12-31-2007, 12:28 AM #1
C kit drama - Phone call from Les
Okay, i just hung up the phone with Les Cooke. We went over lots of information so i will touch on the pertinent facts.
Les measures boost pressure at the supercharger because there are way too many variables to measure it accurately at the manifold.
These varibles include
What type of intercooler?
What size plumbing?
Old dirty intercooler?
Stock sized throttle body?
Stock sized valves?
Performance cam with lots of overlap?
Stock cam, but retarded or advanced?
So as you can see there are many variables that affect boost pressure at the manifold.
One thing Les wanted everyone to know is he DOES NOT recommend shimming the C kit superchargers. There are quite a few things that can cause clutch slippage other than the tension on the supercharger clutch.
He said it is very important that we only run the BRP 4-Stroke non synthetic oil in our skis. No matter how much you think or someone tells you another oil is suitable he says it is not. BRP oil only!
This all made sense as he told me this because i remember quite some time back i was running Castrol GTX 10W40 and i was having massive clutch slippage issues. I would go home, pull my supercharger, shim it, hit the water and it would start slipping again. I was due an oil change and decided to put the BRP oil back in the engine and my clutch slippage problem went away.
Another issue that causes clutch slippage is too hot of an oil temperature. He said we all need to be running the 158 degree thermostats. This means the Riva or Rotax Racing thermostats. The oil cooler is cooled from the closed loop cooling system so the cooler running thermostat helps keep the oil temps down.
Not only does this help prevent the clutch from slipping it also makes for a better protected better running engine.
So you can see that many variables can cause inconsistant results. One guy might get X amount of boost and another guy might get something way less due to an old dirty intercooler, wrong or hot thinned out oil causing slippage.
Les is a very smart guy and we all can stand to learn a lot from him if we only open our minds and listen. I know a lot of people have bashed on him and his products, but when you look at the big picture and see that there are many varibles that might cause a product not to perform as expected its easy to blame it on him or a bad product.
So the big question is how much boost should a C Kit supercharger make at the manifold at 8500 RPM's?
Well, with an engine in proper running condition, stock valves, cam in stock position, stock sized throttle body, brand new CLEAN Riva intercooler, proper oil with a 158 degree thermostat and a 4" air intake feeding the supercharger we should be seeing 15 PSI at the manifold.
Les also noted that we should notice lots more acceleration at lower RPM's as the C kit delivers a massive amount of air at low RPM's.
So there you have it, straight from the horses mouth
12-31-2007, 12:38 AM #2
12-31-2007, 12:42 AM #3
- Join Date
- Dec 2006
- Crest Hill, IL
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12-31-2007, 12:44 AM #4
Essentially, this setup means take a brand new Riva stage 3 setup w/ a 4" rear air intake and replace the Riva S3 SC with a Les C-kit and u should see 15psi on your boost gauge that is tapped on the block off or on a vac port on one of the runners...
which would mean there should be even more than 15 psi @ 8500 when measured AT the supercharger
while he does not recommend shimming the chargers, they will eventually need to be shimmed after a good amount of abuse. what is his recommended service limit for the slipping moment? what does he view as an acceptable slip moment that a c-kit owner should aim for?
12-31-2007, 12:45 AM #5
Sounds clear enough for me Ive been running castrol forever, bout time to change back I guess, someone said they were the same oil
Last edited by Rendog; 12-31-2007 at 12:46 AM. Reason: ..
12-31-2007, 12:47 AM #6
Seadoo XP-S oil does come from Castrol, no doubt about that. Order a 55 gallon drum of oil from Seadoo and it comes on a Catrol pallet with a BRP sticker slapped on the side of the drum. You never really know for a fact tho without extensive anaylsis if off the shelf Castrol is the same additives and blend found in Seadoo XPS oil.... i myself used to use Castrol as it was recommended by another site when i first came into watercraft performance, but i have since gone back to Seadoo oil myself also
12-31-2007, 12:48 AM #7
12-31-2007, 12:50 AM #8
Originally Posted by Shibby1485
He said he has a supercharger dyno with tacho for the gear that he uses to measure for any slip of the gear at RPM and that he runs relatively low slip (7-8 ft lbs) with no slippage. He can measure impeller speed VS gear speed. I want one of those!!!
His explanation is that the billet impeller is so light it doesn't take a large amount of tension to keep from slipping. He reitterated that with the proper oil and proper oil temperature slippage will be prevented.
12-31-2007, 12:51 AM #9
12-31-2007, 12:52 AM #10
Jerry, correct me if im wrong, but wasn't one of the big deals was the fact that 15 pounds was advertised @ 8100 rpm's?
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