Supercharged slipping clutch ?

[lelef]

Hallo,
May be I've some problems with my clutch
The engine is a 1640cc supercharged Microsquirt EFI
You can see the work on the engine here:
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0
At the engine rebuild I've changed the clutch also if the old one was ok
Before adding the compressor never a problem, then working on the engine I've not done a lot of attention at the clutch, when the engine work was at a good point the original ratio seemed to be a little short and a Renault R5 transalex replaced the VW one adding also an hydraulic clutch.
In normal driving everything seems to be ok but after climbing an hill when I stop there is some clutch smell , I've tried starting in 3rd gear and the clutch slips, I had to register the clutch, should be I've not done it well the fist time no more clutch smell but sometimes it seems slipping , the hydraulic piston free play at hot decreases near to 0 like if the clutch disk "grows" and also the clutch feeling is different.
I've no idea of how much torque has the engine,it's also true that under 1800-2000rpm when the blower starts to work there is not a lot torque so became instinctive to use more the clutch when start moving.
What can I do before thinking to upgrade the clutch?

[ps2375]

Might only need a new disc. You'll have to pull the motor and inspect the disc and pp. Maybe all it needs is a new disc with better friction material. Sounds to me you have left "stock clutch" components level behind and upgraded items meybe needed, at least to last under your current power/tq levels.

[gt1953]

Are you using the spring style clutch disc or a solid one?
See this photo.
https://www.thesamba.com/vw/forum/album_page.php?pic_id=1779736
The spring style has three rivets to transfer torque while the rigid has eight rivets.

A buddy wanted to try the old school pressure plate = PP one which I had, he tried and complained as it was very stiff but did not slip. Gave it back to me and installed a softer one.
_________________
Volkswagen: We tune what we drive.
Numbers Matching VW's are getting harder to find. Source out the most Stock vehicle and keep that way. You will be glad you did.

72 type 1
72 Squareback
({59 Euro bug, 62, 63, 67, 68, 69, 73 type ones 68 & 69 type two, 68 Ghia all sold})

[lelef]

Hi,
Yes it has springs and it's completely stock

[clonebug]

Stock clutch and PP is good for around 120 lb. ft of torque if I remember correctly.
With your supercharger you could be exceeding that limit.

I made a stock clutch slip at approximately 13-15 lbs boost with my turbo engine.
I went to a Kennedy Stage I PP and CB Super disc until I hit 22 lbs boost with intercooler. That would no longer hold at a little over 200 lb. ft torque to the wheels.
A Stage II and CB Super disc is holding 250 lb. Ft torque checked with a torque wrench on the disc.
That would probably be overkill for you.
_________________

[woodoctr]

I've had many supercharged cars which included 4, 6, and 8 cylinder cars as well as a rotary. It's not that they develop so much ultimate boost it is "where" they start to develop it it. My last supercharged rotary car would start boosting as low as 1200 rpm and carry that through until 8000 rpm. When I had first done that conversion it was naturally aspirated and I drove it for a couple of years without problems right at about 190/200 h.p. with a stock pressure plate and fairly decent performance disc. Once I had put a supercharger on it I dumped the hammer on it about the third time and.....smoked the clutch, broke 2 CVs, and put a "twist" to one axle. I finally settled on a Kennedy Stage III with a premium Dakin disc. Later I even went down to a Stage II so I could keep that part of the drivetrain "expendable" to save the bigger bucks I had in my transaxle.
Not sure exactly what you need with your setup but I would say at least a Kennedy Stage I as said and a premium disc.

[lelef]

hi,
The engine is a compromise , started with a small pulley to have boost near idle with overheating problems for the compressor I've changed pulley ratios 4 times to have from 8 psi boost to 12 psi in a good range,,conservative for the compressor, and also a conservative rev limiter it can reach 15 psi but in a limited range and I usually don't reach it , psi readings are after intercooler.
my engine started STD ,when I restored the car the engine was really good ,starting the work with a complete rebuilt idea it was so good that I've put a 1640 slip on kit just to have a little more and a little porting to the heads as on a 2valve 4 cylinder is quite a fast work.
searcing the web the best std VW tipe 1 1600cc is rated for 80lb/ft
the stock clutch should handle 120lb/ft
I know that calculate torque and hp is a nonsense only a dynamometer is the right way but..
boosted HP/tq = (hp or tq stock) * ( boost + 14.7 / 14.7) * .8 or .7(pressure ratiow/wo intercooling, density ratio converter)
so for 12psi 116 lb/ft that is in the limit of the standard clutch
with 15psi 129lb/ft that is just a little more
So as you suggested a stage 1 PP and a better disc should be enough ?

[woodoctr]

Well, yeah, I think that would work. Not exactly sure on which disc, there seem to be quite a few out there now......

[Howard 111]

I run a turbo, and never do hole shots. It's too hard on the axels and especially the CVs. But it will chirp the tires on 2nd, 3rd, and 4th gear shifts. I run a KEP stage 2, with a Berg Super Street disc.
_________________
1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270

[lelef]

Ok Thanks,
This will be a work for this winter as this is a car that usually I drive in summer
KEP stage 1 and ?
can you suggest a disc for normal street use?

O.T. for another project if you can help me
I'm making a v8 engine swap on a Unimog 404 the std engine is a 2.2l straight six ,the easiest swap is with the 2.8 l 78' Mercedes SL engine that has 170lb/ft of torque and the standard clutch has no problems ,it's the same engine at it's maximum bore/stroke .
I've a M113 engine, 5.0l Mercedes v8 and it has 339 lb/ft, this engine is only with auto trans, the v6 flywheel is the only for manual trans with the same bolt pattern but it has a really less torque and the clutch is to big for the Unimog bellhousing that I've to use with an adapter plate and so I've to use the Unimog flywheel and clutch
If I've understood the main work of a reinforced clutch is done by the pressure plate for example the std type 1 PP has 1200 Lbs ,the KEP stage 1 1700 Lbs and stage 2 2200 Lbs , the Unimog clutch has 9 helical springs , if I use springs with at least 50% more load it should handle the extra torque

[Howard 111]

http://www.geneberg.com/cat.php?cPath=2_59_2690
_________________
1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270

[lelef]

Thank You

[181´rn]

My 1915 With amr500 worked fine on the street With a KEP stage 1 and cushlock disc. At the track With dot slicks not so well With the stage 1, had to change to stage 2 to prevent toasting the disc

Alex

[lelef]

hi,
for KEP PP seems to be no alternatives but, where can I buy cushlock disc in europe? from USA shipping plus taxes doubles the price

With stage 2 PP the pedal becomes very hard to operate ?
the price is the same so for safety should be better use the stage 2

[woodoctr]

Can't really help too much with where to buy a cush loc in France however there is still a pretty big VW performance scene in England. You might try reaching out to John Maher Racing. Here is their web site.....
http://johnmaherracing.com/ I'd just email them to start with.....

A stage II pressure plate does not need to be hard to operate if you consider getting a longer clutch arm for the transaxle. Mine was about an inch or so longer than stock and it made a stage III tolerable for the street and made a stage II almost feel like a stock effort disc.

Not sure on what to tell you to choose. Based on your figures I think a Stage I would suffice however if you are planning on future increases in boost/performance it might be wise to consider a Stage II.

[clonebug]

I used a Kennedy Stage I and CB Super Disc for a couple years.

It would hold 165 ft lbs. checking it with a torque wrench and right at 200 lb. ft torque on the dyno. It held at 20.5 lbs boost but slipped at 22 lbs. boost.

I now have a Stage II PP with the same disc and it holds 250 Ft lbs torque on a torque wrench with .031" spacers between the PP and Flywheel.
It might hold more but that is as high as the torque wrench would go.
It doesn't slip at 24 lbs boost so you should be good with a Stage I and either stock Disc of a Daiken 503A disc.

It's pretty easy to check if you have an old transmission input shaft you can weld a nut to.
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[lelef]

I'm satisfied about the engine ,brakes suspension and engine are a god mix , more hp aren't needed but in another way the hydraulic clutch has a better ratio than STD,it's not a ready made kit, I've used master and slave cylinders quite near to what they should be ,the result is as the pedal/ actuator ratio is like a little longer clutch arm
So why not a stage 2 PP and a STD disc ?
cheap and easy to find clutch disc and a clutch pedal not too different to operate from stock

[woodoctr]

I just think you are beyond a standard disc already. Just one hard launch, everything holds but that disc, and you smoke it/glaze it. You'll be pulling it all down again.....

[Brian]

What about the copperhead disc?
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'69 Bug
'68 Baja Truck
'71 Bug
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[lelef]

not a lot of experience with copper clutch but for street use should it be too aggressive
at the end to not do the work 2 times ok for stage1 + a better disc
They seems to have good prices here
https://aapistons.com/collections/clutchs-kits