Ok i was talking to the guy at jackson racing and he said to determine the amount of boost ill get with a 3 in pulley i have to figure out how big or small the d16y5 crank is what its mesurements are to the d16a6 weather its bigger or smaler than the stock one on a 88-91 civic si model so if anyoen could tell me what size the d16y5 crank pulley s cpmpared to the si motor crank. i really need some help on this so if someone knows what model has the smallest crank let me know i dont want to run that much boost and if the d16y5 is bigger than the 88-91 si model i will be boosting way to much.

 

anyone??

 

if i were to get a underdrive pulley for a 88-91 civic would that make the pulley smaller than stock?

 

The 2 pully both have a 24MM snout, And im pretty damn sure that the pullys are the same size, but differ in number of belts they run, as the Si came with or without A/C or P/S its one or the other, im not 100% sure on that. but they should be the same size.

if you want assurance call honda, ask them if they are the same size

 

yeah the guy from jackson racing said they all have different sizes? i dont know what the hell this guy was talking about. so he sent me a 3 in pulley that i think will blow the motor up? i see everyone else using a 3.4 in pulley at 7-8 psi i cant imagine how much more that will put out in my car? he said the crankshafts are different and would make a difference in boost? not only that but the part is not returnable how bad does thst suck ass