Pulley, tensioner , idler and belt questions

[gazim]

First off i know this is a very basic and old question, but i do own a virgin 03 Cobra ( no pulley or tune ) car is a real legit virgin...

i have slowly been acquiring parts and will be running a....
2.8 upper
3x 92 mm idlers billet flow
and 1x 100mm aux idler billet flow

i also want to run a gates belt and need to know am i leaving anything out here parts wise?

I also have questions on gates belt length... I know all about cobra bob's chart but i still find it a bit misleading... as there are special additions to lengths at the bottom ...
long story short doe anyone have their .02 cents for me or is running what i will be running and have some useful input for me?
again i know this is a pretty old school question but its all new to me... LOL what is the real belt length i need here boys...

here is the link https://stangshiftergaskets.com/belt_length_chart.htm


74" 0r 74.5" or what thanks in advance.

 

[cj428mach]

Metco has a page that tells you how to figure your belt length.

 

[CobraBob]

The Metco page you refer to is the same as the one on my website. That's where I got it from.

 

[CobraBob]

Gazim, the simplest way to get your belt size is to use the "string/yarn method" on my website. Lot's of folks here have used this method and it works well. Might take a few minutes, but you'll get the correct length.

 

[cj428mach]

I hadn't checked your site in a while Bob, last I knew I thought there were just a list of combo's people had run and what belt size they had used. I apologize.

It looks like off the chart you need a 72.5" belt.

 

[gazim]

Gazim, the simplest way to get your belt size is to use the "string/yarn method" on my website. Lot's of folks here have used this method and it works well. Might take a few minutes, but you'll get the correct length.

Thanks for the reply... much appreciated but I'm planning on having all this stuff installed at one time and can't afford to have my car down to order a belt

I hadn't checked your site in a while Bob, last I knew I thought there were just a list of combo's people had run and what belt size they had used. I apologize.

It looks like off the chart you need a 72.5" belt.

I don't see 72.5" even on there??? LOL
i get something totally different.... 73.5" is on the chart. then it has add ons at the bottom of add 1" for aux idler, then says add .5 for 100mm idler ?

all I'm doing to my car is a 2.8 pulley and 100mm aux idler.... i don't get how this is so hard. LOL

the thing is i can't afford to install and have my car down for a day or 2 to order a belt . needs to get tuned right after so i can drive home.

 

[cj428mach]

Im sorry I wasn't thinking and subtracted you need to add. ive always just added 1" for my 100mm idler and it worked fine.

I suggest just buying the belts on rockauto as you can get multiple belts for the price of 1.

 

[gazim]

Im sorry I wasn't thinking and subtracted you need to add. ive always just added 1" for my 100mm idler and it worked fine.

I suggest just buying the belts on rockauto as you can get multiple belts for the price of 1.

cool man i think that the basic formula...add 1" for the 100mm. I know i had no idea that the belt thing was so in depth.

just figured that if i threw up all the parts i was running someone would know exactly what i needed. LOL

 

[MalcolmV8]

If its your only car and can't afford to be down then just buy several belts, a few sizes below and above your calculated size. Do the work, find the right belt, and then return the others.

 

[Bdubbs]

I've run a 74.5" with that combo. Never ran a smaller belt than that on the Eaton.

 

[bigmoose]

Your quantities are backwards. You want 3x 100mm and a 90/92mm. That's the typical configuration.

 

[Bdubbs]

Your quantities are backwards. You want 3x 100mm and a 90/92mm. That's the typical configuration.

I missed that! I guess I don't have the same setup as op.

 

[CobraBob]

I hadn't checked your site in a while Bob, last I knew I thought there were just a list of combo's people had run and what belt size they had used. I apologize.

It looks like off the chart you need a 72.5" belt.

No worries Mike. Yeah, my Belt Selection Guide used to be made up of a list of uppers/lowers/idlers combos submitted by scores of different people, but unfortunately a good number of them turned out to be incorrect. So I had no choice but to discontinue the Guide and use the belt selection info from Metco's site. I still have the old Guide available, just in case.

 

[Bdubbs]

A great reason why the whipple pulley tensioner is awesome! Only problem I have now is with the thump racing tensioner. The notch where a breaker bar fits onto is angled different than a oem tensioner. So I can't push down as far, the bar hits.

 

[Franco]

Ok so here's my question. Looking on upgrading my factory idlers. Checked bobs website and my setup wasn't listed.

I'm currently running factory idlers
Stock lower
2.4 supercharger pulley
100 mm snub

Current belt length is 73.8 as per the gates site

I'm looking to upgrade my idlers

Should I keep the factory sizes 3-90mm and 1-100mm snub

Or should I upgrade to 3-100mm and 1-90mm.

If so what are the benefits. Also what belt size would I run?

If my calculations from bobs website are correct it should be 74.8 belt

Your help is appreciated

 

[c6zhombre]

A great reason why the whipple pulley tensioner is awesome! Only problem I have now is with the thump racing tensioner. The notch where a breaker bar fits onto is angled different than a oem tensioner. So I can't push down as far, the bar hits.

The few, the proud....the whipple adjustable pulley tensioner owners! :rockon: Lol. I love not ever worrying about sizing a belt!

Sucks about that racing tensioner limiting the breaker bar movement tho