Ian's S4s refurb

[Sparky]

Been there, done that, died in a ditch.  I had a couple of good friends in the trade try and chase it down. Even Valeo admitted they had no idea.

Alan, prove me wrong!

[Barrykearley]

@swindon_alan - sounds like a challenge 

[Sparky]

It's the pressure plate that stopped us. Couldn't get the higher clamping force.

[Barrykearley]

29 minutes ago, Sparky said:

It's the pressure plate that stopped us. Couldn't get the higher clamping force.

Valeo kit 801299

its for a Renault 25 v6

[Sparky]

I was led to believe that's a lower clamp!

[Barrykearley]

Spoke with valeo technical this morning - it's the only kit that has those two items in.........

[eeyoreish]

Maybe you have one for a Renault 25 and not for an Esprit...? 

 

[Barrykearley]

Maybe @eeyoreish 

its the kit sj sent - so I'm presuming it's correct

[swindon_alan]

Anybody got a spare one in a Lotus box for comparison? Or can you get your part numbers off the knackered one @Barrykearley, assuming that is the original?

[Barrykearley]

The old friction plate has the same number on it. Didn't see a number on the pressure plate - but I will have another look tonight. I somehow doubt it's the original clutch ? - I'm sure I saw a receipt for replacement in the file

[swindon_alan]

Then if it works fine it doesn't matter about the original...

Thoughts @Sparky?

[Giniw]

@Barrykearley > interesting, thanks

I just found it here https://www.oscaro.com/kit-d-embrayage-renault-r25-2-5-v6-turbo-205cv-479-11428-1818-gt#1818 (Since it includes the tax it's a bit cheaper but the SJS price is not ridiculous)

Does anyone know why it's not listed as compatible for the Sport 300 and S4s? I never had a look but I would have assumed it would be the same.

Edited June 30, 2017 by Giniw

[Chillidoggy]

1 hour ago, Giniw said:

@Barrykearley > interesting, thanks

I just found it here https://www.oscaro.com/kit-d-embrayage-renault-r25-2-5-v6-turbo-205cv-479-11428-1818-gt#1818 (Since it includes the tax it's a bit cheaper but the SJS price is not ridiculous)

Does anyone know why it's not listed as compatible for the Sport 300 and S4s? I never had a look but I would have assumed it would be the same.

 

The S4s and Sport 300 have higher torque/power ratings, hence different clutch.

The S4s and Sport 300 use the same pressure plate, which presumably has a higher clamping load than the S4. The S4s/Sport 300 release bearing has a different carrier, but both bearings are standard. The S4s/Sport 300 flywheel is different, in as much as it's a harder steel than the S4, and it's drilled with a different bolt pattern, too. The clutch driven plate is the same for S4/S4s and Sport 300.

I've been using an S4s/Sport 300 flywheel, drilled to accommodate PNM's uprated S4 pressure plate, and an S4 release bearing. No problems with it at all.

 

 

[Giniw]

Thanks a lot for the details! (I didn't think the ~20 bhp difference would have required such a difference in the clutch)

[Barrykearley]

There's plenty of choice for r25 upgraded clutch !! Funny thing 

[Barrykearley]

@CHANGES Any suggestions chap ??

[Chillidoggy]

4 hours ago, Giniw said:

Thanks a lot for the details! (I didn't think the ~20 bhp difference would have required such a difference in the clutch)

 

 I wonder if Lotus had bought a load of clutches and flywheels for the Sport 300, never sold as many as they thought they would, so the bits left over ended up being used on the S4s! 

 

 

[Sparky]

8 hours ago, swindon_alan said:

Thoughts @Sparky?

All I can tell you is that when I was looking into this, even Valeo couldn't source a pressure plate with the appropriate clamping force.  The R25 one was allegedly around 30% too low.  To overcome this, PNM supplies the lower force pressure plate with a larger disc.

Edited June 30, 2017 by Sparky

[Barrykearley]

Well if that's the case - I've just been sold a pup by sj.......

[Giniw]

Not so sure about that, since it's probably an off the shelf component even for the R25 you never know the specifications it was designed built for. I would say we only know it was rated as tough enough to handle 200bhp by Renault engineers. (Or Renault sales services Oo)
And even so, maybe it's a bit less durable but as long as it's cheap and it doesn't slide, I would say it's not big deal if you change it yourself.

On a side note, the Renault engines (at least the 4pot R21 Turbo, I don't know the v6 R25) were slow engines (8 valves), which means that they had a lot of torque to peak at 200+ bhp. So the clutch is probably not that far.
EDIT: I just found a S4 develops 261 lbs f (353.9 N.m) and the R25 29m.kgf (284.4 N.m). OK it's less than 30% but not by much (354/285=1.25).

@ian29gte > lol yes probably, I think you just have summed up the whole S4s concept
(It's just a shame they didn't have enough engine braces, I don't know if it makes a sensible difference but it looks cool!! )

Edited June 30, 2017 by Giniw

[Chillidoggy]

Looking at the Renault V6 turbo engine specs, they were 200 bhp, and 210 lb/ft of torque. The S4s is 300bhp, and 290lb/ft. And it's that torque that the clutch needs to cope with.

So Julien, your S4s is more powerful than the S4. And for road use, the brace probably means more weight for no real benefit. But that's just my opinion, of course. I'm an old fart, so have a cynical view of the world. Like one of those old men who sit outside the cafe playing cards or dominos, drinking red wine or Pastis.

 

[Giniw]

Yes of course, I was talking about the S4 since it was the initial subject of @Barrykearley

As for the brace, I totally agree with you: I once read that the best enhancement for any sports car would be for the average driver to take a course on a track, and I agree with that. As a plus, you don't need to buy it again when you buy another car!

Edited June 30, 2017 by Giniw

[Barrykearley]

ive started another topic - I hate to drag Ian's off piste. It'll degrade into underwear and sausage discussions soon....

[davevr6car]

the S4s 's flywheel is also stepped by about 1-2mm this is why you have to be careful if your going to get the face of the flywheel machined....and thats why the bolt pattern is different.....there's no reason why the friction plate and pressure plate can't be refurbed.....

[Chillidoggy]

Dave, the S4 flywheel is also stepped the same as the S4s. The reason the S4s bolt flywheel bolt pattern is different is that it uses the Sport 300 pressure plate, not the S4 version. I bought my flywheel from Dave Lisle already drilled to accept the S4 pressure plate, and had it reground locally.