underdrive crank pulley and bigger waterpump pulley ?

[zaquanh]

me and my friend was talking about this tonight , i didnt think it would be that big of a diffrence but can you guys tell me if this would be a good or bad situation

on a sr20det ,
if i were to have a underdrive crank pulley
ie* NST 15% (idk of any other good brands that make them ),

and also having a over sized water pump pulley ,
ie*yashio factory or stance ,both 8% larger than oem

[zaquanh]

any one have info on this

[Soup Nazi]

Crank pulley i have no clue. But as to the Water pump pulley yes get one.

[brokeAs240sx]

I ran an Unorthodox Racing Pulley on my ka24e while I had it & temps stayed fine for autox - of course, I'm n/a & ka so can't rev that high anyway.

One of my racing buddies runs a ka24det w/ either an ASP or UR pulley & only has heating issues when drifting for a while - of course, I think most setups w/ t3/t4 w/o oil cooler have heating issues when drifting - w/ the new t25 or t28 bottom mount setup, there doesn't seem to be as much heating issues. Stock water pump pulley - again, KA, so not as high revving, but I'm trying to give you as close to first hand experience as possible.

Here's what I've noticed: the people pushing oversized water pump pulleys are usually the ones selling them.

When I last talked with Unorthodox about this (they seem to be relatively highly recommended in this department, not sure if they make one for SR), depending on your driving style, w/ an underdrive crank pulley you will actually have less chance of cavitation (think that's the term - water pump spins too fast & doesn't move any water) at high revving.

From the internet reviews (so have no clue how accurate this is) I have found people who had overheating/cavitation w/ the stock pulley. By installing the underdrive one, the water pump spins slower @ high revs, in turn actually keeping your engine cooler, relatively speaking.

Haven't found any reviews of people who have overheating issues mainly because of installing a crank pulley.

[zaquanh]

well see thats the thing im talkin about , because the over sized water pulley slows down revolutions of the waterpump for better cooling and so does the underdrive pulley , could be a chance of the coolant moving to slow beacause of the both of these (BTW i only drift , )

i wouldnt think there would be a problem but im juss makin sure ,


btw this isnt a thread for over heating i dont have over heating problems even while drifting , this is one about keeping the car too cool , and having the water pump spining alot slower than usual ?

[brokeAs240sx]

Sorry, I was thinking about the overdriven water pump pulleys that 300zx guys usually buy when they upgrade crank pulleys to maintain oem water pump speeds.

Then to answer your question, I have no idea, hahaha.

If you are really that curious, you could always be the first to get a gauge, test temps w/ oem pulley, (maybe oem pulley w/ yashio pulley), crank pulley w/ oem water pump pulley, crank pulley w/ yashio pulley. :)

[zaquanh]

yea true well ill find out , i know ima going to get the waterpump pulley in soon , right know with stock water pump and stock crank its at 180 degrees with altima fans but ill see soon

[!Zar!]

From the internet reviews (so have no clue how accurate this is) I have found people who had overheating/cavitation w/ the stock pulley. By installing the underdrive one, the water pump spins slower @ high revs, in turn actually keeping your engine cooler, relatively speaking.

Haven't found any reviews of people who have overheating issues mainly because of installing a crank pulley.

The cavitation issue with the sr and stock pulley is true for the most part.

So overdriving it would in fact help.

[zaquanh]

The cavitation issue with the sr and stock pulley is true for the most part.

So overdriving it would in fact help.


but what about over driving it plus a bigger water pump pulley?

[!Zar!]

Well, over driving the pump would make the water pump spin faster than stock.

Which would be a horrible thing since cavitation is already an issue.

So once you put the under drive pulley on the water pump, it would slow it back down.

So after all that is said, the water pump would spin somewhere close to stock.

But wouldn't buying both those parts damn near cancel each other out?

[zaquanh]

i meant underdrive my bad

underdriving and over sized pulley = slower spining than stock ?

is there a chance that a certain speed would be to slow , or cool it to much or anything like that ,

personaly i think it would juss spin slower , meaning alot cooler motor , but mabye im wrong