4lb lower safe?

[carguy96]

2.93/4# on E85 is alot of fun on the street, even though a TVS would be even better

You’re right! 2.3 blowers are more fun which is why I’ve ended up sending it and am currently swapping a 2.3 Whipple on the car now.

 

[stangfreak]

16 years with a 4lb lower. all is fine. Just don't do a 19lb 20lb combo like some of the guys on this forum. No idea why everyone loves a 2.93 upper 6lb lower. I have seen people say 2.76 6lb lower. Its comical. That first dyno run you make and see all that tq, is not what you are really running when cruising on the street. That little eaton will get heat soaked so fast. There is so much air the eaton can move. If you want 19lbs go to a tvs or aany other bigger blower.

 

[Midnight_Cobra]

The pulley doesn't put pressure on the crank. The pressure comes from the belt and tensioner. If anything a larger pulley can reduce pressure because you don't have to run a tight belt to fight slip. The larger pulley has more contact surface. For that reason I prefer to run larger pullies to hit the boost level I want. Tight belts kill main bearings.

I will disagree with you on that. More surface area does mean better grip, but a larger circumference will change moment about the crank. Therefore increasing 'pressure' on the crank.

Will this hurt anything on a street car, probably not.

 

[01yellercobra]

I will disagree with you on that. More surface area does mean better grip, but a larger circumference will change moment about the crank. Therefore increasing 'pressure' on the crank.

Will this hurt anything on a street car, probably not.

Well, my experience is I ran an overly tight belt with a stock pulley. I still had belt slip and tore up the front main bearing. I swapped to a larger lower crank pulley, ran a Thump tensioner, and a proper length belt. When I pulled the engine apart the front main bearing was fine. Most issues crop from people running the tight belts and big blowers.

YMMV.