Motorsports Serpantine Belt upgrade
12-12-2006, 08:00 PM
#1
Former Vendor
Thread Starter
Join Date: May 2002
Location: Tampa
Posts: 6,849
Likes: 0
Received 0 Likes
on
0 Posts
Motorsports Serpantine Belt upgrade
I found a place that had some old stock of the Porsche Motorsports belt upgrade. If you think the RS pulley and alternator piece is nice, take a look at these. They are INCREDIBLE pieces. The last of these types of things for this car I'm afraid. The crank pulley weighs in right at a 1 lb. Unreal stuff. Hope you like it.
Last edited by viperbob; 05-21-2009 at 09:22 PM.
12-12-2006, 09:40 PM
#2
Why do I feel so left out!
Rennlist Member
Rennlist Member
Hi Bob,
Glad to see your'e back!
How much?
Simon.
Glad to see your'e back!
How much?
Simon.
12-12-2006, 10:38 PM
#5
Former Vendor
Thread Starter
Join Date: May 2002
Location: Tampa
Posts: 6,849
Likes: 0
Received 0 Likes
on
0 Posts
Very good Kevin... You noticed that.. I took the pic at that angle so you could see tha marks. Pretty cool though huh?
You are looking a little under $2K for the upgrade kit. I think though that it would be a shame to install it as it is a work of art...
You are looking a little under $2K for the upgrade kit. I think though that it would be a shame to install it as it is a work of art...
Trending Topics
12-13-2006, 10:02 AM
#8
Former Vendor
Thread Starter
Join Date: May 2002
Location: Tampa
Posts: 6,849
Likes: 0
Received 0 Likes
on
0 Posts
Now remember, there is NO provision for A/C. There is also a modification for the Motor Console required (big aluminum thing that forms the cavity where the pulleys sit).
12-13-2006, 04:56 PM
#10
Just out of curiosity, if the crank pulley does nothing more than turn the impeller (aka fan) why does it have so many bolts? Why not use just five bolts; or any balanced arrangement?
I read somewhere that switching from v-belt to serpentine saves several hp in energy at higher rpm, has less drag against acceleration (find a slow-mo video of a high rpm engine and you'll see the belt moves a lot as it resists acceleration ... you know, that inertia thingy.) I'm curious to know more, so maybe someone has a link to a before/after test of v-belt vs the snake belt.
I read somewhere that switching from v-belt to serpentine saves several hp in energy at higher rpm, has less drag against acceleration (find a slow-mo video of a high rpm engine and you'll see the belt moves a lot as it resists acceleration ... you know, that inertia thingy.) I'm curious to know more, so maybe someone has a link to a before/after test of v-belt vs the snake belt.
12-13-2006, 07:22 PM
#11
Rennlist Member
Hi Carrera GT.
I try it, sorry if my english is too poor...
A V-belt has a best case efficiency of 97% (that means 3% of the transmitted power is lost), and mostly 5 to 10%. Could be something like 15 to 20% if the pulleys are totally misaligned (offset or plan angle) and not correctly centered (vibration that would make a flat belt jump) but in that case it would quickly burn.
However the V-belt has a very large capacity to adapt and resist in these bad conditions (up to 6° at high linear speed for instance is not a problem to work 12.000 hours for a basic automotive v-belt), where a flat belt would be quickly damaged (2-3° is the top max after what the number of hours can be divided by ten, even hundred).
So, mostly for automotive application where components can be removed and put back in place with tolerance regarding the location, we mostly use V belts to make it safer.
For a valve distribution belt, we use flat belts since the pulleys are always perfectly aligned (same plan, low offset).
On a race car, because we want to save any horse power, it's better to have a flat belt but this means the pulleys are on the same plan.
This is why by the way it's a good idea to keep a lot of nuts on the main pulley, to make sur there won't be any torsion (which would make the plan change and the pulley vibrate) under heavy acceleration. Porsche Motorsport engineers never make things for fun reasons, it is because it has to be, and can always be explained.
I hope mechanics here will be able to explain this in a correct English
cheers
-Luc
I try it, sorry if my english is too poor...
A V-belt has a best case efficiency of 97% (that means 3% of the transmitted power is lost), and mostly 5 to 10%. Could be something like 15 to 20% if the pulleys are totally misaligned (offset or plan angle) and not correctly centered (vibration that would make a flat belt jump) but in that case it would quickly burn.
However the V-belt has a very large capacity to adapt and resist in these bad conditions (up to 6° at high linear speed for instance is not a problem to work 12.000 hours for a basic automotive v-belt), where a flat belt would be quickly damaged (2-3° is the top max after what the number of hours can be divided by ten, even hundred).
So, mostly for automotive application where components can be removed and put back in place with tolerance regarding the location, we mostly use V belts to make it safer.
For a valve distribution belt, we use flat belts since the pulleys are always perfectly aligned (same plan, low offset).
On a race car, because we want to save any horse power, it's better to have a flat belt but this means the pulleys are on the same plan.
This is why by the way it's a good idea to keep a lot of nuts on the main pulley, to make sur there won't be any torsion (which would make the plan change and the pulley vibrate) under heavy acceleration. Porsche Motorsport engineers never make things for fun reasons, it is because it has to be, and can always be explained.
I hope mechanics here will be able to explain this in a correct English
cheers
-Luc
Last edited by IrocMan; 12-13-2006 at 07:25 PM. Reason: made a mistake on numbers
12-14-2006, 04:53 AM
#14
Hi Bob, really great to see you back. There are serpentine belt kits made by:
http://www.clewett.com/
How would theirs compare to this one?
http://www.clewett.com/
How would theirs compare to this one?
12-14-2006, 02:10 PM
#15
Rennlist Member
Hi AVoyoda,
The clewett items look cool, not as strong and light than Porsche ones which are made of strong casted anodized aluminum -so probably lighter-. The 50° mark is also useful on the Motorsports pulley. Motorsport items also look more 'factory' like.
But I must admit the difference at dyno would be virtualy invisible
Cheers
-Luc
The clewett items look cool, not as strong and light than Porsche ones which are made of strong casted anodized aluminum -so probably lighter-. The 50° mark is also useful on the Motorsports pulley. Motorsport items also look more 'factory' like.
But I must admit the difference at dyno would be virtualy invisible
Cheers
-Luc