life. The LWFW was specifically designed to work with the OEM Sachs sports clutch so it's something Porsche could have done if they'd wanted to. However, they seem to favour DMFWs in everything these days for smoothness.

Jeff - I don't have to be any more careful taking off from standstill, you wouldn't notice the difference pulling away slowly. Like I said, it feels virtually indistinguishable from standard.

I've been out for a couple of hours today and I can confirm the car goes like an absolute rocket now. I suspect it's a combination of both mods making the engine spin up a bit quicker and breathe a little easier.

I'm currently weighing up adding a couple of parts to make the geo a bit more focused as I think the car could benefit from it. Other than that, it just needs the wheels driving off, it which I'm happy to do! :ROFLMAO:

 
I agree, the exhaust looks amazing and an upgrade I would consider. I look forward to hearing it at some point. 🤞

Can I ask , Is the warranty still valid for the engine if this is done ?

 
Peter,

I think that you’d find it an uphill struggle arguing with the factory that any unapproved device doesn’t invalidate their warranty, even more so if you’re planning to take out the insurance-based Extended Warranty at a later date.

Jeff

 
As I understand it, under the factory warranty regs if there's an engine issue Porsche will need to show that the exhaust caused the issue. How likely is that? Who knows, and it would depend what issue arose. If you want to run an extended warranty after year 3 then you'll need to have the stock exhaust fitted to pass the 111-point check. You could then swap it to something else of course, but my view is play by the rules or not at all.

My current thinking is that the risk of issues is low, my car is a keeper as I think NA/ICE/manual Caymans are going to become extinct and I won't be running the extended warranty in the future so I'm making it how I want it now. Both exhaust and flywheel are reversible in case I change my mind though, so I'm keeping my options open to a certain extent. What I haven't and won't do is mess with the ECU, cats, GPFs etc.

 
Motorhead said:
I think that you’d find it an uphill struggle arguing with the factory that any unapproved device doesn’t invalidate their warranty...
Click to expand...

I'm not so sure I agree, Jeff. It's a different silencer fitted after all filters etc. The effect on fuelling will be pretty minimal I think. People have fitted similar things to many cars once the years and I've not heard of any major issues occurring, so a factory proving it DID cause a problem would be the struggle I think.

All in my opinion of course!

 
Whilst I agree with your comments Dave, the add-on exhaust in particular, but playing Devil’s advocate I wouldn’t like to have to argue the toss with the factory lawyers, especially if they were to turn around the issue and say that the onus is on you to demonstrate that exhaust didn’t cause an engine issue!

I think you’ve got the right attitude, which I admire greatly ... so just do what you want, enjoy the mods and hope for the best.

Jeff

 
They can't turn around the issue during the factory warranty period Jeff, that's EU regs for you!

 
As I said on PH, for a stock silencer it's worth doing for a little more noise.

With a sports silencer it's a waste of money IMHO.

 
Twinfan said:
Motorhead said:
I think that you’d find it an uphill struggle arguing with the factory that any unapproved device doesn’t invalidate their warranty...
Click to expand...

I'm not so sure I agree, Jeff. It's a different silencer fitted after all filters etc. The effect on fuelling will be pretty minimal I think. People have fitted similar things to many cars once the years and I've not heard of any major issues occurring, so a factory proving it DID cause a problem would be the struggle I think.

All in my opinion of course!
Click to expand...

My concern is that in practice it would probably be that you need to prove it did NOT cause a problem.

It will help if you have an OPC that is on your side.

I think a silencer after filters will make a significant difference but I will probably want an extended warranty which as you say will give me a problem.

I had a drive out recently with a friend who has a 981 Spyder and the sound difference is massive.

Not sure if you all have seen the YouTube video from Archie Hamilton with the straight piped JCR exhaust on a 718GT4 now that is how the car should sound.

I think its a brave move Dave to do the flywheel as well and seeing as you have accepted that you have probably invalidated your warranty why did you not go the whole hog and do a full exhaust ECU etc. That JCR system really sounds the business.

I think as others on P/heads have said you have had a real change of heart regarding modifications with GEO mods next on the agenda, it will I expect be a much better car but with an acceptance that should anything go wrong (particularly as you are the guinea pig ) it will be a fight with Porsche or a bill.

I have been looking at silencer mods and reading with interest the many options and it does make me wonder if I should just spend an extra £30k and buy a 991.2 GT3. My GT4 is the first GT car I have bought new, I have way over specced it and love it but for the sound which is such a major part of the experience.

I am very grateful in the current climate to be in a position to have these debates and decisions to make.

 
As I said earlier Geoff, I'm not messing with the ECU/cats/filters. I have no idea how the JCR car gets insurance for starters!

Everyone's attitude to risk is different, and regarding engine and gearbox I think I'm at low risk of issues. If I'm wrong and things go pop then I'll deal with the issue if it happens. Life's too short not to enjoy it, and I'm very happy with my improved (for me) car [:D] I've already tweaked the geo a bit and may not do anything else, I'm merely investigating options right now.

I'm not sure why changing my mind to try a few track days next year is causing such comment. I never chastised anyone else for doing them, I just commented that they weren't for me (at that time). Does nobody else ever change their mind about anything?

 
Not being critical, I think you will have a nice car and you have addressed the major weak point in fact you appear to be really going for it.

Something a lot of us would like to do but don't necessarily have the courage of our convictions.

 
Dave, i grew up in Birmingham and the rule was that you only teased people you like - I reckon itha‘s why youve got a bit of gentle stick...

I was a bit surprised that you have modded your GT4 from some of your comments on Pistonheads (but I don't know why) but it is brilliant that you have and Im looking forward to seeing your car and hearing the new exhaust at a track day soon.

You are right in the ECU tune, leave it for 12 months until they have perfected it!

If we are ever allowed back on a track that is....

Snowy

PS you guys are right about PS4s; Cuo2s nearly killed me a couple of weeks back at 85mph hitting water on M40. PS4s coped brilliantly this weekend in the deluge!

 
Cheers folks. I'd like to think I'm a reasonable and amiable chap, so if anyone ever sees me knocking about please so come up and say hello. I'm always happy to receive mickey taking in person about my tastelessly specced and poorly modded custard coloured car :ROFLMAO:

 
After getting a few more miles in over the weekend I've got to say the changes to car have worked an absolute treat. It really punches out of corners/off roundabouts now and the whole car feels so much more alive. Such a difference, more than I was expecting for sure.

The flywheel is the biggest contributor to the changes, and if anyone wants to add more zing and kick to their car I can't recommend it enough! [:D]

 
Twinfan said:
The flywheel is the biggest contributor to the changes, and if anyone wants to add more zing and kick to their car I can't recommend it enough! [:D]
Click to expand...

Having past experience with LWAF's I wholeheartedly agree with your comment above. You are a very brave man Dave splitting your engine/transaxle on your new GT4 4.0 while still under warranty. Given your reasons as stated for doing so, I would be inclined to agree with your reasoning. If your car is keeper, go for it.

I would still be interested in seeing comparative torque and power curves between your modded GT4 and the standard car.

Usually, LWFW's offer improvements in both torque and power outputs, with the torque peak arriving higher up the rev range by around 500-750rpm. The mid-range throttle response is hugely improved as you have noted already.

Brian



 
Pete at 9m would like to throw my car on the dyno at some point to see how it's doing, so it may happen at some point...

 
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