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I am running a cog belt on my renegade 2000 setup. I am being told by paxton and others, that my HKS bypass valve is not big enough to flow the air needed for deceleration at the end of the track, and that this is where most cog belts get thrown or ripped ribs. The first pass on the new motor shredded the belt at half track, and I am not sure why. any tips on running a cog belt would be appreciated.
P.S. Half throttle,short shifted, lost belt, and ran 10.48 at 126.
Its gonna be fun!
Randy
When you go through the traps the throttle is obviously wide open, an immediate closing of the throttle body closes the blade which pushes the air back from where it came from (towards the blower discharge). If your bypass valve can't flow close to the same amount of air that was going into the throttlebody its going to make the impeller stall because the air just created a pressurized cushion. The immediate stop of the belt at the blower pulley which was just traveling at an extreme speed will shred the teeth off the belt because the crank pulley is still moving with the motor/crank. Thats why you have to have an adequete bypass valve. HKS is great for lil imports, but their race valves don't really compare to a mondo bypass. Compare the rated cfm.
Makes sense. What does the mounting pad look like for the Mondo bypass? Is it the same 2 bolt pattern that is fairly standard for all Vortech bypasses? I already have that pad welded and mounted to discharge tube(3"pipe) what about just adding a second mounting flange and adding a second bypass? seems this would flow plenty of air, maybe even more than any one large bypass could, simply because of the hole the flange has. ie: A single 2" hole as opposed to two 1.5" holes.
I am considering just selling the 2 idlers and blower pulley, and investing in a 50mm setup. ASP recomends this simply because I will be turning 7000 rpm, on a 30mm belt. seems cheaper in the long run instead of buying a belt every weekend.
This car is not street driven.
Thanks in advance for your replys.
Randy
it's a 3 bolt mounting pad, different from the 2 bolt. Vortech sells a flange you can weld onto your discharge pipe. You could add a second mondo bypass and then you should be ok. I think you can get away with a 50mm cog on a driver side mount since all the pulleys sit closer to the block. If you have a passenger mount (curved discharge) you will have clearance issues. I'm having to run 2 spal pusher fans. None of the higher rated cfm puller fans were thin enough to fit.
Thank you. I think I will add a second bypass. If problem persists I will look at a 50mm setup.
Randy
Thanks for the help Hustler.
Made a couple passes last night and took it up to 6 grand. no belt faults at all. I will still be putting a Mondo Bypass on for good measure. Laptop died so I didnt get any data from the run, but under part throttle it still went 6.40 at 112 in the 1/8th. After a good tune and more boost I will look for 5.90s.
Thanks
Randy
No problem, just passing on what I've learned and been told from others. Did you change anything on your setup? Make sure the pulleys are aligned also, that seems like the culpret in most peoples problems.
Tightened the idler/tensioner pulley lockdown bolt better. alignment looks good.
Randy