Just trying to do some more research on cog and serpentine setups regarding superchargers.

So far here is what I have come up with:



Cog Pros:
-No slip
-Can be narrower
-less torsional stress on crank nose
-Self tracking/aligning

Cog Cons:
-Puts more vibration into the crankshaft (vs. serpentine)
-PSI increment are less graduated as you can only reduce the tooth count rather than the OD.
-Noisey

Serp Pros:
-Less vibration into the crankshaft
-More graduated adjustment of PSI via pulley OD.

Serp Cons:
-more prone to slip and require wider belts to prevent or more tension
-more torsional stress on the crankshaft nose

Now I have heard some people say that cog setups are bad because they can shatter your crank (taken with a grain of salt since this is an extreme instance I bet). I have also heard that serpentine belts can snap the nose off of the crank eventually due to torsional stress.

What is everyone's opinion on this subject regarding safety of the crankshaft. Would you consider a ATI super damper with a cog setup to be safe?

 

The cog set up I got from DSport G35 is set up to hook up a cog pulley [ large pulley ] to an ATI crank pulley . WHat effects from one to the other is, I have no idea . But to run a serp belt and not have it slip at higher psi , the belt needs to be tight as hell . And it seems it would put alot of stress on the bearings in the AC , Alt. . I would just stick to a serp belt set up if you dont plan on pushing any thing more than 10 or 11psi . Over that , belt slip will start to become a problem and you'll never keep building boost to redline

BEEN THERE....DONE THAT !!!!!!

 

Interesting.

 

booger-

So you are saying that you would prefer a cog then?

 

In my case yes ....if I didnt have a T-trim blower....no..I would stay with the kit as is . Beside , the cost of having Vortech or some one else make a cog set up would be costly .

Where did you get the info that led you to believe you will get more vibration ? I'm not doubting you...just like to know where that info comes from . thanks

 

One of the people I know who has been autoXing for years says that in many of the books that he has read that is the concensus. Of course I take that info with a grain of salt as I do everything else.

Regarding the T-trim, is the head unit physically any bigger than the S-trim? If so how much?

 

exact same size....I have one for sale ...less than 2000 mile on it !!!!

 

How much more can it flow in comparison to the S-Trim

 

I think roughly about 50 more whp

 

lets see , looking at one of my logs . 4psi @ 3500rpm 7psi @ 4450rpm 9psi @ 4900rpm 12psi @ 5600rpm 13psi @ 5900rpm . Then after that it jumps around from 13 psi to 14.9 psi till red line . I have to take it kinda easy with the tune because of it . But it was good for 430whp and 348trq. on a AT5

 

forgot to add that Im running the 3.12 and a 34 tooth cog pulley . I think it would equal out to a 2.87 pulley

 

do you know of any good suppliers for timing belts?

 

I have gates belts on mine...all three of the cog belts . By the way...the S-trim flows 1000cmf at 20psi and the T-trim is 1200cmf at 26psi ., So it looks like it flows 20% more air

 

Thanks for the CFM specs. That is exactly what I was looking for.

Regarding the cog belts, did you use their automotive belts or their power transfer belts?

I am assuming that they had to find a belt that fit properly from another application and deal with whatever width it was.

 

I actually just got a hold of Gates and get them to send me a complete spec sheet of all of their belts (cog) and the specs for them so that should be useful.

 

I can look to see what I have on part numbers for the belts . The one cog belt thats on the blower , is a stock kit belt .

 

I plan on using the rear stock cog belt as I don't see it being a problem. But I will need different belts than yours as I will have the blower in a different location and a different tooth crank cog so I am basically starting from scratch and just need to know where to look for my options in the next few months.

 

Booger-

Do you know what material Dsport had that cog pulley for the crank made out of?

 

It s same as the rest . Anodized aluminum . Its the same size as the crank pulley .

 

Any clue on the exact material?

6061? 6063? 7075?