MRAMG1

Okay guys, who can help me:

Long story short, I need a smaller, ie underdrive water pump pulley to make my newest effort work on the C32. Would like to buy, TODAY, and have Overnighted tomorrow at my dime.

Come on Erick, Jerry, or Brandon, I KNOW YOU HAVE ONE

See yeah

PS: Will send payment ANYWAY you like

suicidal4life

Wouldn't a smaller pulley overdrive the pump? If the circumference of the stock pulley is 2" and the smaller pulley is 1" (obviously made up #'s that are not correct but make the math easy) then for every 2 inches of belt travel the stock pulley would rotate one time and the smaller pulley would rotate twice thus overdriving the pump. Is my thinking backwards?

AWDman

it's not. mramg prob has a humongous crank pulley ready to install and wants to bring the speed of the water pump back to normal.

MB_Forever

If you can't find one here, Evosport may have used ones for sale, so you may want to contact them. If not, you may have to get their whole ODPS.

MRAMG1

You read my mind my friend

See yeah

Will post results soon!

sales@eurocharged.com

How small do you need?

suicidal4life

I'm not trying to start fights here but I do want to see if my thinking is flawed. (once again to make the math easy lets assume the stock crank pulley's circumference is 10" and the new one is 20") This means for every rotation of the crank the belt now moves 20" (or twice the stock 10"). Now lets assume the stock water pump pulley is 2" and the new "underdrive" pulley is 1" circumference (made up figures). This means the stock waterpump pulley with a stock crank pulley turns the waterpump 5 times (10" belt travel divided by 2" pulley travel) . When we increase to the larger crank pulley the waterpump now turns 10 times (20/2=10). Going to the smaller waterpump pulley would increase it even further to 20 rotations per crank revolution (20/1=20) thus overdriving it. If we installed a larger waterpump pulley (say 4") we would then bring the waterpump revolutions back down to 5 revs per crank rotation (20/4=5). So doesn't it take a larger pulley to underdrive an accessory like a waterpump or alternator? A larger crank pulley changes things on a global level essentially overdriving all the other pulleys. When we make a single accessory pulley larger doesn't that end up underdriving that single accessory?

Am I way off base here??

MRAMG1

[QUOTE=MRAMG1;2583587]Okay guys, who can help me:

Long story short, I need a smaller, ie underdrive water pump pulley to make my newest effort work on the C32. Would like to buy, TODAY, and have Overnighted tomorrow at my dime.

Update:

Thanks to Erick and Jerry for the help/replies for help on this part. ASP hooked me up with a little help from LET, will have results SOON


See yeah:

Zeppelin

Your correct, but he is not using the smaller pulley to reduce water pump speed he is using it for clearance with the larger crank pulley.

Eurocharged Rick

[quote=MRAMG1;2589010]Glad i could help, hopefully you have that car back together by now...

MRAMG1

Okay guys went for my first drive with my new pulley:

One word AWESOME

For anybody that has wanted more umph for their C32, don't wait another day, BUY A PULLEY NOW!

I did not do the ecu tune, and the difference so far is night and day. Heck you can even hear the blower more now, if you turn down the tunes. I will post some 0-60 times today. My previous best was a 4.81

See yeah

Oh yeah I would like to thank Erick and Jerry AGAIN for all of their help and info during my install. TRUELY anyone can do this mod in their garage.

Zeppelin

So how many more HP did you get with your new smaller water pump pulley?

MRAMG1

Hey Zeppelin:

It wasn't a smaller water pump pulley that was good, it was the LARGER crank pulley. Come on now, you knew this

The smaller water pump pulley was needed for clearance my friend

See yeah

Going for some runs now, will post results later today

Update, rain/snow limited traction today, 5.2 was best, but again this was from MASSIVE tire spin. Side note the Computer said I was using 189 HP, last time it said 168 HP, or a 21 HP gain

AWDman

did you get the 185mm pulley??

ohlord

the water pump cavitates the coolant what will be the solution to the lack of cooling and the abnormal wear on the water pump?Inquiring minds would like to know.
Has anyone overdriven a water pump and not had it fail?

AWDman

duh! see posts #2 and 3 above. inquiring minds ought to read?

ohlord

I do read,and if you have ever taken a basic gear or pulley design class you would know that a smaller secondary pulley diameter is going to overdrive the water pump in much the same way as the larger crank pulley is overdriving the SC.
So the original question still applies.What happens when the water pump stops moving coolant? and has anyone overdriven their water pump?
no need to insult,just asking a question.

MRAMG1

Hey there ohlord:

yes, you are correct that at a HIGH enough speed, the pump would cavitate, causing only air to move about, with no colant flow. However, we are not talking about great enough speeds to have the pump cavitate here. Many, if not ALL overdrive crank pullies sold for our toys, give you this smaller waterpump pulley for clerance around the new larger crank pulley. There are MANY gentlemen on this fourm that have used these pullies for 20,000, 40,000 and some near 100,000 miles WITHOUT issue to their water pump. Your logic is sound my friend, but the speed isn't HIGH enough to worry about it.

See yeah

AWDman

ohlord you're right i had it all wrong my apologies. we need a LARGER wp pulley to bring back down the speed.

thx for the explanation mr amg. glad to know it doesn't cavitate. i know cars like my nissan nx2000 (sr20de) do have this problem.

AWDman

next forum i join i'll be "ohchit".

ohlord

was puzzled on that one because I've seen anr driven pump be the cause of mysterious cooling issues on a race BMW,they ended up going to a steady speed electric driven pump and picked up about 10hp in the bargain.

SRT6

Why cant you tell us what pulley you installed it couldn't have been the 185 if you were asking for Erick to hook you up with the pulley. His kit comes with it.

MRAMG1

Sorry about that, it is NOT any secret. Its the pulley on EBAY/Evosport. It's suppose to increase boost by 3 pounds. I did not measure it. Nice product for the price!!

See yeah

And OH YEAH does it work NICE