I been searching for my answer on the greddy pullies myth about running them without a idler pulley when you remove the smog pump. My smog pump is about to go and i want to run a single belt. I heard that running with out a idler pully is bad for the front bearing.

I do have the greddy pullies.

 

Hey Alex. Not a myth imho. I'd suggest grabbing a Garfinkle or Tweakit idler pulley.

 

^^ yup I got the Tweakit and I'm extremely happy with it

https://www.rx7club.com/group-buy-center-69/tweakit-racing-air-pump-deletion-idler-pulley-kits-882388/

 

False.

What is bad for the front bearing is over tightening ANY belt. It doesn't matter what pullies you have installed, if you over tighten the belt you will put strain on the front pulley. Where the myth starts is that typically people who remove the airpump end up over tightening the belt to ensure there is contact with the water pump pulley. Using an idler pulley won't help if you over tighten the belt there too.

 

So will i be ok if i remove the pump and dont run the idler

 

From my research of people who remove their air pumps, there are more who do not use an idler pulley then those who do. Myself included, although I've only had it off for a month or so.

As far as I knew, people use idler pulleys because they have big sound systems and they don't want to underdrive the alternator, or because they use a set of pulleys which they can't get the right belt size for. I don't remember reading about anyone who's had issues with their front bearings because of pulleys.

 

On all my past FDs, I ran Greddy pullies without idle pullies for years without any issues. From what I have learn is that people like idle pullies to make better contact with the water pump pullie.

 

This can be debated for years to come....

I ran the pullies with and without an idler.

1) From my experience, my water temps are cooler when running the Tweak It idler (about 5 to 8 degrees cooler). It makes better contact and prevents the belt from slipping.

2) As far as bearing wear....I can only assume that with time, running them without an idler can cause quicker wear on the bearings but since I only drive my FD on weekends it would probably take a LONG time to cause damage.

In the end it's your choice. So YES.. you can run it without and be fine... I did for a while and know of a few guys that have done it for years...


L8R

 

ok so the belt i have is a bit long it measures 30.5 , i read that a 28'' is best where can i get one like today

 

The purpose of the idler pulleys like the garfinkle, and tweakit ones are to ensure a proper contact patch to the water pump to prevent the pulley from slipping, once you get the belt on try turning the waterpump by hand, I bet you can do it. With an idler pulley you prevent this by having a larger contact patch for the the belt to the pulley. Overtightening the alternator will have a similar effect, but it will eventually result in bearing wear. Dan Chadwick made a post about it with a bunch of pictures showing what happens.

 

I am gonna get a tweak unit soon but i need the car now since its my daily cant risk the pump seizeing on me. Who will carry the belt?

 

You'll have to shop around at NAPA, Autozone and any other place which carries belts. In the 28" size, I was only able to find a 4-rip locally which works just fine. Keep in mind that the belt size is dependent on your pulley sizes (alt, wp and main). IIRC, I'm using a 28.5" 4-rib belt but I have underdrive pulleys for all three of those. You can check sizes here:

http://banzai-racing.com/store/93+_r...lley_belt.html

 

Great link man thanks alot

 

FWIW, I run a larger waterpump pulley and a stock alternator pulley and don't see temps above 85C on the track on a 75F day... By the way, you can find the right lenght 6 rib belt and cut out 1 rib with a sharp utility knife. Works perfect...

 

Thanks Mike what size belt did you use?

 

just cuz your temps are normal doesn't mean your water pump isn't slipping, this is one of those things that you do to keep bad things from happening.

 

I can see the water pump pulley slipping if i am running the car hard. But i am driving it normal to commute to work no racing or hard pulls.

I also found out some new stuff about my greddy pullies. They are a bit bigger but the reason it has the groves on the belt surface is to minimize slipping.

 

Yes. The Greddy pullies are a little bit larger to increase contact with the belt which also adds some underdriving as well. The Greddy airpump removal pullies have been used for years without issues. It's not a problem as long as you tension the belt properly. Being able to spin the waterpump pulley with your hand is NOT an indication that your pulley is slipping.

 

Do any of the idler kits (Tweekit or Garfinkle) allow you to run a single turbo setup. I am running the stock twin turbo set up but would hate to purchase one of these kits only to find that they don't fit when I convert my car to single turbo.

 

Yes to both pulley kits i believe the tweak it unit is more tucked away and uses a small pulley the size of the altenator one. The other one is big anf goes in place of the smog pump. When i get home i will post pics. And pineapple racing has one too that is tucked closer to the water pump.

 

Don't remember the size, but you can always use a string to loop around and size it...then just run down to the parts store and match the string length with something close.

Btw, you goin' to Streets of Willow this weekend? So far we've got two FD's signed up.

 

No i talked to Dave from speedventures and asked for a group hook up but we are going to be training that weekend. I am really trying to make the 19th race though.

 

there are two versions of the tweakit pulley, one specifically for twins and one specifically for singles. The one for twins can work on some single set ups, but its not guaranteed. obviously the one for singles will work for the twins as well.

 

I searched every autoparts store and settled for the 28.5 4Rib

 

I'm curious about this now that you mention it, my belt is fairly tight on the greddy pulleys, however I can rather easily turn the water pump pulley with my hand. Is there an easy way you can tell if it's slipping too much or not?